Showing 1–50 of 2,693 results for author: Wang, J

Novel Light Dark Matter Detection with Quantum Parity Detector Using Qubit Arrays

Authors: Xuegang Li, Yuxiang Liu, Jing Shu, Ningqiang Song, Yidong Song, Junhua Wang, Yue-Liang Wu, Tiantian Zhang, Yu-Feng Zhou

Abstract: We present the design and the sensitivity reach of the Qubit-based Light Dark Matter detection experiment. We propose the novel two-chip design to reduce signal dissipation, with quantum parity measurement to enhance single-phonon detection sensitivity. We demonstrate the performance of the detector with full phonon and quasiparticle simulations. The experiment is projected to detect $\gtrsim 30$… ▽ More We present the design and the sensitivity reach of the Qubit-based Light Dark Matter detection experiment. We propose the novel two-chip design to reduce signal dissipation, with quantum parity measurement to enhance single-phonon detection sensitivity. We demonstrate the performance of the detector with full phonon and quasiparticle simulations. The experiment is projected to detect $\gtrsim 30$ meV energy deposition with nearly $100\%$ efficiency and high energy resolution. The sensitivity to $m_χ\gtrsim 0.01$ MeV dark matter scattering cross section is expected to be advanced by orders of magnitude for both light and heavy mediators, and similar improvements will be achieved for axion and dark photon absorption in the $0.04$-$0.2$ eV mass range. △ Less

Submitted 23 December, 2025; originally announced December 2025.

Comments: 22 pages, 11 figures, 2 tables

Discovery of a Luminosity-dependent Continuum Lag in NGC 4151 from Photometric and Spectroscopic Continuum Reverberation Mapping

Authors: Hai-Cheng Feng, Sha-Sha Li, Mouyuan Sun, Ciro Pinto, Shuying Zhou, Yerong Xu, J. M. Bai, Elena Dalla Bontà, ZhongNan Dong, Neeraj Kumari, Jiaqi Lin, H. T. Liu, Kai-Xing Lu, Bin Ma, Ji-Rong Mao, Emanuele Nardini, Enrico Piconcelli, Fabio Pintore, Jian-Guo Wang, Ding-Rong Xiong

Abstract: Accretion onto supermassive black holes (SMBHs) powers active galactic nuclei (AGNs) and drives feedback that shapes galaxy evolution. Constraining AGN accretion disk structure is therefore essential for understanding black hole growth and feedback processes. However, direct constraints on disk size remain rare -- particularly from long-term, multi-season spectroscopic reverberation mapping (RM),… ▽ More Accretion onto supermassive black holes (SMBHs) powers active galactic nuclei (AGNs) and drives feedback that shapes galaxy evolution. Constraining AGN accretion disk structure is therefore essential for understanding black hole growth and feedback processes. However, direct constraints on disk size remain rare -- particularly from long-term, multi-season spectroscopic reverberation mapping (RM), which is critical for isolating the intrinsic disk response from the broad-line region (BLR). We present results from an intensive multi-wavelength RM campaign of NGC 4151 during its brightest state in nearly two decades. This represents the third high-cadence monitoring over the past decade, capturing accretion states spanning the transitional regime between thin and thick disks, making NGC 4151 the only AGN with continuum RM observations across such a wide range in accretion states. Combining spectroscopy from the Lijiang 2.4 m telescope with coordinated Swift UV/X-ray monitoring, we measure inter-band continuum lags from UV to optical. The wavelength-dependent lags follow a tight $τ\propto λ^{4/3}$ relation, consistent with reprocessing in a thin disk, but exceed theoretical predictions by a factor of 6.6. Our lag spectrum reveals clear excesses near the Balmer and possibly Paschen jumps, confirming diffuse continuum (DC) contamination from the BLR. By comparing the three campaigns, we discover a non-monotonic lag-luminosity trend ($>3σ$), which cannot be explained by DC emission alone. We propose the lags reflect combined disk and BLR contributions, and present the first evidence that the DC component follows an intrinsic Baldwin effect. These results offer new insights into SMBH mass measurements and theoretical models of AGN inner structure. △ Less

Submitted 20 December, 2025; originally announced December 2025.

Comments: 13 pages, 6 figures, 2 tables. Accepted for publication in The Astrophysical Journal

Surveying Ultra-hot Jupiters using Phase Curves with $\textit{Twinkle}$

Authors: Kaz Gary, Ji Wang, Anusha Pai Asnodkar, Ian Wong

Abstract: Due to their high equilibrium temperatures ($T_{eq}$ $>$ 2000 K), ultra-hot Jupiters (UHJs) are the best characterized exoplanets to date. However, many questions about their formation, evolution, and atmospheres remain unanswered. Phase curve observations can reveal answers to these questions by constraining multiple atmospheric properties including circulation, albedo, and chemistry. To this end… ▽ More Due to their high equilibrium temperatures ($T_{eq}$ $>$ 2000 K), ultra-hot Jupiters (UHJs) are the best characterized exoplanets to date. However, many questions about their formation, evolution, and atmospheres remain unanswered. Phase curve observations can reveal answers to these questions by constraining multiple atmospheric properties including circulation, albedo, and chemistry. To this end, we simulate and forecast a survey of UHJ atmospheres via phase curve observations with the upcoming $\textit{Twinkle}$ mission. $\textit{Twinkle}$ is a spectroscopic satellite covering 0.5--4.5 micron with a spectral resolving power of R $\sim$ 50--70. Using a physically motivated model, we simulate white-light photometric phase curve observations for 14 UHJs in $\textit{Twinkle's}$ field of regard. We project that $\textit{Twinkle}$ will be able to detect all phase curve signals in our survey. Additionally, we simulate spectroscopic phase curves for the UHJ, WASP-189b. From our simulated spectroscopic phase curves, we generate mock phase-resolved emission spectra. Previously detected UHJ molecules (e.g. H$_2$O, CO and CO$_2$) produce notable features in the resulting spectra, allowing for detailed atmospheric characterization to study the 3D structure of UHJ atmospheric chemistry and dynamics. For planets with hotspot phase offsets, $\textit{Twinkle}$ will be capable of detecting them both in the optical and infrared wavelength ranges. This future survey would represent the first UHJ phase curve survey with simultaneous coverage in optical and infrared wavelengths and will provide new constraints and reveal intriguing trends in these extreme environments. △ Less

Submitted 18 December, 2025; originally announced December 2025.

Comments: 25 pages, 10 figures, 5 tables, submitted to AAS Journals (ApJ) on December 16th

Creation of spin-3/2 dark matter via cosmological gravitational particle production

Authors: Edward W. Kolb, Andrew J. Long, Evan McDonough, Jingyuan Wang

Abstract: We study the cosmological gravitational particle production (CGPP) of spin-3/2 particles during and after cosmic inflation, and map the parameter space that can realize the observed dark matter density in stable spin-3/2 particles. Originally formulated by Rarita and Schwinger, the relativistic theory of a massive spin-3/2 field later found a home in supergravity as the superpartner of the gravito… ▽ More We study the cosmological gravitational particle production (CGPP) of spin-3/2 particles during and after cosmic inflation, and map the parameter space that can realize the observed dark matter density in stable spin-3/2 particles. Originally formulated by Rarita and Schwinger, the relativistic theory of a massive spin-3/2 field later found a home in supergravity as the superpartner of the graviton, and in nuclear physics as baryonic resonances and nuclear isotopes. We study a minimal model realization, namely a free massive spin-3/2 field minimally coupled to gravity, and adopt the name raritron for this field. We demonstrate that CGPP of raritrons crucially depends on the hierarchy between the raritron mass $m_{3/2}$ and the Hubble parameter at the end of inflation $H_e$, with high-mass and low-mass cases distinguished by the evolution of the sound speed $c_s$ of the longitudinal (helicity-1/2) mode, which is approximately unity at all times for heavy (relative to Hubble) raritrons and can become small or vanish for lighter raritrons, leading to a dramatic enhancement of production of high momentum particles in the latter case. Assuming the raritrons are stable, this leads to a wide parameter space to produce the observed dark matter density. Finally, we consider a time-dependent raritron mass, which can be chosen to remove the vanishing sound speed of the longitudinal mode, but which nonetheless enhances the production relative to the constant high-mass case, and in particular does not necessarily tame the high momentum tail of the spectrum. We perform our calculations using the Bogoliubov formalism and compare, when applicable, to the Boltzmann formalism. △ Less

Submitted 18 December, 2025; originally announced December 2025.

Comments: 17+5 pages, 7 figures

Einstein Probe Discovery of an X-ray Flare from K-type Star PM J23221-0301

Authors: Guoying Zhao, WeiKang Zheng, Rong-Feng Shen, Qingcang Shui, Dongyue Li, Chang Zhou, Tianci Zheng, Weimin Yuan, Chong Ge, Junfeng Wang, Alexei V. Filippenko, Thomas G. Brink, Jordan Forman, Mayra Gutierrez, Isabelle Jones, Ravjit Kaur, Naunet Leonhardes-Barboza, Petra Mengistu, Avi Patel, Andrew Skemer, Anavi Uppal, Nicole Wolff, Michele N. Woodland

Abstract: Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily concentrated in the optical and X-ray bands, with the X-ray flux potentially increasing by tens or even hundreds of times. Einstein Probe (EP) detected a new X-r… ▽ More Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily concentrated in the optical and X-ray bands, with the X-ray flux potentially increasing by tens or even hundreds of times. Einstein Probe (EP) detected a new X-ray transient EP J2322.1-0301 on 27 September 2024. Its spatial localization shows a high positional coincidence with the nearby high proper motion K-type star PM J23221-0301. Follow-up X-ray observations confirmed the flux enhancement of the source, while optical spectroscopic monitoring revealed time-variable features, particularly the disappearance of the H-alpha emission line. This X-ray flare is consistent with a characteristic fast-rise-exponential-decay (FRED) light curve, with a rise timescale of 1.4 ks, a decay timescale of 5.7 ks, and a total duration of about 7.1 ks. The peak luminosity in the 0.5-4.0 keV energy band reached about 1.3 x 10^31 erg s^-1, with a total energy release of about 9.1 x 10^34 erg, consistent with the empirical energy correlations observed in magnetic-reconnection-driven stellar flares, as inferred from the multitemperature plasma structure and H-alpha-X-ray energy correlation. This discovery underscores EP's capability in understanding stellar magnetic activity via observing stellar transients. △ Less

Submitted 18 December, 2025; originally announced December 2025.

Comments: 14 pages, 8 figures, 3 tables, accepted for publication in The Journal of High Energy Astrophysics

A Tidal Disruption Event from an Intermediate-mass Black Hole Revealed by Comprehensive Multi-wavelength Observations

Authors: Jialai Wang, Mengqiu Huang, Yongquan Xue, Ning Jiang, Shifeng Huang, Yibo Wang, Jiazheng Zhu, Shifu Zhu, Lixin Dai, Chichuan Jin, Bin Luo, Xinwen Shu, Mouyuan Sun, Tinggui Wang, Fan Zou

Abstract: Tidal disruption events (TDEs) occur when a star crosses the tidal radius of a black hole (BH) and is ripped apart, providing a novel and powerful way to probe dormant BHs over a wide mass range. In this study, we present our late-time observations and comprehensive multi-wavelength analyses of an extraordinary TDE at the center of a dwarf galaxy, which exhibited successive flares in the optical,… ▽ More Tidal disruption events (TDEs) occur when a star crosses the tidal radius of a black hole (BH) and is ripped apart, providing a novel and powerful way to probe dormant BHs over a wide mass range. In this study, we present our late-time observations and comprehensive multi-wavelength analyses of an extraordinary TDE at the center of a dwarf galaxy, which exhibited successive flares in the optical, X-ray, and radio bands. Notably, we discovered an unexpected high-state X-ray plateau phase following the peak until the present time. Along with its reported prolonged rise lasting at least 550 days, these unique characteristics are consistent with the scenario of a TDE caused by an intermediate-mass black hole (IMBH) with a mass of approximately $(1-6) \times 10^5$ solar masses. Furthermore, scaling relations derived from the host-galaxy properties indicated a similar BH mass in concert. This discovery highlights the invaluable role of TDEs in the search for elusive IMBHs. △ Less

Submitted 18 December, 2025; originally announced December 2025.

Comments: 35 pages, 10 figures

A second planetesimal collision in the Fomalhaut system

Authors: Paul Kalas, Jason J. Wang, Maxwell A. Millar-Blanchaer, Bin B. Ren, Mark C. Wyatt, Grant M. Kennedy, Maximilian Sommer, Thomas M. Esposito, Robert J. De Rosa, Michael Fitzgerald

Abstract: The nearby star Fomalhaut is orbited by a compact source, Fomalhaut b, which has previously been interpreted as either a dust-enshrouded exoplanet or a dust cloud generated by the collision of two planetesimals. Such collisions are rarely observed but their debris can appear in direct imaging. We report Hubble Space Telescope observations that show the appearance in 2023 of a second point source a… ▽ More The nearby star Fomalhaut is orbited by a compact source, Fomalhaut b, which has previously been interpreted as either a dust-enshrouded exoplanet or a dust cloud generated by the collision of two planetesimals. Such collisions are rarely observed but their debris can appear in direct imaging. We report Hubble Space Telescope observations that show the appearance in 2023 of a second point source around Fomalhaut, resembling the appearance of Fomalhaut b twenty years earlier. We interpret this additional source as a dust cloud produced by a recent impact between two planetesimals. The positions and motion of two impact-generated dust clouds over twenty years provide constraints on the collisional dynamics in the debris belt. △ Less

Submitted 17 December, 2025; originally announced December 2025.

Comments: Published online in Science First Release on December 18, 2025. 32 pgs, 15 figs, 6 tables. This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution

Journal ref: P. Kalas et al., Science 10.1126/science.adu6266 (2025)

Dark matter in ALFALFA galaxies: Investigating galaxy-halo connection

Authors: Meng Yang, Ling Zhu, Niankun Yu, Yu Lei, Runsheng Cai, Jie Wang, Zheng Zheng

Abstract: This paper aims to investigate the galaxy-halo connection using a large sample of individual galaxies with $\mathrm{H\,I}$ integrated spectra. We determine their dark matter content by applying a dynamical method based on $\mathrm{H\,I}$ line widths measured with the curve-of-growth technique, together with inclination corrections inferred from optical images. We build a sample of 2453 gas-rich pr… ▽ More This paper aims to investigate the galaxy-halo connection using a large sample of individual galaxies with $\mathrm{H\,I}$ integrated spectra. We determine their dark matter content by applying a dynamical method based on $\mathrm{H\,I}$ line widths measured with the curve-of-growth technique, together with inclination corrections inferred from optical images. We build a sample of 2453 gas-rich predominantly late-type galaxies spanning a stellar mass range of $10^{8.7}M_\odot$ to $10^{11.4}M_\odot$ by matching them one-to-one with their counterparts from the ALFALFA survey and the TNG100 simulation, ensuring a direct match of stellar mass and $\mathrm{H\,I}$ radius. We generate mock images and mock $\mathrm{H\,I}$ integrated spectra for TNG100 galaxies, and apply the same dynamical method to both ALFALFA and TNG100 mock galaxies to infer their dark matter masses. Across all stellar mass bins, ALFALFA galaxies exhibit lower median dark matter masses than the mock TNG100 simulation results. In each bin, this offset is driven by a tail of galaxies with comparatively low dark matter content, which becomes more prominent toward higher stellar masses. In the highest mass bin ($M_* > 10^{11} M_\odot$), late-type ALFALFA galaxies show a median dark matter mass that is 23% lower than that of their counterparts in the TNG100 dark-matter-only simulation, with 32% of ALFALFA galaxies having $M_\mathrm{DM}(<R_\mathrm{HI})<10^{11.5} M_\odot$, compared to 17% in the mock TNG100 sample. These results suggest that a larger fraction of massive late-type galaxies reside in relatively less massive dark matter haloes than predicted by the TNG100 simulation. △ Less

Submitted 16 December, 2025; originally announced December 2025.

Comments: 12 pages, 12 figures, accepted by A&A

Search for Gravitational Wave Memory in PPTA and EPTA Data: A Complete Signal Model

Authors: Sharon Mary Tomson, Boris Goncharov, Rutger van Haasteren, Rahul Srinivasan, Enrico Barausse, Yirong Wen, Jingbo Wang, John Antoniadis, N. D. Ramesh Bhat, Zu-Cheng Chen, Ismael Cognard, Valentina Di Marco, Huanchen Hu, Gemma H. Janssen, Michael Kramer, Wenhua Ling, Kuo Liu, Saurav Mishra, Delphine Perrodin, Andrea Possenti, Christopher J. Russell, Ryan M. Shannon, Gilles Theureau, Shuangqiang Wang

Abstract: We perform searches for gravitational wave memory in the data of two major Pulsar Timing Array (PTA) experiments located in Europe and Australia. Supermassive black hole binaries (SMBHBs) are the primary sources of gravitational waves in PTA experiments. We develop and carry out the first search for late inspirals and mergers of these sources based on full numerical relativity waveforms with null… ▽ More We perform searches for gravitational wave memory in the data of two major Pulsar Timing Array (PTA) experiments located in Europe and Australia. Supermassive black hole binaries (SMBHBs) are the primary sources of gravitational waves in PTA experiments. We develop and carry out the first search for late inspirals and mergers of these sources based on full numerical relativity waveforms with null (nonlinear) gravitational wave memory. Additionally, we search for generic bursts of null gravitational wave memory, exploring possibilities of reducing the computational cost of these searches through kernel density and normalizing flow approximation of the posteriors. We rule out the mergers of SMBHBs with a chirp mass of 10^10 Solar Mass up to 700 Mpc over 18 years of observation at 95% credibility. We rule out the observation of generic displacement memory bursts with strain amplitudes > 10^-14 in brief periods of the observation time but across the sky, or over the whole observation time but for certain preferred sky positions, at 95%$credibility. △ Less

Submitted 16 December, 2025; originally announced December 2025.

Cold Gas Infall onto A Brightest Group Galaxy via A Gas-Rich Minor Merger

Authors: Ming-Yang Zhuang, Jinyi Shangguan, Yuan Bian, Yue Shen, Luis C. Ho, Min Du, Junyao Li, Zhao-Yu Li, Jing Wang

Abstract: Dust and cold gas are not uncommon in nearby early-type galaxies (ETGs), and represent an important aspect of their evolution. However, their origin has been debated for decades. Potential sources include internal processes (e.g., mass loss from evolved stars), external mechanisms (e.g., minor mergers or cooling flows), or a combination of both. Gas-rich minor mergers have long been proposed as an… ▽ More Dust and cold gas are not uncommon in nearby early-type galaxies (ETGs), and represent an important aspect of their evolution. However, their origin has been debated for decades. Potential sources include internal processes (e.g., mass loss from evolved stars), external mechanisms (e.g., minor mergers or cooling flows), or a combination of both. Gas-rich minor mergers have long been proposed as an important channel for cold gas fueling in both observations and simulations, but direct evidence of cold gas transportation via gas-rich minor mergers remains elusive, particularly in galaxy groups and clusters where environmental effects are prevalent. In this letter, we present the first unambiguous case of direct cold gas transportation onto a brightest group galaxy (BGG) at $z=0.25$, driven by an ongoing close-separation gas-rich minor merger with a mass ratio of $\sim1:56$. High-resolution JWST imaging reveals a heavily obscured, low-mass satellite that is barely visible at restframe optical wavelengths. Tidal stripping from this satellite deposits gas and dust onto the BGG, forming prominent $\sim$10 kpc dust lanes in situ. Cosmological simulations indicate that such interactions preferentially occur in gas-rich satellites undergoing their first infall in highly eccentric orbits. Our results highlight the pivotal role of gas-rich minor mergers in replenishing cold gas reservoirs and shaping the evolution of central ETGs in galaxy groups. △ Less

Submitted 15 December, 2025; originally announced December 2025.

Comments: 15 pages, 7 figures; submitted to ApJL

Direct imaging characterization of cool gaseous planets

Authors: Michiel Min, Jo Barstow, Laura C. Mayorga, Hannah Wakeford, Jason Wang, Renyu Hu, Beth Biller, José A. Caballero, Ludmila Carone, Sarah Casewell, Katy L. Chubb, Mario Damiano, Siddharth Gandhi, Antonio García Muñoz, Christiane Helling, Finnegan Keller, Nataliea Lowson, Evert Nasedkin, Ryan MacDonald, Jean-Baptiste Ruffio, Evgenya Shkolnik, Christopher C. Stark

Abstract: Cool gas giant exoplanets, particularly those with properties similar to those of Jupiter and Saturn, remain poorly characterized due to current observational limitations. This white paper outlines the transformative science case for the Habitable Worlds Observatory (HWO) to directly image and spectroscopically characterize a broad range of gaseous exoplanets with effective temperatures below 400… ▽ More Cool gas giant exoplanets, particularly those with properties similar to those of Jupiter and Saturn, remain poorly characterized due to current observational limitations. This white paper outlines the transformative science case for the Habitable Worlds Observatory (HWO) to directly image and spectroscopically characterize a broad range of gaseous exoplanets with effective temperatures below 400 K. The study focuses on determining key atmospheric properties, including molecular composition, cloud and haze characteristics, and temperature structure, across planets of varying sizes and orbital separations. Leveraging reflected light spectroscopy and polarimetry, HWO will enable comparative planetology of cool gas giants orbiting both solar-type and M-dwarf stars, bridging the observational gap between hot exoplanets and Solar System giants. We present observational requirements and survey strategies necessary to uncover correlations between atmospheric properties and planetary or stellar parameters. This effort will establish critical constraints on planetary formation, cloud microphysics, and the role of photochemistry under diverse irradiation conditions. The unique capabilities of HWO will make it the first facility capable of characterizing true exo-Jupiters in reflected light, thus offering an unprecedented opportunity to place the Solar System in a broader galactic context. △ Less

Submitted 15 December, 2025; originally announced December 2025.

Comments: Habitable Worlds Observatory (HWO) Science Case Development Document (SCDD), presented at the "Towards the Habitable Worlds Observatory: Visionary Science and Transformational Technology" conference in July 2025, and to be published in the conference proceedings

Transitional Dynamics: Unveiling the Coexistence and Interplay of Type-B and Type-C QPOs in MAXI J1348-630

Authors: Xinlei Wang, Zhen Yan, Fu-Guo Xie, Jun-Feng Wang, Ya-Xing Li, Ren-Yi Ma

Abstract: Based on broadband timing analysis of Insight-HXMT and NICER data from the 2019 outburst of the black hole X-ray binary (BHXRB) MAXI J1348-630, we report the detection of the coexistence and competitive interplay between type-C and type-B quasi-periodic oscillations (QPOs). Specifically, the two QPO types were detected simultaneously but exhibited distinct energy dependencies: the type-C QPO was d… ▽ More Based on broadband timing analysis of Insight-HXMT and NICER data from the 2019 outburst of the black hole X-ray binary (BHXRB) MAXI J1348-630, we report the detection of the coexistence and competitive interplay between type-C and type-B quasi-periodic oscillations (QPOs). Specifically, the two QPO types were detected simultaneously but exhibited distinct energy dependencies: the type-C QPO was dominant in the hard X-ray band (10-30 keV), while the type-B QPO was more prominent in the soft X-ray band (1-10 keV). Further analysis reveals that the emergence of the type-C QPO suppresses the strength of the type-B QPO, particularly above 10 keV. Tracking the detailed evolution of these QPOs, we find that the weakening of the type-B QPO coincides with the strengthening of the type-C QPO, indicating a competitive interaction between them. These findings reveal a more complex relationship between type-B and type-C QPOs than previously recognized, suggesting they originate from distinct but interacting physical components within the accretion flow and/or jet, and providing new insights into the dynamics of accretion state transitions. △ Less

Submitted 15 December, 2025; originally announced December 2025.

Comments: 10 pages, 5 figures, Accepted for publication in The Astrophysical Journal

Kinematics of H I and O VI Absorbers: Insights into the Turbulence Driver of the Multiphase Circumgalactic Medium

Authors: Zhijie Qu, Hsiao-Wen Chen, Eliana Schiller, Jing Wang, Max Gronke

Abstract: We investigate large-scale gas kinematics in the multiphase circumgalactic medium (CGM) using the observed correlation between line width and column density for H I and O VI absorbers. Leveraging extensive public galaxy survey data at $z\lesssim0.1$, we construct a new galaxy sample based on the availability of background QSOs with far-ultraviolet spectra from the Far Ultraviolet Spectroscopic Exp… ▽ More We investigate large-scale gas kinematics in the multiphase circumgalactic medium (CGM) using the observed correlation between line width and column density for H I and O VI absorbers. Leveraging extensive public galaxy survey data at $z\lesssim0.1$, we construct a new galaxy sample based on the availability of background QSOs with far-ultraviolet spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE). By combining this FUSE-galaxy sample with literature collections, we find that H I absorbers exhibit a clear inverse correlation between Doppler width and column density over nearly five orders of magnitude in $N_{\rm HI}$, from $N_{\rm HI} \approx 10^{13}\rm~{cm^{-2}}$ to $N_{\rm HI} \approx 10^{18}\rm~{cm^{-2}}$, while O VI absorption follows a positive correlation across $N_{\rm OVI}\approx 3\times10^{13}$-$10^{15}\rm~{cm^{-2}}$. We develop a model framework to interpret these contrasting trends and show that H I absorbers are best described as systems of approximately constant total column density ($N_{\rm H}$), whereas O VI traces regions of roughly constant spatial density ($n_{\rm H}$ and $n_{\rm OVI}$). Under the latter scenario, the observed $b_{\rm OVI}$-$N_{\rm OVI}$ relation maps directly to a velocity-size relation consistent with a Kolmogorov-like turbulent spectrum. Together, these findings reveal a coherent physical picture in which H I and O VI trace a continuous turbulent cascade spanning more than five orders of magnitude in spatial scale-from cool, photoionized clumps to warm, highly ionized halo gas--with accretion in the halo outskirts likely driving the turbulent energy injection that sustains the multiphase CGM. △ Less

Submitted 14 December, 2025; originally announced December 2025.

Comments: 13 pages, 5 figures, 3 Tables. Submitted to AAS journals

Measurement of the cosmic ray nickel energy spectrum from 10 GeV/n to 2 TeV/n with the DAMPE

Authors: F. Alemanno, Q. An, P. Azzarello, F. C. T. Barbato, P. Bernardini, X. J. Bi, H. V. Boutin, I. Cagnoli, M. S. Cai, E. Casilli, J. Chang, D. Y. Chen, J. L. Chen, Z. F. Chen, Z. X. Chen, P. Coppin, M. Y. Cui, T. S. Cui, I. De Mitri, F. de Palma, A. Di Giovanni, T. K. Dong, Z. X. Dong, G. Donvito, J. L. Duan , et al. (123 additional authors not shown)

Abstract: Nickel, one of the most stable elements alongside iron, is the most abundant heavy element beyond iron in cosmic rays. With DAMPE's excellent charge resolution and broad energy range, a high-precision energy spectrum provides valuable insights into the acceleration sources of heavy nuclei and their propagation through the interstellar medium. In this analysis, we report the direct measurement of c… ▽ More Nickel, one of the most stable elements alongside iron, is the most abundant heavy element beyond iron in cosmic rays. With DAMPE's excellent charge resolution and broad energy range, a high-precision energy spectrum provides valuable insights into the acceleration sources of heavy nuclei and their propagation through the interstellar medium. In this analysis, we report the direct measurement of cosmic-ray nickel spectrum from 10 GeV/n to 2 TeV/n with nine years of flight data. The nickel spectrum is consistent with a single power law with spectral index -2.60 +/- 0.03 from 40 GeV/n to 1 TeV/n. This work provides an accurate measurement of differential flux of nickel with kinetic energy extending to TeV/n for the first time. △ Less

Submitted 12 December, 2025; originally announced December 2025.

Observational evidence of tidal torque in the primordial Universe

Authors: Ming-Jie Sheng, Hao-Ran Yu, Min Bao, Bing-Hang Chen, Fang-Na Shao, Qi Guo, Yanmei Chen, Huiyuan Wang, Ue-Li Pen, Jie Wang, Xiaohu Yang

Abstract: Tidal torque theory (TTT) predicts that galaxy angular momenta are imprinted by the early tidal field acting on their proto-structures, which are preserved through cosmic evolution and provide the potentially most precise measurement of the early universe. We test this prediction using the gas component of central massive elliptical galaxies, whose angular momenta respond sensitively to external t… ▽ More Tidal torque theory (TTT) predicts that galaxy angular momenta are imprinted by the early tidal field acting on their proto-structures, which are preserved through cosmic evolution and provide the potentially most precise measurement of the early universe. We test this prediction using the gas component of central massive elliptical galaxies, whose angular momenta respond sensitively to external torques. By comparing the observed gas angular momentum vectors with those predicted from the primordial density field reconstructed by ELUCID for the nearby universe, we conclusively detect a strong direction correlation with a significance of about $7σ$. These results provide the first robust observational confirmation of TTT and open a new window for cosmological measurements of neutrino mass and other cosmological parameters. △ Less

Submitted 12 December, 2025; originally announced December 2025.

Comments: 22 pages, 4 figures, comments welcome

Kennicutt-Schmidt relation of galaxies over 13 billion years in the COLIBRE hydrodynamical simulations

Authors: Claudia del P. Lagos, Joop Schaye, Matthieu Schaller, Danail Obreschkow, Yannick M. Bahe, Alejandro Benitez-Llambay, Evgenii Chaikin, Camila Correa, Timothy A. Davis, Carlos S. Frenk, Filip Husko, Melanie Kaasinen, Robert J. McGibbon, Kyle Oman, Sylvia Ploeckinger, Alexander J. Richings, James W. Trayford, Jing Wang, Ruby J. Wright

Abstract: We investigate the correlation between star formation rate (SFR) surface density and gas surface density (known as the Kennicutt-Schmidt, KS, relation) at kiloparsec (kpc) scales across cosmic time ($0\le z \le 8$) using the COLIBRE state-of-the-art cosmological hydrodynamical simulations. These simulations feature on-the-fly non-equilibrium chemistry coupled to dust grain evolution and detailed r… ▽ More We investigate the correlation between star formation rate (SFR) surface density and gas surface density (known as the Kennicutt-Schmidt, KS, relation) at kiloparsec (kpc) scales across cosmic time ($0\le z \le 8$) using the COLIBRE state-of-the-art cosmological hydrodynamical simulations. These simulations feature on-the-fly non-equilibrium chemistry coupled to dust grain evolution and detailed radiative cooling down to $\approx 10$~K, enabling direct predictions for the atomic (HI) and molecular (H$_2$) KS relations. At $z\approx 0$, COLIBRE reproduces the observed (spatially-resolved) KS relations for HI and H$_2$, including the associated scatter, which we predict to be significantly correlated with stellar surface density, local specific SFR (sSFR), and gas metallicity. We show that the HI KS relation steepens for lower-mass galaxies, while the H$_2$ KS relation shifts to higher normalisation in galaxies with higher sSFRs. The H$_2$ depletion time decreases by a factor of $\approx 20$ from $z = 0$ to $z = 8$, primarily due to the decreasing gas-phase metallicity. This results in less H$_2$ and more HI being associated with a given SFR at higher redshift. We also find that galaxies with higher sSFRs have a larger molecular gas content and higher star formation efficiency per unit gas mass on kpc scales. The predicted evolution of the H$_2$ depletion time and its correlation with a galaxy's sSFR agree remarkably well with observations in a wide redshift range, $0\le z\le 5$. △ Less

Submitted 12 December, 2025; originally announced December 2025.

Comments: 27 pages; 19 main body of the paper. Submitted to MNRAS. Comments are welcome!

Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. XV. Reverberation Mapping of Mg II Emission Lines

Authors: Hua-Rui Bai, Pu Du, Chen Hu, Yong-Jie Chen, Zhu-Heng Yao, Yan-Rong Li, Yi-Xin Fu, Yi-Lin Wang, Yu Zhao, Hao Zhang, Jun-Rong Liu, Sen Yang, Yue-Chang Peng, Feng-Na Fang, Yu-Yang Songsheng, Ming Xiao, Shuo Zhai, Sha-Sha Li, Kai-Xing Lu, Zhi-Xiang Zhang, Dong-Wei Bao, Wei-Jian Guo, Jia-Qi Feng, Yi-Peng Zhao, Jesús Aceituno , et al. (3 additional authors not shown)

Abstract: As the 15th paper in a series reporting on a large reverberation mapping (RM) campaign of super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs), we present the results of measurements of the Mg II lines in 18 SEAMBHs monitored spectroscopically from 2017 to 2024. Among these, the time lags of Mg II have been successfully determined for 8 of the 18 objects, thereb… ▽ More As the 15th paper in a series reporting on a large reverberation mapping (RM) campaign of super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs), we present the results of measurements of the Mg II lines in 18 SEAMBHs monitored spectroscopically from 2017 to 2024. Among these, the time lags of Mg II have been successfully determined for 8 of the 18 objects, thereby expanding the current Mg II RM sample, particularly at higher accretion rates. By incorporating measurements of the line widths, we determine the masses of their central supermassive black holes. Based on these new measurements, we update the relation between the Mg II radius and the monochromatic luminosity at 3000 $\mathring{\mathrm{A}}$ ($R_{\rm MgII}-L_{3000}$ relation), yielding a slope of $0.24 \pm 0.03$, which is slightly shallower than, yet still consistent with, previously reported values. Similar to the H$β$ lines, the Mg II time lags in SEAMBHs are shorter than those of AGNs with normal accretion rates at comparable luminosities. The deviation of AGNs from the best-fit $R_{\rm MgII}-L_{3000}$ relation shows a strong correlation with the accretion rate, while no significant correlation is found between the deviation and the flux ratio of UV iron to Mg II. △ Less

Submitted 8 December, 2025; originally announced December 2025.

Comments: 40 pages, 16 figures, 5 tables, accepted for publication in the Astrophysical Journal Supplement Series

Back-End System of BURSTT

Authors: Kai-Yang Lin, Chih-Yi Wen, Homin Jiang, Jen-Hung Wang, Sujin Eie, Shih-Hao Wang, Yao-Huan Tseng, Hsien-Chun Tseng, Ue-Li Pen

Abstract: The Bustling Universe Radio Survey Telescope in Taiwan (BURSTT) is a new-generation wide-angle radio telescope specifically designed to survey Fast Radio Bursts (FRBs), energetic millisecond-duration pulses of unknown extragalactic origin. To realize its scientific potential, which includes detecting approximately 50 FRBs per year and sub-arcsecond localization capability, the system is designed t… ▽ More The Bustling Universe Radio Survey Telescope in Taiwan (BURSTT) is a new-generation wide-angle radio telescope specifically designed to survey Fast Radio Bursts (FRBs), energetic millisecond-duration pulses of unknown extragalactic origin. To realize its scientific potential, which includes detecting approximately 50 FRBs per year and sub-arcsecond localization capability, the system is designed to perform real-time beamforming and pulse search over the \SI{60}{\degree} $\times$ \SI{120}{\degree} field of view. This paper provides a detailed account of the design, implementation, and performance validation of the BURSTT back-end System. The system employs an efficient multi-stage processing architecture: initial beamforming is executed on the Xilinx ZCU216 RF System-on-Chip (RFSoC) platform; data is then transferred to Intel Xeon servers, where AVX-512 and AMX instruction sets are utilized for the second stage of beamforming and channelization, achieving high computational efficiency to ensure real-time capability. A highly optimized \texttt{bonsai} de-dispersion algorithm performs a real-time pulse search and triggering across 256 beams, which, upon detection, issues commands to the distributed outrigger system to save voltage data for very-long baseline interferometry (VLBI) precise localization. System performance has been validated through beamforming tests using bright radio sources and real-time detection of known pulsars, confirming the high fidelity of the signal processing pipeline. △ Less

Submitted 8 December, 2025; originally announced December 2025.

Comments: submitted to PASP

FEASTS Compared with Simulations: Abnormally Irregular and Extended HI Morphologies at a Column Density of $10^{18}\,\text{cm}^{-2}$ in TNG50 and Auriga

Authors: Xuchen Lin, Jing Wang, Guinevere Kauffmann, Volker Springel, Rüdiger Pakmor

Abstract: With new atomic-hydrogen (HI) observations of FAST Extended Atlas of Selected Targets Survey (FEASTS), we present the first statistical comparison of HI morphology between observations and cosmological simulations, focusing on low-column density ($10^{18}\,\text{cm}^{-2}$) regions of Milky Way-like central galaxies. We select a 330-galaxy sample from IllustrisTNG50 (TNG50) matched to 33 FEASTS gal… ▽ More With new atomic-hydrogen (HI) observations of FAST Extended Atlas of Selected Targets Survey (FEASTS), we present the first statistical comparison of HI morphology between observations and cosmological simulations, focusing on low-column density ($10^{18}\,\text{cm}^{-2}$) regions of Milky Way-like central galaxies. We select a 330-galaxy sample from IllustrisTNG50 (TNG50) matched to 33 FEASTS galaxies by stellar and HI masses, and mock observe them to the FAST resolution and depth at corresponding inclinations and distances for a fair comparison. In contrast to FEASTS, abnormally irregular and extended morphology is found in more than one-third of TNG50 galaxies, especially those massive and HI poor. Stellar feedback is the property that most significantly correlates with the HI morphological deviation from observations, although these deviations mostly occur at a high stellar or black-hole mass. These results indicate that in TNG50, stellar feedback significantly influences the HI morphology at $10^{18}\,\text{cm}^{-2}$, while active galactic nucleus (AGN) feedback has not so direct a role as expected. With an additional sample from Auriga, we find that the magnetic field may help HI to be more regular in its morphology, while improving the mass resolution does not alleviate the discrepancy from observation. This study reveals the potential of constraining future simulations of galaxies by observing low-column density HI. △ Less

Submitted 8 December, 2025; originally announced December 2025.

Comments: 12 pages of main text, 2 pages of appendices, 15 pages in total; 11 figures plus one atlas figure set as the ancillary PDF file

Journal ref: ApJ (2026) TBD

An Ancient Brown Dwarf Transiting a Metal-Poor Thick Disk Star

Authors: Jéa Adams Redai, Vedant Chandra, Samuel W. Yee, Victoria DiTomasso, Sean Andrews, Karin Öberg, Rebecca Woody, David W. Latham, Allyson Bieryla, Samuel N. Quinn, David Charbonneau, Theron W. Carmichael, Chih-Chun Hsu, Noah Vowell, Jason J. Wang, Sebastian Zieba, Paul Benni, Karen A. Collins, David R. Ciardi, Julian van Eyken, William Fong, Michael B. Lund, Andrei M. Tatarnikov

Abstract: We report the discovery of TOI-7019b, the first transiting brown dwarf (BD) known to orbit a star that is part of the Milky Way's ancient thick disk, as defined chemically ([Fe/H] $= -0.79 \pm 0.05$ dex, [$α$/Fe] $= +0.26 \pm 0.05$ dex, [M/H] $= -0.59 \pm 0.06$ dex) and kinematically ($v_{\perp} \approx 150 \pm 1$ km s$^{-1}$). We estimate a system age $τ= 12 \pm 2$ Gyr by fitting the host star's… ▽ More We report the discovery of TOI-7019b, the first transiting brown dwarf (BD) known to orbit a star that is part of the Milky Way's ancient thick disk, as defined chemically ([Fe/H] $= -0.79 \pm 0.05$ dex, [$α$/Fe] $= +0.26 \pm 0.05$ dex, [M/H] $= -0.59 \pm 0.06$ dex) and kinematically ($v_{\perp} \approx 150 \pm 1$ km s$^{-1}$). We estimate a system age $τ= 12 \pm 2$ Gyr by fitting the host star's spectrum and spectral energy distribution to alpha-enhanced isochrones, and independently using the age-metallicity relation of the thick disk. This makes TOI-7019 by far the most metal-poor and ancient BD host known to date. We measure a BD mass of $61.3 \pm 2.1$ $M_{\rm J}$ and radius of $0.82 \pm 0.02$ $R_{\rm J}$ from a joint analysis of transit photometry and radial velocity measurements, along with an orbital period of $48.2592 \pm 0.0001$ days and an orbital eccentricity of $0.403 \pm 0.002$. The measured radius appears $12.3\% \pm 2.8\%$ larger than predicted relative to standard evolutionary models for old, metal-poor brown dwarfs, hinting at missing physics like the magnetic inhibition of convection. TOI-7019b lowers the probed metallicity regime for transiting BDs by over a factor of two, making it a benchmark system to test evolutionary models in the low-metallicity regime. Future measurements of TOI-7019b's atmosphere will test whether a brown dwarf's atmospheric composition tracks its host star's abundances, as expected for binary-like co-formation. △ Less

Submitted 5 December, 2025; originally announced December 2025.

Comments: Submitted to ApJL

Revealing the accelerating wind in the inner region of the colliding-wind binary WR 112

Authors: John D. Monnier, Yinuo Han, Michael F. Corcoran, Sanne Bloot, Joseph R. Callingham, William Danchi, Philip G. Edwards, Lincoln Greenhill, Kenji Hamaguchi, Matthew J. Hankins, Ryan Lau, Jon M. Miller, Anthony F. J. Moffat, Garreth Ruane, Christopher M. P. Russell, Anthony Soulain, Samaporn Tinyanont, Peter Tuthill, Jason J. Wang, Peredur M. Williams

Abstract: Colliding winds in massive binaries generate X-ray-bright shocks, synchrotron radio emission, and sometimes even dusty "pinwheel" spirals. We report the first X-ray detections of the dusty WC+O binary system WR 112 from Chandra and Swift, alongside 27 years of VLA/ATCA radio monitoring and new diffraction-limited Keck images. Because we view the nearly circular orbit almost edge-on, the colliding-… ▽ More Colliding winds in massive binaries generate X-ray-bright shocks, synchrotron radio emission, and sometimes even dusty "pinwheel" spirals. We report the first X-ray detections of the dusty WC+O binary system WR 112 from Chandra and Swift, alongside 27 years of VLA/ATCA radio monitoring and new diffraction-limited Keck images. Because we view the nearly circular orbit almost edge-on, the colliding-wind zone alternates between heavy Wolf-Rayet wind self-absorption and a near-transparent O-star wind foreground each 20-yr orbit, producing phase-locked radio and X-ray variability. This scenario leads to a prediction that the radio spectral index is flatter from a larger non-thermal contribution around the radio intensity maximum, which is indeed observed. Existing models that assume a single dust-expansion speed fail to reproduce the combined infrared geometry and radio light curve. Instead, we require an accelerating post-shock flow that climbs from near-stationary to ~1350 km/s in about one orbital cycle, naturally matching the infrared spiral from about 5" down to within 0.1", while also fitting the phase of the radio brightening. These kinematic constraints supply critical boundary conditions for future hydrodynamic simulations, which can link hot-plasma cooling, non-thermal radio emission, X-ray spectra, and dust formation in a self-consistent framework. WR 112 thus joins WR 140, WR 104, and WR 70-16 (Apep) as a benchmark system for testing colliding-wind physics under an increasingly diverse range of orbital architectures and physical conditions. △ Less

Submitted 5 December, 2025; originally announced December 2025.

Comments: 28 pages; 12 figures; 6 tables; Accepted Astronomical Journal (AJ)

Journal ref: Astronomical Journal (AJ) 170, 218 (2025)

First Statistical Detection of Cool Gas Outflows with JWST Towards Cosmic Dawn

Authors: Cheqiu Lyu, Haoran Yu, Enci Wang, Junxian Wang, Cheng Jia, Jie Song, Yangyao Chen, Jinyang Wang, Zeyu Chen, Chengyu Ma, Yifan Wang, Xu Kong

Abstract: Galactic-scale outflows are a crucial component of galaxy evolution, yet their properties in the early universe remain poorly constrained. We present the first statistical investigation of cool gas outflows in galaxies spanning a wide cosmic timeline from $z \approx 1$ to $z \approx 10$. Using thousands of public JWST/NIRSpec spectra, we employ a signal-to-noise weighted spectral stacking techniqu… ▽ More Galactic-scale outflows are a crucial component of galaxy evolution, yet their properties in the early universe remain poorly constrained. We present the first statistical investigation of cool gas outflows in galaxies spanning a wide cosmic timeline from $z \approx 1$ to $z \approx 10$. Using thousands of public JWST/NIRSpec spectra, we employ a signal-to-noise weighted spectral stacking technique on the \ion{Mg}{2} $λ\lambda2796, 2803$ absorption doublet. We robustly detect blueshifted \ion{Mg}{2} absorption in all stellar mass and redshift bins. The outflow equivalent width exhibits a strong, positive correlation with stellar mass ($M_*$) at all epochs, increasing from $\sim 1$~Å at $M_* \approx 10^9~\mathrm{M}_\odot$ to over $3$~Å at $M_* > 10^{10.5}~\mathrm{M}_\odot$. Our work provides the first statistical constraints on cool outflows in the low-mass ($M_* \lesssim 10^{9.5}~\mathrm{M}_\odot$), high-redshift ($z > 3$) regime, vital for constraining feedback in the numerous progenitors of typical present-day galaxies. Crucially, the scaling relation between outflow properties and stellar mass shows no significant evolution at $z > 3$. This suggests a persistent, unevolving feedback mechanism governing the baryon cycle in the early universe, placing strong constraints on models that invoke a fundamental change in feedback physics at Cosmic Dawn, such as the feedback-free starburst model. △ Less

Submitted 5 December, 2025; originally announced December 2025.

Comments: 16 pages, 6+2 figures, to be submitted

The MALATANG survey: star formation, dense gas, and AGN feedback in NGC 1068

Authors: Shuting Lin, Siyi Feng, Zhi-Yu Zhang, Chunyi Zhang, Qing-Hua Tan, Junzhi Wang, Yu Gao, Xue-Jian Jiang, Yang Gao, Xiao-Long Wang, Junfeng Wang, Jian-Fa Wang, Satoki Matsushita, Aeree Chung, Kotaro Kohno, Tosaki Tomoka, Thomas R. Greve

Abstract: We aim to investigate the interplay between dense molecular gas, star formation, and active galactic nucleus (AGN) feedback in the luminous infrared galaxy (LIRG) NGC 1068 at sub-kiloparsec scales. We present the HCN (4-3) and HCO$^+$ (4-3) maps of NGC 1068, obtained with JCMT as part of the Mapping the dense molecular gas in the strongest star-forming galaxies (MALATANG) project, and perform spat… ▽ More We aim to investigate the interplay between dense molecular gas, star formation, and active galactic nucleus (AGN) feedback in the luminous infrared galaxy (LIRG) NGC 1068 at sub-kiloparsec scales. We present the HCN (4-3) and HCO$^+$ (4-3) maps of NGC 1068, obtained with JCMT as part of the Mapping the dense molecular gas in the strongest star-forming galaxies (MALATANG) project, and perform spatially resolved analyses of their correlations with infrared luminosity and soft X-ray emission. Spatially resolved relations between the luminosities of infrared dust emission and dense molecular gas tracers ($L_{\rm IR}-L'_{\rm dense}$) are found to be nearly linear, without clear evidence of excess contributions from AGN activity. The spatially resolved X-ray emission ($L^{\rm gas}_{0.5-2\,\mathrm{keV}}$) displays a radially-dependent twofold correlation with the star formation rate (SFR), suggesting distinct gas-heating mechanisms between the galaxy center and the outer regions. A super-linear scaling is obtained in galactic center regions with SFR surface density ($Σ_{\rm SFR}$) $>$ 8.2 $\times$ 10$^{-6}$ $M_\odot$ yr$^{-1}$ kpc$^{-2}$: log($L^{\rm gas}_{0.5-2\,\mathrm{keV}}$/erg s$^{-1}$) = 2.2 log(SFR/$M_\odot$ yr$^{-1}$) + 39.1. We further found a statistically significant super-linear correlation ($β= 1.34$ $\pm$ 0.86) between $L^{\rm gas}_{0.5-2\,\mathrm{keV}}$/SFR and HCN(4-3)/CO(1-0) intensity ratio, whereas no such trend is seen for HCO$^+$(4-3)/CO(1-0) or CO(3-2)/CO(1-0). These findings indicate that AGN feedback does not dominate star formation regulation on sub-kiloparsec scales, and that the excitation of dense gas traced by HCN (4-3) may be more directly influenced by high-energy feedback processes compared to HCO$^+$ (4-3) and CO (3-2). △ Less

Submitted 4 December, 2025; originally announced December 2025.

Comments: 12 pages, 7 figures. Accepted for publication in A&A

Transition from Outside-in to Inside-Out at $z\sim 2$: Evidence from Radial Profiles of Specific Star Formation Rate based on JWST/HST

Authors: Jie Song, Enci Wang, Cheng Jia, Cheqiu Lyu, Yangyao Chen, Jinyang Wang, Fujia Li, Weiyu Ding, Guanwen Fang, Xu Kong

Abstract: By combining high-resolution observations from JWST and HST, we have measured the stellar masses, star formation rates (SFRs), and multi-wavelength morphologies of galaxies in the CANDELS fields. Furthermore, based on rest-frame 1 $μ$m morphologies, we have derived spatially resolved stellar mass and SFR surface density ($Σ_*$ and $Σ_{\rm SFR}$) profiles for 46,313 galaxies with reliable structura… ▽ More By combining high-resolution observations from JWST and HST, we have measured the stellar masses, star formation rates (SFRs), and multi-wavelength morphologies of galaxies in the CANDELS fields. Furthermore, based on rest-frame 1 $μ$m morphologies, we have derived spatially resolved stellar mass and SFR surface density ($Σ_*$ and $Σ_{\rm SFR}$) profiles for 46,313 galaxies with reliable structural measurements at $0<z<4$ and $\log(M_\ast /M_{\odot})>8$, and provide the corresponding catalogue. For star-forming galaxies (SFGs), our results show excellent consistency with previous studies in terms of the star formation main sequence and the size-mass relation, demonstrating the robustness of our stellar mass and SFR measurements. For spatially resolved profiles, we find that at higher redshifts ($z>2.5$), the median radial profile of $Σ_{\rm SFR}$ is nearly parallel to but slightly steeper than that of $Σ_*$. This results in mildly negative gradients in the specific SFR (sSFR) profiles across all stellar mass bins considered. These findings indicate that galaxies at $z>2.5$ cannot grow in size via only in-situ star formation, challenging the understanding of galaxy size evolution beyond the cosmic noon. In contrast, at $z<2.0$, the sSFR profiles transition to exhibit more and more positive gradients at lower redshifts, consistent with an inside-out growth scenario where star formation preferentially expands the galactic outskirts. △ Less

Submitted 1 December, 2025; originally announced December 2025.

Comments: submitted to ApJS, comments are welcomed

Spectroscopic and Decade-long Photometric Observations of the Contact Binary V2790 Ori: Evidence for a Brown Dwarf Companion and a Solar-like Magnetic Activity Cycle

Authors: Si-Rui Wang, Kai Li, Qi-Qi Xia, Dong-Yang Gao, Xiang Gao, Jing-Yi Wang, Ya-Ni Guo, Xing Gao, Guo-You Sun

Abstract: We present 22 sets of light curves and one radial velocity curve for the W UMa-type total eclipse contact binary system V2790 Ori, derived by combining all available public photometric data, the photometric data in previous studies, and our own spectroscopic and decade-long photometric observations. Our simultaneous analysis of the light curves and radial velocity curve shows that V2790 Ori is a W… ▽ More We present 22 sets of light curves and one radial velocity curve for the W UMa-type total eclipse contact binary system V2790 Ori, derived by combining all available public photometric data, the photometric data in previous studies, and our own spectroscopic and decade-long photometric observations. Our simultaneous analysis of the light curves and radial velocity curve shows that V2790 Ori is a W-subtype contact binary with a mass ratio of $q = 0.322(\pm0.001)$ and a shallow contact degree of $14.8(\pm0.6)\%$. The orbital period analysis based on 445 eclipsing minima reveals a secular decrease at a rate of $\dot P = -3.18 (\pm 0.75) \times 10^{-8}\mathrm{d~yr^{-1}}$, superimposed with a cyclic variation with an amplitude of $A = 8.98 (\pm 2.19) \times 10^{-4}~\mathrm{d}$ and a period of $ P_3 = 7.44 (\pm 0.52)~\mathrm{yr}$. The secular decrease is caused by AML via magnetic braking, while the cyclic period variation is explained by the light-travel time effect due to a third body, which is likely to be a brown dwarf. Furthermore, our analysis indicates a mass transfer from the more massive component to the less massive one at a rate of $1.22(\pm0.29) \times 10^{-8}~\mathrm{M_{\odot}~yr^{-1}}$. A model with a cool spot on each component was adopted to fit the O'Connell effect observed in the light curves. Since the O'Connell effect varies over time, we identified a solar-like magnetic activity cycle with a period of approximately 5.4 yr by analyzing the magnitude difference ($Δm$) at the two light maxima and the O'Connell effect ratio. In addition, evolutionary analysis suggests that V2790 Ori is a newly formed contact binary that evolved from a detached phase into the present contact configuration. △ Less

Submitted 1 December, 2025; originally announced December 2025.

Comments: 22 pages, 7 figures, 9 tables, accepted by ApJ

Resolving Interchange Reconnection Dynamics in a Fan-Spine-like Topology Observed by Solar Orbiter

Authors: Yadan Duan, Xiaoli Yan, Junchao Hong, Hechao Chen, Yuhang Gao, Zheng Sun, Zhenyong Hou, Jincheng Wang

Abstract: Interchange reconnection is believed to play a significant role in the production of solar jets and solar wind. However, the dynamics of interchange reconnection in the low corona might be more complex than recognized before in higher temporal and spatial resolutions. Using unprecedentedly high-resolution observations from the Extreme Ultraviolet Imager (EUI) onboard the Solar Orbiter, we analyze… ▽ More Interchange reconnection is believed to play a significant role in the production of solar jets and solar wind. However, the dynamics of interchange reconnection in the low corona might be more complex than recognized before in higher temporal and spatial resolutions. Using unprecedentedly high-resolution observations from the Extreme Ultraviolet Imager (EUI) onboard the Solar Orbiter, we analyze the dynamics of interchange reconnection in a small-scale fan-spine-like topology. Interchange reconnection that continuously occurs around the multi-null points of the fan-spine-like system exhibits a quasi-periodicity of ~200 s, nearly covering the entire evolution of this system. Continuous evolution and reversal of multiple current sheets are observed over time near the null point. These results reveal that the dynamics of interchange reconnection are likely modulated by the emerging magnetic structures, such as mini-filaments and emerging arcades. Moreover, a curtain-like feature with a width of 1.7 Mm is also observed near the interchange reconnection region and persistently generates outflows, which is similar to the separatrix curtain reported in the pseudo-streamer structure. This study not only demonstrates the complex and variable reconnection dynamics of interchange reconnection within small-scale fan-spine topology but also provides insights into the self-similarity of magnetic field configurations across multiple temporal and spatial scales. △ Less

Submitted 11 December, 2025; v1 submitted 30 November, 2025; originally announced December 2025.

Comments: 11 pages, 7 figures, Accepted for publication in A&A

A robust empirical relationship between speed and turbulence energy in the near-Earth solar wind

Authors: Rohit Chhiber, Yanwen Wang, Jiaming Wang, Sohom Roy

Abstract: The connection between turbulence and solar-wind acceleration, long known in space physics, is further developed in this Letter by establishing a robust empirical law that relates the bulk-flow speed to the magnetohydrodynamic-scale fluctuation energy in the plasma. The model is based on analysis of twenty-five years of near-Earth observations by NASA's Advanced Composition Explorer. It provides a… ▽ More The connection between turbulence and solar-wind acceleration, long known in space physics, is further developed in this Letter by establishing a robust empirical law that relates the bulk-flow speed to the magnetohydrodynamic-scale fluctuation energy in the plasma. The model is based on analysis of twenty-five years of near-Earth observations by NASA's Advanced Composition Explorer. It provides a simple way to estimate turbulence energy from low-resolution speed data -- a practical approach that may be of utility when high-resolution measurements or advanced turbulence models are unavailable. Potential heliospheric applications include space-weather forecasting operations, remote imaging datasets, and energetic-particle transport models that require turbulence amplitudes to specify diffusion parameters. △ Less

Submitted 30 November, 2025; originally announced December 2025.

Investigating the Impacts of AGN Activities on Dwarf Galaxies with FAST HI Observations

Authors: Hong-Ying Chen, Chao-Wei Tsai, Pei Zuo, Niankun Yu, Jialai Wang, Kai Zhang, Guodong Li, Yogesh Chandola, Zheng Zheng, Jingwen Wu, Di Li, Lulu Bao

Abstract: We present the results of Hi line observations towards 26 Active Galactic Nuclei (AGN)-hosting and one star-forming dwarf galaxies (Mstar < 10^9.5 Msun) with the 19-beam spectral line receiver of FAST at 1.4 GHz. Our FAST observed targets are combined with other AGN-hosting dwarf galaxies covered in the ALFALFA footprint to form a more comprehensive sample. Utilizing the information from optical s… ▽ More We present the results of Hi line observations towards 26 Active Galactic Nuclei (AGN)-hosting and one star-forming dwarf galaxies (Mstar < 10^9.5 Msun) with the 19-beam spectral line receiver of FAST at 1.4 GHz. Our FAST observed targets are combined with other AGN-hosting dwarf galaxies covered in the ALFALFA footprint to form a more comprehensive sample. Utilizing the information from optical surveys, we further divide them into isolated and accompanied subsamples by their vicinity of nearby massive galaxies. We compare the Hi gas abundance and star-forming rate (SFR) between the subsamples to assess the role of internal and external processes that may regulate the gas content in dwarf galaxies. As a result, we find that AGN are more commonly identified in accompanied dwarf galaxies than in their isolated counterparts. Meanwhile, AGN-hosting dwarf galaxies have slightly but significant lower Hi mass fraction relatively to the non-AGN control sample in accompanied dwarf galaxies. On the other hand, we find a decreasing SFR in AGN-hosting dwarf galaxies towards denser environments, as well as an extremely low incidence of quenched isolated dwarfs within both AGN and non-AGN subsamples. These results indicate that although these AGN could potentially regulate the gas reservoir of dwarf galaxies, environmental effects are likely the dominant quenching mechanism in the low-mass universe. △ Less

Submitted 28 November, 2025; originally announced November 2025.

Comments: 24 pages, 6 figures

Journal ref: Monthly Notices of the Royal Astronomical Society, Volume 544, Issue 3, pp. 2713-2736 (2025)

The Solar Close Observations and Proximity Experiments (SCOPE) mission

Authors: Jun Lin, Jing Feng, Zhenhua Ge, Jiang Tian, Yuhao Chen, Xin Cheng, Hui Tian, Jiansen He, Alexei Pevtsov, Haisheng Ji, Shangbin Yang, Parida Hashim, Bin Zhou, Yiteng Zhang, Shenyi Zhang, Xi Lu, Yuan Yuan, Liu Liu, Haoyu Wang, Hu Jiang, Lei Deng, Xingjian Shi, Lin Ma, Jingxing Wang, Shanjie Huang , et al. (9 additional authors not shown)

Abstract: The Solar Close Observations and Proximity Experiments (SCOPE) mission will send a spacecraft into the solar atmosphere at a low altitude of just 5 R_sun from the solar center. It aims to elucidate the mechanisms behind solar eruptions and coronal heating, and to directly measure the coronal magnetic field. The mission will perform in situ measurements of the current sheet between coronal mass eje… ▽ More The Solar Close Observations and Proximity Experiments (SCOPE) mission will send a spacecraft into the solar atmosphere at a low altitude of just 5 R_sun from the solar center. It aims to elucidate the mechanisms behind solar eruptions and coronal heating, and to directly measure the coronal magnetic field. The mission will perform in situ measurements of the current sheet between coronal mass ejections and their associated solar flares, and energetic particles produced by either reconnection or fast-mode shocks driven by coronal mass ejections. This will help to resolve the nature of reconnections in current sheets, and energetic particle acceleration regions. To investigate coronal heating, the mission will observe nano-flares on scales smaller than 70 km in the solar corona and regions smaller than 40 km in the photosphere, where magnetohydrodynamic waves originate. To study solar wind acceleration mechanisms, the mission will also track the process of ion charge-state freezing in the solar wind. A key achievement will be the observation of the coronal magnetic field at unprecedented proximity to the solar photosphere. The polar regions will also be observed at close range, and the inner edge of the solar system dust disk may be identified for the first time. This work presents the detailed background, science, and mission concept of SCOPE and discusses how we aim to address the questions mentioned above. △ Less

Submitted 27 November, 2025; originally announced November 2025.

Comments: 27 pages, 15 figures

Journal ref: Astronomical Techniques and Instruments, 2(3), 2025

The First Scientific Flight and Observations of the 50-mm Balloon-Borne White-Light Coronagraph

Authors: Kaifeng Kang, Min Huang, Yang Liu, Jun Lin, Tengfei Song, Xuefei Zhang, Dayang Liu, Tao Zhang, Yan Li, Jingxing Wang, Mingzhe Sun, Mingyu Zhao, Guangqian Liu, Xianyong Bai, Lidong Xia, Yu Liu

Abstract: A 50-mm balloon-borne white-light coronagraph (BBWLC) to observe whitelight solar corona over the altitude range from 1.08 to 1.50 solar radii has recently been indigenously developed by Yunnan Observatories in collaboration with Shangdong University (in Weihai) and Changchun Institute of Optics, Fine Mechanics and Physics, which will significantly improve the ability of China to detect and measur… ▽ More A 50-mm balloon-borne white-light coronagraph (BBWLC) to observe whitelight solar corona over the altitude range from 1.08 to 1.50 solar radii has recently been indigenously developed by Yunnan Observatories in collaboration with Shangdong University (in Weihai) and Changchun Institute of Optics, Fine Mechanics and Physics, which will significantly improve the ability of China to detect and measure inner corona. On 2022 October 4, its first scientific flight took place at the Dachaidan area in Qinghai province of China. We describe briefly the BBWLC mission including its optical design, mechanical structure, pointing system, the first flight and results associated with the data processing approach. Preliminary analysis of the data shows that BBWLC imaged the Kcorona with three streamer structures on the west limb of the Sun. To further confirm the coronal signals obtained by BBWLC, comparisonswere made with observations of the Kcoronagraph of the High Altitude Observatory and the Atmospheric ImagingAssembly on board the Solar Dynamics Observatory. We conclude that BBWLC eventually observed the white-light corona in its first scientific flight. △ Less

Submitted 27 November, 2025; originally announced November 2025.

Comments: 17 pages, 10 figures,

The Faintest, Extremely Variable X-ray Tidal Disruption Event from a Supermassive Black Hole Binary?

Authors: Mengqiu Huang, Yongquan Xue, Shuo Li, Fukun Liu, Shifu Zhu, Jin-Hong Chen, Rong-Feng Shen, Yibo Wang, Yi Yang, Ning Jiang, Franz Erik Bauer, Cristian Vignali, Fan Zou, Jialai Wang, Alexei V. Filippenko, Bin Luo, Chen Qin, Jonathan Quirola-Vásquez, Jun-Xian Wang, Lulu Fan, Mouyuan Sun, Qingwen Wu, Qingling Ni, Thomas G. Brink, Tinggui Wang , et al. (8 additional authors not shown)

Abstract: Tidal disruption events (TDEs), which occur when stars enter the tidal radii of supermassive black holes (SMBHs) and are subsequently torn apart by their tidal forces, represent intriguing phenomena that stimulate growing research interest and pose an increasing number of puzzles in the era of time-domain astronomy. Here we report an unusual X-ray transient, XID 935, discovered in the 7 Ms Chandra… ▽ More Tidal disruption events (TDEs), which occur when stars enter the tidal radii of supermassive black holes (SMBHs) and are subsequently torn apart by their tidal forces, represent intriguing phenomena that stimulate growing research interest and pose an increasing number of puzzles in the era of time-domain astronomy. Here we report an unusual X-ray transient, XID 935, discovered in the 7 Ms Chandra Deep Field-South, the deepest X-ray survey ever. XID 935 experienced an overall X-ray dimming by a factor of more than 40 between 1999 and 2016. Not monotonically decreasing during this period, its X-ray luminosity increased by a factor $> 27$ within 2 months, from $L_{\rm 0.5-7\ keV}<10^{40.87}$ erg s$^{-1}$ (10 October 2014 -- 4 January 2015) to $L_{\rm 0.5-7\ keV}=10^{42.31\pm 0.20}$ erg s$^{-1}$ (16 March 2015). The X-ray position of XID 935 is located at the center of its host galaxy with a spectroscopic redshift of 0.251, whose optical spectra do not display emission characteristics associated with an active galactic nucleus. The peak 0.5--2.0 keV flux is the faintest among all the X-ray-selected TDE candidates to date. Thanks to a total exposure of $\sim 9.5$ Ms in the X-ray bands, we manage to secure relatively well-sampled, 20-year-long X-ray light curves of this deepest X-ray-selected TDE candidate. We find that a partial TDE model could not explain the main declining trend. An SMBH binary TDE model is in acceptable accordance with the light curves of XID 935; however, it fails to match short-timescale fluctuations exactly. Therefore, the exceptional observational features of XID 935 provide a key benchmark for refining quantitative TDE models and simulations. △ Less

Submitted 26 November, 2025; originally announced November 2025.

Comments: 31 pages, 6 figures, 1 table, accepted by The Innovation

Journal ref: The Innovation 7(3), 101169 (2026)

Exomoon search with VLTI/GRAVITY around the substellar companion HD 206893 B

Authors: Q. Kral, J. Wang, J. Kammerer, S. Lacour, M. Malin, T. Winterhalder, B. Charnay, C. Perrot, P. Huet, R. Abuter, A. Amorim, W. O. Balmer, M. Benisty, J. -P. Berger, H. Beust, S. Blunt, A. Boccaletti, M. Bonnefoy, H. Bonnet, M. S. Bordoni, G. Bourdarot, W. Brandner, F. Cantalloube, P. Caselli, G. Chauvin , et al. (108 additional authors not shown)

Abstract: Direct astrometric detection of exomoons remains unexplored. This study presents the first application of high-precision astrometry to search for exomoons around substellar companions. We investigate whether the orbital motion of the companion HD 206893 B exhibits astrometric residuals consistent with the gravitational influence of an exomoon or binary planet. Using the VLTI/GRAVITY instrument, we… ▽ More Direct astrometric detection of exomoons remains unexplored. This study presents the first application of high-precision astrometry to search for exomoons around substellar companions. We investigate whether the orbital motion of the companion HD 206893 B exhibits astrometric residuals consistent with the gravitational influence of an exomoon or binary planet. Using the VLTI/GRAVITY instrument, we monitored the astrometric positions of HD 206893 B and c across both short (days to months) and long (yearly) timescales. This enabled us to isolate potential residual wobbles in the motion of component B attributable to an orbiting moon. Our analysis reveals tentative astrometric residuals in the HD 206893 B orbit. If interpreted as an exomoon signature, these residuals correspond to a candidate (HD 206893 B I) with an orbital period of approximately 0.76 years and a mass of $\sim$0.4 Jupiter masses. However, the origin of these residuals remains ambiguous and could be due to systematics. Complementing the astrometry, our analysis of GRAVITY $R=4000$ spectroscopy for HD 206893 B confirms a clear detection of water, but no CO is found using cross-correlation. We also find that AF Lep b, and $β$ Pic b are the best short-term candidates to look for moons with GRAVITY+. Our observations demonstrate the transformative potential of high-precision astrometry in the search for exomoons, and proves the feasibility of the technique to detect moons with masses lower than Jupiter and potentially down to less than Neptune in optimistic cases. Crucially, further high-precision astrometric observations with VLTI/GRAVITY are essential to verify the reality and nature of this signal and attempt this technique on a variety of planetary systems. △ Less

Submitted 25 November, 2025; originally announced November 2025.

Comments: accepted for publication in A&A

Search for planetary-mass ultra-compact binaries using data from the first part of the LIGO--Virgo--KAGRA fourth observing run

Authors: The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration, A. G. Abac, I. Abouelfettouh, F. Acernese, K. Ackley, C. Adamcewicz, S. Adhicary, D. Adhikari, N. Adhikari, R. X. Adhikari, V. K. Adkins, S. Afroz, A. Agapito, D. Agarwal, M. Agathos, N. Aggarwal, S. Aggarwal, O. D. Aguiar, I. -L. Ahrend, L. Aiello, A. Ain, P. Ajith, T. Akutsu , et al. (1743 additional authors not shown)

Abstract: We present a search for gravitational waves from inspiraling, planetary-mass ultra-compact binaries using data from the first part of the fourth observing run of LIGO, Virgo and KAGRA. Finding no evidence of such systems, we determine the maximum distance reach for such objects and their merger rate densities, independently of how they could have formed. Then, we identify classes of primordial bla… ▽ More We present a search for gravitational waves from inspiraling, planetary-mass ultra-compact binaries using data from the first part of the fourth observing run of LIGO, Virgo and KAGRA. Finding no evidence of such systems, we determine the maximum distance reach for such objects and their merger rate densities, independently of how they could have formed. Then, we identify classes of primordial black-hole mass distributions for which these rate limits can be translated into relevant constraints on the mass distribution of primordial black holes, assuming that they compose all of dark matter, in the mass range $[10^{-6},10^{-3}]M_\odot$. Our constraints are consistent with existing microlensing results in the planetary-mass range, and provide a complementary probe to sub-solar mass objects. △ Less

Submitted 5 December, 2025; v1 submitted 24 November, 2025; originally announced November 2025.

Comments: 6 pages (main) + 7 pages (appendix) + refs; 8 figures

Report number: P2500248

Chemical and Isotopic Homogeneity Between the L Dwarf CD-35 2722 B and its Early M Host Star

Authors: Gavin Wang, Jerry Xuan, Darío Picos, Zhoujian Zhang, Yapeng Zhang, Dimitri Mawet, Chih-Chun Hsu, Jason Wang, Geoffrey Blake, Jean-Baptiste Ruffio, Katelyn Horstman, Ben Sappey, Yinzi Xin, Luke Finnerty, Daniel Echeverri, Nemanja Jovanovic, Ashley Baker, Randy Bartos, Benjamin Calvin, Sylvain Cetre, Jacques-Robert Delorme, Greg Doppmann, Michael Fitzgerald, Joshua Liberman, Ronald López , et al. (7 additional authors not shown)

Abstract: CD-35 2722 B is an L dwarf companion to the nearby, $\sim 50-200$ Myr old M1 dwarf CD-35 2722 A. We present a detailed analysis of both objects using high-resolution ($R \sim 35,000$) $K$ band spectroscopy from the Keck Planet Imager and Characterizer (KPIC) combined with archival photometry. With a mass of $30^{+5}_{-4} M_{\mathrm{Jup}}$ (planet-to-host mass ratio 0.05) and projected separation o… ▽ More CD-35 2722 B is an L dwarf companion to the nearby, $\sim 50-200$ Myr old M1 dwarf CD-35 2722 A. We present a detailed analysis of both objects using high-resolution ($R \sim 35,000$) $K$ band spectroscopy from the Keck Planet Imager and Characterizer (KPIC) combined with archival photometry. With a mass of $30^{+5}_{-4} M_{\mathrm{Jup}}$ (planet-to-host mass ratio 0.05) and projected separation of $67\pm4$ AU from its host, CD-35 2722 B likely formed via gravitational instability. We explore whether the chemical composition of the system tells a similar story. Accounting for systematic uncertainties, we find $\mathrm{[M/H]}=-0.16^{+0.03}_{-0.02} \mathrm{(stat)} \pm 0.25 \mathrm{(sys)}$ dex and $^{12}\mathrm{C}/^{13}\mathrm{C}=132^{+20}_{-14}$ for the host, and $\mathrm{[M/H]}=0.27^{+0.07}_{-0.06} (\mathrm{stat}) \pm 0.12 (\mathrm{sys})$ dex, $^{12}\mathrm{CO}/^{13}\mathrm{CO}=159^{+33}_{-24} \mathrm{(stat)}^{+40}_{-33} \mathrm{(sys)}$, and $\mathrm{C/O} = 0.55 \pm 0.01 (\mathrm{stat}) \pm 0.04 (\mathrm{sys})$ for the companion. The chemical compositions for the brown dwarf and host star agree within the $1.5σ$ level, supporting a scenario where CD-35 2722 B formed via gravitational instability. We do not find evidence for clouds on CD-35 2722 B despite it being a photometrically red mid-L dwarf and thus expected to be quite cloudy. We retrieve a temperature structure which is more isothermal than models and investigate its impact on our measurements, finding that constraining the temperature structure to self-consistent models does not significantly impact our retrieved chemical properties. Our observations highlight the need for data from complementary wavelength ranges to verify the presence of aerosols in likely cloudy L dwarfs. △ Less

Submitted 24 November, 2025; originally announced November 2025.

Comments: 17 pages, 9 figures, 3 tables. Accepted to ApJ

GRB 240715A: Revealing Novel Intrinsic Mechanism by Different Individual Pulse

Authors: Wen-Jun Tan, Chen-Wei Wang, Shao-Lin Xiong, Shi-Jie Zheng, Jiang He, Xiao-Yun Zhao, Yue Huang, Shu-Xu Yi, Bing Li, He Gao, Bo-bing Wu, Bing Zhang, Frederic Daigne, Maria-Grazia Bernardini, Bin-Bin Zhang, Stephane Basa, Bertrand Cordier, Jin-Song Deng, Yong-Wei Dong, Damien Dornic, Olivier Godet, Xu-Hui Han, Mao-Hai Huang, Cyril Lachaud, Hua-Li Li , et al. (15 additional authors not shown)

Abstract: The Space-based multiband astronomical Variable Objects Monitor (SVOM), detected its first short gamma-ray burst, GRB 240715A, in-flight, which was jointly observed by Fermi. Based on observational data of SVOM/GRM and Fermi/GBM, we perform a comprehensive temporal and spectral analysis for individual pulse in the prompt emission of this burst, and novel characteristics are revealed. Firstly, oppo… ▽ More The Space-based multiband astronomical Variable Objects Monitor (SVOM), detected its first short gamma-ray burst, GRB 240715A, in-flight, which was jointly observed by Fermi. Based on observational data of SVOM/GRM and Fermi/GBM, we perform a comprehensive temporal and spectral analysis for individual pulse in the prompt emission of this burst, and novel characteristics are revealed. Firstly, opposite evolutions of spectral lag are found in the first and third pulse of this burst. Second, the large negative lag of the first pulse is an outlier in short GRB sample, especially when the pulse duration is considered. Spectral analysis shows that the negative lag of the first pulse is caused by the evolution of spectrum index, and is irrelevant to Epeak, which is inconsistent with the previous study. The intrinsic mechanism is probably attributed to electron cooling in the decaying magnetic field, which leads to the continuous hardening of the spectrum index and results in negative lag. Furthermore, spectral analysis also shows that the third pulse is more likely to be described by a quasi-thermal spectrum, indicating the existence of photospheric emission. It is difficult to explain how the synchrotron radiation appears before photospheric emission in a single GRB and some assumptions are discussed. △ Less

Submitted 23 November, 2025; originally announced November 2025.

Comments: 21 pages, 4 figures, accepted by The Astrophysical Journal Letters

Chemical evolution of bulges of active galactic nuclei in the early Universe: roles of accreting stars

Authors: Shuo Zhai, Jian-Min Wang, Yan-Rong Li, Wei-Jian Guo, Gang Zhao

Abstract: JWST/NIRCam observations reveal dense stellar cores in high-redshift galactic bulges, indicative of sustained star formation and potential stellar accretion. We introduce accretion-modified star (AMS) as a new component in the chemical evolution of high-redshift bulges hosting active galactic nuclei (AGNs). The gas-phase chemical evolution of bulge environments containing AMS is modeled within 1 G… ▽ More JWST/NIRCam observations reveal dense stellar cores in high-redshift galactic bulges, indicative of sustained star formation and potential stellar accretion. We introduce accretion-modified star (AMS) as a new component in the chemical evolution of high-redshift bulges hosting active galactic nuclei (AGNs). The gas-phase chemical evolution of bulge environments containing AMS is modeled within 1 Gyr by combining population evolution and galactic chemical evolution formalisms, and observational signatures are tracked via photoionization modeling on Baldwin-Phillips-Terlevich (BPT) diagrams. Sustained high accretion onto AMSs leads to rapid gas-phase metal enrichment of the bulge, producing abundance peaks up to five times solar metallicity within 0.1 Gyr and significantly modifying elemental ratios in the gas phase. Atypical gas-phase abundance patterns during early, high-accretion phases and gradually diminish as the accretion rate declines. In BPT diagrams, high-AMS-accretion scenarios shift the modeled emission-line sequence toward the local AGN branch and extend into the high-metallicity regime. Super-solar narrow-line regions observed in AGNs at z>15 may reflect such AMS-driven gas-phase enrichment of host bulge under extreme gas densities. While direct detection of AMSs within AGN bulges remains challenging, the model provides testable predictions for future spectroscopic surveys and motivates further exploration of non-canonical stellar populations in AGN host bulges. △ Less

Submitted 20 November, 2025; originally announced November 2025.

Comments: 19 pages, 11 figures, 1 table. Accepted for publication in ApJ

Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. IV. Broad Emission Line Evolution Sequence Among Hα, Mg II, and Hβ

Authors: Wei-Jian Guo, Victoria A. Fawcett, Małgorzata Siudek, Yan-Rong Li, Cheng Cheng, Swayamtrupta Panda, Zhiwei Pan, Shengxiu Sun, Claire L. Greenwell, David M. Alexander, John Moustakas, Shuo Zhai, Jun-Jie Jin, Huaqing Cheng, Jingwei Hu, Yong-Jie Chen, Zhi-Xiang Zhang, Jian-Min Wang

Abstract: From a parent catalog of 561 changing-look active galactic nuclei (CL-AGNs) identified by Guo et al. (2025), we investigate the evolutionary sequence of broad emission lines using a redshift-selected subset (0.35 < z < 0.45) of 54 CL-AGNs whose Dark Energy Spectroscopic Instrument (DESI) spectra simultaneously cover the Hα, H\b{eta}, and Mg II emission lines. To provide a baseline for comparison,… ▽ More From a parent catalog of 561 changing-look active galactic nuclei (CL-AGNs) identified by Guo et al. (2025), we investigate the evolutionary sequence of broad emission lines using a redshift-selected subset (0.35 < z < 0.45) of 54 CL-AGNs whose Dark Energy Spectroscopic Instrument (DESI) spectra simultaneously cover the Hα, H\b{eta}, and Mg II emission lines. To provide a baseline for comparison, we construct a control sample of 19,897 normal Type 1 AGNs within the same redshift range from the DESI Year 1 data. Through stacked spectral analysis and line-continuum luminosity correlations, we identify a clear evolutionary sequence in all AGN where broad H\b{eta} fades first, followed by Mg II, and then Hα, as the AGN luminosity declines - consistent with expectations from reverberation mapping. This trend reflects a radially stratified broad line region (BLR), where each line's responsivity depends on its ionization potential and radial distance from the central engine. In addition, we find that more massive supermassive black holes (SMBHs) require lower Eddington ratios to fully suppress broad emission lines, suggesting that the critical accretion threshold for the CL phenomenon is mass-dependent. Our results present the first statistical confirmation of a stratified broad line fading sequence in AGNs, reinforcing the central role of accretion state in shaping BLR structure and visibility. △ Less

Submitted 19 November, 2025; originally announced November 2025.

Comments: Accepted by APJ

Deep Andromeda JCMT-SCUBA2 Observations. The Submillimeter Maps and Giant Molecular Clouds

Authors: Sihan Jiao, Jingwen Wu, Hauyu Baobab Liu, Chao-Wei Tsai, Yuxin Lin, Di Li, Zhi-Yu Zhang, Yu Cheng, Linjing Feng, Henrik Beuther, Junzhi Wang, Lihwai Lin, Jakob den Brok, Ludan Zhang, Fengwei Xu, Fanyi Meng, Zongnan Li, Ryan P. Keenan, Si-Yue Yu, Niankun Yu, Zheng Zheng, Junhao Liu, Yuxiang Liu, Hao Ruan, Fangyuan Deng , et al. (1 additional authors not shown)

Abstract: We have carried out unprecedentedly deep, nearly confusion-limited JCMT-SCUBA2 mapping observations on the nearest spiral galaxy, M31 (Andromeda). The 850 $μ$m image with a $\sim$50 pc resolution yields a comprehensive catalog of 383 giant molecular clouds (GMCs) that are associated with the spiral arms. In addition, it unveiled a population of 189 compact inter-arm GMCs in M31, which are mostly u… ▽ More We have carried out unprecedentedly deep, nearly confusion-limited JCMT-SCUBA2 mapping observations on the nearest spiral galaxy, M31 (Andromeda). The 850 $μ$m image with a $\sim$50 pc resolution yields a comprehensive catalog of 383 giant molecular clouds (GMCs) that are associated with the spiral arms. In addition, it unveiled a population of 189 compact inter-arm GMCs in M31, which are mostly unresolved or marginally resolved. The masses of all these GMCs are in the range of 2$\times$10$^4$ -- 6$\times$10$^6$ $M_{\odot}$; the sizes are in the range of 30--130 pc. They follow a mass-size correlation, $M$ $\propto$ $R_{c}$$^{2.5}$. The inter-arm GMCs are systematically less massive, more diffuse, colder, and have lower star-forming efficiency (SFE) than on-arm GMCs. Moreover, within individual spatially resolved on-arm and off-arm M31 GMCs, the SFE is considerably lower than the SFE in molecular clouds in main sequence and green valley galaxies. Follow-up investigations on M31 GMCs may provide clues for how star formation may be quenched in galactic environments. Finally, we reconstrained the dust opacity spectral index $β$ in the M31 galaxy by combining our new JCMT observations with archival Herschel and Planck data and found that the radial variation of $β$ may not be as large as was proposed by previous studies. △ Less

Submitted 18 November, 2025; originally announced November 2025.

Comments: 24 pages, 14 figures. Accepted for publication in ApJS

Unveiling the Sources of X-ray Luminosity in DESI Galaxy Groups: Insights from the SRG/eROSITA All-Sky Survey

Authors: YunLiang Zheng, Xiaohu Yang, Teng Liu, Shijiang Chen, Esra Bulbul, Ang Liu, Yi Zhang, Dawei Li, Xi Kang, Yizhou Gu, Yirong Wang, Qingyang Li, Jiaqi Wang

Abstract: We use the first eROSITA all-sky survey (eRASS1) to investigate the contributions of AGN and extended gas to the total X-ray luminosity ($L_X$) of galaxy groups with different halo masses ($M_h$) at different redshifts. The presence of AGN in their central galaxies is identified using multi-wavelength catalogs, including the X-ray counterparts, the ASKAP radio catalog, and the DESI spectroscopic m… ▽ More We use the first eROSITA all-sky survey (eRASS1) to investigate the contributions of AGN and extended gas to the total X-ray luminosity ($L_X$) of galaxy groups with different halo masses ($M_h$) at different redshifts. The presence of AGN in their central galaxies is identified using multi-wavelength catalogs, including the X-ray counterparts, the ASKAP radio catalog, and the DESI spectroscopic measurements. We apply the stacking method to obtain sufficient statistics for the X-ray surface brightness profile and the $L_X$ for groups with different central AGN properties. We find that the X-ray groups exhibit the highest $L_X$, followed by groups with QSO, radio, BPT-AGN, and non-AGN centrals. Moreover, the $L_X$ of the $M_h \lesssim 10^{13}h^{-1}M_\odot$ groups is dominated by the central AGN, while the X-ray emission from extended gas tends to be more prominent in the $M_h \gtrsim 10^{13}h^{-1}M_\odot$ groups. In groups where the AGN play a major role in X-ray emission, the contribution from extended gas is minor, resulting in significant uncertainties concerning the extended X-ray emission. When the subset containing the X-ray detected counterparts is excluded, the extended gas component becomes easier to obtain. A correlation has been identified between the X-ray luminosity of the central AGN and extended gas. However, once we account for the positional offset, their correlation becomes less prominent. Currently, the results are not conclusive enough to confirm whether there is a connection between the AGN feedback and extended gas. However, they provide a new perspective on the feedback processes in the history of group assembly. △ Less

Submitted 18 November, 2025; originally announced November 2025.

Comments: 29 pages, 14 figures, ApJ accepted

Detection of disk-jet co-precession in a tidal disruption event

Authors: Yanan Wang, Zikun Lin, Linhui Wu, Weihua Lei, Shuyuan Wei, Shuang-Nan Zhang, Long Ji, Santiago del Palacio, Ranieri D. Baldi, Yang Huang, Jifeng Liu, Bing Zhang, Aiyuan Yang, Rurong Chen, Yangwei Zhang, Ailing Wang, Lei Yang, Panos Charalampopoulos, David R. A. Williams-Baldwin, Zhu-Heng Yao, Fu-Guo Xie, Defu Bu, Hua Feng, Xinwu Cao, Hongzhou Wu , et al. (24 additional authors not shown)

Abstract: Theories and simulations predict that intense spacetime curvature near black holes bends the trajectories of light and matter, driving disk and jet precession under relativistic torques. However, direct observational evidence of disk-jet co-precession remains elusive. Here, we report the most compelling case to date: a tidal disruption event (TDE) exhibiting unprecedented 19.6-day quasi-periodic v… ▽ More Theories and simulations predict that intense spacetime curvature near black holes bends the trajectories of light and matter, driving disk and jet precession under relativistic torques. However, direct observational evidence of disk-jet co-precession remains elusive. Here, we report the most compelling case to date: a tidal disruption event (TDE) exhibiting unprecedented 19.6-day quasi-periodic variations in both X-rays and radio, with X-ray amplitudes exceeding an order of magnitude. The nearly synchronized X-ray and radio variations suggest a shared mechanism regulating the emission regions. We demonstrate that a disk-jet Lense-Thirring precession model successfully reproduces these variations while requiring a low-spin black hole. This study uncovers previously uncharted short-term radio variability in TDEs, highlights the transformative potential of high-cadence radio monitoring, and offers profound insights into disk-jet physics. △ Less

Submitted 16 November, 2025; originally announced November 2025.

Comments: 76 pages, 13 figures (initial submission; in press at Science Advances)

PEPSI Investigation, Retrieval, and Atlas of Numerous Giant Atmospheres (PIRANGA). IV. High-Resolution Phased-Resolved Spectroscopy of The Ultra Hot Jupiter KELT-20 b

Authors: Victoria Bonidie, Marshall C. Johnson, Ji Wang, Sydney Petz, Jake Kamen, Calder Lenhart, Alison Duck, Carles Badenes, Klaus Strassmeier, Ilya Ilyin

Abstract: We present five datasets of high-resolution optical emission spectra of the ultra-hot Jupiter KELT-20 b with the PEPSI spectrograph. Using a Bayesian retrieval framework, we constrain its dayside pressure-temperature profile and abundances of Fe, Ni, and Ca, providing the first measurements for Ni and Ca for KELT-20 b in emission. We retrieve the pre- and post-eclipse datasets separately (correspo… ▽ More We present five datasets of high-resolution optical emission spectra of the ultra-hot Jupiter KELT-20 b with the PEPSI spectrograph. Using a Bayesian retrieval framework, we constrain its dayside pressure-temperature profile and abundances of Fe, Ni, and Ca, providing the first measurements for Ni and Ca for KELT-20 b in emission. We retrieve the pre- and post-eclipse datasets separately (corresponding to the evening and morning sides, respectively), and compare the constraints on their thermal structures and chemical abundances. We constrain lower abundances in the pre-eclipse datasets compared to the post-eclipse datasets. We interpret these results with an equilibrium chemistry model which suggests ~10-30x supersolar refractory abundances. Due to the well-known degeneracy between absolute abundances and continuum opacities, the abundance ratios are more precise probes of the planetary abundances. Therefore we measure the abundance ratios [Ni/Fe] and [Ca/Fe] across these datasets and find they agree within 1-sigma. We constrain [Ni/Fe] to be consistent with solar within 2-sigma, and [Ca/Fe] to be 0.001-0.01x solar, not accounting for ionization. We compare these abundance ratios with literature results for KELT-20 b in transmission, and find they agree within 2-sigma, suggesting that even though the abundances vary significantly as a function of phase, the abundance ratios of these species remain relatively constant. We find a ~100 K difference in temperature at the top of the thermal inversion, suggesting a hotter evening side than morning side and underscoring the importance of considering 3D effects when studying ultra-hot Jupiters. △ Less

Submitted 12 November, 2025; originally announced November 2025.

Comments: 14 pages, 9 figures

Little red dots as embryos of active galactic nuclei

Authors: Jian-Min Wang, Yi-Lin Wang, Yong-Jie Chen, Jun-Rong Liu, Yu-Yang Songsheng, Cheng Cheng, Yan-Rong Li, Pu Du, Hao Zhang, Yu Zhao

Abstract: As an unprecedented large population in the early universe, the JWST-discovered little red dots (LRDs) have garnered much attention for formation of massive black holes and galaxies, but their nature remains a mystery. The LRDs appearing as ``Chimeras" like both active galactic nuclei (AGNs) and galaxies have stimulated renewed interest in the roadmap of central massive black hole (cMBH) formation… ▽ More As an unprecedented large population in the early universe, the JWST-discovered little red dots (LRDs) have garnered much attention for formation of massive black holes and galaxies, but their nature remains a mystery. The LRDs appearing as ``Chimeras" like both active galactic nuclei (AGNs) and galaxies have stimulated renewed interest in the roadmap of central massive black hole (cMBH) formation in AGNs. In this paper, we suggest that the LRDs contain $M_{\bullet}\lesssim 10^6\,M_{\odot}$ cMBHs as demonstrated by the Sołtan argument and there is a large population of stellar-mass black holes (sMBHs with total mass of $\mathscr{M}_{m_{\bullet}}$) embedded inside cMBH accretion disks (cMBH-disk) as motivated by anomalous reverberations of broad H$β$ line in local AGNs. This embryo structure of LRDs ($M_{\bullet}<\mathscr{M}_{m_{\bullet}}$) is formed as a consequence of gravitational collapse of primordial clouds. In this Chimera, accretion onto sMBHs powers the rest-frame optical continuum of the LRDs but the UV continuum is jointly contributed by slim parts of the cMBH-disks and nuclear starbursts in the core of collapsing clouds governing the appearance of the observed V-shaped spectral energy distributions (SEDs). Outflowing clumped-envelopes are unavoidably formed by radiation pressure leading to absorption features of the Balmer lines. The present model works very well for LRDs' SEDs and avoids the issues of overly massive cMBHs. Evolution of LRDs is briefly discussed including gravitational waves. △ Less

Submitted 12 November, 2025; originally announced November 2025.

Comments: 22 pages, 6 figures

CoronaGraph Instrument Reference stars for Exoplanets (CorGI-REx) I. Preliminary Vetting and Implications for the Roman Coronagraph and Habitable Worlds Observatory

Authors: Justin Hom, Schuyler G. Wolff, Catherine A. Clark, David R. Ciardi, Sarah J. Deveny, Steve B. Howell, Alexandra Z. Greenbaum, Colin Littlefield, Ramya M. Anche, Vanessa P. Bailey, Wolfgang Brandner, Gaël Chauvin, Julien H. Girard, Brian Kern, Eric Mamajek, Bertrand Mennesson, Dmitry Savransky, Karl R. Stapelfeldt, Beth A. Biller, Marah Brinjikji, Masayuki Kuzuhara, Maxwell A. Millar-Blanchaer, Toshiyuki Mizuki, Nicholas T. Schragal, Macarena C. Vega-Pallauta , et al. (6 additional authors not shown)

Abstract: The upcoming Roman Coronagraph will be the first high-contrast instrument in space capable of high-order wavefront sensing and control technologies, a critical technology demonstration for the proposed Habitable Worlds Observatory (HWO) that aims to directly image and characterize habitable exoEarths. The nominal Roman Coronagraph observing plan involves alternating observations of a science targe… ▽ More The upcoming Roman Coronagraph will be the first high-contrast instrument in space capable of high-order wavefront sensing and control technologies, a critical technology demonstration for the proposed Habitable Worlds Observatory (HWO) that aims to directly image and characterize habitable exoEarths. The nominal Roman Coronagraph observing plan involves alternating observations of a science target and a bright, nearby reference star. High contrast is achieved using wavefront sensing and control, also known as "digging a dark hole", where performance depends on the properties of the reference star, requiring V<3, a resolved stellar diameter <2 mas, and no stellar multiplicity. The imposed brightness and diameter criteria limit the sample of reference star candidates to high-mass main sequence and post-main sequence objects, where multiplicity rates are high. A future HWO coronagraph may have similarly restrictive criteria in reference star selection. From an exhaustive literature review of 95 stars, we identify an initial list of 40 primary and 18 reserve reference star candidates relevant to both the Roman Coronagraph and HWO. We present results from an initial survey of these candidates with high-resolution adaptive optics imaging and speckle interferometry and identify no new companions. We discuss the need for higher-contrast observations to sufficiently vet these reference star candidates prior to Roman Coronagraph observations along with the implications of reference star criteria on observation planning for Roman and HWO. △ Less

Submitted 11 November, 2025; originally announced November 2025.

Comments: Accepted for Publication in AJ, 27 pages, 8 figures, 6 tables

Journal ref: AJ 171 36 (2026)

Detection of unexpected leading delays in broad Hβ line reverberations in the quasar PHL 1092

Authors: Jian-Min Wang, Chen Hu, Yong-Jie Chen, Yu-Yang Songsheng, Yi-Lin Wang, Hao Zhang, Pu Du, Yan-Rong Li, Bin Luo, Michael S. Brotherton, Jin-Ming Bai, Wei-Jian Guo, Seng Yang, Zhu-Heng Yao, Jesus Aceituno

Abstract: Delayed reverberations of broad emission lines in response to optical continuum variations have been widely observed in active galactic nuclei (AGNs). They serve as a powerful tool for probing inner structures of AGNs and estimating the masses of supermassive black holes (SMBHs). The delays exhibit a strong correlation with approximately the square root of the optical luminosity - a relationship k… ▽ More Delayed reverberations of broad emission lines in response to optical continuum variations have been widely observed in active galactic nuclei (AGNs). They serve as a powerful tool for probing inner structures of AGNs and estimating the masses of supermassive black holes (SMBHs). The delays exhibit a strong correlation with approximately the square root of the optical luminosity - a relationship known as the "standard structure" of AGN broad-line regions (BLRs). Here, we report the discovery of leading delays in Hβ line reverberations (LDRs) in the quasar PHL 1092 preceding variations of the 5100 Å continuum by 17-57 days, based on our eight-year continuous campaign of reverberation mapping of super Eddington AGNs. The LDRs suggest that the 5100 Å continuum regions are so extensive that they are larger than the BLRs. This phenomenon not only fundamentally disrupts the well-established BLR size-luminosity relation but also violates the principle of causality. This unprecedented LDRs challenge the conventional methods for estimating SMBH mass as well as the standard model of AGNs. A preferred scenario to explain the LDRs is that the SMBH-disk contains a population of accreting stellar-mass black holes (sMBHs) as extra heating sources of the disk. Consequently, continuum regions of the disk are efficiently stretched so that the 5100 Å regions exceed the BLRs, yielding the observed LDRs. Generally, sMBH activities there could provide new physics of AGN phenomena, which can be tested by LIGO, LISA/Tianqin and ET detections of gravitational waves from sMBH mergers. △ Less

Submitted 10 November, 2025; originally announced November 2025.

Comments: Revised. Comments greatly appreciated and warmly welcomed!

A Timescale-Resolved Analysis of the Breathing Effect in Quasar Broad Line Regions

Authors: C. -Z. Jiang, J. -X. Wang, H. Sou, W. -K. Ren

Abstract: The single-epoch virial method is a fundamental tool for estimating supermassive black hole (SMBH) masses in large samples of AGNs and has been extensively employed in studies of SMBH-galaxy co-evolution across cosmic time. However, since this method is calibrated using reverberation-mapped AGNs, its validity across the entire AGN population remains uncertain. We aim to examine the breathing effec… ▽ More The single-epoch virial method is a fundamental tool for estimating supermassive black hole (SMBH) masses in large samples of AGNs and has been extensively employed in studies of SMBH-galaxy co-evolution across cosmic time. However, since this method is calibrated using reverberation-mapped AGNs, its validity across the entire AGN population remains uncertain. We aim to examine the breathing effect-the variability of emission line widths with continuum luminosity-beyond reverberation-mapped AGNs, to assess the validity and estimate potential systematic uncertainties of single-epoch virial black hole mass estimates. We construct an unprecedentedly large multi-epoch spectroscopic dataset of quasars from SDSS DR16, focusing on four key broad emission lines (Ha, Hb, MgII, and CIV). We assess how breathing behavior evolves with the rest-frame time interval between observations. We detect no significant breathing signal in Ha, Hb, or MgII at any observed timescale. In contrast, CIV exhibits a statistically significant anti-breathing trend, most prominent at intermediate timescales. Notably, for Hb, which has shown breathing in previous reverberation-mapped samples, we recover the effect only in the small subset of quasars with clearly detected BLR lags and only during the epochs when such lags are measurable-suggesting that both the lag and breathing signals are intermittent, possibly due to a weak correlation between optical and ionizing continua. These results highlight the complex, variable, and timescale-dependent nature of line profile variability and underscore its implications for single-epoch black hole mass estimates. △ Less

Submitted 10 November, 2025; originally announced November 2025.

Comments: 8 pages, 7 figures, accepted for publication in A&A, comments are welcomed

SVOM Follow-up Observation Coordinating Service

Authors: Xu-hui Han, Pin-pin Zhang, Yu-jie Xiao, Ruo-song Zhang, Chao Wu, Li-ping Xin, Hong-bo Cai, Hai Cao, Hui-jun Chen, Jin-song Deng, Wen-long Dong, Guo-wang Du, Lei Huang, Lin Lan, Hua-li Li, Guang-wei Li, Xiao-meng Lu, Yu-lei Qiu, Jian-feng Tian, Jing Wang, Wen-jin Xie, Da-wei Xu, Yang Xu, Zhu-heng Yao, Xue-ying Zhao , et al. (5 additional authors not shown)

Abstract: The Sino-French SVOM (Space Variable Objects Monitor) mission is a space-based astronomy mission complemented with ground-based dedicated instrumentation. It aims to explore and study high-energy cosmic phenomena, such as gamma-ray bursts (GRBs). This unprecedented combination of space-based and ground-based instruments will provide leading multi-wavelength observational capabilities in gamma-rays… ▽ More The Sino-French SVOM (Space Variable Objects Monitor) mission is a space-based astronomy mission complemented with ground-based dedicated instrumentation. It aims to explore and study high-energy cosmic phenomena, such as gamma-ray bursts (GRBs). This unprecedented combination of space-based and ground-based instruments will provide leading multi-wavelength observational capabilities in gamma-rays, X-rays, optical, and near-infrared bands. The complete observation sequence of each GRB triggered by the SVOM mission consists of three stages, the GRB detections, followed by the on-board and grounded automatic follow-ups, and rapid deep multi-band photometry and spectroscopy re-visit observations. To efficiently organize all grounded instruments performing automatic follow-ups and re-visit observations, we develop a follow-up observation coordinating service (FOCS), which is capable of performing GRB trigger distributing, automatic observation scheduling and observation coordination supporting by providing a user support platform. The FOCS also facilitates the provision of observational planning for ground-based telescopes to conduct synchronized observations of identical celestial regions as SVOM. The FOCS is utilized for the SVOM-dedicated ground-based telescopes as well as for associated partner telescopes. Since the launch of SVOM in June 2024, as the FOCS system joining the operations of SVOM, multiple successful observations have been made for SVOM GRBs. In this paper, we present the goals of the FOCS system as well as the principle and workflow developed to achieve these goals. The structure, technical design, implementation, and performance of the FOCS system are also described in detail. We conclude with a summary of the current status of the FOCS system and our near-future development plan. △ Less

Submitted 9 November, 2025; originally announced November 2025.

Comments: 10 pages, 5 figures

Particle loads for cosmological simulations with equal-mass dark matter and baryonic particles

Authors: Shihong Liao, Yizhou Liu, Haonan Zheng, Ming Li, Jie Wang, Liang Gao, Bingqing Sun, Shi Shao

Abstract: Traditional cosmological hydrodynamical simulations usually assume equal-numbered but unequal-mass dark matter and baryonic particles, which can lead to spurious collisional heating due to energy equipartition. To avoid such a numerical heating effect, a simulation setup with equal-mass dark matter and baryonic particles, which corresponds to a particle number ratio of… ▽ More Traditional cosmological hydrodynamical simulations usually assume equal-numbered but unequal-mass dark matter and baryonic particles, which can lead to spurious collisional heating due to energy equipartition. To avoid such a numerical heating effect, a simulation setup with equal-mass dark matter and baryonic particles, which corresponds to a particle number ratio of $N_{\rm DM}:N_{\rm gas} = Ω_{\rm cdm} / Ω_{\rm b}$, is preferred. However, previous studies have typically used grid-based particle loads to prepare such initial conditions, which can only reach specific values for $N_{\rm DM}:N_{\rm gas}$ due to symmetry requirements. In this study, we propose a method based on the glass approach that can generate two-component particle loads with more general $N_{\rm DM}:N_{\rm gas}$ ratios. The method simultaneously relaxes two Poisson particle distributions by introducing an additional repulsive force between particles of the same component. We show that the final particle load closely follows the expected minimal power spectrum, $P(k) \propto k^{4}$, exhibits good homogeneity and isotropy properties, and remains sufficiently stable under gravitational interactions. Both the dark matter and gas components individually also exhibit uniform and isotropic distributions. We apply our method to two-component cosmological simulations and demonstrate that an equal-mass particle setup effectively mitigates the spurious collisional heating that arises in unequal-mass simulations. Our method can be extended to generate multi-component uniform and isotropic distributions. Our code based on Gadget-2 is available at https://github.com/liaoshong/gadget-2glass . △ Less

Submitted 8 November, 2025; originally announced November 2025.

Comments: 16 pages, 11 figures, accepted for publication in The Astrophysical Journal. The code is publicly available at https://github.com/liaoshong/gadget-2glass

Journal ref: The Astrophysical Journal, 995, 147 (2025)

Radio AGN feedback sustains quiescence only in a minority of massive galaxies

Authors: Huiling Liu, Yan Lu, Hui Hong, Huiyuan Wang, Houjun Mo, Jing Wang, Wanli Ouyang, Ziwen Zhang, Enci Wang, Hongxin Zhang, Yangyao Chen, Qinxun Li, Hao Li, Mengkui Zhou

Abstract: Radio active galactic nuclei (AGNs) eject a huge amount of energy into the surrounding medium and are thought to potentially prevent gas cooling and maintain the quiescence of massive galaxies. The short-lived, sporadic, and anisotropic nature of radio activities, coupled with the detection of abundant cold gas around some massive quiescent galaxies, raise questions about the efficiency of radio f… ▽ More Radio active galactic nuclei (AGNs) eject a huge amount of energy into the surrounding medium and are thought to potentially prevent gas cooling and maintain the quiescence of massive galaxies. The short-lived, sporadic, and anisotropic nature of radio activities, coupled with the detection of abundant cold gas around some massive quiescent galaxies, raise questions about the efficiency of radio feedback in massive galaxies. Here we present an innovative method rooted in artificial intelligence to separate galaxies in which radio feedback is effective (RFE), regardless of current radio emission, from those in which radio feedback is ineffective (RFI), according to their optical images. Galaxies categorized as RFE are all dynamically hot, whereas quiescent RFI (RFI-Q) galaxies usually have extended cold-disk components. At given stellar mass, dark matter halos hosting RFE galaxies are between four to ten times more massive than those of RFI-Q galaxies. We find, for the first time, that almost all RFE galaxies have scant cold gas, irrespective of AGN activity. In contrast, many RFI-Q galaxies are surrounded by substantial amounts of condensed atomic gas, indicating a different evolutionary path from RFE galaxies. Our finding provides direct and compelling evidence that a radio AGN has gone through about 300 on-off cycles and that radio feedback can prevent gas cooling over a timescale much longer than that of radio activity. Contrary to general belief, our analysis shows that only a small fraction of massive galaxies are influenced by strong radio AGNs, suggesting that current galaxy formation models need serious revision. △ Less

Submitted 8 November, 2025; originally announced November 2025.

Comments: 46 pages, 12 figures

Supermassive Black Hole and Broad-line Region in NGC 5548: 2023 Reverberation Mapping Results

Authors: Wen-Zhe Xi, Kai-Xing Lu, Jin-Ming Bai, Zhang Yue, Weimin Yi, Liang Xu, Sha-Sha Li, Hai-Cheng Feng, Jian-Guo Wang

Abstract: We present the results of the 2023 spectroscopic reverberation mapping (RM) campaign for active galactic nuclei (AGN) of NGC 5548, continuing our long-term monitoring program. Using the Lijiang 2.4-meter telescope, we obtained 74 spectra with a median cadence of 1.9 days. Through detailed spectral decomposition, we measured the light curves of the optical continuum at 5100~Å and the broad He~{\sc… ▽ More We present the results of the 2023 spectroscopic reverberation mapping (RM) campaign for active galactic nuclei (AGN) of NGC 5548, continuing our long-term monitoring program. Using the Lijiang 2.4-meter telescope, we obtained 74 spectra with a median cadence of 1.9 days. Through detailed spectral decomposition, we measured the light curves of the optical continuum at 5100~Å and the broad He~{\sc ii}, He~{\sc i}, H$γ$, and H$β$ emission lines. The time lags of these lines relative to the continuum are measured as $1.3^{+1.6}_{-0.6}$, $2.3^{+1.5}_{-2.1}$, $10.0^{+2.0}_{-1.8}$, and $15.6^{+2.6}_{-2.9}$ days (rest-frame), respectively. Velocity-resolved lag profiles for H$γ$ and H$β$ were constructed. Combined with data from previous seasons (2015$-$2021), we find that the radial ionization stratification of the broad-line region (BLR) is stable; the average virial mass of the supermassive black hole in NGC~5548 is $(2.6\pm1.1)\times 10^{8}M_{\odot}$, consistent with the $M_{\rm BH}-σ_*$ relation; the broad He~{\sc ii} line exhibits the largest responsivity, followed by broad He~{\sc i} (or H$γ$) and H$β$ lines; the BLR kinematics show significant temporal evolution, transitioning from virialized motions to signatures of inflow and outflow. Furthermore, an analysis of 35 years of historical data confirms a 3.5-year time lag between variations in the optical luminosity and the BLR radius, potentially implicating the role of radiation pressure or dynamical structure changes in the inner accretion disk. Long-term campaign demonstrates that the BLR in NGC 5548 is a robust yet dynamically evolving entity, providing crucial insights into AGN structure and accretion physics. △ Less

Submitted 7 November, 2025; originally announced November 2025.

Comments: 15 pages, 6 figures, 4 Tables, accepted by ApJ

Charge-dependent spectral softenings of primary cosmic-rays from proton to iron below the knee

Authors: DAMPE Collaboration, Francesca Alemanno, Qi An, Philipp Azzarello, Felicia-Carla-Tiziana Barbato, Paolo Bernardini, Xiao-Jun Bi, Hugo Valentin Boutin, Irene Cagnoli, Ming-Sheng Cai, Elisabetta Casilli, Jin Chang, Deng-Yi Chen, Jun-Ling Chen, Zhan-Fang Chen, Zi-Xuan Chen, Paul Coppin, Ming-Yang Cui, Tian-Shu Cui, Ivan De Mitri, Francesco de Palma, Adriano Di Giovanni, Tie-Kuang Dong, Zhen-Xing Dong, Giacinto Donvito , et al. (124 additional authors not shown)

Abstract: In most particle acceleration mechanisms, the maximum energy of the cosmic rays can achieve is charge dependent. However, the observational verification of such a fundamental relation is still lack due to the difficulty of measuring the spectra of individual particles from one (kind of) source(s) up to very high energies. This work reports direct measurements of the carbon, oxygen, and iron spectr… ▽ More In most particle acceleration mechanisms, the maximum energy of the cosmic rays can achieve is charge dependent. However, the observational verification of such a fundamental relation is still lack due to the difficulty of measuring the spectra of individual particles from one (kind of) source(s) up to very high energies. This work reports direct measurements of the carbon, oxygen, and iron spectra from ~ 20 gigavolts to ~ 100 teravolts (~ 60 teravolts for iron) with 9 years of on-orbit data collected by the Dark Matter Particle Explorer (DAMPE). Distinct spectral softenings have been directly detected in these spectra for the first time. Combined with the updated proton and helium spectra, the spectral softening appears universally at a rigidity of ~ 15 teravolts. A nuclei mass dependent softening is rejected at a confidence level of > 99.999%. Taking into account the correlated structures at similar energies in the large-scale anisotropies of cosmic rays, one of the most natural interpretations of the spectral structures is the presence of a nearby cosmic ray source. In this case, the softening energies correspond to the acceleration upper limits of such a source, forming the so-called Peters cycle of the spectra. The results thus offer observational verification of the long-standing prediction of the charge-dependent energy limit of cosmic ray acceleration. △ Less

Submitted 10 November, 2025; v1 submitted 7 November, 2025; originally announced November 2025.

Comments: This update corrects typos in the tables