GCN Circular 29173

Rahul Gupta (ARIES), Dimple (ARIES), Amit Kumar (ARIES), Vineet Ojha
(ARIES), Ankur Ghosh (ARIES), Amar Aryan (ARIES),  Shashi B. Pandey
(ARIES), and Kuntal Misra (ARIES) report:

We observed the optical afterglow ( Lipunov et al., GCN 29157
Not found
 
 
; Gropp
et al., GCN 29158
Not found
 
 
; Zhu et al., GCN 29159
Not found
 
 
; Hu et al., GCN 29160
Not found
 
 
;
Hosokawa et al., GCN 29164
Not found
 
 
; Romanov et al., GCN 29165
Not found
 
 
; Xin et al., GCN
29166
Not found
 
 
; Belkin et al., GCN 29167
Not found
 
 
; and Kumar et al., GCN 29168
Not found
 
 
) of Swift
and Fermi detected GRB 201223A (Gropp et al., GCN 29158
Not found
 
 
; and Wood et
al., GCN 29161
Not found
 
 
) using the 1.3m Devasthal Fast Optical Telescope (DFOT)
and 1.04m Sampurnanand Telescope (ST) of Aryabhatta Research Institute
of Observational Sciences (ARIES), India. The observations were
started on 2020-12-23 at 19:01:46 UT. Multiple frames having an
exposure time of 300 s were taken in the I filter using DFOT and in
BVRI filters using ST. We clearly detected the optical counterpart at
the position reported by Gropp et al., GCN 29158
Not found
 
 
.


The preliminary photometric estimate of the afterglow using I band
data of DFOT is the following :


Date Start_UT           T_start-T0 (hrs)      Filter      Exp time (s)
  Magnitude    Mag_err
------------------------------ ------------------------------
------------------------------ ------------------------------

2020-12-23   19:07:55      1.158              I              300*1
          18.71           0.04

------------------------------ ------------------------------
------------------------------ ------------------------------


The magnitude is not corrected for the Galactic and Host extinction in
the direction of the burst. Photometric calibration is performed using
the standard stars from the USNO-B1.0 catalogue.  Further processing
of data is going on.

This circular may be cited.