AN ULTRASOFT X-RAY FLARE FROM 3XMM J152130.7+074916: A TIDAL DISRUPTION EVENT CANDIDATE
AN ULTRASOFT X-RAY FLARE FROM 3XMM J152130.7+074916: A TIDAL DISRUPTION EVENT CANDIDATE
We report on the discovery of an ultrasoft X-ray transient source, 3XMM J152130.7+074916. It was serendipitously detected in an XMM-Newton observation on 2000 August 23, and its location is consistent with the center of the galaxy SDSS J152130.72+074916.5 (z=0.17901 and d_L=866 Mpc). The high-quality X-ray spectrum can be fitted with …