GCN Circular 45765
GRB260914A: MAO/AZT-22 optical observations
From: Yodgor Rajabov at UBAI
Issued: 2026-09-26 19:32 UTC
Type: GRB, Optical Transient
Why this event is posted: it has drawn 16 GCN Circulars, at or above the top-10% threshold of 14.

Y. Rajabov, O. Burkhonov, B.Abidkhanov, S. Ehgamberdiev, Y. Tillayev (UBAI), A. Shaymanov, T. Boyqobilov (Maidanak Observatory/UBAI) report on behalf of UBAI team.

We observed the field of the GRB 260914A detected by SVOM/ECLAIR (Wang et al., GCN 45562) and Fermi/GBM (Hamburg, GCN 45569) at z = 0.778 (Saccardi et al., GCN 45579) with the AZT-22 1.5m telescope of the Maidanak Observatory (MAO) starting on 2026-09-14 at 22:54:33UT, i.e, ~11.7 hours after the SVOM/ECLAIRs trigger. In total we obtained 4x300 and 3x300 s exposures in B and R-band respectively, using 4kx4k CCD SNUCAM camera (Im et al., 2010).

The optical/NIR counterpart (Akl et al., GCN 45564; Palmerio et al., GCN 45565; Li et al., GCN 45566; Shi et al., GCN 45567; Saccardi et al., GCN 45568; Saccardi et al., GCN 45579; Yang et al., GCN 45582; Brivio et al., GCN 45583; Volnova et al., GCN 45595; Castro-Tirado et al., GCN 45605) is detected in the stacked frames of both observatories.

Preliminary photometry is as follows:
Date UTstart Exptime Filter OT Err. UL SNR Site/Telescope
(nxs)
2026-09-14 22:54:33 4x300 B 23.43 0.16 23.09 6.32 MAO/AZT-22
2026-09-14 23:16:27 3x300 R 21.87 0.07 23.22 14 MAO/AZT-22

All the data have been reduced by a single data processing pipeline, STDWeb (Karpov 2025). Images obtained in Johnson Cousins filters were calibrated using the Gaia DR3 Synphot catalog. Our measurements in Vega magnitude system and the data has not corrected for the Galactic extinction.

The photometry of the source is affected by the underlying host galaxy reported by Saccardi et al. (GCN 45579) with Legacy survey. The red shift z = 0.778 was measured by 10.4m GTC telescope equipped with OSIRIS+ (GCN 45605).

Maidanak astronomical observatory (MAO) is an observational facility of the Ulugh Beg Astronomical Institute (UBAI), Uzbekistan Academy of Sciences (Maidanak observatory - Main Page (maidanak.uz)).

Filter: gamma-ray bursts are posted only if in the top 10% of the past year's — by fluence (total energy received per cm², from Fermi GBM, Konus-Wind, GECAM and similar circulars; now ≥ 3.9×10^-5 erg/cm²) or by the number of GCN Circulars about the burst (now ≥ 14). Thresholds are recalculated monthly.
Relayed automatically from NASA's General Coordinates Network.