{
  "submitter": "Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>",
  "bibcode": "2023GCN.33699....1R",
  "circularId": 33699,
  "body": "T. Roychowdhury(IITB), V. Swain (IITB), A. Suresh (IITB), H. Kumar(IITB),\nD. Raman(IITB), Kaysang (IAO), V. Bhalerao(IITB), G. C. Anupama(IIA), S.\nBarway(IIA) report on behalf of the GIT team:\n\nWe observed GRB 230427A detected by Swift-BAT (Troja et al., GCN 33687)\nwith 0.7m GROWTH-India Telescope (GIT). The observations started at\n14:20:43 UT on 2023-04-27, 3.8 hours after the Swift-BAT trigger. We\nobtained 10 images of 300-sec exposures in the r' filter and 5 images of\n300-sec exposures in the i', z' and g' filters. We did not detect any new\nsource in our stacked image within the 2.4 arcsec circle, around R.A.= 10h\n13m 15.16s, DEC.=+48d 12' 14.2\". The obtained upper limits follow as:\n\n———————————————————————————————————————————————————————————————————\n—————————————\n\nJD (mid)  |  T_mid-T0(hrs)  |  Exposure (sec)  |  Filter |  Lim_mag\n(5-sigma) |\n\n——————————————————————————————————————————————————————————————————\n——————————————\n\n2460062.1148169  |  4.22  |  10 x 300 (stacked)  |  r' | > 21.70  |\n\n2460062.1433660 |  4.91  |  5 x 300 (stacked) |  i' | > 20.76  |\n\n2460062.1604599 |  5.31 |  5 x 300 (stacked) | z' | > 19.42  |\n\n2460062.1775733  |  5.73  |  5 x 300 (stacked) | g' | > 21.35  |\n\n———————————————————————————————————————————————————————————————————\n—————————————\n\nOur results are consistent with the upper limit reported by AKO (M. Odeh,\nGCN #33693), BOOTES-5/JGT (Y.-D. Hu et al., GCN #33695), OHP/T193 (D.\nTurpin et al., GCN #33696), GMG (J. Mao et al., GCN #33697) and Bassano\nBresciano Observatory (U.Quadri et al., GCN #33698). The magnitudes are\ncalibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected\nfor Galactic extinction.\n\nThe GROWTH India Telescope (GIT, Kumar et al. 2022) is a 70-cm telescope\nwith a 0.7-degree field of view, set up by the Indian Institute of\nAstrophysics (IIA) and the Indian Institute of Technology Bombay (IITB)\nwith funding from DST-SERB and IUSSTF. It is located at the Indian\nAstronomical Observatory (Hanle), operated by IIA. We acknowledge funding\nby the IITB alumni batch of 1994, which partially supports the operations\nof the telescope. Telescope technical details are available at\nhttps://sites.google.com/view/growthindia/.\n",
  "eventId": "GRB 230427A",
  "createdOn": 1682673384249,
  "subject": "GRB 230427A: GIT optical upper limit"
}