GCN Circular 28621
Subject
GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
Date
2020-10-14T16:20:40Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), V. Kim (AFIF, Pulkovo Observatory),
R. Ya. Inasaridze (AbAO), M. Krugov (AFIF), A. Volnova (IKI) report
on behalf of IKI-GRB-FuN:
We observed the field of Swift GRB 201013A (Page et al., GCN 28607; see
also detection by CALET Tamura et al, GCN 28618) with Zeiss-1000(W) 1-m
telescope of Tien Shan Astronomical Observatory (TSHAO) and AS-32
telescope of Abastumani observatory (AbAO) in R-filter. Within enhanced
XRT position (Beardmore et al., GCN 28608), at 1.6 arc seconds from
the center of the position, we observed an object mentioned by Jelinek
et al. (GCN 28615) and listed at least in the USNO-B.10 and PS1
catalogs. Aperture photometry of the object are brighter than R2=16.22
magnitude of the object in USNO-B1.0 1470-0207304 in both our
observations. Flux subtraction of our photometry and R2=16.22 result in
photometry of possible afterglow suggested in earlier observations by
FRAM-ORM (Jelinek et al. GCN 28615). Results of the flux subtraction
assuming negligible error of R2 presented in USNO-B1.0 are following
Date, UT start, T0+ Exp., Filter, OT, Err., UL, observatory
(mid, days)
2020-10-13 21:44:47 0.79464 22*360 R 19.00 (+0.22 -0.18) 20.0 TSHAO
2020-10-13 23:33:56 0.84197 50* 60 R 19.39 (+0.08 -0.08) 21.3 AbAO
The photometry is based on nearby USNO-B1.0 star
USNO-B1.0_id R2
1470-0207278 14.89
While we cannot definitely detect fading the possible afterglow, the
brightness of possible afterglow faded significantly between earlier
(Jelinek et al. GCN 28615) and our observations.
The cross section profile of the object in our observation at
Zeiss-1000(W) of TSHAO is differ from point like source. The reason of
the extended profile might be due to offset of the afterglow from the
foreground star or could be due to the object USNO-B1.0 1470-0207304 is
not the star but a galaxy. In the latter case, USNO-B1.0 may be a small
neighboring host galaxy GRB 201013A.