{
  "format": "text/plain",
  "circularId": 44319,
  "subject": "EP260416a: COLIBRÍ confirmation of the optical rebrightening",
  "eventId": "EP260416a",
  "createdOn": 1776404215558,
  "body": "William H. Lee (UNAM), Stéphane Basa (UAR Pytheas), Rosa L. Becerra (UNAM), Alan M. Watson (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), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Diego López-Cámara (UNAM), Nikos Mandarakas (LAM), Enrique Moreno Méndez (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM) and Antonio de Ugarte Postigo (LAM) report:\n\nWe reimaged the field of the EP260416a (Hu et al., GCN Circ. 44307) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-04-17 04:20 to 04:43 UTC (from 22.85 to 23.24 hours after the trigger) and obtained 4/11/3/18 minutes of exposure in the g/r/i/z filters, respectively.\n\nThe data were reduced and coadded with COLIBRÍ 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\nThe candidate reported previously by Ducoin et al. (GCN Circ. 44310) is clearly detected in all our filters with preliminary magnitudes of:\n\nr = 20.60 +/- 0.02\nz = 19.88 +/- 0.02   \n\nOur values confirm the rebrightening reported by the WFST Collaboration (Hua et al. GCN Circ. 44318), and suggests a photo-z <2.5 (90% conf.).\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",
  "submittedHow": "web",
  "submitter": "William H. Lee at UNAM  <wlee@astro.unam.mx>",
  "bibcode": "2026GCN.44319....1L"
}