IGR J04571+4527 and Swift J0525.6+2416 are two hard X-ray sources detected in the Swift/BAT and INTEGRAL/IBIS surveys. They were proposed to be magnetic cataclysmic variables of the intermediate polar (IP) type, based on optical spectroscopy. IGR J04571+4527 also showed a 1218 s optical periodicity, suggestive of the rotational period of a white dwarf, further pointing towards an IP classification. We here present detailed X-ray (0.3-10 keV) timing and spectral analysis performed with XMM-Newton, complemented with hard X-ray coverage (15-70 keV) from Swift/BAT. These are the first high-S/N observations in the soft X-ray domain for both sources, allowing us to identify the white dwarf X-ray spin period of Swift J0525.6+2416 (226.28 s), and IGR J04571+4527 (1222.6 s). A model consisting of multitemperature optically thin emission with complex absorption adequately fits the broadband spectrum of both sources. We estimate a white dwarf mass of about 1.1 and 1.0 M⊙ for IGR J04571+4527 and Swift J0525.6+2416, respectively. The above characteristics allow us to unambiguously classify both sources as IPs, confirming the high incidence of this subclass among hard X-ray emitting cataclysmic variables.
- White dwarfs
- X-rays: individual: IGR J04571+4527 (1RXS J045707.4+452751, as Swift J0457.1+4528)
- X-rays: individual: Swift J0525.6+2416 (1RXS J052523.2+241331, as WISE J052522.84+24133333.6)
- novae, cataclysmic variables
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science