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

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

arXiv · 2608.02725

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

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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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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. 2026-08-03. AT 2022csn: A Photometrically Peculiar Optical/UV Tidal Disruption Event in a Type II AGN. https://arxiv.org/abs/2608.02725

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