[vsnet-grb-info 27488] GRB 210217A: 3.6m DOT optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29591
SUBJECT: GRB 210217A: 3.6m DOT optical observations
DATE:    21/03/01 07:26:44 GMT
FROM:    Dimple Panchal at ARIES, India  <dimplepanchal96 at gmail.com>

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

We carried out the follow-up observations of GRB 210217A ( Simpson et al.
GCN #29521) with Aries Devasthal Faint Object Spectrograph and Camera
(ADFOSC) mounted on the 3.6m Devasthal Optical Telescope (DOT) at Devasthal
observatory of Aryabhatta Research Institute of observational sciencES
(ARIES), India.  We detected the optical afterglow (Simpson et al. GCNs
#29521,29555; Zhu et al. GCN #29523; Zheng et al. GCN #29533; Shrestha et
al. GCN #29535; Kumar et al., GCN #29539) at ~ 1.7 days after the burst.

Preliminary photometry is following :

Date               UT start         Filter       Exp. (s)    Mag       err
2021-02-19     15:47:38          r            4*900     22.32      0.17
2021-02-20     16:30:35          r           10*300    >22.60     ----

The reported magnitudes are calibrated with the nearby PanSTARRS field and
are not corrected for Galactic extinction in the direction of the burst.

Using our data along with the data taken from  Zhu et al. GCN #29523; Zheng
et al. GCN #29533; Kumar et al., GCN #29539, we obtain a decay index of
0.47 +-  0.03 consistent with the value quoted by Shrestha et al. # GCN
29535.



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