A Serendipitous Observation of the Recently Discovered Cataclysmic Variable TUVO-21acq

Abstract

The recently discovered non-magnetic cataclysmic variable TUVO-21acq was serendipitously observed in a quiescent state during an XMM-Newton observing campaign for the starburst galaxy NGC 4945. Data from this campaign was combined with archival serendipitous XMM observations to examine its X-ray and UV/optical characteristics. TUVO-21acq was found to have X-ray flux F _X(0.4–3.0 keV) ∼ 1.3 × 10^‑14 erg s^‑1 cm^‑2 and features similar to other quiescent dwarf novae, with X-ray luminosity L _X(0.4–3.0 keV) ∼ 8 × 10³⁰ erg s^‑1 and a white dwarf mass ${M}_{\mathrm{WD}}={0.78}_{-0.27}^{+0.37}\,{M}_{\odot }$ . Its UV/optical spectrum was variable between observations, possibly due to changes in the accretion disk or the visibility of the bright spot.