A multiwavelength study of Swift J0503.7-2819: a chimeric magnetic CV

ABSTRACT We present multiwavelength temporal and spectral characteristics of a magnetic cataclysmic variable (MCV) Swift J0503.7-2819, using far ultraviolet and X-ray data from AstroSat, supplemented with optical data from the Southern African Large Telescope and X-ray data from the XMM-Newton and Swift observatories. The X-ray modulations at 4897.6657 s and 3932.0355 s are interpreted as the orbital (PΩ) and spin (Pω) period, respectively, and are consistent with prior reports. With a spin-orbit period ratio of 0.8 and PΩ falling below the period gap (2–3 h) of CVs, Swift J0503.7-2819 would be the newest addition to the growing population of nearly synchronous MCVs, which we call EX Hya-like systems. Hard X-ray luminosity of