2022A&A...661A..39Z -
Astronomy and Astrophysics, volume 661A, 39-39 (2022/5-1)
Identification of three cataclysmic variables detected by the ART-XC and eROSITA telescopes on board the SRG during the all-sky X-ray survey.
ZAZNOBIN I., SAZONOV S., BURENIN R., USKOV G., SEMENA A., GILFANOV M., MEDVEDEV P., SUNYAEV R. and ESELEVICH M.
Abstract (from CDS):
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 x 1032-3 x 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.
Abstract Copyright:
© ESO 2022
Journal keyword(s):
novae, cataclysmic variables - surveys - catalogs - X-rays: stars
Simbad objects:
3
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