Swift X-ray and UV Observations of SDSS J141118.31+481257.6 During its First Ever Recorded Superoutburst

Abstract

SDSS J141118.31+481257.6 is an ultracompact white dwarf binary (or AM CVn system) with an orbital period of 46 min. We analyze ~23 ks of X-ray and UV data taken with the Neil Gehrels Swift Observatory during its first ever recorded outbursts. The events took place 13 years after the system was discovered. We detected 3 events in our UV data, all with amplitudes of ~7 mags with respect to quiescence, the largests detected for an AM CVn system so far. The first 2 events correspond to a superoutburst and the third one to another detected outburst. The 3 episodes that we identified occurred in a period of 24 days, each one displaying very rapid brightness changes. At ~120 days since the detection of the superoutburst, the system remains 1 magnitude brighter in UV compared to the quiescence level. The X-ray observations suggest that the X-ray emission is not correlated with the UV.