[vsnet-grb-info 26647] GRB 201020A: GROWTH-India Telescope late-time optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28747
SUBJECT: GRB 201020A: GROWTH-India Telescope late-time optical upper limit
DATE:    20/10/22 15:21:06 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13 at gmail.com>

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


We observed GRB 201020A reported by Swift-BAT (E. Ambrosi et al., GCN
#28696) with 0.7m GROWTH-India telescope. The field was observed in the
SDSS r’ filter with multiple 300-sec exposures. We obtained the following
late time upper limit:
----------------------------------------------------------------------

 JD (mean)| T-T0(hrs) | Filter | Exposure (sec) | Lim_mag (5-sigma) |

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

2459144.094375 | 32.47 | r’ | 14 * 300 (stacked) | > 21.47 |

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

This upper limit is consistent with our best-fit power-law decay from H.
Kumar et al., GCN #28711. Magnitudes are in the AB system and calibrated
against PanSTARRs PS1 data release, (Flewelling et al., 2018).


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).