{
  "submittedHow": "web",
  "eventId": "EP260917a",
  "createdOn": 1789716159435,
  "body": "Marion Guelfand (CPPM), Enrique Moreno Méndez (UNAM), Rosa L. Becerra (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP),  Leonardo García-García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM),  Alan M. Watson (UNAM) report:\n\nWe imaged the field of the EP260917a (Huang et al. GCN Circ. 45621) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed in two epochs from 2026-08-09 03:25 to 03:48  (from 17.8 to 18.4  hours after the trigger) and restarted our campaign from 2026-08-09 05:45 to 06:24 (from 20.1 to 20.8  hours after the trigger, starting 14 min after the GCN circular). We obtained a total of 1.32 hr of simultaneous exposure in the r and z filters.\n\nThe data were reduced and coadded with the ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction.\n\nIn the stacked images, after performing image subtraction with STDWeb/STDPipe (Karpov 2025), using templates from the DESI Legacy Survey DR10 (Dey et al. 2019), we do not detect any uncatalogued source at the WXT source position (Huang et al. GCN Circ. 45621) down to the following 5-sigma limits:\n\nr > 24.0,\n\nz > 22.5\n\nWe thank the staff of the Observatorio Astronómico Nacional at Sierra de San Pedro Mártir, as well as the technical and engineering teams at CEA, CPPM, IRAP, LAM, OHP, OSU Pytheas, and UNAM.\n\nCOLIBRÍ 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.\n",
  "eventType": [
    "X-ray Transient"
  ],
  "circularId": 45624,
  "format": "text/plain",
  "subject": "EP260917a: COLIBRÍ optical upper limits ",
  "submitter": "Marion G <marion.guelfand@gmail.com>"
}