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  1. No Access

    Article

    Increase in the Brightness of the Cosmic Radio Background toward Galaxy Clusters

    We explore the possibility of detecting the excess of the cosmic radio background toward galaxy clusters due to its Compton scattering by electrons of the hot intergalactic gas. When map** the background flu...

    S. A. Grebenev, R. A. Sunyaev in Astronomy Letters (2024)

  2. No Access

    Article

    Optical Identification and Spectroscopic Redshift Measurements of 216 Galaxy Clusters from the SRG/eROSITA All-Sky Survey

    We present the results of the optical identification and spectroscopic redshift measurements of 216 galaxy clusters detected in the SRG/eROSITA all-sky X-ray survey. The spectroscopic observations were perform...

    I. A. Zaznobin, R. A. Burenin, A. A. Belinski, I. F. Bikmaev… in Astronomy Letters (2023)

  3. No Access

    Article

    SRGz: Classification of eROSITA Point X-ray Sources in the 1 \({\%}\) DESI Region and Calibration of Photometric Redshifts*

    We consider the population of point X-ray sources from the two-year SRG/eROSITA survey in the 1 \(\%\) DESI spectros...

    A. V. Meshcheryakov, G. A. Khorunzhev, S. A. Voskresenskaya… in Astronomy Letters (2023)

  4. No Access

    Article

    X-ray Properties of the Luminous Quasar PG 1634+706 at \(z=1.337\) from SRG and XMM-Newton Data

    In the fall of 2019, during the in-flight calibration phase of the SRG observatory, the onboard eROSITA and Mikhail Pavlinsky ART-XC telescopes carried out a series of observations of PG 1634+706 — one of the ...

    G. S. Uskov, S. Yu. Sazonov, M. R. Gilfanov, I. Yu. Lapshov… in Astronomy Letters (2023)

  5. No Access

    Article

    Optical Identification of Galaxy Clusters among SRG/eROSITA X-ray Sources Based on Photometric Redshift Estimates for Galaxies

    We discuss an algorithm whereby the massive galaxy clusters detected in the SRG/eROSITA all-sky survey are identified and their photometric redshifts are estimated. For this purpose, we use photometric redshif...

    I. A. Zaznobin, R. A. Burenin, A. V. Meshcheryakov, M. R. Gilfanov… in Astronomy Letters (2023)

  6. No Access

    Article

    SRGz: Machine Learning Methods and Properties of the Catalog of SRG/eROSITA Point X-ray Source Optical Counterparts in the DESI Legacy Imaging Surveys Footprint

    We describe the methods of the SRGz system for the physical identification of eROSITA point X-ray sources from photometric data in the DESI Legacy Imaging Surveys footprint. We consider the models included in ...

    A. V. Meshcheryakov, V. D. Borisov, G. A. Khorunzhev, P. A. Medvedev… in Astronomy Letters (2023)

  7. No Access

    Article

    Transient Events in the Circumnuclear Regions of AGNs and Quasars As Sources of Imitations of Proper Motions

    This paper is an extension of the study by Khamitov et al. (2022) with regard to the catalog and the astrophysical interpretation of the imitation of significant proper motions in active galactic nuclei (AGNs)...

    I. M. Khamitov, I. F. Bikmaev, M. R. Gilfanov, R. A. Sunyaev… in Astronomy Letters (2023)

  8. No Access

    Article

    X-ray Halo of the Pulsar 4U 1538–52 from SRG Data

    We present the first results of the SRG observation of the pulsar 4U 1538–52 based on ARC-XC and eROSITA data. An extended emission in the form of a halo is detected around the source in the 0.5–8 keV energy b...

    A. E. Shtykovsky, A. A. Lutovinov, R. A. Krivonos, M. R. Gilfanov… in Astronomy Letters (2023)

  9. No Access

    Article

    New Active Galactic Nuclei Detected by the ART-XС and eROSITA Telescopes during the First Five SRG All-Sky X-ray Surveys

    We present the results of our identification of 14 X-ray sources detected in the eastern Galactic sky ( \(0^{\circ}<l<180^{\circ}\) ...

    G. S. Uskov, S. Yu. Sazonov, I. A. Zaznobin, R. A. Burenin… in Astronomy Letters (2023)

  10. No Access

    Article

    Search for Tidal Disruption Events Based on the SRG/eROSITA Survey with Subsequent Optical Spectroscopy

    The four completed six-month sky surveys with the eROSITA telescope onboard the SRG orbital observatory allow tidal disruption events (TDEs) in galactic nuclei to be searched for by their X-ray variability. In...

    G. A. Khorunzhev, S. Yu. Sazonov, P. S. Medvedev, M. R. Gilfanov… in Astronomy Letters (2022)

  11. No Access

    Article

    Detection of AGNs and Quasars with Significant Proper Motions Based on Gaia Data in the SRG/eROSITA Catalog of X-ray Sources

    Based on a comparison of the SRG/eROSITA catalog of X-ray active stars and the Gaia catalog, we have obtained a sample of 502 peculiar objects for which Gaia, on the one hand, detects statistically significant...

    I. M. Khamitov, I. F. Bikmaev, M. R. Gilfanov, R. A. Sunyaev… in Astronomy Letters (2022)

  12. No Access

    Article

    Highly Variable Active Galactic Nuclei in the SRG/eROSITA Sky Survey: I. The Constriction of a Sample and the Catalog of Objects Detected in a Low State

    We present the results of our search for highly variable active galactic nuclei (AGNs) the X-ray flux from which changed by more than an order of magnitude during the SRG/eROSITA all-sky survey. Using the eROS...

    P. S. Medvedev, M. R. Gilfanov, S. Yu. Sazonov, R. A. Sunyaev… in Astronomy Letters (2022)

  13. No Access

    Article

    Observations of Massive Galaxy Clusters from the All-Sky Survey with the eROSITA Telescope Onboard the SRG Space Observatory

    We present the results of our search for massive galaxy clusters among extended X-ray sources from the SRG/eROSITA survey using data from the Planck survey and data from optical and infrared sky surveys. Optic...

    R. A. Burenin, I. A. Zaznobin, P. S. Medvedev, M. R. Gilfanov… in Astronomy Letters (2022)

  14. No Access

    Article

    An Extended Catalog of Sunyaev–Zeldovich Objects from Planck Data with Deep Learning

    We present an extended catalog of Sunyaev–Zeldovich (SZ) sources from Planck data based on a combination of the samples obtained by two independent approaches to the detection of objects in microwave data: the...

    A. V. Meshcheryakov, A. Nemeshaeva, R. A. Burenin, M. R. Gilfanov… in Astronomy Letters (2022)

  15. No Access

    Article

    SRGe J214919.3+673634—a Candidate for AM Her Variables Discovered by the eROSITA Telescope onboard the Spectrum–Roentgen–Gamma Orbital Observatory

    We present the results of the optical identification, classification, and analysis of our photometric and spectroscopic observations of the X-ray transient SRGe J214919.3+673634 discovered by the eROSITA teles...

    I. F. Bikmaev, A. I. Kolbin, V. V. Shimansky, I. M. Khamitov… in Astronomy Letters (2022)

  16. No Access

    Article

    New Active Galactic Nuclei Detected by the ART-XС and eROSITA Telescopes Onboard the SRG Observatory during an All-Sky X-ray Survey

    We present the results of our identification of 17 X-ray sources detected in the 4–12 keV energy range by the Mikhail Pavlinsky ART-XC telescope during the first year of the SRG all-sky survey. Three of them h...

    G. S. Uskov, I. A. Zaznobin, S. Yu. Sazonov, A. N. Semena… in Astronomy Letters (2022)

  17. No Access

    Article

    Search for Distant and X-ray Luminous Quasars during the SRG/eROSITA Sky Survey (the DaLeQo Program). The First Results from Observations at the BTA Telescope

    We discuss the results of our spectroscopy for 17 candidates for distant quasars selected by the SRGz classification system based on data from the first and second sky surveys with the eROSITA telescope onboar...

    G. A. Khorunzhev, S. N. Dodonov, A. V. Meshcheryakov, A. V. Moiseev… in Astronomy Letters (2022)

  18. No Access

    Article

    Estimation of the Mass of the Very Massive Galaxy Cluster SRGe CL2305.2-2248 from Strong Lensing

    SRGe CL2305.2–2248 (SPT-CL J2305–2248, ACT-CL J2305.1–2248) is one of the most massive galaxy clusters at high redshifts ( $$z\simeq 0....

    I. M. Khamitov, I. F. Bikmaev, N. S. Lyskova, A. A. Kruglov… in Astronomy Letters (2022)

  19. No Access

    Article

    Optical Spectroscopy of Quasars Discovered by SRG/eROSITA with a 2.5-m Telescope at the Caucasus Mountain Observatory of SAI MSU

    Based on observations with the transient double-beam spectrograph (TDS) at the 2.5-m telescope of the Caucasus Mountain Observatory of SAI MSU, we have determined the redshifts for 15 new quasars detected in X...

    A. V. Dodin, N. I. Shatsky, A. A. Belinski, K. E. Atapin, M. A. Burlak… in Astronomy Letters (2021)

  20. No Access

    Article

    Observation of a Very Massive Galaxy Cluster at \(\boldsymbol{z}\) = 0.76 in the SRG/eROSITA All-Sky Survey

    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 has also been...

    R. A. Burenin, I. F. Bikmaev, M. R. Gilfanov, A. A. Grokhovskaya… in Astronomy Letters (2021)

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