GCN Circular 31619

Anna Y. Q. Ho (UCB), Daniel Perley (LJMU), Igor Andreoni (JSI), Mansi
Kasliwal (Caltech), Dmitry Svinkin (Ioffe Institute), Aaron Tohuvavohu (U.
Toronto), Harsh Kumar (IITB) on behalf of the Zwicky Transient Facility
(ZTF) collaboration:

We report the discovery of ZTF22aabjpxh (AT2022cva
Not found
 
 
), a rapidly fading red
transient located at

16:03:39.35  +31:14:04.72 (J2000)
240.9139656,  31.2346451 (J2000)

first detected as part of the ZTF partnership survey.

The source was discovered on JD 2459630.0001 at r=16.59 �� 0.01 mag, which
was 0.98 days after the last non-detection (r>19.34). The transient
position is 2'' from a galaxy in SDSS with a photometric redshift of 0.25 ��
0.05. Due to the rapid rise of almost 3 magnitudes in one day, and the
possible high luminosity, we triggered follow-up photometry with the
Spectral Energy Distribution Machine (SEDM) on the 60-inch telescope at
Palomar Observatory (P60). SEDM photometry obtained the night after
discovery established a rapid fade rate of 2.25 magnitudes in 0.88 days as
well as red colors (g-r=0.41 �� 0.08, corrected for Galactic extinction).
The transient was also detected as part of the ZTF public survey that
night, and the rapid fade triggered the ZTFReST pipeline (Andreoni &
Coughlin et al. 2021).

Konus-Wind detected a long-duration GRB at UT 2022-02-19 09:27:25.350 that
is consistent with the position of AT2022cva
Not found
 
 
. The GRB burst time is 2.5
hours before the first ZTF detection. The GRB was also weakly detected by
BAT. The ZTF optical position was outside the coded BAT FoV at the time of
the burst, and the observed counts are consistent with a relatively soft
burst coming from outside the BAT field of view. The Konus-BAT IPN annulus
is consistent with the position of the ZTF transient, and the association
is highly likely.

We conclude that AT2022cva
Not found
 
 
 is the likely afterglow to the Konus-Wind GRB.
Given the possible low redshift (z~0.3) continued photometric and
spectroscopic observations are encouraged.


Based on observations obtained with the Samuel Oschin Telescope 48-inch and
the 60-inch Telescope at the Palomar Observatory as part of the Zwicky
Transient Facility project. ZTF is supported by the National Science
Foundation under Grant No. AST-2034437 and a collaboration including
Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center
at Stockholm University, the University of Maryland, Deutsches
Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of
Taiwan, the University of Wisconsin at Milwaukee, Trinity College Dublin,
Lawrence Livermore National Laboratories, IN2P3, University of Warwick,
Ruhr University Bochum and Northwestern University. Operations are
conducted by COO, IPAC, and UW.

-- 
Anna Ho