GRB 201020A: GROWTH-India Telescope late-time optical upper limit

We observed GRB 201020A reported by Swift-BAT (E. Ambrosi et al., GCN #28696) with 0.7m GROWTH-India telescope. The field was observed in the SDSS r' filter with multiple 300-sec exposures. We obtained the following late time upper limit: ---------------------------------------------------------------------- JD (mean)| T-T0(hrs) | Filter | Exposure (sec) | Lim_mag (5-sigma) | ---------------------------------------------------------------------- 2459144.094375 | 32.47 | r' | 14 * 300 (stacked) | > 21.47 | ---------------------------------------------------------------------- This upper limit is consistent with our best-fit power-law decay from H. Kumar et al., GCN #28711. Magnitudes are in the AB system and 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).