Issue |
A&A
Volume 661, May 2022
The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG mission
|
|
---|---|---|
Article Number | A39 | |
Number of page(s) | 9 | |
Section | Galactic structure, stellar clusters and populations | |
DOI | https://doi.org/10.1051/0004-6361/202141777 | |
Published online | 18 May 2022 |
Identification of three cataclysmic variables detected by the ART-XC and eROSITA telescopes on board the SRG during the all-sky X-ray survey
1
Space Research Institute,
84/32 Profsouznaya str.,
Moscow 117997, Russia
e-mail: sazonov@iki.rssi.ru
2
Moscow Institute of Physics and Technology,
Institutsky per. 9,
141700
Dolgoprudny, Russia
3
Max-Planck-Institut für Astrophysik (MPA),
Karl-Schwarzschild-Str. 1,
85741
Garching, Germany
4
Institute of Solar-Terrestrial Physics, Russian Academy of Sciences,
Siberian Branch,
Irkutsk, Russia
Received:
12
July
2021
Accepted:
10
November
2021
We report the discovery of three cataclysmic variables in the data of the first year of the all-sky X-ray survey by the SRG orbital observatory. The sources were selected for their brightness in the 4-12 keV band in the data of the Mikhail Pavlinsky ART-XC telescope. They are also detected by the eROSITA telescope, which provides accurate localizations and spectral data for a broadband spectral analysis. All three objects were previously known as X-ray sources from the ROSAT all-sky survey and XMM-Newton slew survey, but their nature remained unknown. The X-ray spectra obtained by eROSITA and ART-XC are consistent with optically thin thermal emission with a temperature kT ≳ 18 keV for SRGA J194638.9+704552 and SRGA J225412.8+690658 and kT ≳ 5 keV for SRGAJ204547.8+672642. Together with the inferred high X-ray luminosities (2 × 1032-3 × 1033 erg s-1), this strongly suggests that all three sources are cataclysmic variables (CVs). We have obtained optical photometry and spectroscopy for these objects using the AZT-33IK 1.6 m telescope of the Sayan Observatory. The optical properties confirm the CV nature of the objects. We conclude that SRGA J194638.9+704552 is an intermediate polar, SRGA J204547.8+672642 is likely a polar or intermediate polar, and SRGA J225412.8+690658 is either a magnetic or nonmagnetic CV. We have also measured an orbital period of 2.98 h for SRGA J204547.8+672642 based on TESS data. Three out of the planned eight SRG all-sky surveys have now been completed. We expect to find many new CVs, in particular, magnetic systems, during the survey, and we plan to continue our optical follow-up program.
Key words: novae, cataclysmic variables / surveys / catalogs / X-rays: stars
© ESO 2022
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