[vsnet-grb-info 25700] GRB 200524A: GROWTH-India confirmation of optical afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27800
SUBJECT: GRB 200524A: GROWTH-India confirmation of optical afterglow
DATE:    20/05/24 19:58:19 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13 at gmail.com>

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

We followed up GRB 200524A (F. F. Dirirsa et al., GCN 27797, A. Ho et al.,
GCN 27799) with 0.7m GROWTH-India telescope. We obtained 600-sec exposures
in SDSS g, r, i filters starting at UT 2020-05-24T10:41:57 (~5.6 hrs after
the burst). We detect a faint transient with magnitudes r = 20.56 +- 0.14
and i = 20.59 +- 0.28 (calibrated against PanSTARRs PS1 data release,
Flewelling
et al., 2018). The source position matches with the likely afterglow
candidate by A. Ho et al. (GCN 27799). The fading rate is approximately 3
magnitudes in four hours, consistent with the fading rate reported in the
ZTF GCN. We hereby, confirm ZTF20abbiixp as the afterglow of GRB 200524A.

We obtained the following photometric results:-

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

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

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

2458993.946 | 5.64 | g | > 21.01 (5-sigma)

2458993.954 | 5.83 | r | 20.56 +/- 0.14

2458993.962 | 6.02 | i | 20.59 +/- 0.28

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Given the fast fading, we encourage the followup of the source. 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).