TITLE:   GCN CIRCULAR
NUMBER:  28450
SUBJECT: GRB 200917A: GROWTH-India Telescope optical upper limit.
DATE:    20/09/18 03:53:27 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13@gmail.com>

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

We observed GRB 200917A reported by Swift-BAT (E. Sonbas et al., GCN 28435,
M.R. Goad et al., GCN 28436) with 0.7m GROWTH-India Telescope (GIT). The
field was observed in the SDSS r’ filter starting at 2020-09-17T14:15:12.96 UT
i.e. ~10.37 hrs after the event detection by Swift-BAT. We obtained 6
exposures of 300 sec each, at an airmass of ~2.5. We did not find any
source in the stacked image within the uncertainty region of 1.9 arcsec
around the Swift-XRT position of RA(J2000): 15h 42m 53.84s, Dec(J2000):
-04d 42' 02.1" (GCN  28436). We obtained an upper limit of r > 20.23
mag (5-sigma),
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).