INTEGRAL view on Cataclysmic Variables and Symbiotic Binaries

Abstract

Accreting white dwarfs (WDs) constitute a significant fraction of the hard X-ray sources detected by the INTEGRAL observatory. Most of them are magnetic Cataclysmic Variables (CVs) of the intermediate polar (IP) and polar types, but the contribution of the Nova-likes systems and the systems with optically thin boundary layers, Dwarf Novae (DNs) and Symbiotic Binaries (or Symbiotic Stars, SySs) in quiescence is also not negligible. Here we present a short review of the results obtained from the observations of cataclysmic variables and symbiotic binaries by INTEGRAL. The highlight results include the significant increase of the known IP population, determination of the WD mass for a significant fraction of IPs, the establishment of the luminosity function of magnetic CVs, and uncovering origin of the Galactic ridge X-ray emission which appears to largely be associated with hard emission from magnetic CVs.

Chandra, NuSTAR, and Optical Observations of the Cataclysmic Variables IGR J17528-2022 and IGR J20063+3641

“…The International Gamma-ray Astrophysics Laboratory (INTEGRAL; Winkler et al 2003) has played a pivotal role in uncovering the relatively faint end (F X ∼ > 10 −11 erg cm −2 s −1 ) of the Galactic hard X-ray source population (see e.g., Bird et al 2016;Krivonos et al 2017;Lutovinov et al 2020). While INTEGRAL has uncovered many new sources, a large fraction of them still remain unidentified due to their large positional uncertainties (∼ 1 − 4 ), making it difficult to confidently locate their longer wavelength counterparts.…”