XMM-Newton and optical follow-up observations of three new polars from the Sloan Digital Sky Survey

• Published in: arXiv.org 2004-11
• Main Authors: Lee, Homer, Szkody, Paula, Chen, Bing, Henden, Arne, Schmidt, Gary D, Fraser, Oliver J, Saloma, Karla, Silvestri, Nicole M, Taylor, Hilda, Brinkmann, J
• Format: Article
• Language: English
• Subjects: Blackbody; Bremsstrahlung; Deposition; Luminosity; Sky surveys (astronomy); Soft x rays; X ray spectra; X-rays; XMM (spacecraft)
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0411175

We report follow-up XMM-Newton and optical observations of three new polars found in the Sloan Digital Sky Survey. Simple modeling of the X-ray spectra, and consideration of the details of the X-ray and optical lightcurves corroborate the polar nature of these three systems and provide further insights into their accretion characteristics. During the XMM-Newton observation of SDSS J072910.68+365838.3, X-rays are undetected apart from a probable flare event, during which we find both the typical hard X-ray bremsstrahlung component and a very strong line O VII (E=0.57 keV), but no evidence of a soft blackbody contribution. In SDSS J075240.45+362823.2 we identify an X-ray eclipse at the beginning of the observation, roughly in phase with the primary minimum of the optical broad band curve. The X-ray spectra require the presence of both hard and soft X-ray components, with their luminosity ratio consistent with that found in other recent XMM-Newton results on polars. Lastly, SDSS J170053.30+400357.6 appears optically as a very typical polar, however its large amplitude optical modulation is 180 degrees out of phase with the variation in our short X-ray lightcurve.