TITLE: GCN CIRCULAR NUMBER: 40820 SUBJECT: GRB 241018A: Maidanak optical observations DATE: 25/06/25 10:30:21 GMT FROM: Alina Volnova at IKI RAS alinusss@gmail.com
A. Volnova (IKI), A. Pozanenko (IKI), N. Pankov (HSE,IKI), O. Burhonov (UBAI), Sh. Ehgamberdiev (UBAI) report on behalf of GRB IKI FuN:
We observed the field of GRB 241018A (SVOM team, GCN 37812) with AZT-22 1.5m telescope of Maidanak observatory in R-filter on 2024-10-18 (UT) 20:12:00 and in I-filter on 2024-10-19 (UT) 19:07:59 under very good weather conditions (seeing ~1"). The afterglow (SVOM/VT: GCN 37819; Swift XRT: Osborne et al., GCN 37823, Optical NOT: Malesani et al. GCN 37821; SVOM/VT commissioning team, GCN 37826; SVOM/C-GFT team, GCN 37841) is marginally detected in stacked images of 1 hour total exposure each. Preliminary photometry of the source is the following:
Date UT start t-T0 Exp. Filter OT Err. UL(3 sigma) (mid, days) (s) 2024-10-18 20:12:00 0.37616 60x60 R 22.2 0.3 22.3 2024-10-19 19:07:59 1.33287 61x60 I 22.4 0.3 22.4
The photometry is based on nearby USNO-B1.0 stars:
USNO-B_id RA Dec R2 I 1330-00124435 04:32:02.23 +43:02:33.2 17.00 16.39 1330-00124413 04:32:00.31 +43:01:30.1 16.80 15.94 1330-00124450 04:32:03.82 +43:01:22.9 16.55 16.24
The result is consistent with previously reported optical non-detection (Turpin et al., GCN 37818; Ferro et al., GCN 37822; Song et al., GCN 37824; Mohan et al., GCN 37825; Pankov et al., GCN 37827; Fernandez-Garcia et al., GCN 37828; Liu et al., GCN 37830; Ror et al., GCN 37837).
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