TITLE:   GCN CIRCULAR
NUMBER:  43071
SUBJECT: IceCube-251210A: DDOTI Optical Upper Limit
DATE:    25/12/11 05:40:15 GMT
FROM:    Rosa Leticia Becerra at Instituto de Astronomía,  UNAM <rbecerra@astro.unam.mx>

Rosa L. Becerra (UNAM), Simone Dichiara (Penn State University), Alan M. Watson (UNAM), Camila Angulo Valdez (UNAM), Nat Butler (ASU), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl López (UNAM), Margarita Pereyra (UNAM) and Eleonora Troja (U Roma) report:

We observe the field of the IceCube-251210A (gold) event (IceCube Collaboration, GCN Circ. 43064) with the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on the Sierra of San Pedro Martir (http://ddoti.astroscu.unam.mx) on the night of 2025-12-11 UTC.

DDOTI observed from 01:54 UTC to 04:34 UTC (T+14.8 h to T+17.5 h after the trigger), with a total exposure time of 81 minutes, covering the entire error region reported by IceCube (IceCube Collaboration, GCN Circ. 43064).

Comparing our observations to the USNO-B1 and PanSTARRS PS1 DR2 catalogues, we detect no uncatalogued or credible fading sources within the observed field to a 10-sigma limiting AB magnitude of:

w > 20.5

Further observations are planned to assess variability.

This value is not corrected for the Galactic extinction.

We thank the staff of the Observatorio Astronómico Nacional on the Sierra of San Pedro Mártir