TITLE: GCN CIRCULAR NUMBER: 38948 SUBJECT: GRB 250114A: LCO optical counterpart detection. DATE: 25/01/15 04:57:30 GMT FROM: ankur ghosh at CAPP, University of Johannesburg Ankur Ghosh, Soebur Razzaque (CAPP, University of Johannesburg), Alexander Moskvitin, Yulia Sotnikova (SAO RAS), Naveen Dukiya (ARIES), Rahul Gupta (NASA GSFC) on behalf of a larger collaboration. We observed the field of the GRB 250114A triggered by Swift (Klingler et al., GCN 38927) in V, r filter of the 1-meter Sinistro telescope at the Las Cumbres Observatory Global Telescope (LCOGT) node located at South African Astronomical Observatory (SAAO). The 1-m Sinistro telescope is equipped with a 4K x 4K CCD (FOV: 26 x 26 arcmin, scale: 0.39 arcsec/pixel). Observations began on January 14, 2025, starting from 6.06 hours after the GRB trigger. We clearly detect the optical transient (OT) reported by GCNs (Beardmore et al., GCN 38936, An et al., GCN 38929; Malesani & Izzo, GCN 38930; Francile et al., GCN 38931; Brivio et al., GCN 38933, Malesani et al., GCN 38934, Pérez-Fournon & Poidevin, GCN 38943) in our V, r band image. The optical afterglow detected in our images is consistent with the UVOT coordinates (Klingler et al., GCN 38927). |Date| |UTstart| |t-T0 (hours)| |Exp (sec)| |Filter| |Magnitude| -------------------------------------------------------------------------------------------------- 2025-01-14 13:36:54.720 6.06 1 x 1200 V V = 21.88 +/- 0.52 2025-01-14 14:11:39.552 6.64 1 x 1200 r r = 22.01 +/- 0.35 -------------------------------------------------------------------------------------------------- The field was calibrated against nearby APASS stars, with magnitudes converted using Lupton (2005) equations, and has not been corrected for Galactic extinction.