TITLE: GCN CIRCULAR NUMBER: 30336 SUBJECT: GRB 210626A: GIT optical upper limit DATE: 21/06/28 08:53:15 GMT FROM: Harsh Kumar at Indian Inst of Tech,Bombay H. Kumar(IITB), J. Stanzin (IAO), V. Bhalerao(IITB), G. C. Anupama(IIA), S. Barway(IIA) report on behalf of the GIT team: We observed GRB 210626A detected by Fermi GBM (GCN #30323) with 0.7 m GROWTH-India Telescope (GIT). The GRB was also detected by Swift/BAT-GUANO (GCN #30325) and later on, Swift-XRT detected X-ray afterglow candidate (GCN #30329). We obtained exposures in the r' filter. We did not detect any new source in our stacked image within the 5.7 arcsec circle, around RA: 14:46:05.83, Dec: -01:09:22.5 (GCN #30329). Further, we did not find any new source within the 5 arcmin region identified by BAT localisation (GCN #30325). The obtained upper limit follow as: ------------------------------------------------------------------------- JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) | ------------------------------------------------------------------------- 2459392.2353 | 9.37 | 2 x 300 (stacked) | r' | > 20.5 | ------------------------------------------------------------------------- The magnitudes are calibrated against PanSTARRS (Flewelling et al., 2018) and 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).