[vsnet-grb-info 25667] GRB 200519A: GROWTH-India optical follow-up

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27767
SUBJECT: GRB 200519A: GROWTH-India optical follow-up
DATE:    20/05/20 16:32:17 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13 at gmail.com>

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

We followed up GRB200519A (R. Sbarufatti et al., GCN 27756, A. Kong et al., GCN
27757, R. Strausbaugh et al., GCN 27759, Y. Hu et al., GCN 27760, A Kumar
et al., GCN 27764) with 0.7m GROWTH-India telescope. We obtained 600-sec
exposures in SDSS g, r, i filters starting at UT 20-05-19T17:11:06 (~5.85
hrs after the burst).

We obtained the following magnitudes with PSF photometry, calibrated
against PanSTARRs PS1 data release (Flewelling et al., 2018).

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

 JD(Start) | T-T0(hrs) | Filter | Mag |

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

2458989.216 | 5.85 | g | 19.926 +/- 0.09

2458989.321 | 8.36 | g | 20.514 +/- 0.09

2458989.354 | 9.16 | g | 20.779 +/- 0.13

2458989.281 | 7.41 | r | 19.359 +/- 0.07

2458989.305 | 7.98 | r | 19.505 +/- 0.06

2458989.329 | 8.56 | r | 19.788 +/- 0.06

2458989.361 | 9.33 | r | 19.891 +/- 0.08

2458989.265 | 7.02 | i | 19.529 +/- 0.12

2458989.313 | 8.17 | i | 19.984 +/- 0.14

2458989.369 | 9.52 | i | 20.206 +/- 0.18

2458989.392 | 10.07| i | 20.583 +/- 0.26

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

We found that the source is fading with a power-law of 1.65 +/- 0.28 in g
band, 2.36 +/- 0.4 using in r band and 2.37 +/- 0.33 in i band observations.

The magnitudes 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).