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

TL;DR

ASASSN-14ae is a well-observed tidal disruption event at 200 Mpc, characterized by a consistent temperature, exponential luminosity decline, and broad emission lines, providing insights into TDE properties and detection rates.

Contribution

This study presents detailed multi-wavelength observations of a TDE at low redshift, demonstrating its unique spectral features and estimating future detection rates by ASAS-SN.

Findings

Peak luminosity of ~8×10^43 erg/s

Exponential luminosity decline with t_0 ≈ 39 days

Broad emission lines, including Balmer and He II

Abstract

ASASSN-14ae is a candidate tidal disruption event (TDE) found at the center of SDSS J110840.11+340552.2 ($d\simeq200$~Mpc) by the All-Sky Automated Survey for Supernovae (ASAS-SN). We present ground-based and Swift follow-up photometric and spectroscopic observations of the source, finding that the transient had a peak luminosity of $L\simeq8\times10^{43}$~erg~s$^{-1}$ and a total integrated energy of $E\simeq1.7\times10^{50}$ ergs radiated over the $\sim5$ months of observations presented. The blackbody temperature of the transient remains roughly constant at $T\sim20,000$~K while the luminosity declines by nearly 1.5 orders of magnitude during this time, a drop that is most consistent with an exponential, $L\propto e^{-t/t_0}$ with $t_0\simeq39$~days. The source has broad Balmer lines in emission at all epochs as well as a broad He II feature emerging in later epochs. We compare the color and spectral evolution to both supernovae and normal AGN to show that {\name} does not resemble either type of object and conclude that a TDE is the most likely explanation for our observations. At $z=0.0436$, ASASSN-14ae is the lowest-redshift TDE candidate discovered at optical/UV wavelengths to date, and we estimate that ASAS-SN may discover $0.1 - 3$ of these events every year in the future.