The Transient UV Objects Project

Poster and lightning talk for 'Exploring the Transient Universe with the Nancy Grace Roman Space Telescope': The Transient UV Objects Project, David Modiano.

Note: apologies for the incorrect date in the first slide of the presentation! 

Abstract: Despite the prevalence of transient-searching facilities operating across most wavelengths, the ultraviolet (UV) transient sky remains to be systematically studied. Therefore, we have recently initiated the Transient Ultraviolet Objects (TUVO) project, with which we search for serendipitous UV transients in data obtained using currently available UV instruments with a strong focus on the UV/Optical (UVOT) telescope aboard the Neil Gehrels Swift Observatory. We constructed a pipeline (named TUVOpipe) in order to find such transients in the UVOT data, using difference image analysis. The pipeline is run daily on all new public UVOT data (which are available 6-8 hours after the observations are performed), so we discover transients in near real-time. Using TUVOpipe we have processed 111 330 individual UVOT images and we currently detect an average rate of ∼100 transient candidates per day. Of these daily candidates, on average ∼30% are real transients (separated by human vetting from the remaining ‘bogus’ transients which were not discarded automatically within the pipeline). Most of the real transients correspond to known variable stars, though we also detect a significant number of known active galactic nuclei and accreting white dwarfs. Some of the transients we find represent previously unreported new transients, or undiscovered outbursts of previously known transients, predominantly outbursts from cataclysmic variables. Here we describe TUVOpipe and some of the initial results we have so far obtained.