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GCN Circular 35189

GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
2023-11-26T08:22:44Z (7 months ago)
Alexei Pozanenko at IKI, Moscow <>
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N. Pankov (HSE, IKI), A. Pozanenko (IKI), I. Sokolov (INASAN), R. Inasaridze (AbAO), O. Burhonov (UBAI), E. Klunko (ISTP),  V. Kim (FAI),  Sh. Ehgamberdiev (UBAI), S. Belkin (IKI) report on behalf of GRB-IKI-FuN collaboration:

We observed the field of GRB 231111A (Melandri et al., GCN 34981; Zhang et al, GCN 34990) at with several telescopes,  Zeiss-2000 telesope (Terskol),  AS-32 (Abastumani), AZT-22 (Maidanak), AZT-33IK (Mondy) and AZT-20 (Assy).The observations started at Terskol on 2023-11-11 17:37:54, i.e. 3.359712 hr since Swift trigger. The optical source is detected only in the stacked image of 12*300 sec from Maidanak Observatory in the R-filter,  while in other cases we obtained the upper limits. The results are in consistent with observations previously reported by other teams and us (Melandri et al., GCN 34981; Jiang et al, GCN 34982; Lipunov et al, GCN 34983; Kumar et al, GCN 34984; Sun et al, GCN 34985; Pankov et al, GCN 34994; Ruocco et al, GCN 34997; Wang et al, GCN 35000; Li et al, GCN 35001; Sun et al, GCN 35002; Moretti et al, GCN 35003; Komesh et al, GCN 35004; D'Avanzo et al, GCN 35007; Thoene et al, GCN 35009; Jiang et al, GCN 35012; Sun et al, GCN 35014). Preliminary photome!
 try is following:

Date       UT start t-T0    Exp.  Filter OT Err. UL(3sigma)  Telescope

2023-11-11 17:37:54 0.13998  2*120 R n/d  n/d   19.5 Zeiss-2000 
2023-11-12 14:47:53 1.02157 86*60  R n/d  n/d   20.5 AS-32  
2023-11-12 19:25:37 1.21583 12*300 R 21.06 0.08 22.7 AZT-22  
2023-11-13 11:14:51 1.87399 50*120 R n/d  n/d   20.7 AZT-33IK  
2023-11-13 15:09:27 2.07092 200*30 r n/d  n/d   23.0 AZT-20  

The photometry is based on nearby stars from USNO-B1.0 and PS1 catalogs.

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