TITLE: GCN CIRCULAR NUMBER: 39382 SUBJECT: GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart DATE: 25/02/20 08:17:18 GMT FROM: Alan Watson at UNAM alan@astro.unam.mx
Francesco Magnani (CPPM), Alan M. Watson (UNAM), Sarah Antier (OCA), Jean-Grégoire Ducoin (CPPM), Diego López-Cámara (UNAM), Benjamin Schneider (LAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Dalya Akl (AUS), Camila Angulo (UNAM), Jean-Luc Atteia (IRAP), Rosa L. Becerra (U Roma), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), and Antonio de Ugarte Postigo (LAM) report:
We imaged the field of the SVOM/ECLAIRs GRB 250219A (Daigne et al., GCN Circ. 39376) with the DDRAGO wide-field imager on the COLIBRÍ telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico.
We observed from 2025-02-20 05:19 to 07:41 UTC (13.47 to 15.85 hours after the trigger) and obtained 90 minutes of exposure in the i filter. The data were coadded with custom software and analyzed in STDWeb/STDPipe (Karpov 2021), with photometric calibration against Pan-STARRS DR1. Our photometry is in the AB system and is not corrected for Galactic extinction.
At the position of the optical afterglow found by Xin et al. (GCN Circ. 39380), close to the uncataloged Swift/XRT source reported by Kennea et al. (GCN Circ. 39379), we detect a source with
i = 23.53 +/- 0.21
We cannot yet confirm fading, as none of the previously reported photometry is in the i filter (Xin et al., GCN Circ. 39380; Lagioia et al., GCN Circ. 39381).
Further observations are planned.
We warmly thank the COLIBRÍ and DDRAGO engineering teams and the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir.
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