Some galaxies show little to no sign of active galactic nucleus (AGN)
activity, yet exhibit strong coronal emission lines (CLs) relative to common
narrow emission lines. Many of these coronal lines have ionization potentials
of ≥100 eV, thus requiring strong extreme UV and/or soft X-ray flux. It
has long been thought that such events are powered by tidal disruption events
(TDEs), but owing to a lack of detailed multi-wavelength follow-up, such a
connection has not been firmly made. Here we compare coronal line emitters
(CLEs) and TDEs in terms of their host-galaxy and transient properties. We find
that the mid-infrared (MIR) colors of CLE hosts in quiescence are similar to
TDE hosts. Additionally, many CLEs show evidence of a large dust reprocessing
echo in their mid-infrared colors, a sign of significant dust in the nucleus.
The stellar masses and star formation rates of the CLE hosts are consistent
with TDE hosts, and both populations reside within the green valley. The
blackbody properties of CLEs and TDEs are similar, with some CLEs showing hot
(T ≥40,000 K) blackbody temperatures. Finally, the location of CLEs on
the peak-luminosity/decline-rate parameter space is much closer to TDEs than
many other major classes of nuclear transients. Combined, these provide strong
evidence to confirm the previous claims that CLEs are indeed TDEs in gas-rich
environments. We additionally propose a stricter threshold of CL flux ≥1/3× [O III] flux to better exclude AGNs from the sample of CLEs.Comment: 9 pages, 7 figures. Will be submitted to MNRAS. Comments welcom