ASASSN-14ae: A Tidal Disruption Event at 200 Mpc

ASASSN-14ae is a candidate tidal disruption event (TDE) found at the center of SDSS J110840.11+340552.2 (d ' 200 Mpc) by the All-Sky Automated Survey for Su-pernovae (ASAS-SN), a global array of 14-cm telescopes. The host galaxy is an early type spiral with no signs of an active galactic nucleus (AGN) and with little recent star formation. We present follow-up photometric and spectroscopic observations of the source, including optical data from ground-based telescopes and ultraviolet and optical data from Swift. From blackbody fits to the host-subtracted spectral energy distribu-tion, we find that the transient had a peak luminosity of L ' 8×1043 erg s−1 and a total integrated energy of E ' 1.5×1050 ergs over the ∼ 3 months of observations presented. The blackbody temperature of the transient remains roughly constant at T ∼ 20, 000 K while the luminosity declines by nearly 1.5 orders of magnitude during this time, a drop that is most consistent with an exponential, L ∝ e−t/t0 with t0 ' 32.5 days. The source has broad Balmer lines in emission at all epochs, with the Hα width evolving from ∼ 17000 km s−1 near discovery to ∼ 8000 km s−1 three months later. We also detec