GCN Circular 42476

Subject

GRB 251026A: Mondy optical upper limit

Event

GRB 251026A

Date

2025-10-27T13:34:08Z (4 days ago)

From

Alina Volnova at IKI RAS <alinusss@gmail.com>

Via

Web form

A. Volnova (IKI), A. Pozanenko (IKI) , N. Pankov (HSE, IKI), E. Klunko (ISTP) report on behalf of IKI-GRB-FuN:

We observed the field of GRB 251026A detected by SVOM/ECLAIRs (Cao et al., GCN 42454Loading...
 
 ) in the R-filter with the AZT-33IK 1.5m telescope of the Sayan Solar Observatory (Mondy) starting Oct. 26, 2025, 20:15:58 (UT) taking several frames with 120 s exposures. Inside the error box of the SVOM/MXT (Cao et al., GCN 42454Loading...
 
 ) we did not detect any new uncatalogued source. Photometry and observational details are the following:

Date        UT start  t-T0       Exp.    Filter  OT     Err.  UL
                     (mid,days)  (n*s)                       (3sigma)
2025-10-26  20:15:58  0.51293    30*120  R       n/d    n/d   22.4

The photometry is based on several nearby PS1 stars (R-magnitudes Lupton's transformation) and is not corrected for the Galactic extinction.