{
  "circularId": 42074,
  "createdOn": 1759464246729,
  "submitter": "Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu>",
  "subject": "GRB 251003A: LCOGT Optical Detection",
  "submittedHow": "email",
  "body": "R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:\n\nWe observed the Swift GRB 251003A field (Beardmore et al., GCN 42070)  with the LCOGT 1-meter Sinistro instrument at the McDonald Observatory, USA site, on October 3, from 03:07 to 03:39 UT (corresponding to 1.15 to 1.68 hours after the GRB trigger time) with the SDSS i and r filters.\n\nWe performed a series of 3x300s exposures in i-band and r-band.  We detect an uncatalogued source in the XRT enhanced error region (Evans et al. GCNC 42071) consistent with other optical counterpart observations (Aceituno et al., GCN 42072; Méndez et al., GCN 42073) in both bands. We note that the r-i color of this event may indicate a moderate redshift source (z>4).\n\nThe following magnitudes are calculated using the PanSTARRS catalog as reference:\n\nr = 20.97 +/- 0.12\ni = 19.25 +/- 0.04\n\nThese magnitudes are not corrected for galactic extinction.\n",
  "bibcode": "2025GCN.42074....1S",
  "eventId": "GRB 251003A"
}