[vsnet-grb-info 25738] GRB 200528A: 1.3m DFOT Optical Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27838
SUBJECT: GRB 200528A: 1.3m DFOT Optical Upper Limits
DATE:    20/05/28 17:52:58 GMT
FROM:    Amit Kumar at ARIES, India  <amitkundu515 at gmail.com>

A. Kumar (ARIES), S. B. Pandey (ARIES), R. Gupta (ARIES), K. Misra (ARIES),
A. Aryan (ARIES), A. Ghosh (ARIES), and Dimple (ARIES) report:

We carried out observation of Fermi GBM detected GRB 200528A (GCN 27831,
Ambrosi et al., GCN 27832) with the 1.3m Devasthal Fast Optical Telescope
(DFOT) at Devasthal observatory of Aryabhatta Research Institute of
observational sciencES (ARIES), India.

The observation was started on 2020-05-28T15:37:05 UTC. We observed a
series of 4 x 300s exposures using the Bessell I filter covering Swift XRT
enhanced position (Evans et al., 27836).

We do not detect any new optical source within the Swift XRT enhanced error
circle in individual as well as in the stacked image (Adachi et al., GCN
27834, Lipunov et al., GCN 27835 and Zhu et al., GCN 27837).

We obtained the 3-sigma upper limit as follows:

T_start-T0(hrs) Start Date (UTC)  End Date (UTC)   Filter  Limit (mag)
-----------------------------------------------------------------------------------------------
5.161    2020-05-28T15:37:05  2020-05-28T15:58:42   I     20.2 +- 0.2



Photometry is done based on the USNO-B1.0 catalog. This magnitude is not
corrected for Galactic extinction in the direction of the GRB.