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 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 ------------------------------------------------------------------ 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). [GCN OPS NOTE(24may20): Please see Circular 27804 for a correction to this Circular.]