TITLE: GCN CIRCULAR NUMBER: 40376 SUBJECT: GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit DATE: 25/05/07 08:57:04 GMT FROM: J.-G. Ducoin at CPPM ducoin@cppm.in2p3.fr
Jean-Grégoire Ducoin (CPPM), Alan M. Watson (UNAM), Fredd Alvarez (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Fredd Alvarez (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (AUS), Sarah Antier (OCA), Rosa L. Becerra (U Roma), Nathaniel R. Butler (ASU) , Damien Dornic (CPPM), Francis Fortin (IRAP), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Z. Wang (GXU) and Y. Liang (PMO):
We imaged the field of the SVOM GRB 250507A (Wang et al., GCN 40374) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2025-05-07 06:36:04 to 07:34:42 UTC (from 79 to 3597 seconds after the trigger) and obtained 2560 seconds of exposure in the i filter.
The data were reduced and coadded with the COLIBRÍ pipeline and analyzed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog and is not corrected for Galactic extinction.
In the stacked image, we do not detect any new source at the MXT source position (Wang et al., GCN 40374) down to the following 5-sigma limit (AB):
i > 22.3 mag
Further observations are ongoing.
We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams.
COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico.
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