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 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).