TXS 1727+488: COLIBRI optical upper limit
ATel #17300; University of Rome
on 23 Jul 2025; 12:09 UT
Credential Certification: Rosa Leticia Becerra Godinez (rosa.becerra@roma2.infn.it)
Jean-Gregoire Ducoin (CPPM), Noemie Globus (UNAM), Alan M. Watson (UNAM), Rosa L. Becerra (U Roma), Stephane Basa (UAR Pytheas), William H. Lee (UNAM), Fredd Alvarez (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (AUS), Sarah Antier (OCA), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Leonardo Garcia Garcia (UNAM), Ramandeep Gill (UNAM), Kin Ocelotl Lopez (UNAM), Diego Lopez-Camara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Mendez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Benjamin Schneider (LAM) and Antonio de Ugarte Postigo (LAM):
We imaged the field of the Fermi/LAT detection in the field of the Radio Source TXS 1727+488 (Bartolini et al., ATel #
17299) using the DDRAGO wide-field imager on the COLIBRI telescope. We observed from 2025-07-23 04:42 to 05:45 UTC and obtained 16 minutes of exposure in the g, r and i filters (each).
The data were reduced and coadded with the COLIBRI pipeline and analysed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction.
In the stacked image, we do not detect any significant variation in the flux of TXS 1727+488 nor a new source at the enhanced Fermi/LAT error region of 0.17 deg (Bartolini et al., ATel #
17299) down to the following 5-sigma limit:
g > 23.63
r > 23.28
i > 22.70
We thank the staff of the Observatorio Astronomico Nacional on the Sierra de San Pedro Martir and the COLIBRI and DDRAGO engineering teams.
COLIBRI 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 Astronomico Nacional on the Sierra de San Pedro Martir, Baja California, Mexico.
