[vsnet-grb-info 26773] ZTF20acozryr (GRB 201103B): GROWTH-India Telescope optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28876
SUBJECT: ZTF20acozryr (GRB 201103B): GROWTH-India Telescope optical observations
DATE:    20/11/10 15:25:55 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13 at gmail.com>

K. Sharma (IITB), H. Kumar (IITB), P. Dorjay (IAO), J. Stanzin (IAO), U.
Stanzin (IAO), V. Bhalerao (IITB), G. C. Anupama (IIA), S. Barway (IIA),
report on behalf of the GROWTH-India collaboration:

We followed-up the optical afterglow ZTF20acozryr (Michael Coughlin et.
al., GCN #28841) of GRB 201103B, detected by the AGILE (GCN #28831) and IPN
(D. Svinkin et. al. GCN #28844), with 0.7 m GROWTH-India telescope. We
obtained 300-sec exposures in the SDSS r' filter over multiple nights.

Here are the photometric results from GIT observations:-

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JD (mid) | Filter | Exposure | mag | e_mag |

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2459160.322200 | r' | 300 x 20 | 21.08 | 0.08 |

2459163.145455 | r' | 300 x 30 | 21.91 | 0.06 |

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

Combining our photometric results with r/r' band measurements of Michael
Coughlin et. al., GCN #28841; D. Xu et. al., GCN #28846; D. Xu et. al., GCN
#28847; S. Belkin et. al., GCN #28862; we conclude that the source is
fading with a power-law index of 1.16 +/- 0.07. The magnitudes are
calibrated against PanSTARRs PS1 data release, (Flewelling et al., 2018)
and are not corrected for galactic extinction.

The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7 degree
field of view, set up by the Indian Institute of Astrophysics and the
Indian Institute of Technology Bombay with support from the Indo-US Science
and Technology Forum (IUSSTF) and the Science and Engineering Research
Board (SERB) of the Department of Science and Technology (DST), Government
of India (https://sites.google.com/view/growthindia/). It is located at the
Indian Astronomical Observatory (Hanle), operated by the Indian Institute
of Astrophysics (IIA).