AT 2022csn: A Photometrically Peculiar Optical/UV Tidal Disruption Event in a Type II AGN

arXiv:2608.02725 · astro-ph.HE · Submitted 2026-08-03 · Read on arXiv

Yael Dgany, Iair Arcavi, Grisha Zeltyn, Sebastian Gomez, Daichi Hiramatsu, Benny Trakhtenbrot, Megan Newsome, Dalya Baron, Craig Pellegrino, Jamison Burke, Nadejda Blagorodnova, David Jones, Gerard-Garcia Moreno, Erez A. Zimmerman, Asaf Horowicz, Avishay Gal-Yam, Mariusz Gromadzki, Edo Berger, Sara Faris, D. Andrew Howell, Harsh Kumar

astro-ph.HE

Submitted: 2026-08-03

Comments: Accepted for publication in ApJ

Code: https://github.com/svalenti/FLOYDS

License: http://creativecommons.org/licenses/by/4.0/

The gist: The emission mechanism and host galaxy preference of optical/UV tidal disruption events (TDEs) are still not entirely understood.

Terminology

Abstract

The emission mechanism and host galaxy preference of optical/UV tidal disruption events (TDEs) are still not entirely understood. We present observations of the TDE AT 2022csn, which is one of the most distant (d L 726 Mpc) and luminous (L peak=2.487(+0.073)(-0.067)*10(44) erg/s) optical/UV TDEs observed to date. Although it is a spectroscopically normal H+He TDE, it shows some photometric peculiarities, exhibiting a pronounced double-peaked light curve (with peaks separated by 18.30 pm 2.84 days in the g-band), and lying in the low-temperature and large-radius end of the optical/UV TDE population. The host galaxy of AT 2022csn shows evidence for a significant starburst within the last Gyr consistent with other optical/UV TDEs, but also narrow emission lines that place it within the Type II AGN region of the BPT diagram. Interaction between the TDE and a pre-existing AGN accretion disk might explain the peculiar photometric properties. However, it is puzzling that a TDE would be visible in a Type II AGN, where according to the AGN unification picture the central region around the supermassive black hole is obscured. We suggest a few scenarios to reconcile this. AT 2022csn together with AT 2019ahk, which shows similar properties, may belong to a new subset of low-temperature, high-radius TDEs in galaxies with Type II AGN emission features.

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