X-ray Emission of Variable Active Galaxy Candidates from the GALEX Time Domain Survey

Active Galactic Nuclei (AGN) are known to vary at an array of timescales across the electromagnetic spectrum. As such, variability has become a productive method of identifying AGN that lack spectroscopic signatures due to high star formation or obscuration. In previous work we searched for galaxies demonstrating high ultraviolet variability indicative of AGN activity using archival data from the GALEX Time Domain Survey. We identified 48 galaxies as highly variable AGN candidates. We now present the X-ray properties of 23 of these high-probability active galactic nucleus (AGN) candidates with ultraviolet variability. Using data from the Chandra X-ray Observatory and XMM- Newton Observatory, we that find 11/23 nuclei are X-ray detected. We use spectral energy distribution modeling to compute star formation rates and show that the X-ray luminosities are typically in excess of the X-ray emission expected from star formation. This sample shows a diversity of optical spectroscopic properties. We explore possible reasons for why some objects lack optical spectroscopic signatures of black hole activity while still being UV-variable and X-ray bright. We show that UV variability can identify AGN that are missed by other selection techniques and contribute towards a more complete sample of AGN.