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The gMOSS: the galaxy survey and galaxy populations of the large homogeneous field
Authors:
A. Grokhovskaya,
S. N. Dodonov,
T. A. Movsessian,
S. S. Kotov
Abstract:
We present the gMOSS (Galaxies of Medium-band One-meter Schmidt telescope Survey) catalog of $\sim$ 19,000 galaxies in 20 filters (4 broadband SDSS and 16 medium-band filters). We observed 2.386 $\mathrm{deg^2}$ on the central part of the HS47.5-22 field with the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory. The gMOSS is a complete flux-limited sample of galaxies with a threshol…
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We present the gMOSS (Galaxies of Medium-band One-meter Schmidt telescope Survey) catalog of $\sim$ 19,000 galaxies in 20 filters (4 broadband SDSS and 16 medium-band filters). We observed 2.386 $\mathrm{deg^2}$ on the central part of the HS47.5-22 field with the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory. The gMOSS is a complete flux-limited sample of galaxies with a threshold magnitude of $r$ SDSS $\le$ 22.5 AB. From photometric measurements with 16 medium-band filters and $u$ SDSS, we get spectral energy distributions for each object in the field, which are used for further analysis. Galaxy classification and photometric redshift estimation based on spectral template matching with ZEBRA software. The obtained redshift accuracy is $σ_\mathrm{NMAD} < 0.0043$. Using the SED-fitting CIGALE code, we obtained the main properties of the stellar population of galaxies, such as rest-frame $(u - r)_{\mathrm{res}}$ colour, stellar mass, extinction, and mass-weighted age with a precision of $0.16 \pm 0.07$ mag, $0.14 \pm 0.04$ dex, $0.27 \pm 0.1$ mag, and $0.08 \pm 0.04$ dex, respectively. Using a dust-corrected colour-mass diagram, we divided the full sample into populations of red and blue galaxies and considered the dependencies between stellar mass and age. Throughout cosmic time, red sequence galaxies remain older and more massive than blue cloud galaxies. The star formation history of a complete subsample of galaxies selected in the redshift range $0.05\le z\le0.015$ with <$\mathrm{log} M \mathrm{>}_\mathrm{[M_\odot]}$>8.3 shows an increase in the SFRD up to $z\sim3$, under the results obtained in earlier studies.
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Submitted 14 April, 2022;
originally announced April 2022.
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Mass estimation of the very massive galaxy cluster SRGe CL2305.2$-$2248 from strong lensing
Authors:
I. M. Khamitov,
I. F. Bikmaev,
N. S. Lyskova,
A. A. Kruglov,
R. A. Burenin,
M. R. Gilfanov,
A. A. Grokhovskaya,
S. N. Dodonov,
S. Yu. Sazonov,
A. A. Starobinsky,
R. A. Sunyaev,
I. I. Khabibullin,
E. M. Churazov
Abstract:
The galaxy cluster SRGe CL2305.2$-$2248 (SPT-CL J2305$-$2248, ACT-CL J2305.1$-$2248) is one of the most massive clusters at high redshifts ($z \simeq 0.76$) and is of great interest for cosmology. For an optical identification of this cluster, deep images were obtained with the 1.5-m Russian-Turkish telescope RTT-150. Together with the open archival data of the Hubble Space Telescope, it became po…
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The galaxy cluster SRGe CL2305.2$-$2248 (SPT-CL J2305$-$2248, ACT-CL J2305.1$-$2248) is one of the most massive clusters at high redshifts ($z \simeq 0.76$) and is of great interest for cosmology. For an optical identification of this cluster, deep images were obtained with the 1.5-m Russian-Turkish telescope RTT-150. Together with the open archival data of the Hubble Space Telescope, it became possible to identify candidates for gravitationally lensed images of distant blue galaxies in the form of arcs and arclets. The observed giant arc near the brightest cluster galaxies allowed us to estimate the radius of the Einstein ring, which is $ 9.8 \pm 1.3 $ arcseconds. The photometric redshift of the lensed source was obtained ($ z_s = 2.44 \pm 0.07 $). Its use in combination with the Einstein radius estimate made it possible to independently estimate the \cl2305 mass. It was done by extrapolating the strong lensing results to large radii and using the model density distribution profiles in relaxed clusters. This extrapolation leads to mass estimates $ \sim 1.5-3 $ times smaller than those obtained from X-ray and microwave observations. A probable cause for this discrepancy may be the process of cluster merging, which is also confirmed by SRGe CL2305.2-2248 morphology in the optical range.
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Submitted 12 April, 2022;
originally announced April 2022.
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Quasars physical properties study based on the medium-band photometric survey
Authors:
Sergey Kotov,
Sergey Dodonov,
Aleksandra Grokhovskaya
Abstract:
The study is about the quasars cosmological evolution. We used the medium-band photometric survey at the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory. The HS47-22 field with an area of 2.38 square degrees has been selected. We have classified objects and composed a sample of quasars using broadband photometric data and morphological classification from the DECaLS survey, infrare…
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The study is about the quasars cosmological evolution. We used the medium-band photometric survey at the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory. The HS47-22 field with an area of 2.38 square degrees has been selected. We have classified objects and composed a sample of quasars using broadband photometric data and morphological classification from the DECaLS survey, infrared photometry from the WISE survey, spectroscopy from the SDSS survey, ROSAT X-ray data, FIRST radio data and stellar parallax data from the GAIA survey. We have compiled a sample of 682 quasars, determined their photometric redshifts from the medium-band photometric data, and calculated the absolute stellar magnitudes. The space density of quasars was calculated for different luminosity ranges at different redshifts using the $λ$-CDM model with $Ω_m = 0.3$ and $Ω_λ= 0.7$. In this paper, we present the comparison of our results with other works.
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Submitted 4 March, 2022;
originally announced March 2022.
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Observation of a very massive galaxy cluster at z=0.76 in SRG/eROSITA all-sky survey
Authors:
R. A. Burenin,
I. F. Bikmaev,
M. R. Gilfanov,
A. A. Grokhovskaya,
S. N. Dodonov,
M. V. Eselevich,
I. A. Zaznobin,
E. N. Irtuganov,
N. S. Lyskova,
P. S. Medvedev,
A. V. Meshcheryakov,
A. V. Moiseev,
S. Yu. Sazonov,
A. A. Starobinsky,
R. A. Sunyaev,
R. I. Uklein,
I. I. Khabibullin,
I. M. Khamitov,
E. M. Churazov
Abstract:
The results of multiwavelength observations of the very massive galaxy cluster SRGe CL2305.2-2248 detected in X-rays during the first SRG/eROSITA all-sky survey are discussed. This galaxy cluster was also detected earlier in microwave band through the observations of Sunyaev-Zeldovich effect in South Pole Telescope (SPT-CL J2305-2248), and in Atacama Cosmological Telescope (ACT-CL J2305.1-2248) su…
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The results of multiwavelength observations of the very massive galaxy cluster SRGe CL2305.2-2248 detected in X-rays during the first SRG/eROSITA all-sky survey are discussed. This galaxy cluster was also detected earlier in microwave band through the observations of Sunyaev-Zeldovich effect in South Pole Telescope (SPT-CL J2305-2248), and in Atacama Cosmological Telescope (ACT-CL J2305.1-2248) surveys. Spectroscopic redshift measurement, $z=0.7573$, was measured at the Russian 6-m BTA telescope of SAO RAS, in good agreement with its photometric estimates, including a very accurate one obtained using machine learning methods. In addition, deep photometric measurements were made at the Russian-Turkish 1.5-m telescope (RTT150), which allows to study cluster galaxies red sequence and projected galaxies distribution. Joint analysis of the data from X-ray and microwave observations show that this cluster can be identified as a very massive and distant one using the measurements of its X-ray flux and integral comptonization parameter only. The mass of the cluster estimated according to the eROSITA data is $M_{500}=(9.0\pm2.6)\cdot10^{14}\, M_\odot$. We show that this cluster is found among of only several dozen of the most massive clusters in the observable Universe and among of only a few the most massive clusters of galaxies at $z>0.6$.
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Submitted 20 August, 2021;
originally announced August 2021.
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First tidal disruption events discovered by SRG/eROSITA: X-ray/optical properties and X-ray luminosity function at z<0.6
Authors:
S. Sazonov,
M. Gilfanov,
P. Medvedev,
Y. Yao,
G. Khorunzhev,
A. Semena,
R. Sunyaev,
R. Burenin,
A. Lyapin,
A. Meshcheryakov,
G. Uskov,
I. Zaznobin,
K. A. Postnov,
A. V. Dodin,
A. A. Belinski,
A. M. Cherepashchuk,
M. Eselevich,
S. N. Dodonov,
A. A. Grokhovskaya,
S. S. Kotov,
I. F. Bikmaev,
R. Ya. Zhuchkov,
R. I. Gumerov,
S. van Velzen,
S. Kulkarni
Abstract:
We present the first sample of tidal disruption events (TDEs) discovered during the SRG all-sky survey. These 13 events were selected among X-ray transients detected in the 0<l<180 deg hemisphere by eROSITA during its second sky survey (10 June - 14 December 2020) and confirmed by optical follow-up observations. The most distant event occurred at z=0.581. One TDE continued to brighten at least 6 m…
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We present the first sample of tidal disruption events (TDEs) discovered during the SRG all-sky survey. These 13 events were selected among X-ray transients detected in the 0<l<180 deg hemisphere by eROSITA during its second sky survey (10 June - 14 December 2020) and confirmed by optical follow-up observations. The most distant event occurred at z=0.581. One TDE continued to brighten at least 6 months. The X-ray spectra are consistent with nearly critical accretion onto black holes of a few 10^3 to 10^8 M_Sun, although supercritical accretion is possibly taking place. In two TDEs, a spectral hardening is observed 6 months after the discovery. Four TDEs showed an optical brightening apart from the X-ray outburst. The other 9 TDEs demonstrate no optical activity. All 13 TDEs are optically faint, with Lopt/Lx<0.3 (Lopt and Lx being the g-band and 0.2-6 keV luminosity, respectively). We have constructed a TDE X-ray luminosity function, which can be fit by a power law with a slope of -0.6+/-0.2, similar to the trend observed for optically selected TDEs. The total rate is estimated at (1.1+/-0.5)10^-5 TDEs per galaxy per year, an order of magnitude lower than inferred from optical studies. This suggests that X-ray bright events constitute a minority of TDEs, consistent with models predicting that X-rays can only be observed from directions close to the axis of a thick accretion disk formed from the stellar debris. Our TDE detection threshold can be lowered by a factor of ~2, which should allow a detection of ~700 TDEs by the end of the SRG survey.
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Submitted 28 September, 2021; v1 submitted 5 August, 2021;
originally announced August 2021.
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Measurement of the supermassive black hole masses in two active galactic nuclei by the photometric reverberation mapping method
Authors:
E. A. Malygin,
E. S. Shablovinskaya,
R. I. Uklein,
A. A. Grokhovskaya
Abstract:
We present the results of long-term photometric monitoring of two active galactic nuclei, 2MASX J08535955+7700543 (z $\sim$ 0.106) and VII Zw 244 (z $\sim$ 0.131), being investigated by the reverberation mapping method in medium-band filters. To estimate the size of the broad line region, we have analyzed the light curves with the JAVELIN code. The emission line widths have been measured using the…
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We present the results of long-term photometric monitoring of two active galactic nuclei, 2MASX J08535955+7700543 (z $\sim$ 0.106) and VII Zw 244 (z $\sim$ 0.131), being investigated by the reverberation mapping method in medium-band filters. To estimate the size of the broad line region, we have analyzed the light curves with the JAVELIN code. The emission line widths have been measured using the spectroscopic data obtained at the 6-m BTA telescope of SAO RAS. We give our estimates of the supermassive black hole masses $\lg (M/M_{\odot})$, $7.398_{-0.171}^{+0.153}$, and $7.049_{-0.075}^{+0.068}$, respectively
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Submitted 9 March, 2021;
originally announced March 2021.
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Large Scale Distribution of Galaxies in The Field HS 47.5-22. II. Observational Data Analysis
Authors:
Aleksandra Grokhovskaya,
Sergei N. Dodonov,
T. A. Movsessian
Abstract:
The results of the study of the large-scale distribution of galaxies up to z ~0.8 in the field HS 47.5-22 on the basis of photometric data of the 1-meter Schmidt telescope of the BAO NAS Armenia are presented. The full sample contains 28,398 galaxies. Candidates for large-scale structures were determined using two independent methods for reconstructing density contrast maps in 57 narrow slices of…
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The results of the study of the large-scale distribution of galaxies up to z ~0.8 in the field HS 47.5-22 on the basis of photometric data of the 1-meter Schmidt telescope of the BAO NAS Armenia are presented. The full sample contains 28,398 galaxies. Candidates for large-scale structures were determined using two independent methods for reconstructing density contrast maps in 57 narrow slices of the three-dimensional distribution of galaxies: adaptive aperture algorithm with smoothing and 2D Voronoi tessellation. We have identified more than 250 statistically significant overdense structures. The obtained results demonstrate a wide range of overdense structures over the full range of redshifts up to z ~0.8.
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Submitted 8 June, 2020;
originally announced June 2020.
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The density maps of the HS47.5-22 field
Authors:
Sergei N. Dodonov,
Aleksandra Grokhovskaya
Abstract:
We study the reconstruction of overdensity maps of galaxies as function of redshift in the range $0 < \mathrm z < 0.8$ using data from 1-m Schmidt Telescope of Byurakan Astrophysical Observatory (Armenia) in 16 medium band $\sim 250$ A and four broad band (u,g,r,i) filters. The data used in this work homogeneously cover $2.39$ sq. deg with accurate photometric redshiftss, down to $\mathrm R < 23$…
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We study the reconstruction of overdensity maps of galaxies as function of redshift in the range $0 < \mathrm z < 0.8$ using data from 1-m Schmidt Telescope of Byurakan Astrophysical Observatory (Armenia) in 16 medium band $\sim 250$ A and four broad band (u,g,r,i) filters. The data used in this work homogeneously cover $2.39$ sq. deg with accurate photometric redshiftss, down to $\mathrm R < 23$ mag (AB). We reconstructed the density contrast maps for the whole galaxy sample of the HS 47.5-22 ROSAT field in narrow slices for full range of redshifts. We select groups and clusters of galaxies with adaptive kernel based on density peaks which are larger than two times the mean density. The reconstructed overdensity field of galaxies consists of cluster-like structures outlining void-like regions for full redshift range $0 \leq \mathrm z \leq 0.8$. We detect known galaxy clusters in this field with software specially developed for this project. This gives us a possibility to study how star formation properties and galaxy morphology depend on the environments of the galaxies in this field.
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Submitted 3 February, 2020;
originally announced February 2020.
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Medium-band photometric reverberation mapping of AGNs at $0.1 < z < 0.8$. Techniques and sample
Authors:
Eugene Malygin,
Roman Uklein,
Elena Shablovinskaya,
Aleksander Perepelitsyn,
Aleksandra Grokhovskaya
Abstract:
The most popular method of the broad-line region size estimation in active galactic nuclei (AGN) is the reverberation mapping based on measuring the time delay between the continuum flux and the flux in the emission lines. In our work, we apply the method of photometric reverberation mapping in mid-band filters, adapted for observations on the 1-m Zeiss-1000 telescope of Special Astrophysical Obse…
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The most popular method of the broad-line region size estimation in active galactic nuclei (AGN) is the reverberation mapping based on measuring the time delay between the continuum flux and the flux in the emission lines. In our work, we apply the method of photometric reverberation mapping in mid-band filters, adapted for observations on the 1-m Zeiss-1000 telescope of Special Astrophysical Observatory of Russian Academy of Sciences, for the study of AGN with broad lines in the range of redshifts $0.1 < z < 0.8$. This paper provides a sample of 8 objects, describes the technique of observations and data processing for 2 studied objects to demonstrate the stability of the used method.
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Submitted 21 November, 2019;
originally announced November 2019.
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Large Scale Distribution of Galaxies in The Field HS 47.5-22. I. Data Analysis Technique
Authors:
Aleksandra Grokhovskaya,
Sergei N. Dodonov
Abstract:
We present the results of methodological works on automated analysis of the large scale distribution of galaxies. Selecting candidates for clusters and groups of galaxies was carried out using two complementary methods of determining the density contrast maps in the narrow layers of the three-dimensional large scale distribution of galaxies: the filtering algorithm with an adaptive core and the Vo…
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We present the results of methodological works on automated analysis of the large scale distribution of galaxies. Selecting candidates for clusters and groups of galaxies was carried out using two complementary methods of determining the density contrast maps in the narrow layers of the three-dimensional large scale distribution of galaxies: the filtering algorithm with an adaptive core and the Voronoi tesselation. The developed algorithms were tested on 10 data sets of the MICE model catalog; additionally, we determined the statistical parameters of the obtained results (completeness, sample purity, etc.). The constructed density contrast maps were also used to determine voids.
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Submitted 20 November, 2019;
originally announced November 2019.
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Photometric reverberation mapping of AGNs at 0.1 < z < 0.8: I. Observational technique
Authors:
Roman Uklein,
Eugene Malygin,
Elena Shablovinskaya,
Aleksander Perepelitsyn,
Aleksandra Grokhovskaya
Abstract:
The improvement of the calibration relation for determining the size of the broad-line region from the observed optical luminosity of active galactic nuclei (AGN) is a necessary task to study fundamental parameters of distant AGNs such as mass of the central supermassive black hole. The most popular method of the BLR size estimation is the reverberation mapping based on measuring the time delay be…
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The improvement of the calibration relation for determining the size of the broad-line region from the observed optical luminosity of active galactic nuclei (AGN) is a necessary task to study fundamental parameters of distant AGNs such as mass of the central supermassive black hole. The most popular method of the BLR size estimation is the reverberation mapping based on measuring the time delay between the continuum flux and the flux in the emission lines. In our work, we apply the method of photometric reverberation mapping in medium-band filters, adapted for observations at the Zeiss-1000 telescope of the SAO RAS, for the study of AGN with broad lines in the range of redshifts $0.1 < z < 0.8$. This paper describes the technique of observations and data processing, provides a sample of objects and demonstrates the stability of the used method. As a preliminary result for 2MASX J08535955+7700543 at $z=0.1$ we have obtained time delay estimates of $τ(ICCF)=32.2^{\pm10.6}$ days and $τ(JAVELIN)=39.5_{-15.8}^{+23.0}$ days that are consistent with each other and also within the accuracy of the existing calibration relations.
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Submitted 10 November, 2019;
originally announced November 2019.
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An [O III] search for extended emission around AGN with H I mapping: a distant cloud ionized by Mkn 1
Authors:
Erin Darnell Knese,
William C. Keel,
Greg Knese,
Vardha N. Bennert,
Alexei Moiseev,
Aleksandra Grokhovskaya,
Sergei N. Dodonov
Abstract:
Motivated by the discovery of large-scale ionized clouds around AGN host galaxies, and particularly the large fraction of those which are consistent with photoionized gaseous tidal debris, we have searched for [O III] emission over wide fields around a set of Seyfert galaxies previously mapped in H I, many of which show extended gas features. The detection threshold was designed to reach mean emis…
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Motivated by the discovery of large-scale ionized clouds around AGN host galaxies, and particularly the large fraction of those which are consistent with photoionized gaseous tidal debris, we have searched for [O III] emission over wide fields around a set of Seyfert galaxies previously mapped in H I, many of which show extended gas features. The detection threshold was designed to reach mean emission-line surface brightness 10 times fainter than seen in such AGN-ionized clouds as Hanny's Voorwerp, so that similar structures at larger distances (and ages) could be detected. Of 24 Seyfert galaxies, we find one extended emission feature, a discrete cloud projected 12 kpc from the center of Mkn 1 and spanning a transverse extent of 8 kpc. Optical spectroscopy of the Mkn 1 cloud confirms its redshift association with the Mkn 1- NGC 451 galaxy pair, shows it to closely match the kinematics of nearby H I, and reveals emission-line ratios requiring photoionization by the AGN at roughly the direct observed luminosity of the nucleus. Given the small fraction of H I features with detected [O III] emission, we constrain the typical opening angle of ionization cones in Seyfert galaxies to be of order 20 deg, if active episodes are long compared to the light-travel times involved. An appendix presents a derivation of an analytical expression for the probability of intersection of a cone with randomly oriented arcs, approximating the geometry of H I clouds and tails exposed to ionization cones. For the entire sample, the full opening angle of bicones must be <20 deg if the AGN are continuously bright for scales longer than the light-travel times across the H I structures. Since many ionization cones are observed to be much broader than this, our low detection fraction may add to evidence for the ubiquity of strong variations in AGN luminosity on scales 10,000-100,000 years.
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Submitted 29 May, 2019;
originally announced May 2019.