{
  "submitter": "Benjamin Schneider at MIT  <bschn@mit.edu>",
  "createdOn": 1681306217000,
  "circularId": 33607,
  "format": "text/plain",
  "eventId": "GRB 230409B",
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>",
  "bibcode": "2023GCN.33607....1A",
  "body": "C. Adami (LAM), B. Schneider (MIT), S. Basa (LAM), \nE. Le Floc'h, D. Turpin, D. Götz (CEA Paris-Saclay), \nS. D. Vergani (GEPI, Obs. de Paris), report on behalf \nof a larger collaboration:\n\nWe observed the field of GRB 230409B (Beardmore et al., GCN 33592) \nusing the T193cm telescope at Observatoire de Haute-Provence (France) \nequipped with the MISTRAL spectro-imager. Four exposures were obtained \nin the i-band (2x300s + 2x600s) from 2023 10 April 03:03:03 UT to \n2023 10 April 03:44:17 UT (mid time ~22.3h after trigger). In the combined \nframe, we do not detect any source at the position reported by Evans et al., \nGCN 33594 and Kuin et al., GCN 33595 down to the following 3-sigma limit:\n\ni > 20.6 mag (AB)\n\nThe photometric calibration was performed using nearby stars from \nthe PanSTARRS catalog and the magnitude is not corrected for Galactic \nextinction.\n\nWe acknowledge the excellent support from Observatoire de Haute-Provence, \nin particular Jean-Pierre Troncin.",
  "editedOn": 1731773899669,
  "subject": "GRB 230409B: OHP/T193 optical upper limit",
  "email": "bschn@mit.edu",
  "version": 2
}