[vsnet-grb-info 26757] GRB 201104B: 1.3m DFOT optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28860
SUBJECT: GRB 201104B: 1.3m DFOT optical observations
DATE:    20/11/06 19:56:54 GMT
FROM:    Rahul Gupta at ARIES, India  <rahul at aries.res.in>

Rahul Gupta (ARIES), Dimple (ARIES), Amit Kumar (ARIES), Ankur Ghosh (ARIES), Amar Aryan (ARIES), Shubham Kishore (ARIES) , Shashi B. Pandey (ARIES), Kuntal Misra (ARIES), and Alok C. Gupta (ARIES ) report: 

We observed the optical afterglow ( Marshall et al., GCN 28827 ; Vielfaure et al., GCN 28840; Oates et al., GCN 28851; and Belkin et al., GCN 28852, GCN 28856) of Swift triggered GRB 201104B (Sbarufatti et al., GCN 28825) using the 1.3m Devasthal Fast Optical Telescope (DFOT) at Devasthal observatory of Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2020-11-05 at 17:44:45 UT . Multiple frames having an exposure time of 60 s were taken in the R filter. We clearly detected the optical counterpart in the stacked images. 

The preliminary photometric estimate of the afterglow in the stacked images is the following : 


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

2020-11-05 17:44:45 24.18 R 30*60 22.40 0.23 

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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 catalog. 

This circular may be cited.