{
  "bibcode": "2023GCN.33696....1T",
  "circularId": 33696,
  "createdOn": 1682639566264,
  "body": "D. Turpin (CEA Paris-Saclay), C. Adami (LAM), B. Schneider (MIT),\nS. Basa (LAM),  E. 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 230427A (Troja et al., GCN 33687) \nusing the T193cm telescope at Observatoire de Haute-Provence (France) \nequipped with the MISTRAL spectro-imager. 18 exposures were obtained \nin the r-band (16x300s + 2x60s) from 2023 27 April 20:36:47 UT to \n2023 27 April 22:59:06 UT (mid time ~11.27h after trigger). In the combined \nframe, we do not detect any source at the UVOT position reported by \nTroja et al., GCN 33687 and the enhanced XRT position (Beardmore et al.,\nGCN 33688) down to the following 3-sigma limit:\n\nr > 22.3 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 Balcaen.",
  "subject": "GRB 230427A : OHP/T193 optical upper limit",
  "submitter": "Damien Turpin at CEA-Saclay <dturpin-astro@hotmail.com>",
  "eventId": "GRB 230427A"
}