{
  "bibcode": "2021GCN.31227....1K",
  "body": "H. Kumar(IITB), V. Bhalerao(IITB), Rahul Gupta(ARIES), Rigzin Norbu (IAO),\nG. C. Anupama(IIA), D. K. Sahu (IIA), S. Barway(IIA), A. Dutta (IIA), B.\nKumar (ARIES), Dimple (ARIES), S.B. Pandey (ARIES), Kuntal Mishra (ARIES)\nreport on behalf of the HCT and GIT team:\n\nWe observed GRB 211211A detected by Fermi GBM (GCN #31201) and Swift-BAT\n(A. D'Ai et al., GCN #31202); optical counterpart first reported by W Zheng\nand A V. Filippenko, (GCN #31203) with 2.0m Himalayan Chandra Telescope\n(HCT) and 0.7m GROWTH-India Telescope (GIT). We obtained a 900-sec exposure\nin the Bessell R filter using HCT and multiple 300-sec r' band exposures\nwith GIT. We obtained the following photometric results:-\n\n---------------------------------------------------------------------\n\n JD (mid) | T_mid-T0(hrs) | Exposure | Filter | Magnitude | Tel |\n\n---------------------------------------------------------------------\n\n 2459560.50469 | 10.94 | 900 sec | Bessell R | 20.30 +/- 0.13 | HCT |\n\n 2459561.47439 | 34.21 | 1500 sec | r' | > 21.19 | GIT |\n\n---------------------------------------------------------------------\n\nOur results from HCT are similar to R band magnitudes reported in N. Ito\net. al, (GCN #31217) which suggests that there was no significant decay in\nthe early hours ( <~11 hrs). GIT r' band observations at ~34 hrs did not\ndetect the afterglow, with a limiting magnitude of 21.19 - confirming the\nfading of the afterglow at late times reported by R. Strausbaugh et. al.,\n(GCN #31214).\n\nThe magnitudes were calibrated by querying the SDSS catalog (Alam+, 2015).\nWe converted magnitudes to the R band using Lupton (2005) equations for HCT\ncalibration.\n\n\nHCT observations were carried out under the ToO program HCT-2021-C3-P02. We\nthank HCT and GIT observers, staff for undertaking the observations.\n\nThe GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree\nfield of view, set up by the Indian Institute of Astrophysics (IIA) and the\nIndian Institute of Technology Bombay (IITB) with funding from DST-SERB and\nIUSSTF. It is located at the Indian Astronomical Observatory (Hanle),\noperated by IIA. We acknowledge funding by the IITB alumni batch of 1994,\nwhich partially supports operations of the telescope. Telescope technical\ndetails are available at https://sites.google.com/view/growthindia/.",
  "circularId": 31227,
  "createdOn": 1639393913000,
  "email": "harshkosli13@gmail.com",
  "subject": "GRB 211211A: HCT and GIT optical follow up observations",
  "submitter": "Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13@gmail.com>",
  "eventId": "GRB 211211A"
}