DRAFT
2021-06-08 16:01:30
Type: Object/s-Discovery/Classification
Bibcode: 2021TNSAN.170....1M
Classification of AT 2021ont as a Possible Bowen Fluorescence Flare around a Supermassive Black Hole
Authors: Lydia Makrygianni (TAU), Yael Dgany (TAU), Marco Lam (TAU), Benny Trakhtenbrot (TAU), Iair Arcavi (TAU), Claudio Ricci (UDP)
Keywords: Spectroscopy
Abstract:
We classify AT 2021ont as a likely Bowen Fluorescence Flare, related to enhanced accretion onto a SMBH, based on an LT-SPRAT spectrum obtained on UT 2021-06-06 23:25:23. In this sense, AT 2021ont resembles the previously identified class of nuclear transients with such emission features (e.g., AT 2017bgt). The possible Bowen fluorescence lines were not present in the SDSS archival spectrum obtained in April 2003.

AT 2021ont (ZTF21abdmevk) was discovered by the Zwicky Transient Facility in the nucleus of a z=0.028 galaxy on June 3, and it is currently rising. An archival SDSS spectrum of the host galaxy, SDSS J162642.49+390842.8, taken in April 2003 indicates a starburst galaxy, with prominent, narrow Balmer and forbidden emission lines.

 

We obtained an optical spectrum with the SPRAT instrument mounted on the Liverpool Telescope (through OPTICON program OL21A01, PI: Arcavi) at  2021-06-06 23:25:23 UT. The SPRAT spectrum shows a bluer continuum compared to the SDSS spectrum, a significantly higher Hbeta / [OIII]5007 line ratio, and a new emission feature around rest-frame 4680A, consistent with a blend of HeII 4686A and NIII 4640A emission lines. These characteristics have been previously associated with Bowen Fluorescence Flares (BFFs) - a class of enhanced accretion events around supermassive black holes (Trakhtenbrot et al. 2019, Nature Astronomy, 3, 242), likely driven by intense EUV flares that lead to the excitation of the Bowen Fluorescence cascades. 

 

We are pursuing additional spectroscopic and multi-wavelength observations of AT 2021ont.


 

Show current TNS values
Catalog Name Reported RA Reported DEC Reported Obj-Type Reported Redshift Host Name Host Redshift Remarks TNS RA TNS DEC TNS Obj-Type TNS Redshift
TNS 2021ont [ZTF21abdmevk] 16:26:42.485 +39:08:42.86 0.028 WISE J162642.49+390842.7 0.02834 16:26:42.534 +39:08:42.96 SN II 0.02833

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