TITLE:   GCN CIRCULAR
NUMBER:  31394
SUBJECT: GRB 220101A: continued 1.3m DFOT Optical Observations
DATE:    22/01/06 07:39:50 GMT
FROM:    Rahul Gupta at ARIES, India  <rahulbhu.c157@gmail.com>

Amit Ror, Rahul Gupta, Amit Kumar, Dimple, Ankur Ghosh, Amar Aryan, B.
Kumar, S. B. Pandey, and K. Misra (ARIES) report:

We further observed the bright GRB 220101A (Tohuvavohu, et al., GCN 31347)
with 1.3m Devasthal Fast Optical Telescope (DFOT) located at Devasthal
observatory of Aryabhatta Research Institute of Observational Sciences
(ARIES), India. The observation was started on  2022-01-02 at 13:39:49 UT.
We obtained a series of images with an exposure time of 300 seconds in R,
and I filters, respectively.  We clearly detected the optical afterglow of
GRB 220101A (Tohuvavohu et al., GCN 31347; Kuin & Tohuvavohu, GCN 31351; Fu
et al., GCN 31353; Hentunen et al., GCN 31356; Perley, GCN 31357; de Ugarte
Postigo et al., GCN 31358; Fynbo et al., GCN 31359; Vinko et al., GCN
31361; Tomasella et al., GCN 31363; Mao et al., GCNs 31364, 31368; Noschese
et al., GCN 31366; Guelbenzu et al., GCN 31370; Strausbaugh et al., GCNs
31371, 31383, 31389; Dimple et al., GCN 31384; Romanov, GCN 31387;
Caballero-Garcia
et al., GCN 31388; and Belkin et al., GCN 31390) in our individual images
of both the filters. We report the preliminary brightness of the afterglow
to be R = 19.46 +/- 0.06 mag ~ 32.50 hours post burst.

The reported magnitude value is not corrected for the Galactic extinction
in the direction of the burst. Photometric calibration is performed using
the standard stars from the USNO-B1.0 catalog.

This circular may be cited.