Showing 1–50 of 229 results for author: Henry, A

CLASSY. XV. Kinematics and Spatial Distributions of Outflows in Local Highly Star-Forming Galaxies

Authors: Mason S. Huberty, Cody A. Carr, Claudia Scarlata, Alaina Henry, Matthew Hayes, Xinfeng Xu, Timothy Heckman, Karla Z. Arellano-Cordova, Danielle A. Berg, R. Michael Jennings, Crystal L. Martin, Kaelee S. Parker, Stephane Charlot, John Chisholm, Simon Gazagnes, Weida Hu, Bethan L. James, Claus Leitherer, Matilde Mingozzi, Evan D. Skillman

Abstract: Star-forming galaxies drive massive outflows that play an important role in galaxy evolution by regulating feedback and influencing the dynamics of surrounding media. Measuring galactic outflow rates is essential for quantifying feedback efficiency and the amount of mass, momentum, and energy deposited into the circumgalactic medium. In this paper, we examine 17 galactic outflows from the CLASSY s… ▽ More Star-forming galaxies drive massive outflows that play an important role in galaxy evolution by regulating feedback and influencing the dynamics of surrounding media. Measuring galactic outflow rates is essential for quantifying feedback efficiency and the amount of mass, momentum, and energy deposited into the circumgalactic medium. In this paper, we examine 17 galactic outflows from the CLASSY survey with radiative transfer modeling of UV absorption lines presented in M. Huberty et al. (2024), to study their spatial distributions and kinematic properties. We study the SiII, SiIII, and SiIV ionization states that trace the cool and warm phases of the outflows and find that SiII traced winds generally behave differently than the warmer SiIII and SiIV traced winds. We derive the mass, momentum, and energy loading factors, which we find scale inversely proportional to stellar mass. We find that our measurements of the mass and momentum loading factors are in agreement with the hydrodynamic FIRE-2 simulations. We model the velocity profiles of the winds, with profiles reaching a maximum velocity of 620 km/s on average, in agreement with hydrodynamic simulations from CGOLS. We also investigate the relationship between outflow properties and the age of the stellar population from SED fitting. We find that outflows associated with young star forming regions are more likely to have a column density dominated by cooler gas and have mass outflow rates which decrease with radius. △ Less

Submitted 12 August, 2026; originally announced August 2026.

Comments: Accepted to ApJ, 15 pages, 5 figures

OAA: Three Phases of Vocal Guidance in Human-Drone Teleoperation

Authors: Allan Henry, Christian Graff, Solange Rossato, José-Ernesto Gomez-Balderas, Sylvain Huet

Abstract: Voice-guided teleoperation requires systems that adapt to the evolving dynamics of human guidance. Yet most voice-controlled robot systems treat spoken commands as a stationary stream, ignoring how the guide's communicative behavior changes as the task progresses. Using motion capture and speech data from two experimental configurations, humanhuman guidance (finger pointing, N =10 dyads) and human… ▽ More Voice-guided teleoperation requires systems that adapt to the evolving dynamics of human guidance. Yet most voice-controlled robot systems treat spoken commands as a stationary stream, ignoring how the guide's communicative behavior changes as the task progresses. Using motion capture and speech data from two experimental configurations, humanhuman guidance (finger pointing, N =10 dyads) and humandrone teleoperation (gamepad control, N =29 dyads), we show that spontaneous vocal guidance consistently organizes into three kinematically and linguistically distinct phases: Orientation, Approach, and Adjustment. These phases are identified automatically via change point detection on 3D trajectory signals, and validated statistically (Kruskal-Wallis, p<.001). Three lexical families replicate across configurations: rotation vocabulary marks Orientation, translation vocabulary is scarce there, and attenuators accumulate toward Adjustment. Together with inter-utterance silence, these cues mark the Orientation boundary that speech rate alone leaves unmarked. The same three-phase structure emerges in both configurations despite radically different motor interfaces, suggesting it is an intrinsic property of human spatial guidance rather than an artifact of the experimental setup. We discuss implications for OAA-aware adaptive control in voice-guided teleoperation. △ Less

Submitted 11 August, 2026; originally announced August 2026.

Journal ref: Human State?Aware Robotics (H-STAR): From Multimodal Data to Human?Adaptive Behavior in HRI, Aug 2026, Kitakyushu, Japan

MSA-3D: Rotation Curves and Dark Matter Fractions at z~0.5-1.7 with JWST/NIRSpec

Authors: Juan M. Espejo Salcedo, Danail Obreschkow, Karl Glazebrook, Tucker Jones, Ivana Barišić, Natascha M. Förster Schreiber, Takafumi Tsukui, Xin Wang, Mengting Ju, Qianqiao Zhou, Amit Nestor-Schachar, Ryan L. Sanders, Stavros Pastras, Namrata Roy, Alaina Henry, Kyle Westfall, Themiya Nanayakkara, Matthew Malkan, Fahmi M. Al Farisy, Isaac Kanowski

Abstract: We present rotation curves and inner mass distributions for 30 star-forming galaxies at $0.5<z<1.7$, observed with JWST/NIRSpec as part of the MSA-3D Cycle 1 survey. Combining spatially resolved ionised-gas kinematics with JWST/NIRCam imaging, we constrain baryonic and dark matter contributions through forward dynamical modelling for galaxies extending down to stellar masses of… ▽ More We present rotation curves and inner mass distributions for 30 star-forming galaxies at $0.5<z<1.7$, observed with JWST/NIRSpec as part of the MSA-3D Cycle 1 survey. Combining spatially resolved ionised-gas kinematics with JWST/NIRCam imaging, we constrain baryonic and dark matter contributions through forward dynamical modelling for galaxies extending down to stellar masses of $\sim10^{9}M_\odot$. For the 23 galaxies in our primary statistical sample, we find predominantly rotationally supported disks with intrinsic dispersions $σ_0\sim31$-65 km s$^{-1}$ and a wide range of dark matter fractions, $f_{DM}(R_e)\sim0.1$-0.9, with a median of 0.63 and substantial galaxy-to-galaxy scatter of $\sim0.2$ dex. These results are supported by a complementary consistency check using stellar mass maps and SFR-derived gas profiles. Among the 19 galaxies reaching $\gtrsim2R_e$, we identify six rising, six flat, and seven falling rotation curves. These classes define an observed ordering from rotationally dominated, dark-matter-rich disks ($V_{rot}/σ_0\approx4$, $f_{DM}\gtrsim0.7$) to more dispersion-supported systems with centrally concentrated baryonic mass distributions ($V_{rot}/σ_0\approx2$, $f_{DM}\lesssim0.55$). The stellar Tully-Fisher relation lies close to the local relation evolved under the adopted self-similar $Λ$CDM scaling. A simplified seeing-degradation test shifts the inferred normalisation by ~0.2 dex at fixed $V_c$, suggesting that spatial resolution contributes to, but does not fully explain, differences among high-redshift Tully-Fisher measurements. Overall, MSA-3D provides a high-resolution extension of previous surveys toward lower stellar masses, spanning $9.0 < \log(M_\star/M_\odot) < 11.2$, and reinforces that star-forming disks near $z\sim1$ span a broad range of dynamical states and inner mass distributions. △ Less

Submitted 26 June, 2026; originally announced June 2026.

Comments: 21 pages + 8 appendix + 15 supplementary material, 14 figures, submitted to A&A

End-to-End Voice Intent Recognition for Spontaneous Human-Drone Interaction with Naive Users

Authors: Allan Henry, Solange Rossato, Christian Graff, Sylvain Huet, Jose-Ernesto Gomez-Balderas

Abstract: Voice control offers an intuitive alternative to manual drone piloting, yet most existing systems rely on rigid command vocabularies that fail to handle the spontaneous, disfluent speech of naive users. This paper addresses this gap by proposing an End-to-End Spoken Language Understanding architecture for real-time human-drone interaction in French. Our model combines a frozen Self-Supervised Lear… ▽ More Voice control offers an intuitive alternative to manual drone piloting, yet most existing systems rely on rigid command vocabularies that fail to handle the spontaneous, disfluent speech of naive users. This paper addresses this gap by proposing an End-to-End Spoken Language Understanding architecture for real-time human-drone interaction in French. Our model combines a frozen Self-Supervised Learning acoustic encoder with a lightweight LSTM-based classification head, augmented by a cross-modal knowledge distillation objective that aligns acoustic representations with semantic embeddings from a text teacher, without requiring transcription at inference time. We evaluate our approach on VoiceStick, a novel French corpus of spontaneous speech collected during real teleoperation sessions with 29 nonexpert dyads. On simple voice commands, our best configuration achieves 93% accuracy at 7 ms inference latency, outperforming cascade baselines (79%, 202 ms) with a 29x speedup. On the full spontaneous speech test set, our architecture reaches 82% accuracy, with crossmodal distillation consistently improving robustness across all configurations. These results demonstrate that End-to-End architectures are not only feasible but preferable for spontaneous voice-guided UAV teleoperation, combining semantic robustness, low latency, and calibrated confidence. △ Less

Submitted 19 June, 2026; originally announced June 2026.

Comments: This paper has been accepted for publication at the 35th IEEE International Conference on Robot and Human Interactive Communication (RO-MAN 2026), August 24-28, 2026, Kitakyushu, Japan

Unprecedented Constraints on Gas Flows at High Redshift Using Deep JWST/NIRSpec Observations from the LyC22, EXCELS, and AURORA Surveys

Authors: Emily Kehoe, Alice E. Shapley, Adam C. Carnall, Fergus Cullen, Thomas M. Stanton, Daniel Schaerer, Rui Marques-Chaves, Charles C. Steidel, Ryan L. Sanders, Natalie Lam, Karla Z. Arellano-Cordova, Ryan Begley, Sophia R. Flury, Natalia G. Guseva, Timothy Heckman, Alaina Henry, Akio K. Inoue, Yuri I. Izotov, Ho-Hin Leung, Derek J. McLeod, Kate Rowlands, Alberto Saldana-Lopez, Dirk Scholte, Maya Skarbinski, Struan D. Stevenson , et al. (3 additional authors not shown)

Abstract: We investigate how low-ionization gas flows in typical star-forming galaxies at $z\sim3$ depend on galaxy intrinsic properties and viewing angle. For this analysis we use JWST/NIRSpec observations of rest-frame near-UV Fe II and Mg II absorption, and rest-frame optical Na D absorption. This study combines galaxies from the LyC22, EXCELS, and AURORA surveys and contains 176, 197, and 315 galaxies,… ▽ More We investigate how low-ionization gas flows in typical star-forming galaxies at $z\sim3$ depend on galaxy intrinsic properties and viewing angle. For this analysis we use JWST/NIRSpec observations of rest-frame near-UV Fe II and Mg II absorption, and rest-frame optical Na D absorption. This study combines galaxies from the LyC22, EXCELS, and AURORA surveys and contains 176, 197, and 315 galaxies, respectively, with Fe II, Mg II, and Na D coverage. Based on both individual and composite spectra, we find no statistically significant correlations between outflow velocity and galaxy properties. However, galaxies with detected outflows tend towards higher stellar masses, SFR, and $Σ_{\rm SFR}$ than those without outflows, suggesting that the two samples are not drawn from the same parent population. Finally, we additionally find that Mg II emission is preferentially detected in galaxies with lower stellar mass and $A_V$, and higher sSFR, consistent with conditions that favor the escape of resonantly scattered line and ionizing continuum radiation. We present the first evidence in $z\sim3$ star-forming galaxies that properties of the absorption lines depend on galaxy inclination, with more face-on systems showing stronger absorption and higher outflow velocities, while inflowing gas is more frequently detected in more highly inclined galaxies. These trends are consistent with observations at $z\lesssim1$ and predictions from cosmological simulations in which galactic winds are launched perpendicular to the galactic disks, while accretion occurs primarily along the disk plane. △ Less

Submitted 10 June, 2026; originally announced June 2026.

Comments: 31 pages, 14 figures, 3 tables, submitted to ApJ

The short and long of iPhoton science for a boosted Hubble

Authors: Stephan R. McCandliss, Jack Ford, Anne E. Jaskot, Matthew J. Hayes, Alberto Saldana-Lopez, Alaina Henry, Timothy Heckman, Sophia R. Flury, Claudia Scarlata, Cody Carr

Abstract: Boosting the Hubble Space Telescope (HST) will provide unique opportunities to carry out precursor science for the Habitable Worlds Observatory (HWO). Chief among them are science cases for determining the properties of star forming galaxies that contribute to creating and sustaining the universe in a mostly ionized state. The farUV and nearUV spectroscopic capabilities of the Cosmic Origins Spect… ▽ More Boosting the Hubble Space Telescope (HST) will provide unique opportunities to carry out precursor science for the Habitable Worlds Observatory (HWO). Chief among them are science cases for determining the properties of star forming galaxies that contribute to creating and sustaining the universe in a mostly ionized state. The farUV and nearUV spectroscopic capabilities of the Cosmic Origins Spectrograph (COS) and the Space Telescope Imaging Spectrograph (STIS) are unique and unlikely to be replicated in the near future. Here we describe the benefits of a deep panchromatic spectroscopic effort to answer questions concerning the shape of the rest frame ionizing radiation escaping from star forming galaxies at modest redshift, capture crucial missing spectral regions, and explore whether their star formation histories are truly similar to the LyC leakers responsible for initiating and later sustaining the mostly-ionized-state of the universe. An observing program emphasizing multi-orbit observations, unencumbered by HST orbit competition and freely accessible to the wider ionizing photon (iPhoton) community, will catalyze crowd-sourced answers to these questions and offer a lower operating cost price point. △ Less

Submitted 4 June, 2026; originally announced June 2026.

Comments: 5 pages + 1 page references, 5 figures, a White Paper submitted to the STScI request for Building a Roadmap for Hubble science into the 2030s

Metal-Poor Gas Accretion Drives Giant Clump Formation at 0.6 < z < 2.6

Authors: Visal Sok, Adam Muzzin, Ben Forrest, Gillian Wilson, Jialu Chen, Vivian Yun Yan Tan, Sunna Withers, Roberto Abraham, Maruša Bradač, Vicente Estrada-Carpenter, Kartheik G. Iyer, Nicholas S. Martis, Gaël Noirot, Ghassan T. E. Sarrouh, Marcin Sawicki, Chris J. Willott, Aurélien Henry, Naadiyah Jagga, Danilo Marchesini, Ian McConachie, Katherine Myers, Nelson Nunes, Luke Robbins

Abstract: The physical properties of kiloparsec-scale clumps in high-redshift star-forming galaxies (SFGs) contain crucial constraints on how they assemble. Building on recent work that indicates the presence of a metallicity offset in clumpy galaxies compared to nonclumpy SFGs, we analyze the chemical abundance in a large sample of ${\sim}300$ SFGs between $0.6<z<2.6$ using LEGA-C, MOSDEF and CANUCS near-i… ▽ More The physical properties of kiloparsec-scale clumps in high-redshift star-forming galaxies (SFGs) contain crucial constraints on how they assemble. Building on recent work that indicates the presence of a metallicity offset in clumpy galaxies compared to nonclumpy SFGs, we analyze the chemical abundance in a large sample of ${\sim}300$ SFGs between $0.6<z<2.6$ using LEGA-C, MOSDEF and CANUCS near-infrared spectroscopic observations. We find that clumpy galaxies generally have lower gas-phase metallcities compared to the mass-metallicity relation, while nonclumpy galaxies have higher metallicities. We further investigate the relationship between the resolved stellar properties of clumps and the integrated gas-phase metallicity of the host galaxies using a subset of galaxies observed in the CANUCS fields. In particular, clumps in SFGs with metallicity below the mass-metallicity relation (i.e., $ΔZ \leq 0$) are generally younger and have higher SFRs, compared to clumps whose host galaxies have $ΔZ > 0$. We do not find a significant mass difference between these two clump populations. Finally, we compute the merger statistic using the Gini-M20 morphological parameters and find that the majority of clumpy galaxies are not classified as mergers based on their stellar mass maps. The results suggest that the clumpy nature of cosmic noon galaxies is linked to metal-poor gas accretion events that trigger star formation and dilute metallicities. △ Less

Submitted 3 June, 2026; originally announced June 2026.

Comments: 16 pages, 7 figures, submitted to ApJ

From Local Geometry to Global Pseudo Labeling for Robust Positive Unlabeled Learning under Covariate Shift

Authors: Firas Gabetni, Alexandre Rocchi Henry, Nacim Belkhir, Ziyi Liu, Gianni Franchi

Abstract: Detecting covariate shift is critical for building reliable vision systems. While most prior work focuses on improving robustness to shift, explicitly detecting covariate shift remains underexplored. Existing approaches typically rely on fully supervised training, requiring labeled examples from both original and shifted distributions, which is often impractical. In this paper, we show that covari… ▽ More Detecting covariate shift is critical for building reliable vision systems. While most prior work focuses on improving robustness to shift, explicitly detecting covariate shift remains underexplored. Existing approaches typically rely on fully supervised training, requiring labeled examples from both original and shifted distributions, which is often impractical. In this paper, we show that covariate shift detection can be effectively addressed with weaker supervision using Positive Unlabeled (PU) learning. However, under covariate shift, in distribution and shifted data overlap significantly, making classical PU methods unstable and sensitive to noise. To overcome this challenge, we introduce Spectral PU Neighborhood Annotation (SPUNA), a geometry aware framework that progressively discovers shifted data by leveraging the local manifold structure of visual features. Extensive experiments show that SPUNA achieves state of the art performance in PU settings and remarkably matches the performances of fully supervised methods. Moreover, our approach transfers robustly across different types of shifts, demonstrating strong generalization capabilities. △ Less

Submitted 29 May, 2026; originally announced May 2026.

Extending Hubble into the 2030s to Resolve the Physics of LyC Escape

Authors: Cody Carr, Stephan McCandliss, Michelle Berg, Renyue Cen, Kevin France, Matthew Hayes, Alaina Henry, M. S. Oey, Alberto Saldana-Lopez

Abstract: Current observations with the James Webb Space Telescope (JWST) suggest that star-forming galaxies produce enough ionizing (LyC; $λ< 91.2$ nm) photons to drive cosmic reionization, but the efficiency with which these photons escape their host galaxies remains uncertain. Absorption by the neutral intergalactic medium progressively suppresses direct LyC detections above redshift $z\sim3$, forcing as… ▽ More Current observations with the James Webb Space Telescope (JWST) suggest that star-forming galaxies produce enough ionizing (LyC; $λ< 91.2$ nm) photons to drive cosmic reionization, but the efficiency with which these photons escape their host galaxies remains uncertain. Absorption by the neutral intergalactic medium progressively suppresses direct LyC detections above redshift $z\sim3$, forcing astronomers to rely on indirect diagnostics of LyC escape calibrated at low redshift. Low-resolution ultraviolet observations of high-redshift analogs obtained with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope (HST) have been critical for developing these diagnostics. These studies suggest that stellar feedback plays a central role in regulating LyC escape, although the role of galactic winds and the underlying physical mechanisms remain poorly constrained. High-resolution spectroscopy blueward of 160.0 nm (rest-frame) is required to resolve the kinematic structure of the winds and reveal the physics governing LyC escape. Such observations are currently only possible with HST and represent a major science driver for the future Habitable Worlds Observatory (HWO). Extending the lifetime of HST and prioritizing ultraviolet observations are essential for interpreting current JWST studies of the early Universe and important preparatory science for HWO. △ Less

Submitted 28 May, 2026; originally announced May 2026.

Comments: 8 pages, 3 figures, Space Telescope Science Institute (STScI) - Building a Roadmap for Hubble science into the 2030s - White Paper

MAMMOTH-Grism: Gas-phase Metallicity Gradients of Star-forming Galaxies in Protocluster Environments at Cosmic Noon

Authors: Yi-Ming Yang, Xin Wang, Chao-Wei Tsai, Zihao Li, Zheng Cai, Anahita Alavi, Fuyan Bian, James Colbert, Xiaohui Fan, Alaina L. Henry, Matthew A. Malkan, Dong Dong Shi, Harry I. Teplitz, Xian Zhong Zheng

Abstract: Environment plays a crucial role in shaping galaxy formation, yet the impact of overdensities on the internal chemical structure of galaxies at cosmic noon is still under debate. Here, we present spatially resolved gas-phase metallicity gradients for 42 star-forming galaxies in three massive protoclusters at $z \sim 2.3$, derived fromHubble Space Telescope (HST) slitless grism spectroscopy from th… ▽ More Environment plays a crucial role in shaping galaxy formation, yet the impact of overdensities on the internal chemical structure of galaxies at cosmic noon is still under debate. Here, we present spatially resolved gas-phase metallicity gradients for 42 star-forming galaxies in three massive protoclusters at $z \sim 2.3$, derived fromHubble Space Telescope (HST) slitless grism spectroscopy from the MAMMOTH-Grism survey. We find that the majority (29 of 42, $\sim$69%) of these protocluster members exhibit positive (inverted) metallicity gradients, a fraction significantly higher than observed in field galaxies of similar mass and redshift. By examining correlations with global properties, we show that these positive gradients are strongly associated with galaxies that are metal-deficient relative to the field mass-metallicity relation, particularly among the massive population ($\log(M_*/M_\odot) > 9.95$). These trends suggest that galaxies in dense protocluster environments experience substantial, enhanced inflows of pristine gas toward their central regions, which dilute the central metallicity and produce the observed inverted gradients. Our results provide observational evidence that environmental effects actively regulate gas accretion and chemical redistribution during the peak epoch of cosmic star formation. △ Less

Submitted 28 May, 2026; originally announced May 2026.

Comments: 11 pages, 5 figures. Accepted for publication in ApJ

MAGAZ3NE: Spatially Resolved Ages and Chemical Abundances of Ultra-Massive Quiescent Galaxies at z $\sim$ 3.5 using JWST/NIRSpec IFU

Authors: Adit H. Edward, Jacqueline Antwi-Danso, Adam Muzzin, Ben Forrest, Ian McConachie, Aliza Beverage, Wenjun Chang, M. C. Cooper, Percy Gomez, Massissilia L. Hamadouche, Aurélien Henry, Han Lei, Danilo Marchesini, Allison Noble, Stephanie M. Urbano Stawinski, Gillian Wilson, M. E. Wisz

Abstract: We present spatially-resolved measurements of stellar age, [Fe/H], and [$α$/Fe] in three ultra-massive ($\rm{log(M_{\ast}/M_{\odot})>11}$), compact ($\rm{R_e} \lesssim 2$ kpc) quiescent galaxies at $z\sim3.5$ using JWST/NIRSpec IFU spectroscopy. These observations provide the first spatially-resolved constraints on $α$-enhancement at this epoch, enabling a direct test of quenching mechanisms befor… ▽ More We present spatially-resolved measurements of stellar age, [Fe/H], and [$α$/Fe] in three ultra-massive ($\rm{log(M_{\ast}/M_{\odot})>11}$), compact ($\rm{R_e} \lesssim 2$ kpc) quiescent galaxies at $z\sim3.5$ using JWST/NIRSpec IFU spectroscopy. These observations provide the first spatially-resolved constraints on $α$-enhancement at this epoch, enabling a direct test of quenching mechanisms before late-time assembly processes such as mergers can erase chemical signatures. The central regions of all three galaxies show both uniformly young ages ($\approx0.6-0.7$ Gyr) and elevated [$α$/Fe] ($\approx0.2-0.5$), indicating rapid, enhanced star formation shortly before recent quenching. Beyond the cores, two galaxies display positive age gradients and negative [$α$/Fe] gradients, consistent with rapid merger-driven quenching, while the third shows a flat age profile indicative of uniform quenching. The [Fe/H] gradients are also consistent with these trends, though we note that the metallicities reported by codes using $α$-enhanced models differ significantly ($\approx0.2-0.4$ dex) from those reported using solar-scaled templates. These data demonstrate that quenching pathways are diverse by $z\sim3.5$, with rapid, merger-driven quenching already operating in a subset of massive quiescent galaxies in the first two billion years of cosmic time. Furthermore, these results establish that explicit treatment of $α$-enhancement is essential for interpreting the star-formation histories of the earliest quenched systems. △ Less

Submitted 26 May, 2026; originally announced May 2026.

Comments: Submitted to ApJ

Quasiautomorphic forms are isomorphic to vector-valued automorphic forms

Authors: Michael Andrew Henry

Abstract: We utilize the structure of quasiautomorphic forms over a Hecke triangle group to define a mapping from a quasiautomorphic form to a vector-valued automorphic form (vvaf). This kind of vvaf we call a Hecke vector-form. First we supply a proof of the functional equations that hold for Hecke vector-forms modulo the group generators. Then, utilizing the multiplier system for these Hecke vector-forms,… ▽ More We utilize the structure of quasiautomorphic forms over a Hecke triangle group to define a mapping from a quasiautomorphic form to a vector-valued automorphic form (vvaf). This kind of vvaf we call a Hecke vector-form. First we supply a proof of the functional equations that hold for Hecke vector-forms modulo the group generators. Then, utilizing the multiplier system for these Hecke vector-forms, we prove the opposite direction and complete the bijection. Since the modular group is a special instance of the Hecke triangle groups, our results hold for quasimodular forms. △ Less

Submitted 20 May, 2026; originally announced May 2026.

Resolving the Unresolved Galactic Winds in Multi-phase Models. I. Methodology and Application

Authors: Xinfeng Xu, Drummond Fielding, Timothy Heckman, Greg L. Bryan, Alaina Henry, Karla Z. Arellano-Cordova, Cody Carr, John Chisholm, Claude-Andre Faucher-Giguere, Matthew Hayes, Mason Huberty, Michael Jennings, Crystal L. Martin, Claudia Scarlata, Allison L. Strom

Abstract: Galactic winds shape galaxy evolution; however, the outflowing gas is complex: it consists of multiple ionization phases, and its properties vary spatially. Therefore, methods that combine high-fidelity observations with state-of-the-art galactic-wind models are limited. Here we investigate methods for fitting the column density profiles derived from high-quality outflow observations with the mult… ▽ More Galactic winds shape galaxy evolution; however, the outflowing gas is complex: it consists of multiple ionization phases, and its properties vary spatially. Therefore, methods that combine high-fidelity observations with state-of-the-art galactic-wind models are limited. Here we investigate methods for fitting the column density profiles derived from high-quality outflow observations with the multiphase, multiscale wind model from Fielding & Bryan 2022. We identify three key outflow parameters: the initial hot-phase mass-loading factor ($η_\text{ M,hot,0}$), the initial cool-phase mass-loading factor ($η_\text{ M,cool,0}$), and the initial cool-cloud mass. We obtain good fits for most galaxies, with tight constraints on $η_\text{ M,cool,0}$ and moderate constraints on the other two parameters. We find the inferred $η_\text{ M,cool,0}$ and $η_\text{ M,hot,0}$ are mostly of order unity, with significant scatter. The constraints on $η_\text{ M,hot,0}$ suggest that the interaction between the cool and hot phases allows us to indirectly constrain the properties of the hot wind from cool-outflow observations. The model also predicts various radial trends. First, for all galaxies, the cool-phase outflow velocity increases between $1-2$ times of the half-light radius, then reaches a plateau. Second, most galaxies exhibit increasing $η_\text{ M,cool}$ and decreasing $η_\text{ M,hot}$ with radius, with a few showing the reverse trends. These results are effective, model-conditional constraints, and are consistent with other recent multiphase simulations and observations. This highlights that the velocity-radius mapping encoded in UV absorption profiles enables recovery of outflow spatial structures from spatially integrated spectra. Our method paves the way for future broad parameter studies and guides updates of outflow simulations in future work. △ Less

Submitted 1 May, 2026; originally announced May 2026.

Comments: 18 pages, 8 figures, 1 table, accepted by the Astrophysical Journal

Chaotic CNN for Limited Data Image Classification

Authors: Anusree M, Akhila Henry, Pramod P Nair

Abstract: Convolutional neural networks (CNNs) often exhibit poor generalisation in limited training data scenarios due to overfitting and insufficient feature diversity. In this work, a simple and effective chaos-based feature transformation is proposed to enhance CNN performance without increasing model complexity. The method applies nonlinear transformations using logistic, skew tent, and sine maps to no… ▽ More Convolutional neural networks (CNNs) often exhibit poor generalisation in limited training data scenarios due to overfitting and insufficient feature diversity. In this work, a simple and effective chaos-based feature transformation is proposed to enhance CNN performance without increasing model complexity. The method applies nonlinear transformations using logistic, skew tent, and sine maps to normalised feature vectors before the classification layer, thereby reshaping the feature space and improving class separability. The approach is evaluated on greyscale datasets (MNIST and Fashion-MNIST) and an RGB dataset (CIFAR-10) using CNN architectures of varying depth under limited data conditions. The results show consistent improvement over the standalone (SA) CNN across all datasets. Notably, a maximum performance gain of 5.43% is achieved on MNIST using the skew tent map with a 3-layer CNN at 40 samples per class. A higher gain of 9.11% is observed on Fashion-MNIST using the sine map with a 3-layer CNN at 50 samples per class. Additionally, a strong gain of 7.47% is obtained on CIFAR-10 using the skew tent map at 200 samples per class. The consistent improvements across different chaotic maps indicate that the performance gain is driven by the shared nonlinear and dynamical properties of chaotic systems. The proposed method is computationally efficient, requires no additional trainable parameters, and can be easily integrated into existing CNN architectures, making it a practical solution for data-scarce image classification tasks. △ Less

Submitted 16 April, 2026; originally announced April 2026.

The Prevalence of Turbulence-Regulated Multiphase Galactic Winds in Star-Forming Galaxies

Authors: Zhihui Li, Timothy Heckman, Max Gronke, Xinfeng Xu, Alaina Henry, Evan Schneider, Matthew Abruzzo, Danielle Berg, Bethan James, Crystal Martin, John Chisholm

Abstract: We build upon our previously developed multi-ion radiative transfer (RT) framework, PEACOCK, to investigate the kinematic and energetic structure of cool-to-warm galactic winds in a sample of 50 nearby star-forming galaxies. Using self-consistent constraints derived from joint modeling of Ly-alpha and multiple ultraviolet metal lines, we analyze how bulk outflows and turbulent motions contribute t… ▽ More We build upon our previously developed multi-ion radiative transfer (RT) framework, PEACOCK, to investigate the kinematic and energetic structure of cool-to-warm galactic winds in a sample of 50 nearby star-forming galaxies. Using self-consistent constraints derived from joint modeling of Ly-alpha and multiple ultraviolet metal lines, we analyze how bulk outflows and turbulent motions contribute to the dynamics and energy budget of galactic winds in the circumgalactic medium (CGM). We find that macroscopic turbulent velocities are often comparable to, and sometimes exceed, the coherent bulk outflow velocity. The associated turbulent pressure frequently dominates over both microscopic pressure and ram pressure, indicating that turbulence is a major contributor to the kinetic energy budget of the CGM wind. Wind kinematics, ionic column densities, and metal mass outflow rates all scale systematically with stellar mass and star formation rate, demonstrating a strong coupling between stellar feedback and CGM structure. Including turbulent motions strengthens these CGM-galaxy scaling relations and favors an energy-driven feedback regime. The total kinetic energy flux of the cool-to-warm CGM correlates tightly with the mechanical energy injection rate from star formation, implying that stellar feedback provides sufficient power to sustain both coherent outflows and turbulence. Comparisons with phenomenological line-profile fitting methods further show that simplified treatments can introduce systematic biases in inferred wind properties. Together these results support a turbulence-regulated picture of galactic winds in which a substantial fraction of feedback energy is stored in turbulent motions within a multiphase CGM. △ Less

Submitted 6 March, 2026; originally announced March 2026.

Comments: 27 pages + 16 figures main text + 9 pages appendix, comments are welcome

Kinematically Coherent Multiphase Galactic Winds in Star-Forming Galaxies Revealed by Unified Radiative Transfer Modeling of UV Emission and Absorption Lines

Authors: Zhihui Li, Timothy Heckman, Max Gronke, Xinfeng Xu, Alaina Henry, Evan Schneider, Matthew Abruzzo, Danielle Berg, Bethan James, Crystal Martin, John Chisholm

Abstract: We present PEACOCK, a three-dimensional Monte Carlo radiative transfer (RT) framework designed to self-consistently model rest-frame ultraviolet emission and absorption lines arising from multiphase, clumpy galactic winds. Applied to deep HST/COS spectra of 50 nearby star-forming galaxies, PEACOCK reproduces 220 observed profiles of Ly-alpha, Si II, C II, Si III, Si IV, and C IV spanning absorptio… ▽ More We present PEACOCK, a three-dimensional Monte Carlo radiative transfer (RT) framework designed to self-consistently model rest-frame ultraviolet emission and absorption lines arising from multiphase, clumpy galactic winds. Applied to deep HST/COS spectra of 50 nearby star-forming galaxies, PEACOCK reproduces 220 observed profiles of Ly-alpha, Si II, C II, Si III, Si IV, and C IV spanning absorption, emission, and P-Cygni-like morphologies within a single CGM model. By combining Monte Carlo RT with deep-learning acceleration and nested sampling, the framework enables fully converged multi-line inference at a small fraction of the cost of traditional RT grids. Systematic experiments show that ion column densities, bulk outflow velocities, and turbulent motions leave distinct imprints on line profiles, allowing the underlying gas properties to be constrained with minimal degeneracy. Purely radial accelerating flows often fail to reproduce the observed absorption morphologies, whereas macroscopic velocity dispersion naturally produces the broad asymmetric troughs seen in the data, indicating that turbulent motions are a key component of outflow kinematics. The inferred kinematics reveal strong coherence among low- and high-ionization metal lines in both bulk and turbulent velocities, consistent with a dynamically coupled multiphase wind. In contrast, neutral hydrogen shows weaker correspondence with metals, suggesting incomplete mixing and a distinct kinematic structure. By unifying emission and absorption diagnostics across multiple ions, PEACOCK provides a physically grounded bridge between UV observations and theoretical models of galactic winds. △ Less

Submitted 6 March, 2026; originally announced March 2026.

Comments: 35 pages, 18 figures in the main text; 35-page appendix. Comments welcome

MAGAZ3NE: Dust Deficiency in Ultramassive Quiescent Galaxies at $3<z<4$ with ALMA Observations

Authors: Wenjun Chang, Gillian Wilson, Ben Forrest, Ian McConachie, Allison Noble, Adam Muzzin, Danilo Marchesini, Michael C. Cooper, Tracy Webb, Gabriela Canalizo, Percy L. Gomez, Yongda Zhu, Adit Edward, Han Lei, Aurélien Henry, Stephanie M. Urbano Stawinski, Marie E. Wisz

Abstract: A major challenge in identifying massive quiescent galaxies at $z>3$ is distinguishing truly passive systems from dust-obscured star-forming galaxies, as both populations exhibit similar red ultraviolet (UV)-to-near-infrared (NIR) colors. In this work, we present ALMA Band 7 dust-continuum observations of five ultramassive galaxies (UMGs; $\log (M_\star / M_\odot) > 11$) spectroscopically confirme… ▽ More A major challenge in identifying massive quiescent galaxies at $z>3$ is distinguishing truly passive systems from dust-obscured star-forming galaxies, as both populations exhibit similar red ultraviolet (UV)-to-near-infrared (NIR) colors. In this work, we present ALMA Band 7 dust-continuum observations of five ultramassive galaxies (UMGs; $\log (M_\star / M_\odot) > 11$) spectroscopically confirmed at $z_{\rm spec} > 3$ from the MAGAZ3NE survey. Our results reveal that only one galaxy shows a faint 870 \um\ dust continuum detection, while the remaining four UMGs are undetected down to the $3σ$ depth . By incorporating ALMA constraints into the spectral energy distribution analysis, we confirm that these UV-NIR-selected systems are truly quiescent UMGs, lying more than one dex below the star-forming main sequence with $\mathrm{\log (sSFR/Gyr^{-1}) < -1}$, thereby ruling out the possibility of obscured star formation. We then estimate dust masses using both spectral energy distribution modeling and modified blackbody fitting, with consistent results between the two methods. We find that three UMGs have evolved into extremely dust-poor quiescent galaxies, with $M_{\mathrm{dust}}/M_\star \lesssim 10^{-4}$, while the ALMA-detected galaxy has a comparatively higher dust reservoir with $M_{\mathrm{dust}}/M_\star \sim 10^{-3}$. Our results present the most massive and extremely dust-poor spectroscopically confirmed quiescent galaxies known at $3 < z < 4$, providing valuable observational constraints on rapid dust removal and quenching processes in the early universe. Future molecular line observations will be essential to directly measure the gas content and verify the efficiency of the depletion process. △ Less

Submitted 30 January, 2026; originally announced January 2026.

Comments: 15 pages, 9 figures. Submitted to ApJ

Direct Abundance Maps and Radial Metallicity Gradients of two Galaxies at z~4-5 in the GARDEN Survey

Authors: L. Stanghellini, S. A. Kassin, C. Pacifici, J. E. Morrison, M. E. Dickinson, E. Sukay, C. R. Mulcahey, L. E. Bergeron, M. W. Regan, C. N. A. Willmer, B. J. Weiner, N. Dencheva, D. Law, A. de la Vega, A. M. Koekemoer, C. Conselice, J. P. Gardner, Y. Guo, F. Hammer, A. Henry, B. W. Holwerda, J. Kartaltepe, R. A. Lucas, M. Puech, M. Rafelski , et al. (4 additional authors not shown)

Abstract: We investigate galaxies in the GARDEN (Galaxies at All Redshifts Deciphered and Explained with the NIRSpec MSA) survey that exhibit auroral emission lines, enabling spatially resolved measurements of electron temperature and direct oxygen abundances. Two galaxies in this survey have spectra suitable for this analysis: CANDELS 8005 at z=3.794 and CANDELS 7986 at z=4.702. For both galaxies, we measu… ▽ More We investigate galaxies in the GARDEN (Galaxies at All Redshifts Deciphered and Explained with the NIRSpec MSA) survey that exhibit auroral emission lines, enabling spatially resolved measurements of electron temperature and direct oxygen abundances. Two galaxies in this survey have spectra suitable for this analysis: CANDELS 8005 at z=3.794 and CANDELS 7986 at z=4.702. For both galaxies, we measure auroral and key nebular emission-line fluxes across their full extent, allowing direct-method oxygen abundance determinations in individual spatial pixels (spaxels). These observations demonstrate the viability of deep JWST/NIRSpec MSA spectroscopy for spatially resolved chemical analyses at high redshift, aided by weak nebular continua and low interstellar extinction. We derive global direct abundances of 12 + log(O/H) = 8.008$^{+0.025}_{-0.027}$ for CANDELS~8005 and 7.89$^{+0.027}_{-0.028}$ for CANDELS~7986. Emission-line diagnostics indicate neither galaxy hosts an active galactic nucleus. A first-order kinematic analysis suggests a potential merger in CANDELS~8005. The direct abundances are consistent with strong-line estimates based on our data and recent high-redshift calibrations. We build emission line, radial velocity, strong-line abundance indices, electron temperature, and direct abundance maps for both galaxies, thanks to the excellent spatial resolution. From the direct abundance maps we measure linear radial metallicity gradients of $-$0.111$^{+0.026}_{-0.025}$ dex kpc$^{-1}$ for CANDELS~8005 (statistically significant), and $-$0.0928$\pm$0.0880 dex kpc$^{-1}$ for CANDELS~7986, where the large uncertainties limit the significance of the result. These results provide a rare direct measurement of a radial metallicity gradient at $z>0$ from direct-method abundances, offering key observational support for inside-out galaxy growth with feedback-regulated chemical enrichment. △ Less

Submitted 31 March, 2026; v1 submitted 23 January, 2026; originally announced January 2026.

Comments: The Astrophysical Journal, in press

MSA-3D: Connecting the Chemical and Kinematic Structures of Galaxies at $z \sim 1$

Authors: Mengting Ju, Xin Wang, Tucker Jones, Ivana Barišić, Juan M. Espejo Salcedo, Karl Glazebrook, Danail Obreschkow, Takafumi Tsukui, Qianqiao Zhou, Kevin Bundy, Alaina Henry, Matthew A. Malkan, Themiya Nanayakkara, Namrata Roy, Xunda Sun

Abstract: We investigate the connection between ionized gas kinematics and gas-phase metallicity gradients in 21 star-forming galaxies at $0.5 < z < 1.7$ from the MSA-3D survey, using spatially resolved JWST/NIRSpec slit-stepping observations. Galaxy kinematics are characterized by the ratio of rotational velocity to intrinsic velocity dispersion, $v/σ$, measured at $1.5\,R_e$, where $R_e$ is the effective… ▽ More We investigate the connection between ionized gas kinematics and gas-phase metallicity gradients in 21 star-forming galaxies at $0.5 < z < 1.7$ from the MSA-3D survey, using spatially resolved JWST/NIRSpec slit-stepping observations. Galaxy kinematics are characterized by the ratio of rotational velocity to intrinsic velocity dispersion, $v/σ$, measured at $1.5\,R_e$, where $R_e$ is the effective radius. We find that dynamically hotter disks exhibit systematically flatter metallicity gradients, with a moderate anti-correlation between metallicity gradient and $v/σ$ (Pearson $r=-0.43$, $p=0.05$) and a linear fit yields a slope of $\sim 0.005$ dex per dex in $v/σ$, weaker than the dependence on stellar mass. A significantly stronger anti-correlation is observed with $R_e/σ$, interpreted as a proxy for the radial mixing timescale ($r=-0.59$, $p=0.005$), indicating that cumulative radial mixing more directly regulates chemical stratification. The metallicity gradients in our sample are uniformly shallow, indicating that efficient turbulent mixing in kinematically settled disks regulates the chemical structure of typical star-forming galaxies at $z\sim1$. △ Less

Submitted 24 May, 2026; v1 submitted 21 January, 2026; originally announced January 2026.

Comments: 30 pages, 8 figures, 2 table; Accepted for publication in ApJL

Nitrogen abundances in star-forming galaxies 2.2 Gyr after the Big Bang are not elevated

Authors: D. Schaerer, Y. I. Izotov, R. Marques-Chaves, C. C. Steidel, N. Reddy, A. E. Shapley, S. Mascia, J. Chisholm, S. R. Flury, N. Guseva, T. Heckman, A. Henry, A. K. Inoue, I. Jung, H. Kusakabe, K. Mawatari, P. Oesch, G. Oestlin, L. Pentericci, N. Roy, A. Saldana-Lopez, R. Sato, E. Vanzella, A. Verhamme, B. Wang

Abstract: Using deep medium-resolution JWST rest-optical spectra of a sample of typical star-forming galaxies (Lyman break galaxies and Lyman-$α$ emitters) from the LyC22 survey at $z \sim 3$, we determined the nebular abundances of N, O, and Ne relative to H for a subsample of 25 objects with the direct method, based on auroral [OIII]4363 line detections. Our measurements increases the number of accurate N… ▽ More Using deep medium-resolution JWST rest-optical spectra of a sample of typical star-forming galaxies (Lyman break galaxies and Lyman-$α$ emitters) from the LyC22 survey at $z \sim 3$, we determined the nebular abundances of N, O, and Ne relative to H for a subsample of 25 objects with the direct method, based on auroral [OIII]4363 line detections. Our measurements increases the number of accurate N/O determinations at $z \sim 2-4$ using a homogeneous approach. We found a mean value of $\log({\rm N/O})=-1.29^{+0.25}_{-0.21} $ over a metallicity range 12+log(O/H)=7.5 to 8.44. The observed N/O ratio and scatter are indistinguishable from that observed in low-z galaxies and HII regions over the same metallicity range, showing thus no redshift evolution of N/O for typical galaxies over a significant fraction of cosmic time. We also show that typical $z \sim 3$ galaxies show a similar offset in the BPT diagram as galaxies from the low-z Lyman Continuum Survey (LzLCS), when compared to the average of SDSS galaxies, and show that this offset is not due to enhanced nitrogen abundances. Our results establish a basis for future studies of the evolution of N and O at higher redshifts. △ Less

Submitted 11 January, 2026; originally announced January 2026.

Comments: 7 pages, 5 figures. Submitted to Astronomy and Astrophysics (after 1st revision)

Journal ref: A&A 708, A242 (2026)

Automorphic vector-forms using the Cohn-Elkies magic functions

Authors: Michael Andrew Henry

Abstract: In this study, we introduce the theory of what we call Hecke vector-forms. A Hecke vector-form can be viewed as a vector function representation of some quasiautomorphic form that transforms like an automorphic form on an arbitrarily chosen Hecke triangle group. In other words, because quasiautomorphic forms have complicated transformation behavior when compared with automorphic forms, the constru… ▽ More In this study, we introduce the theory of what we call Hecke vector-forms. A Hecke vector-form can be viewed as a vector function representation of some quasiautomorphic form that transforms like an automorphic form on an arbitrarily chosen Hecke triangle group. In other words, because quasiautomorphic forms have complicated transformation behavior when compared with automorphic forms, the construction of a Hecke vector-form is to retrieve a transformation behavior analogous to the simpler, automorphic case. In this way, a Hecke vector-form can be viewed as the vector function analogue of an automorphic form. Since our work is for any quasi-automorphic form over an arbitrary Hecke triangle group, we briefly review the construction of such groups. Furthermore, we review the derivation of the hauptmodul, the automorphic forms, and the normalized quasiautomorphic form of weight 2 for any Hecke triangle group. We then proceed to the theory of Hecke vector-forms and establish the desired transformation behavior with respect to the generators of the associated group. A proof of this fact is strictly elementary, relying on fine properties of binomial coefficients. Lastly, we relate the vector-forms to Hecke automorphic linear differential equations, which are analogues of the frequently researched modular linear differential equations. Our results include Hecke vector-forms of the classical quasimodular forms as the simplest case. △ Less

Submitted 11 January, 2026; v1 submitted 8 January, 2026; originally announced January 2026.

The NIRISS PASSAGE Spectroscopic Redshift Catalog in COSMOS

Authors: Mason S. Huberty, Kalina V. Nedkova, Zahra Sattari, Vihang Mehta, Claudia Scarlata, Marc Rafelski, Matthew J. Hayes, Peter J. Watson, Ayan Acharyya, Jacob Levine, Benedetta Vulcani, Alexandra Le Reste, Farhanul Hasan, James Colbert, Michele Trenti, Xin Wang, Axel Runnholm, Matthew A. Malkan, Andrew J. Bunker, Anahita Alavi, Hakim Atek, Andrew J. Battisti, Y. Sophia Dai, Keunho Kim, Alaina Henry , et al. (12 additional authors not shown)

Abstract: We present the Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE) spectroscopic redshift catalog in the COSMOS field. PASSAGE is a JWST Cycle 1 Near Infrared Imager and Slitless Spectrograph (NIRISS) wide-field slitless spectroscopy (WFSS) pure-parallel survey, obtaining near-infrared spectra of thousands of extragalactic sources. 15 out of 63 PASSAGE fields fall w… ▽ More We present the Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE) spectroscopic redshift catalog in the COSMOS field. PASSAGE is a JWST Cycle 1 Near Infrared Imager and Slitless Spectrograph (NIRISS) wide-field slitless spectroscopy (WFSS) pure-parallel survey, obtaining near-infrared spectra of thousands of extragalactic sources. 15 out of 63 PASSAGE fields fall within the Hubble Space Telescope (HST) COSMOS footprint, of which 11 overlap with COSMOS-Web, a JWST treasury survey providing additional space-based photometry. We present our custom line-finding algorithm and visual inspection effort used to identify emission lines and derive the spectroscopic redshifts for line-emitting sources in PASSAGE. The line-finding algorithm identifies between ~200 and 950 line-emitting candidates per field, of which typically 47% were identified as true emission lines post visual inspection. We identify 2183 emission line sources at 0.08<z<4.7, 1896 of which have available COSMOS photometric redshifts. We find excellent redshift agreement between the COSMOS photometric redshifts and the PASSAGE spectroscopic redshifts for strong (S/N>5), multi-line emitting sources. This agreement weakens for PASSAGE single-line emitters with ambiguous identities. These single-line emitters are likely mis-identified around 18% of the time based on comparisons to photometric redshifts. We derive stellar masses using PASSAGE photometry and spectroscopic redshifts, in broad agreement with existing COSMOS-Web stellar masses, but with some discrepancy driven by redshift disagreements. We publicly release this spectroscopic redshift catalog, which will enable community-led science in prime extragalactic fields and serve as a crucial dataset for validating Euclid and Roman spectroscopy. △ Less

Submitted 28 April, 2026; v1 submitted 5 January, 2026; originally announced January 2026.

Comments: Accepted to ApJS. 24 pages, 9 figures

Self-Training the Neurochaos Learning Algorithm

Authors: Anusree M, Akhila Henry, Pramod P Nair

Abstract: In numerous practical applications, acquiring substantial quantities of labelled data is challenging and expensive, but unlabelled data is readily accessible. Conventional supervised learning methods frequently underperform in scenarios characterised by little labelled data or imbalanced datasets. This study introduces a hybrid semi-supervised learning (SSL) architecture that integrates Neurochaos… ▽ More In numerous practical applications, acquiring substantial quantities of labelled data is challenging and expensive, but unlabelled data is readily accessible. Conventional supervised learning methods frequently underperform in scenarios characterised by little labelled data or imbalanced datasets. This study introduces a hybrid semi-supervised learning (SSL) architecture that integrates Neurochaos Learning (NL) with a threshold-based Self-Training (ST) method to overcome this constraint. The NL architecture converts input characteristics into chaos-based ring-rate representations that encapsulate nonlinear relationships within the data, whereas ST progressively enlarges the labelled set utilising high-confidence pseudo-labelled samples. The model's performance is assessed using ten benchmark datasets and five machine learning classifiers, with 85% of the training data considered unlabelled and just 15% utilised as labelled data. The proposed Self-Training Neurochaos Learning (NL+ST) architecture consistently attains superior performance gain relative to standalone ST models, especially on limited, nonlinear and imbalanced datasets like Iris (188.66%), Wine (158.58%) and Glass Identification (110.48%). The results indicate that using chaos-based feature extraction with SSL improves generalisation, resilience, and classification accuracy in low-data contexts. △ Less

Submitted 3 January, 2026; originally announced January 2026.

A simple inequality relating the Euler-Riemann zeta function, digamma, and cotangent over the unit interval

Authors: Michael Andrew Henry

Abstract: We prove an inequality featuring three well-known functions from analysis, namely the cotangent, the Euler-Riemann zeta function, and the digamma function. Aside from a simple proof of our result, we give a conjectured strengthening. We offer various remarks about the origins of this problem. We prove an inequality featuring three well-known functions from analysis, namely the cotangent, the Euler-Riemann zeta function, and the digamma function. Aside from a simple proof of our result, we give a conjectured strengthening. We offer various remarks about the origins of this problem. △ Less

Submitted 2 January, 2026; originally announced January 2026.

A new kind of automorphic form and a proof of the essential transformation laws

Authors: Michael Andrew Henry

Abstract: We utilize the structure of quasiautomorphic forms over an arbitrary Hecke triangle group to define a new vector analogue of an automorphic form. We supply a proof of the functional equations that hold for these functions modulo the group generators. We utilize the structure of quasiautomorphic forms over an arbitrary Hecke triangle group to define a new vector analogue of an automorphic form. We supply a proof of the functional equations that hold for these functions modulo the group generators. △ Less

Submitted 29 December, 2025; originally announced December 2025.

MAMMOTH-LyC: Investigating the Role of Galaxy Mergers in a Strong Lyman Continuum Leaker at $z=2.39$

Authors: Shengzhe Wang, Xin Wang, Matthew A. Malkan, Harry I. Teplitz, Rebecca L. Davies, Karl Glazebrook, Keunho J. Kim, Themiya Nanayakkara, Hang Zhou, Yiming Yang, Chao-Wei Tsai, Yuxuan Pang, Zheng Cai, Xiaohui Fan, Alaina Henry, Zihao Li, Dong Dong Shi, Xian Zhong Zheng, Zhiyu Yan

Abstract: The MAMMOTH-LyC survey is a cycle 30 Hubble Space Telescope (HST) medium program obtaining 18-orbit-deep WFC3/UVIS F225W imaging in two massive galaxy protocluster fields at $z\sim2.2$. We introduce this survey by reporting the discovery of J1244-LyC1, a strong Lyman continuum (LyC) leaker at $z = 2.39$, exhibiting clear merger signatures. J1244-LyC1 has a highly significant ($10σ$) LyC detection,… ▽ More The MAMMOTH-LyC survey is a cycle 30 Hubble Space Telescope (HST) medium program obtaining 18-orbit-deep WFC3/UVIS F225W imaging in two massive galaxy protocluster fields at $z\sim2.2$. We introduce this survey by reporting the discovery of J1244-LyC1, a strong Lyman continuum (LyC) leaker at $z = 2.39$, exhibiting clear merger signatures. J1244-LyC1 has a highly significant ($10σ$) LyC detection, corresponding to an absolute escape fraction of $f_{\mathrm{esc}} \! =\!36\%\pm4\%$ ($1σ$). The LyC emission is spatially resolved into multiple peaks that coincide with the system's disturbed morphology, confirming genuine multi-site LyC leakage. With a stellar mass of $10^{10.2}{M_\odot}$, J1244-LyC1 is both the first confirmed high-redshift LyC-leaking merger and the most massive LyC emitter known to date. We interpret J1244-LyC1 as a merger-driven starburst system in which tidal interactions have disrupted the interstellar medium, creating multiple low-column-density pathways that facilitate LyC escape. This discovery provides the first direct evidence of spatially resolved LyC escape in a merging system, offering new insight into the potential role of major mergers in driving the cosmic reionization. △ Less

Submitted 9 February, 2026; v1 submitted 28 December, 2025; originally announced December 2025.

Comments: 18 pages, 6 figures, 4 tables, submitted

Spatially Resolved Physical Properties of Young Star Clusters and Star-forming Clumps in the Brightest z>6 Galaxy, the Strongly Lensed Cosmic Spear at z=6.2

Authors: Abdurro'uf, Dan Coe, Tom Resseguier, Calla Murphy, Xinfeng Xu, Angela Adamo, Namrata Roy, Alaina Henry, Vasily Kokorev, Gabriel Brammer, Seiji Fujimoto, Henry C. Ferguson, Amanda Pagul, Rogier A. Windhorst, Timothy Heckman, Jose M. Diego, Hollis B. Akins, Joseph Allingham, Ricardo O. Amorín, Danielle A. Berg, Maruša Bradač, Larry D. Bradley, Wenlei Chen, John Chisholm, Christopher J. Conselice , et al. (27 additional authors not shown)

Abstract: We present spatially resolved analysis of stellar populations in the brightest $z>6$ galaxy known to date (AB mag 23), the strongly lensed MACS0308$-$zD1 (dubbed the ``Cosmic Spear'') at $z_{\rm spec}=6.2$. New JWST NIRCam imaging and high-resolution NIRSpec IFU spectroscopy span the rest-frame ultraviolet to optical. The NIRCam imaging reveals bright star-forming clumps and a tail consisting of t… ▽ More We present spatially resolved analysis of stellar populations in the brightest $z>6$ galaxy known to date (AB mag 23), the strongly lensed MACS0308$-$zD1 (dubbed the ``Cosmic Spear'') at $z_{\rm spec}=6.2$. New JWST NIRCam imaging and high-resolution NIRSpec IFU spectroscopy span the rest-frame ultraviolet to optical. The NIRCam imaging reveals bright star-forming clumps and a tail consisting of three distinct, extremely compact star clusters that are multiply-imaged by gravitational lensing. The star clusters have effective radii of $R_{\rm{eff}} \sim 5$ pc, stellar masses of $M_{*} \sim 10^{6}-10^{7}\,M_{\odot}$, and high stellar mass surface densities of $Σ_{*} > 10^{4}\,M_{\odot}~\rm{pc}^{-2}$. While their stellar populations are very young ($\sim 5-9$ Myr), their dynamical ages exceed unity, consistent with the clusters being gravitationally bound systems. Placing the star clusters in the size vs.~stellar mass density plane, we find they occupy a region similar to other high-redshift star clusters within galaxies observed recently with JWST, being significantly more massive and denser than local star clusters. Spatially resolved analysis of the brightest clump reveals a compact, intensely star-forming core. The ionizing photon production efficiency ($ξ_{\rm{ion}}$) is slightly suppressed in this central region, potentially indicating a locally elevated Lyman continuum escape fraction facilitated by feedback-driven channels. △ Less

Submitted 8 December, 2025; originally announced December 2025.

Comments: 27 pages, 13 figures, submitted to ApJ

CLASSY XIV: The Nitrogen Exception -- Multi-Phase Enrichment and Feedback in High-$z$ Analogs

Authors: Bethan L. James, Valentina Abril-Melgarejo, Karla Z. Arellano-Córdova, Adarsh Ranjan, Kaelee S. Parker, Danielle A. Berg, Matilde Mingozzi, Alessandra Aloisi, John Chisholm, Timothy Heckman, Alaina Henry, Svea Hernandez, Kristen B. W. McQuinn, Xinfeng Xu, Chiaki Kobayashi, The CLASSY Collaboration

Abstract: We present a first-of-its-kind analysis of the metal content across two interstellar medium (ISM) phases in a sample of 31 local star-forming galaxies from the COS Legacy Archive Spectroscopic SurveY (CLASSY), selected as analogues of high-$z$ systems. Using co-spatial UV absorption and optical emission-line spectroscopy, we compare abundances of N, O, S, and Fe in the low-ionization (neutral) and… ▽ More We present a first-of-its-kind analysis of the metal content across two interstellar medium (ISM) phases in a sample of 31 local star-forming galaxies from the COS Legacy Archive Spectroscopic SurveY (CLASSY), selected as analogues of high-$z$ systems. Using co-spatial UV absorption and optical emission-line spectroscopy, we compare abundances of N, O, S, and Fe in the low-ionization (neutral) and high-ionization (ionized) gas, providing a multi-phase view of enrichment shortly after the current starburst and over longer timescales when ejecta from previous episodes have cooled and mixed. We find that O and S, produced predominantly in short-lived massive stars, are well mixed between the two phases, with scatter reflecting local inhomogeneities. Fe, predominantly produced by Type Ia supernovae on $\sim$1 Gyr timescales, is higher in the neutral gas, reflecting either delayed mixing of older Fe-enriched material or preferential depletion of Fe from the ionized phase through dust formation in core-collapse supernova ejecta. N exhibits the largest phase offset, with N/H$_{ion}$ systematically $\sim$0.7 dex higher than N/H$_{neu}$, and the magnitude of this offset correlates with stellar mass, metallicity, star-formation rate, and most strongly with the ISM outflow velocity. N/O ratios in the ionized phase rise rapidly within 3-6 Myr relative to the neutral gas, consistent with N enrichment dominated by Wolf-Rayet stars rather than intermediate-mass AGB stars on longer timescales. These results demonstrate that localized stellar feedback, outflows, and phase-dependent mixing collectively regulate the chemical evolution of star-forming galaxies, providing key insight into the extreme N/O abundances recently observed in galaxies at cosmic dawn. △ Less

Submitted 5 December, 2025; originally announced December 2025.

Comments: 32 pages, 15 figures, 10 tables, submitted to ApJ

MAMMOTH-Grism: Revisiting the Mass-Metallicity Relation in Protocluster Environments at Cosmic Noon

Authors: Yiming Yang, Xin Wang, Xianlong He, Chao-Wei Tsai, Zheng Cai, Zihao Li, Matthew A. Malkan, Dong Dong Shi, Anahita Alavi, Fuyan Bian, James Colbert, Xiaohui Fan, Alaina L. Henry, Harry I. Teplitz, Xian Zhong Zheng

Abstract: We present one of the first measurements of the mass-metallicity relation (MZR) in multiple massive protoclusters at cosmic noon, using Hubble Space Telescope (HST) G141 slitless spectroscopy from the MAMMOTH-Grism survey. We identify 63 protocluster member galaxies across three overdense structures at $z = 2\text{-}3$ with robust detections of [OIII], H$β$, and [OII] emission. The sample spans ga… ▽ More We present one of the first measurements of the mass-metallicity relation (MZR) in multiple massive protoclusters at cosmic noon, using Hubble Space Telescope (HST) G141 slitless spectroscopy from the MAMMOTH-Grism survey. We identify 63 protocluster member galaxies across three overdense structures at $z = 2\text{-}3$ with robust detections of [OIII], H$β$, and [OII] emission. The sample spans gas-phase metallicities of $12 + \log(\text{O/H}) = 8.2\text{-}8.6$, dust-corrected H$β$-based star formation rates (SFRs) of $10$-$250\,M_\odot\,\text{yr}^{-1}$, and stellar masses of $M_\ast \sim 10^{9.4}$-$10^{10.5}\,M_\odot$, derived via spectral energy distribution fitting using deep HST and ground-based photometry. We stack spectra in five $M_\ast$ bins to obtain average metallicities and SFRs. Relative to field galaxies at similar redshifts, protocluster members show elevated SFRs at $M_\ast < 10^{10.25}\,M_\odot$ and a systematically shallower MZR: $12 + \log(\text{O/H}) = (6.96 \pm 0.13) + (0.143 \pm 0.017) \times \log(M_{\ast}/M_{\odot})$. We detect a mass-dependent environmental offset: massive protocluster galaxies are metal-poor compared to field counterparts of similar mass, whereas lower-mass systems exhibit comparable or mildly enhanced metallicities. This trend is consistent with a scenario where cold-mode accretion dilutes the interstellar medium (ISM) across the full mass range, while efficient recycling of feedback-driven outflows preferentially enriches the ISM in low-mass galaxies. Finally, we assess the dependence of metallicity offsets on local overdensity and find no significant trend, likely reflecting the survey's bias toward protocluster cores. △ Less

Submitted 20 November, 2025; originally announced November 2025.

Comments: 18 pages, 8 fqures, resubmitted after addressing the referee report

CLASSY XIII. Cutting through the Clouds - Comparing Indirect Tracers of Ionizing Photon Escape

Authors: Kaelee S. Parker, Danielle A. Berg, John Chisholm, Simon Gazagnes, Sophia R. Flury, Cody Carr, Mason Huberty, Anne E. Jaskot, Matthew J. Hayes, Alberto Saldana-Lopez, Svea Hernandez, Themiya Nanayakkara, Bethan L. James, Karla Z. Arellano-Córdova, Allison Strom, Peter Senchyna, Matilde Mingozzi, Timothy Heckman, Xinfeng Xu, Alaina Henry, Ricardo O. Amorín, Valentin Mauerhofer, Crystal L. Martin, Dawn K. Erb, Evan D. Skillman , et al. (3 additional authors not shown)

Abstract: The Epoch of Reionization (EoR) provides critical insights into the role of early galaxies in shaping the ionization state of the universe. However, because of the opacity of the intergalactic medium, it is often not possible to make direct measurements of the ionizing photon escape fraction ($f_{\mathrm{esc}}^{\: \mathrm{LyC}}$) of high-redshift ($z \gtrsim 4$) galaxies. To explore the agreement… ▽ More The Epoch of Reionization (EoR) provides critical insights into the role of early galaxies in shaping the ionization state of the universe. However, because of the opacity of the intergalactic medium, it is often not possible to make direct measurements of the ionizing photon escape fraction ($f_{\mathrm{esc}}^{\: \mathrm{LyC}}$) of high-redshift ($z \gtrsim 4$) galaxies. To explore the agreement and systematics of common indirect approaches, we applied six empirically calibrated diagnostics to predict $f_{\mathrm{esc}}^{\: \mathrm{LyC}}$ for the 45 nearby star-forming galaxies from the COS Legacy Spectroscopic SurveY (CLASSY). These methods- based on ultraviolet (UV) absorption lines, the UV continuum slope, Ly$α$ kinematics, a multivariate model, radiation-hydrodynamic simulations, and nebular emission line ratios- enable us to explore systematic differences between predictions and assess how galactic properties influence inferred LyC escape. Despite significant variations in method predictions, there is broad consistency in the resulting weak and strong LyC leaker classifications, with approximately half exhibiting predicted escape fractions $>$1%. We find evidence for two different pathways of LyC escape in nearby star-forming galaxies: (1) an early escape model driven by very young stellar populations, and (2) a delayed escape model that is consistent with supernova-driven outflows and time-dependent ISM clearing. The early escape model is favored among galaxies with a single, intense burst of recent star formation. In contrast, the delayed escape model is common among galaxies with more extended starburst histories. To interpret ionizing photon escape during the EoR, it will be necessary to recognize and understand this diversity in LyC escape mechanisms. △ Less

Submitted 19 November, 2025; originally announced November 2025.

Comments: 26 pages with 12 figures and 4 tables. Accepted to ApJ

MSA-3D: Uncovering Weak AGNs and Resolved Outflows in Disguise in $z\sim1$ Star-Forming Galaxies

Authors: Namrata Roy, Alaina Henry, Tucker Jones, Ivana Barisic, Ryan L. Sanders, Kevin Bundy, Matthew A. Malkan, Themiya Nanayakkara, Karl Glazebrook, Timothy Heckman, Juan M. Espejo Salcedo, Xin Wang, Danail Obreschkow, Tommaso Treu

Abstract: We present spatially resolved rest-optical spectroscopy of 38 star-forming galaxies at 0.5 < z < 1.7 from the JWST/NIRSpec MSA-3D survey, which uses slit-stepping to build IFU-like datacubes at 0.1'' resolution. We map emission-line morphology, excitation, and kinematics of the warm ionized gas using [N II]/H$α$, [S II]/H$α$, and [O III]/H$β$. Relative to z$\sim$0 galaxies at fixed stellar mass, o… ▽ More We present spatially resolved rest-optical spectroscopy of 38 star-forming galaxies at 0.5 < z < 1.7 from the JWST/NIRSpec MSA-3D survey, which uses slit-stepping to build IFU-like datacubes at 0.1'' resolution. We map emission-line morphology, excitation, and kinematics of the warm ionized gas using [N II]/H$α$, [S II]/H$α$, and [O III]/H$β$. Relative to z$\sim$0 galaxies at fixed stellar mass, our sources show systematically lower [N II]/H$α$ and [S II]/H$α$ and elevated [O III]/H$β$, consistent with harder radiation fields and lower metallicities. Radially, [O III]/H$β$ profiles are typically flat or mildly positive, whereas [N II]/H$α$ also remains flat or declines outward, mirroring metallicity trends. On kpc scales, we find a strong positive correlation between [N II]/H$α$ and velocity dispersion ($σ$), linking local excitation to turbulent or shock-driven kinematics. Six galaxies ($\sim$ 16% of the sample) host spatially localized regions with elevated [N II]/H$α$, high EW(H$α$), and V_RMS = $\sqrt{V^2 + σ^2} > 200$ km/s, indicative of weak AGN activity, shocks, or outflows. For these candidates we infer modest warm-ionized outflow rates of 1-4 Msun/yr and kinetic powers $\sim$ 0.1-1% of the AGN bolometric luminosity (from central [O III] or H$α$). These values place our sample at the low-energy tail of known AGN-driven outflows yet in continuity with $\dot{M_{out}}-L_{AGN}$ scaling relations across 0 < z < 6. A completeness assessment shows MSA-3D is sensitive to AGN with $L_{AGN} \geq 10^{43}$ erg/s, underscoring both the promise and current limitations of detecting weak AGN activity in distant galaxies with resolved spectroscopy. △ Less

Submitted 13 October, 2025; originally announced October 2025.

Comments: 26 pages, 16 figures. Submitted to ApJ

A numerical stabilization scheme for the shallow shelf approximation

Authors: Tilda Westling Dolling, A. Clara J. Henry, Josefin Ahlkrona

Abstract: We present the Thickness Stabilization Scheme (TSS), a numerical stabilization scheme suitable for the Shallow Shelf Approximation (SSA), one of the most widely-used models for large-scale Antarctic and Greenland ice sheet simulations. The TSS is constructed by inserting an adapted, explicit Euler thickness evolution equation into the driving stress term, thereby treating the term implicitly. We i… ▽ More We present the Thickness Stabilization Scheme (TSS), a numerical stabilization scheme suitable for the Shallow Shelf Approximation (SSA), one of the most widely-used models for large-scale Antarctic and Greenland ice sheet simulations. The TSS is constructed by inserting an adapted, explicit Euler thickness evolution equation into the driving stress term, thereby treating the term implicitly. We investigate the applicability of TSS across low- and high-shear idealized scenarios, by altering the inflow velocity and initial ice thickness. TSS demonstrates an increase in the numerical stability of SSA, allowing large time-step sizes of dt = 50-100 years to remain numerically stable and accurate, while time-step sizes of dt > 5 in high-shear simulations show significant error without TSS. Remarkably, a time step size as large as dt = 10 000 years is numerically stable with TSS, albeit with a reduction in accuracy. TSS offers greater flexibility for ice-sheet modeling by allowing the re-allocation of computational resources. This method is applicable not only to ice-sheet modeling, including in coupled frameworks, but also to other vertically-integrated computational fluid dynamics problems that couple momentum and geometry evolution equations. △ Less

Submitted 3 October, 2025; originally announced October 2025.

Comments: 20 pages, 14 figures

Polarimeter to Unify the Corona and Heliosphere (PUNCH)

Authors: Craig E. DeForest, Sarah E. Gibson, Ronnie Killough, Nick R. Waltham, Matt N. Beasley, Robin C. Colaninno, Glenn T. Laurent, Daniel B. Seaton, J. Marcus Hughes, Madhulika Guhathakurta, Nicholeen M. Viall, Raphael Attie, Dipankar Banerjee, Luke Barnard, Doug A. Biesecker, Mario M. Bisi, Volker Bothmer, Antonina Brody, Joan Burkepile, Iver H. Cairns, Jennifer L. Campbell, Traci Case, Amir Caspi, David Cheney, Rohit Chhiber , et al. (52 additional authors not shown)

Abstract: The Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission is a NASA Small Explorer to determine the cross-scale processes that unify the solar corona and heliosphere. PUNCH has two science objectives: (1) understand how coronal structures become the ambient solar wind, and (2) understand the dynamic evolution of transient structures, such as coronal mass ejections, in the young solar win… ▽ More The Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission is a NASA Small Explorer to determine the cross-scale processes that unify the solar corona and heliosphere. PUNCH has two science objectives: (1) understand how coronal structures become the ambient solar wind, and (2) understand the dynamic evolution of transient structures, such as coronal mass ejections, in the young solar wind. To address these objectives, PUNCH uses a constellation of four small spacecraft in Sun-synchronous low Earth orbit, to collect linearly polarized images of the K corona and young solar wind. The four spacecraft each carry one visible-light imager in a 1+3 configuration: a single Narrow Field Imager solar coronagraph captures images of the outer corona at all position angles, and at solar elongations from 1.5 degrees (6 R$_\odot$) to 8 degrees (32 R$_\odot$); and three separate Wide Field Imager heliospheric imagers together capture views of the entire inner solar system, at solar elongations from 3 degrees (12 R$_\odot$) to 45 degrees (180 R$_\odot$) from the Sun. PUNCH images include linear-polarization data, to enable inferring the three-dimensional structure of visible features without stereoscopy. The instruments are matched in wavelength passband, support overlapping instantaneous fields of view, and are operated synchronously, to act as a single ``virtual instrument'' with a 90 degree wide field of view, centered on the Sun. PUNCH launched in March of 2025 and began science operations in June of 2025. PUNCH has an open data policy with no proprietary period, and PUNCH Science Team Meetings are open to all. △ Less

Submitted 21 January, 2026; v1 submitted 18 September, 2025; originally announced September 2025.

Comments: As accepted by Solar Physics journal; substantially similar (but not identical) to the article as it will appear in the journal

Journal ref: Solar Physics, Vol. 301, 16 (57pp); 2026 January 27

The Ly$α$ and Continuum Origins Survey. III. Investigating the Link between Galaxy Morphology, Merger Properties and LyC Escape

Authors: Alexandra Le Reste, Anne E. Jaskot, Jordanne Brazie, Claudia Scarlata, Sophia R. Flury, Kameswara B. Mantha, Alaina Henry, Matthew J. Hayes, Göran Östlin, Alberto Saldana-Lopez, Trinh X. Thuan, Maxime Trebitsch, Xinfeng Xu, Ricardo O. Amorín, Cody A. Carr, Floriane Leclercq, Daniel Schaerer, Aaron Smith, Jens Melinder, M. S. Oey, Swara Ravindranath, Michael Rutkowski, Bingjie Wang

Abstract: Characterizing the mechanisms and galaxy properties conducive to the emission and escape of ionizing (LyC) emission is necessary to accurately model the Epoch of Reionization, and identify the sources that powered it. The Ly$α$ and Continuum Origins Survey (LaCOS) is the first program to obtain uniform, multi-wavelength subkiloparsec imaging for a large sample (42) of galaxies observed in LyC and… ▽ More Characterizing the mechanisms and galaxy properties conducive to the emission and escape of ionizing (LyC) emission is necessary to accurately model the Epoch of Reionization, and identify the sources that powered it. The Ly$α$ and Continuum Origins Survey (LaCOS) is the first program to obtain uniform, multi-wavelength subkiloparsec imaging for a large sample (42) of galaxies observed in LyC and enable statistically robust studies between LyC and resolved galaxy properties. Here, we characterize the morphology and galaxy merger properties of LaCOS galaxies and investigate their connection with the escape fraction of LyC emission $f_{esc}^{LyC}$. We find strong anticorrelations between $f_{esc}^{LyC}$ and size ($r_{20}$, $r_{50}$, and $r_{80}$) measured in filters containing emission from star-forming regions, and with the asymmetry and clumpiness in F150LP, the bluest filter in our dataset, tracing UV continuum and Ly$α$. We find that $\geq48\%$ of LaCOS galaxies, and $\geq41\%$ of LaCOS LyC-emitters are visually classified as galaxy mergers. Galaxies robustly identified as mergers in LaCOS are at advanced stages of interaction, close to coalescence. The $f_{esc}^{LyC}$ properties of robust mergers and low-probability mergers cannot be differentiated statistically, and we only find significant difference between the two populations in terms of their of their sizes and LyC luminosity: robust mergers having larger values. We conclude that (i) $f_{esc}^{LyC}$ tends to be larger in galaxies with a small number of compact, centrally-located, UV-emitting star-forming regions, (ii) at advanced stages of interaction represent a sizable fraction of LyC-emitting samples at $z\sim0.3$, $z\sim0$, and (iii) mergers can facilitate the escape of LyC photons from galaxies. △ Less

Submitted 11 February, 2026; v1 submitted 8 September, 2025; originally announced September 2025.

Comments: Published in ApJ

Journal ref: ApJ, 888, 222 (2026)

Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE): Survey Overview

Authors: Matthew A. Malkan, Vihang Mehta, Ayan Acharyya, Hollis Akins, Anahita Alavi, Hakim Atek, Ivano Baronchelli, Andrew J. Battisti, Kit Boyett, Marusa Bradac, Sean Tyler Bruton, Andrew Bunker, Adam J. Burgasser, Caitlin Casey, Nuo Chen, James Colbert, Y. Sophia Dai, Max Franco, Clea Hannahs, Santosh Harish, Farhanul Hasan, Matthew James Hayes, Alaina L. Henry, Mason Huberty, Jeyhan Kartaltepe , et al. (27 additional authors not shown)

Abstract: During the second half of Cycle 1 of the James Webb Space Telescope (JWST), we conducted the Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE) program. PASSAGE received the largest allocation of JWST observing time in Cycle 1, 591 hours of NIRISS observations to obtain direct near-IR imaging and slitless spectroscopy. About two thirds of these were ultimately exec… ▽ More During the second half of Cycle 1 of the James Webb Space Telescope (JWST), we conducted the Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE) program. PASSAGE received the largest allocation of JWST observing time in Cycle 1, 591 hours of NIRISS observations to obtain direct near-IR imaging and slitless spectroscopy. About two thirds of these were ultimately executed, to observe 63 high-latitude fields in Pure Parallel mode. These have provided more than ten thousand near-infrared grism spectrograms of faint galaxies. PASSAGE brings unique advantages in studying galaxy evolution: A) Unbiased spectroscopic search, without prior photometric pre-selection. By including the most numerous galaxies, with low masses and strong emission lines, slitless spectroscopy is the indispensable complement to any pre-targeted spectroscopy; B) The combination of several dozen independent fields to overcome cosmic variance; C) Near-infrared spectral coverage, often spanning the full range from 1.0--2.3 $μ$m, with minimal wavelength gaps, to measure multiple diagnostic rest-frame optical lines, minimizing sensitivity to dust reddening; D) JWST's unprecedented spatial resolution, in some cases using two orthogonal grism orientations, to overcome contamination due to blending of overlapping spectra; E) Discovery of rare bright objects especially for detailed JWST followup. PASSAGE data are public immediately, and our team plans to deliver fully-processed high-level data products. In this PASSAGE overview, we describe the survey and data quality, and present examples of these accomplishments in several areas of current interest in the evolution of emission-line galaxy properties, particularly at low masses. △ Less

Submitted 30 August, 2025; originally announced September 2025.

Comments: 22 pages, 18 figures

Mapping Jet-Gas Coupling and energetic ionized outflows in High-Redshift Radio Galaxies with JWST/NIRSpec

Authors: Namrata Roy, Timothy Heckman, Alaina Henry

Abstract: We present spatially resolved maps of morphology, kinematics, and energetics of warm ionized gas in six powerful radio galaxies at z=3.5-4, using JWST/NIRSpec IFU to quantify jet-driven feedback in the early universe. All sources exhibit broad [OIII] emission-line profiles with W80 (line width) values of 950-2500 km/s across $\sim$10s of kpc, signifying large-scale outflows. The outflowing nebulae… ▽ More We present spatially resolved maps of morphology, kinematics, and energetics of warm ionized gas in six powerful radio galaxies at z=3.5-4, using JWST/NIRSpec IFU to quantify jet-driven feedback in the early universe. All sources exhibit broad [OIII] emission-line profiles with W80 (line width) values of 950-2500 km/s across $\sim$10s of kpc, signifying large-scale outflows. The outflowing nebulae are preferentially aligned with the radio jet axis, suggesting jet-driven origin. On average, the regions with the broadest lines and highest velocities are co-spatial with radio lobes or cores, and exhibit the strongest kinetic power. Ionized gas masses associated with the outflows span 1 to 8 $\times 10^{9} \ M_\odot$, with total mass outflow rates of 80-950 Msun/yr and kinetic powers between 10^{43.2} and 10^{45.0} erg/s. The outflow kinetic power corresponds to 0.15%-2% of the AGN bolometric luminosity, sufficient to impact galaxy evolution. However, only $\lesssim 1$\% of the jet mechanical energy couples to the warm ionized gas via outflows, consistent with predictions from hydrodynamic simulations. A large fraction of the jet energy may instead reside in shock-heated hot gas, supported by X-ray detection, or used to thermalize the gas and produce the observed emission-line nebulae. Our results demonstrate that radio jets in massive, gas-rich systems at high-redshift can inject significant kinetic and thermal energy to the surroundings, providing direct evidence for jet-driven feedback operating during the peak epoch of galaxy formation. △ Less

Submitted 8 August, 2025; originally announced August 2025.

Comments: 30 pages, 23 figures, Submitted to ApJ

Hyperparameter-Free Neurochaos Learning Algorithm for Classification

Authors: Akhila Henry, Nithin Nagaraj

Abstract: Neurochaos Learning (NL) is a brain-inspired classification framework that employs chaotic dynamics to extract features from input data and yields state of the art performance on classification tasks. However, NL requires the tuning of multiple hyperparameters and computing of four chaotic features per input sample. In this paper, we propose AutochaosNet - a novel, hyperparameter-free variant of t… ▽ More Neurochaos Learning (NL) is a brain-inspired classification framework that employs chaotic dynamics to extract features from input data and yields state of the art performance on classification tasks. However, NL requires the tuning of multiple hyperparameters and computing of four chaotic features per input sample. In this paper, we propose AutochaosNet - a novel, hyperparameter-free variant of the NL algorithm that eliminates the need for both training and parameter optimization. AutochaosNet leverages a universal chaotic sequence derived from the Champernowne constant and uses the input stimulus to define firing time bounds for feature extraction. Two simplified variants - TM AutochaosNet and TM-FR AutochaosNet - are evaluated against the existing NL architecture - ChaosNet. Our results demonstrate that AutochaosNet achieves competitive or superior classification performance while significantly reducing training time due to reduced computational effort. In addition to eliminating training and hyperparameter tuning, AutochaosNet exhibits excellent generalisation capabilities, making it a scalable and efficient choice for real-world classification tasks. Future work will focus on identifying universal orbits under various chaotic maps and incorporating them into the NL framework to further enhance performance. △ Less

Submitted 2 August, 2025; originally announced August 2025.

A Lyman continuum analysis for $\sim 100$ galaxies at $z_{\text{spec}} \sim 3$ in the Abell 2744 Cluster Field

Authors: Y. Liu, S. Mascia, L. Pentericci, P. Watson, A. Alavi, P. Bergamini, M. Bradač, A. Calabrò, K. Glazebrook, A. Henry, M. Llerena, E. Merlin, B. Metha, T. Nanayakkara, L. Napolitano, N. Roy, B. Siana, E. Vanzella, B. Vulcani, X. Wang

Abstract: Identifying Lyman continuum (LyC) leakers at intermediate redshifts is crucial for understanding the properties of cosmic reionizers, as the opacity of the intergalactic medium (IGM) prevents direct detection of LyC emission from sources during the Epoch of Reionization (EoR). In this study, we confirm two new LyC candidate leakers at $z \sim 3$ in the Abell 2744 cluster field, with absolute escap… ▽ More Identifying Lyman continuum (LyC) leakers at intermediate redshifts is crucial for understanding the properties of cosmic reionizers, as the opacity of the intergalactic medium (IGM) prevents direct detection of LyC emission from sources during the Epoch of Reionization (EoR). In this study, we confirm two new LyC candidate leakers at $z \sim 3$ in the Abell 2744 cluster field, with absolute escape fractions ($f_{\text{esc}}$) of $0.90^{+0.07}_{-0.86}$ and $0.60^{+0.37}_{-0.56}$, respectively. The LyC emission was detected using HST/WFC3/F275W and F336W imaging. These two candidate leakers appear faint ($ M_{\text{UV}} = -18.1 \pm 0.1 \text{ and } -17.81 \pm 0.11$), exhibit blue UV continuum slopes ($β= -2.42 \pm 0.05 \text{ and } -1.78 \pm 0.19$), have low masses ($M_\star \sim 10^{7.73} \pm 0.1 \text{ and } 10^{7.07} \pm 0.05 M_\odot$) and show \lya\ equivalent widths of $90 \pm 3$ Å and $28 \pm 12$ Å, respectively. The discovery of these two LyC candidate leakers was achieved in a catalog of 91 spectroscopically confirmed sources using JWST and/or MUSE public spectra. We also analyze properties that have been proposed as indirect indicators of LyC emission, like \lya, O32 ratio, and $M_\star$: we create subsample of galaxies selected according to such properties, stack the LyC observations of these subsample and assess the limits in escape fractions in the stacks. By analysing the individual candidates and the stacks, in the context of the currently limited sample of known LyC leakers at $z \sim 3$, we aim to enhance our understanding of LyC escape mechanisms and improve our predictions of the LyC $f_{\text{esc}}$ during the EoR. △ Less

Submitted 15 July, 2025; originally announced July 2025.

Comments: 12 pages,7 figures,2 tables

Journal ref: A&A 704, A328 (2025)

Noema formIng Cluster survEy (NICE): A Census of Star Formation and Cold Gas Properties in Massive protoclusters at 1.5<z<4

Authors: Luwenjia Zhou, Tao Wang, Emanuele Daddi, Rosemary Coogan, Hanwen Sun, Ke Xu, Vinodiran Arumugam, Shuowen Jin, Daizhong Liu, Shiying Lu, Nikolaj Sillassen, Sicen Guo, Guillaume Elias, Yijun Wang, Yong Shi, Zhi-Yu Zhang, Qinghua Tan, Qiusheng Gu, David Elbaz, Aurelien Henry, Benjamin Magnelli, Carlos Gomez-Guijarro, Chiara d'Eugenio, Georgios E. Magdis, Francesco Valentino , et al. (14 additional authors not shown)

Abstract: Massive protoclusters at z~1.5-4, the peak of the cosmic star formation history, are key to understanding the formation mechanisms of massive galaxies in today's clusters. However, studies of protoclusters at these high redshifts remain limited, primarily due to small sample sizes and heterogeneous selection criteria. In this work, we conduct a systematic investigation of the star formation and co… ▽ More Massive protoclusters at z~1.5-4, the peak of the cosmic star formation history, are key to understanding the formation mechanisms of massive galaxies in today's clusters. However, studies of protoclusters at these high redshifts remain limited, primarily due to small sample sizes and heterogeneous selection criteria. In this work, we conduct a systematic investigation of the star formation and cold gas properties of member galaxies of eight massive protoclusters in the COSMOS field, using the statistical and homogeneously selected sample from the Noema formIng Cluster survEy (NICE). Our analysis reveals a steep increase in the star formation rates per halo mass ($Σ_{\rm SFR} /M_{\rm halo}$) with redshifts in these intensively star-forming protoclusters, reaching values one to two orders of magnitude higher than those observed in the field at z>2. We further show that, instead of an enhancement of starbursts, this increase is largely driven by the concentration of massive and gas-rich star-forming galaxies in the protocluster cores. The member galaxies still generally follow the same star formation main sequence as in the field, with a moderate enhancement at the low mass end. Notably, the most massive protocluster galaxies ($M_\star$>8$\times$10$^{10}$M$_\odot$) exhibit higher $f_{\rm gas}$ and $τ_{\rm gas}$ than their field counterparts, while remaining on the star forming main sequence. These gas-rich, massive, and star-forming galaxies are predominantly concentrated in the protocluster cores and are likely progenitors of massive ellipticals in the center of today's clusters. These results suggest that the formation of massive galaxies in such environments is sustained by substantial gas reservoirs, which support persistent star formation and drive early mass assembly in forming cluster cores. △ Less

Submitted 1 August, 2025; v1 submitted 14 July, 2025; originally announced July 2025.

Comments: 12 pages, 7 figures, 1 table and 1 figure in appendix. A&A in press

Report number: aa53996-25

Journal ref: A&A 701, A234 (2025)

A Careful Examination of Large Behavior Models for Multitask Dexterous Manipulation

Authors: TRI LBM Team, Jose Barreiros, Andrew Beaulieu, Aditya Bhat, Rick Cory, Eric Cousineau, Hongkai Dai, Ching-Hsin Fang, Kunimatsu Hashimoto, Muhammad Zubair Irshad, Masha Itkina, Naveen Kuppuswamy, Kuan-Hui Lee, Katherine Liu, Dale McConachie, Ian McMahon, Haruki Nishimura, Calder Phillips-Grafflin, Charles Richter, Paarth Shah, Krishnan Srinivasan, Blake Wulfe, Chen Xu, Mengchao Zhang, Alex Alspach , et al. (57 additional authors not shown)

Abstract: Robot manipulation has seen tremendous progress in recent years, with imitation learning policies enabling successful performance of dexterous and hard-to-model tasks. Concurrently, scaling data and model size has led to the development of capable language and vision foundation models, motivating large-scale efforts to create general-purpose robot foundation models. While these models have garnere… ▽ More Robot manipulation has seen tremendous progress in recent years, with imitation learning policies enabling successful performance of dexterous and hard-to-model tasks. Concurrently, scaling data and model size has led to the development of capable language and vision foundation models, motivating large-scale efforts to create general-purpose robot foundation models. While these models have garnered significant enthusiasm and investment, meaningful evaluation of real-world performance remains a challenge, limiting both the pace of development and inhibiting a nuanced understanding of current capabilities. In this paper, we rigorously evaluate multitask robot manipulation policies, referred to as Large Behavior Models (LBMs), by extending the Diffusion Policy paradigm across a corpus of simulated and real-world robot data. We propose and validate an evaluation pipeline to rigorously analyze the capabilities of these models with statistical confidence. We compare against single-task baselines through blind, randomized trials in a controlled setting, using both simulation and real-world experiments. We find that multi-task pretraining makes the policies more successful and robust, and enables teaching complex new tasks more quickly, using a fraction of the data when compared to single-task baselines. Moreover, performance predictably increases as pretraining scale and diversity grows. Project page: https://toyotaresearchinstitute.github.io/lbm1/ △ Less

Submitted 7 July, 2025; originally announced July 2025.

Exceptional point rings and $PT$-symmetry in the non-Hermitian XY model

Authors: Robert A. Henry, D. C. Liu, Murray T. Batchelor

Abstract: The XY spin chain is a paradigmatic example of a model solved by free fermions, in which the energy eigenspectrum is built from combinations of quasi-energies. In this article we show that by extending the XY model's anisotropy parameter $λ$ to complex values, it is possible for two of the quasi-energies to become degenerate. In the non-Hermitian XY model these quasi-energy degeneracies give rise… ▽ More The XY spin chain is a paradigmatic example of a model solved by free fermions, in which the energy eigenspectrum is built from combinations of quasi-energies. In this article we show that by extending the XY model's anisotropy parameter $λ$ to complex values, it is possible for two of the quasi-energies to become degenerate. In the non-Hermitian XY model these quasi-energy degeneracies give rise to exceptional points (EPs) where two of the eigenvalues and their corresponding eigenvectors coalesce. The distinct $λ$ values at which EPs appear form concentric rings in the complex plane which are shown in the infinite system size limit to converge to the unit circle coinciding with the boundary between distinct topological phases. The non-Hermitian model is also seen to possess a line of broken $PT$ symmetry along the pure imaginary $λ$-axis. For finite systems, there are four EP values on this broken $PT$-symmetric line if the system size is a multiple of 4. △ Less

Submitted 4 September, 2025; v1 submitted 6 July, 2025; originally announced July 2025.

Comments: 12 pages, 3 figures, minor changes, additional references

Journal ref: AAPPS Bull. 35, 29 (2025)

Multi-dimensional frequency-bin entanglement-based quantum key distribution network

Authors: George Claudiu Crisan, Antoine Henry, Dario Alessandro Fioretto, Juan Rafael Alvarez, Stéphan Monfray, Frédéric Boeuf, Laurent Vivien, Eric Cassan, Carlos Alonso-Ramos, Nadia Belabas

Abstract: Quantum networks enhance quantum communication schemes and link multiple users over large areas. Harnessing high dimensional quantum states - i.e. qu-d-its - allows for a denser transfer of information with increased robustness to noise compared to qubits. Frequency encoding enables access to such qu-d-its at telecom wavelengths, while manipulating quantum information with off-the-shelf fibered de… ▽ More Quantum networks enhance quantum communication schemes and link multiple users over large areas. Harnessing high dimensional quantum states - i.e. qu-d-its - allows for a denser transfer of information with increased robustness to noise compared to qubits. Frequency encoding enables access to such qu-d-its at telecom wavelengths, while manipulating quantum information with off-the-shelf fibered devices. We use a low free spectral range silicon microresonator to generate Bell states of dimension d=2 (qubits) and d=3 (qutrits) via spontaneous four wave mixing, to implement and optimize a multi-dimensional frequency-bin entanglement-based quantum key distribution network. We tune the source (via pump power), the signal processing (via coincidence window size) and qu-d-it encoding (d=2 or 3) using a single fibered hardware based on Fourier-transform pulse shaping and electro-optic modulation depending on interconnection lengths. We achieve secure key rates of 1374 bit/s with qutrits, and estimate the communication range to 295 km with qubits. We access up to 80 frequency modes, resulting in 21 quantum channels, that provide stable communication over more than 21 hours. We demonstrate a competitive communication range in a multi-dimensional entanglement-based quantum key distribution network that lays the groundwork for larger dimensionality implementations deployed on metropolitan fiber links. △ Less

Submitted 1 July, 2025; originally announced July 2025.

Comments: 12 pages, 6 figures

Power-law Emission-line Wings and Radiation-Driven Superwinds in Local Lyman Continuum Emitters

Authors: Lena Komarova, Sally Oey, Rui Marques-Chaves, Ricardo Amorín, Alaina Henry, Daniel Schaerer, Alberto Saldana-Lopez, Alexandra Le Reste, Claudia Scarlata, Matthew J. Hayes, Omkar Bait, Sanchayeeta Borthakur, Cody Carr, John Chisholm, Harry C. Ferguson, Vital Gutierrez Fernandez, Brian Fleming, Sophia R. Flury, Mauro Giavalisco, Andrea Grazian, Timothy Heckman, Anne E. Jaskot, Zhiyuan Ji, Göran Östlin, Laura Pentericci , et al. (5 additional authors not shown)

Abstract: We investigate broad emission-line wings, reaching $\leq 800\rm~km~s^{-1}$, observed in 26 galaxies with Lyman continuum (LyC) observations, primarily from the Low-redshift Lyman Continuum Survey (LzLCS). Using Magellan/MIKE, VLT/X-shooter, and WHT/ISIS high-resolution spectroscopy, we show that this fast gas appears to probe the dominant feedback mechanisms linked to LyC escape. We find that in 1… ▽ More We investigate broad emission-line wings, reaching $\leq 800\rm~km~s^{-1}$, observed in 26 galaxies with Lyman continuum (LyC) observations, primarily from the Low-redshift Lyman Continuum Survey (LzLCS). Using Magellan/MIKE, VLT/X-shooter, and WHT/ISIS high-resolution spectroscopy, we show that this fast gas appears to probe the dominant feedback mechanisms linked to LyC escape. We find that in 14 galaxies, the wings are best fit with power laws of slope $α\sim -3.5 \text{ to } -1.6$, with four others best fit by Gaussians of width $σ_{\rm BW} \sim 300~\rm km~s^{-1}$; the remaining eight show ambiguous wing morphologies. Gaussian wings are found only at low $O_{32}$ = $[\rm O~III]\lambda5007/[O~II]\lambda3726,3729$ and high metallicity, while power-law wings span the full range of these parameters. The general evidence suggests a dual-mode paradigm for LyC escape: radiation-driven superwinds traced by power-law wings and supernova-driven feedback traced by Gaussian wings. For the former, the $<3$ Myr-old, pre-supernova stellar population correlates with more luminous, faster winds. The data also show that radiation-driven wind parameters like wind luminosity and power-law slope $α$ depend on the UV luminosity more than the optically thick covering fraction, consistent with ``picket-fence" radiative transfer. Observed $α$ values flatten with both escaping LyC luminosity and higher extinction, while still preserving the anticorrelation between these two quantities. Additionally, the differential between red and blue slopes implies that extinction and dense gas are centrally concentrated relative to the wind emission. Overall, our results show that power-law emission-line wings probe LyC-driven winds and LyC escape in metal-poor starbursts. △ Less

Submitted 29 September, 2025; v1 submitted 24 June, 2025; originally announced June 2025.

Comments: 39 pages, 21 figures. Accepted for publication in ApJ

Augmented Regression Models using Neurochaos Learning

Authors: Akhila Henry, Nithin Nagaraj

Abstract: This study presents novel Augmented Regression Models using Neurochaos Learning (NL), where Tracemean features derived from the Neurochaos Learning framework are integrated with traditional regression algorithms : Linear Regression, Ridge Regression, Lasso Regression, and Support Vector Regression (SVR). Our approach was evaluated using ten diverse real-life datasets and a synthetically generated… ▽ More This study presents novel Augmented Regression Models using Neurochaos Learning (NL), where Tracemean features derived from the Neurochaos Learning framework are integrated with traditional regression algorithms : Linear Regression, Ridge Regression, Lasso Regression, and Support Vector Regression (SVR). Our approach was evaluated using ten diverse real-life datasets and a synthetically generated dataset of the form $y = mx + c + ε$. Results show that incorporating the Tracemean feature (mean of the chaotic neural traces of the neurons in the NL architecture) significantly enhances regression performance, particularly in Augmented Lasso Regression and Augmented SVR, where six out of ten real-life datasets exhibited improved predictive accuracy. Among the models, Augmented Chaotic Ridge Regression achieved the highest average performance boost (11.35 %). Additionally, experiments on the simulated dataset demonstrated that the Mean Squared Error (MSE) of the augmented models consistently decreased and converged towards the Minimum Mean Squared Error (MMSE) as the sample size increased. This work demonstrates the potential of chaos-inspired features in regression tasks, offering a pathway to more accurate and computationally efficient prediction models. △ Less

Submitted 19 May, 2025; originally announced May 2025.

MAMMOTH-MOSFIRE: Environmental Effects on Galaxy Interstellar Medium at $z\sim2$

Authors: Hang Zhou, Xin Wang, Matthew A. Malkan, Tommaso Treu, Yiming Yang, Zheng Cai, Xiaohui Fan, Mengting Ju, Dong Dong Shi, Anahita Alavi, Fuyan Bian, James Colbert, Alaina L. Henry, Sijia Li, Zihao Li, Harry I. Teplitz, Hu Zhan, Xian Zhong Zheng, Zheng Zheng

Abstract: The MAMMOTH-MOSFIRE program is a deep Keck/MOSFIRE K-band spectroscopic follow-up of emission-line galaxies identified in the MAMMOTH-Grism HST/WFC3 G141 slitless spectroscopic survey, targeting the core regions of three most massive galaxy protoclusters at cosmic noon. To introduce this program, we present a comprehensive analysis of the $\rm [N\,II]λ$6584, $\rm [S\,II]λλ$6717,6731, and… ▽ More The MAMMOTH-MOSFIRE program is a deep Keck/MOSFIRE K-band spectroscopic follow-up of emission-line galaxies identified in the MAMMOTH-Grism HST/WFC3 G141 slitless spectroscopic survey, targeting the core regions of three most massive galaxy protoclusters at cosmic noon. To introduce this program, we present a comprehensive analysis of the $\rm [N\,II]λ$6584, $\rm [S\,II]λλ$6717,6731, and $\rm [O\,I]λ$6300 BPT diagnostics for a unique sample of 43 protocluster member galaxies at $z\sim2$, investigating how the overdense environment influences their interstellar medium ionization conditions. We find that, similar to their field counterparts at $z\sim2$, protocluster galaxies exhibit a systematic offset in the $\rm [N\,II]$ BPT diagram relative to the local star-forming sequence, but no such offset in the $\rm [S\,II]$ BPT diagram. Notably, we detect significantly elevated $\rm [O\,I]$/$\rm H α$ ratios, which can be well reproduced by photoionization models incorporating both $\rm H II$ regions and low-velocity shocks ($v$ $\sim$ 200 km s$^{-1}$). We caution that neglecting shock excitation can bias abundance measurements, leading to an overestimation of nitrogen enrichment. This provides a potential explanation for the long-standing puzzle of enhanced $\rm [N\,II]$/$\rm H α$ ratios observed in $z\sim2$ galaxies. We further suggest that these shocks are likely environmentally driven, e.g., by ram-pressure stripping or tidal interactions, which requires future confirmation through direct observations of features such as stripped gas tails. △ Less

Submitted 10 September, 2025; v1 submitted 7 May, 2025; originally announced May 2025.

Comments: 23 pages, 10 figures, 7 tables, accepted by ApJ

Highly squeezed nanophotonic quantum microcombs with broadband frequency tunability

Authors: Yichen Shen, Ping-Yen Hsieh, Dhruv Srinivasan, Antoine Henry, Gregory Moille, Sashank Kaushik Sridhar, Alessandro Restelli, You-Chia Chang, Kartik Srinivasan, Thomas A. Smith, Avik Dutt

Abstract: Squeezed light offers genuine quantum advantage in enhanced sensing and quantum computation; yet the level of squeezing or quantum noise reduction generated from nanophotonic chips has been limited. In addition to strong quantum noise reduction, key desiderata for such a nanophotonic squeezer include frequency agility or tunability over a broad frequency range, and simultaneous operation in many d… ▽ More Squeezed light offers genuine quantum advantage in enhanced sensing and quantum computation; yet the level of squeezing or quantum noise reduction generated from nanophotonic chips has been limited. In addition to strong quantum noise reduction, key desiderata for such a nanophotonic squeezer include frequency agility or tunability over a broad frequency range, and simultaneous operation in many distinct, well-defined quantum modes (qumodes). Here we present a strongly overcoupled silicon nitride squeezer based on a below-threshold optical parametric amplifier (OPA) that produces directly detected squeezing of 5.6 dB $\pm$ 0.2 dB, surpassing previous demonstrations in both continuous-wave and pulsed regimes. We introduce a seed-assisted detection technique into such nanophotonic squeezers that reveals a quantum frequency comb (QFC) of 16 qumodes, with a separation of 11~THz between the furthest qumode pair, while maintaining a strong squeezing. Additionally, we report spectral tuning of a qumode comb pair over one free-spectral range of the OPA, thus bridging the spacing between the discrete modes of the QFC. Our results significantly advance both the generation and detection of nanophotonic squeezed light in a broadband and multimode platform, establishing a scalable, chip-integrated path for compact quantum sensors and continuous-variable quantum information processing systems. △ Less

Submitted 6 May, 2025; originally announced May 2025.

The Lyman-alpha and Continuum Origins Survey II: the connection between the escape of ionizing radiation and Lyman-alpha halos in star-forming galaxies

Authors: A. Saldana-Lopez, M. J. Hayes, A. Le Reste, C. Scarlata, J. Melinder, A. Henry, F. Leclercq, T. Garel, R. Amorin, H. Atek, O. Bait, C. A. Carr, J. Chisholm, S. R. Flury, T. M. Heckman, A. E. Jaskot, I. Jung, Z. Ji, L. Komarova, Y-H. Lin, M. S. Oey, G. Ostlin, L. Pentericci, A. Runnholm, D. Schaerer , et al. (2 additional authors not shown)

Abstract: One of the current challenges in galaxy evolution studies is to establish the mechanisms that govern the escape of ionizing radiation from galaxies. Here, we investigate the connection between Lyman Continuum (LyC) escape and the conditions of the Circumgalactic Medium (CGM), as probed by Ly$α$ halos (LAHs) in emission. We use Ly$α$ and UV continuum imaging data from the Lyman alpha and Continuum… ▽ More One of the current challenges in galaxy evolution studies is to establish the mechanisms that govern the escape of ionizing radiation from galaxies. Here, we investigate the connection between Lyman Continuum (LyC) escape and the conditions of the Circumgalactic Medium (CGM), as probed by Ly$α$ halos (LAHs) in emission. We use Ly$α$ and UV continuum imaging data from the Lyman alpha and Continuum Origins Survey (LaCOS), targeting 42 nearby ($z \simeq 0.3$), star-forming galaxies with LyC observations (escape fractions of $f_{\rm esc}^{\rm LyC} \simeq 0.01-0.49$). LaCOS galaxies show extended Ly$α$ emission ubiquitously, with LyC emitters (LCEs) having more compact Ly$α$ morphologies than non-LCEs, and Ly$α$ spatial offsets that do not exceed the extent of the UV continuum. We model the diffuse LAHs using a combined Sérsic plus exponential 2D profile, and find that the characteristic scale length of the Ly$α$ halo is ten times larger than the UV, on average. We unveil a significant anti-correlation between $f_{\rm esc}^{\rm LyC}$ and the Ly$α$ Halo Fraction (HF, or contribution of the halo to the total Ly$α$ luminosity), that we propose as a new LyC indicator. Our observations show that halo scale lengths and HFs both scale positively with the optical depth of the neutral gas in the ISM, revealing a picture in which Ly$α$ and LyC photons in LCEs either emerge directly from the central starbursts or escape isotropically and, in the case of Ly$α$, minimize the number of scattering interactions in a less-extended CGM. △ Less

Submitted 24 February, 2026; v1 submitted 9 April, 2025; originally announced April 2025.

Comments: 18 pages, 12 figures, 2 tables; accepted for publication in ApJ on January 10, 2026

The Lyman-alpha and Continuum Origins Survey. I. Survey description and Ly$α$ imaging

Authors: Alexandra Le Reste, Claudia Scarlata, Matthew Hayes, Jens Melinder, Alberto Saldana-Lopez, Aaron Smith, Axel Runnholm, Yu-Heng Lin, Ricardo O. Amorín, Hakim Atek, Sanchayeeta Borthakur, Cody A. Carr, Brian Fleming, Sophia R. Flury, Mauro Giavalisco, Alaina Henry, Anne E. Jaskot, Zhiyuan Ji, Intae Jung, Floriane Leclercq, Rui Marques-Chaves, Stephan R. McCandliss, M. S. Oey, Göran Östlin, Swara Ravindranath , et al. (3 additional authors not shown)

Abstract: Understanding the mechanisms driving the escape of ionizing or Lyman continuum (LyC) emission from the interstellar medium of galaxies is necessary to constrain the evolution of reionization, and the sources responsible for it. While progress has been made into identifying the global galaxy properties linked to the escape fraction of ionizing radiation, $f_{esc}^{LyC}$, little is currently known a… ▽ More Understanding the mechanisms driving the escape of ionizing or Lyman continuum (LyC) emission from the interstellar medium of galaxies is necessary to constrain the evolution of reionization, and the sources responsible for it. While progress has been made into identifying the global galaxy properties linked to the escape fraction of ionizing radiation, $f_{esc}^{LyC}$, little is currently known about how spatially resolved galaxy properties impact this parameter. We present Hubble Space Telescope (HST) imaging data obtained as part of the Lyman $α$ and Continuum Origins Survey (LaCOS). LaCOS consists of HST imaging in 5 filters covering rest-frame optical and UV bands for a subsample of 42 galaxies in the Low redshift Lyman Continuum Survey, 22 being Lyman continuum emitters ($f_{esc}^{LyC}=0.01-0.49$). Here, we describe the sample, observations and data reduction, and investigate connections between global and sub-kpc Lyman $α$ (Ly$α$) emission, and $f_{esc}^{LyC}$. We confirm the correlation between $f_{esc}^{LyC}$ and EW$_{Lyα}$ , and the anticorrelation with $r_{50}$, when using values obtained via global photometry. We also find correlations previously found with spectroscopy with global photometric $L_{Lyα}$, $f_{esc}^{Lyα}$, $Σ_{SFR}$ , and $f_{esc}^{LyC}$, but with a smaller degree of correlation ($\overline{|Δτ|}\sim0.1$). We find correlations are strongest between $Lyα$ observables ($L_{\rm Lyα}$, EW$_{\rm Lyα}$) and $f_{\rm esc}^{\rm LyC}$ when measured in a small aperture around the brightest UV source in each galaxy. We interpret these results as evidence that LyC photons escaping on the line-of-sight are contributed by a small number of UV-bright compact regions in most galaxies in LaCOS. △ Less

Submitted 1 September, 2025; v1 submitted 9 April, 2025; originally announced April 2025.

Comments: Accepted for publication in ApJS

The Parallel Ionizing Emissivity Survey (PIE). I. Survey design and selection of candidate Lyman Continuum leakers at 3.1<z<3.5

Authors: Alexander Beckett, Marc Rafelski, Claudia Scarlata, Wanjia Hu, Keunho Kim, Ilias Goovaerts, Matthew A. Malkan, Wayne Webb, Harry Teplitz, Matthew Hayes, Vihang Mehta, Anahita Alavi, Andrew J. Bunker, Annalisa Citro, Nimish Hathi, Alaina Henry, Alexandra Le Reste, Alessia Moretti, Michael J. Rutkowski, Maxime Trebitsch, Anita Zanella

Abstract: We present the survey design and initial results from the Parallel Ionizing Emissivity (PIE) survey. PIE is a large HST survey designed to detect Lyman continuum (LyC) emitting galaxies at 3.1$<$ z $<$3.5 and stack their images in order to measure average LyC escape fractions as a function of galaxy properties. PIE has imaged 37 independent fields in three filters (F336W, F625W and F814W), of whic… ▽ More We present the survey design and initial results from the Parallel Ionizing Emissivity (PIE) survey. PIE is a large HST survey designed to detect Lyman continuum (LyC) emitting galaxies at 3.1$<$ z $<$3.5 and stack their images in order to measure average LyC escape fractions as a function of galaxy properties. PIE has imaged 37 independent fields in three filters (F336W, F625W and F814W), of which 18 are observed with a fourth band (F475W) from the accompanying PIE+ program. We use photometric colors to select candidate Lyman Break Galaxies (LBGs) at 3.1$<$ z $<$3.5, which can be followed up using ground-based spectrographs to confirm their redshifts. Unlike previous surveys, we use many independent fields to remove biases caused by correlated absorption in the IGM. In this paper, we describe the survey design, photometric measurements, and the use of mock galaxy samples to optimize our color selection. With 3 filters, we can select a galaxy sample of which $\approx$90\% are LBGs and over 30\% lie in the 3.1$<$ z $<$3.5 range for which we can detect uncontaminated LyC emission in F336W. We also use mock IGM sightlines to measure the expected transmission of the IGM, which will allow us to determine escape fractions from our stacked galaxies. We color-select $\approx$1400 galaxies, and predict that this includes $\approx$80 LyC-emitting galaxies and $\approx$500 that we can use in stacking. Finally, we present the Keck/LRIS spectrum of a galaxy at z $\approx$ 2.99, demonstrating that we can confirm the redshifts of z $\sim$ 3 galaxies from the ground. △ Less

Submitted 13 October, 2025; v1 submitted 26 March, 2025; originally announced March 2025.

Comments: 21 pages, 7 tables, 15 figures, published in the Astrophysical Journal

Journal ref: 2025 ApJ 992 155

High emissivity, thermally robust emitters for high power density thermophotovoltaics

Authors: Minok Park, Shomik Verma, Alina LaPotin, Dustin P. Nizamian, Ravi Prasher, Asegun Henry, Sean D. Lubner, Costas P. Grigoropoulos, Vassilia Zorba

Abstract: Thermal radiative energy transport is essential for high-temperature energy harvesting technologies, including thermophotovoltaics (TPVs) and grid-scale thermal energy storage. However, the inherently low emissivity of conventional high-temperature materials constrains radiative energy transfer, thereby limiting both system performance and technoeconomic viability. Here, we demonstrate ultrafast f… ▽ More Thermal radiative energy transport is essential for high-temperature energy harvesting technologies, including thermophotovoltaics (TPVs) and grid-scale thermal energy storage. However, the inherently low emissivity of conventional high-temperature materials constrains radiative energy transfer, thereby limiting both system performance and technoeconomic viability. Here, we demonstrate ultrafast femtosecond laser-material interactions to transform diverse materials into near-blackbody surfaces with broadband spectral emissivity above 0.96. This enhancement arises from hierarchically engineered light-trapping microstructures enriched with nanoscale features, effectively decoupling surface optical properties from bulk thermomechanical properties. These laser blackened surfaces (LaBS) exhibit exceptional thermal stability, retaining high emissivity for over 100 hours at temperatures exceeding 1000°C, even in oxidizing environments. When applied as TPV thermal emitters, Ta LaBS double electrical power output from 2.19 to 4.10 W cm-2 at 2200°C while sustaining TPV conversion efficiencies above 30%. This versatile, largely material-independent technique offers a scalable and economically viable pathway to enhance emissivity for advanced thermal energy applications. △ Less

Submitted 22 May, 2025; v1 submitted 17 March, 2025; originally announced March 2025.

Comments: 20 pages, 6 figures