TITLE:   GCN CIRCULAR
NUMBER:  31299
SUBJECT: GRB 211211A: observations with the 3.6m Devasthal Optical Telescope
DATE:    21/12/24 16:40:23 GMT
FROM:    Rahul Gupta at ARIES, India  <rahulbhu.c157@gmail.com>

Rahul Gupta, S. B. Pandey, A. Ror, A. Kumar, A. Aryan, Dimple, A. Ghosh, B.
Kumar, and K. Misra (ARIES) as a part of larger international collaboration:


We performed late-time photometric observations of the optical afterglow (Zheng
and Filipenko GCN 31203) of Fermi (Fermi GBM team, GCN 31201) and Swift (D'Ai
et al., GCN 31202) detected GRB 211211A using the 4Kx4K CCD Imager (Pandey
et al. 2017, arXiv:1711.05422v1) mounted at the axial port of the 3.6m
Devasthal Optical Telescope of ARIES Nainital at multiple epochs in several
filters. We report the preliminary brightness of the afterglow to be R =
21.66 +/- 0.07 mag ~ 1.41 days after the GBM trigger. At successive epochs,
we obtained the limiting mag of 23.7 mag ~ 4.42 days post-burst. Our
observations are consistent with the rapid decay nature of the afterglow
reported by de Ugarte Postigo et al. GCN 31229 and A. Moskvitin et al. GCN
31234.

The magnitude value reported is calibrated against UNSO B1 nearby stars.

This circular may be cited. 3.6m Devasthal Optical Telescope (DOT) is
the recently commissioned facility in the Northern Himalayan region of
India (long:79 41 04E, lat:29 21 40N, alt:2540m) owned and operated by the
Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (
https://www.aries.res.in). Authors of this GCN circular thankfully
acknowledge consistent support from the staff members to run and maintain
the 3.6m DOT.