TITLE: GCN CIRCULAR NUMBER: 35046 SUBJECT: GRB 231115A: MASTER optical observations DATE: 23/11/15 21:39:48 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs P.Balanutsa (Lomonosov MSU), N.Budnev, O.Gress (ISU,API),A.Sankovich V. Lipunov, E. Gorbovskoy, N. Tiurina, D.Vlasenko, Yu.Tselik, Ya.Kechin, A.Kuznetsov, K.Zhirkov, A.Chasovnikov, I.Gorbunov, D.Zimnukhov, V.Senik, V.Topolev, D.Cheryasov, A.Sosnovskij, V.Senik (Lomonosov Moscow State University, SAI, Physics Department), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the GRB 231115A (Fermi GBM Team GCN 35035, Mereghetti et al., GCN 35037) errorbox 4607 sec after notice time and 4634 sec after trigger time at 2023-11-15 16:53:37 UT, with upper limit up to 21.3 mag. Our first images (till T0+10669) are ruined due to bad weather conditions. Sinces T0+10669, during the observations the weather improved. The list of limits up to 21.3 is presented in the table below. In pictures with the maximum limit we do not see the source. In all our frames, the object GAIA 1070550388423847680 with a magnitude of 19.44, closest to the indicated area in (Kumar et al GCN 35041), is clearly visible. The localization region of OT (Kumar et al GCN 35041) has a diffuse structure, but we definitely do not see a source there with a brightness of 19.5 or brighterat given position. Despite the presence of images with deeper upper limits, due to the diffuse structure of the galaxy in the localization region, it is difficult to talk about weaker sources in the preliminary analysis. We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 4725 | MASTER-Tunka | C | 180 | 18.8 | 5241 | MASTER-Tunka | C | 90 | 17.9 | 5473 | MASTER-Tunka | C | 90 | 17.6 | 5708 | MASTER-Tunka | C | 90 | 17.6 | 10669 | MASTER-Tunka | C | 180 | 19.2 | 10829 | MASTER-Tunka | C | 90 | 18.8 | 11178 | MASTER-Tunka | C | 90 | 19.2 | 11409 | MASTER-Tunka | C | 90 | 19.4 | 11524 | MASTER-Tunka | C | 90 | 19.5 | 11638 | MASTER-Tunka | C | 90 | 19.6 | 11724 | MASTER-Tunka | C | 30 | 19.8 | 11840 | MASTER-Tunka | C | 30 | 20.0 | 11885 | MASTER-Tunka | C | 120 | 20.7 | Coadd 12230 | MASTER-Tunka | C | 810 | 21.1 | Coadd 11898 | MASTER-Tunka | C | 30 | 20.0 | 11968 | MASTER-Tunka | C | 60 | 14.5 | 11968 | MASTER-Tunka | C | 60 | 20.2 | 12056 | MASTER-Tunka | C | 60 | 20.4 | 12146 | MASTER-Tunka | C | 240 | 20.4 | Coadd 12158 | MASTER-Tunka | C | 90 | 19.9 | 12273 | MASTER-Tunka | C | 90 | 19.9 | 12399 | MASTER-Tunka | C | 90 | 20.0 | 12489 | MASTER-Tunka | C | 270 | 20.4 | Coadd 12514 | MASTER-Tunka | C | 90 | 20.0 | 12630 | MASTER-Tunka | C | 90 | 20.0 | 12848 | MASTER-Tunka | C | 90 | 19.9 | 13045 | MASTER-Tunka | C | 60 | 20.5 | 13105 | MASTER-Tunka | C | 180 | 21.1 | Coadd 13285 | MASTER-Tunka | C | 540 | 21.0 | Coadd 13132 | MASTER-Tunka | C | 60 | 20.5 | 13218 | MASTER-Tunka | C | 60 | 20.5 | 13306 | MASTER-Tunka | C | 60 | 20.5 | 13366 | MASTER-Tunka | C | 180 | 21.0 | Coadd 13391 | MASTER-Tunka | C | 60 | 20.5 | 13478 | MASTER-Tunka | C | 60 | 20.5 | 13564 | MASTER-Tunka | C | 60 | 20.5 | 13624 | MASTER-Tunka | C | 180 | 21.1 | Coadd 13648 | MASTER-Tunka | C | 60 | 14.9 | 13648 | MASTER-Tunka | C | 60 | 20.5 | 13733 | MASTER-Tunka | C | 60 | 20.5 | 13820 | MASTER-Tunka | C | 60 | 15.2 | 13821 | MASTER-Tunka | C | 60 | 20.5 | 13881 | MASTER-Tunka | C | 180 | 21.0 | Coadd 13907 | MASTER-Tunka | C | 60 | 20.5 | 13993 | MASTER-Tunka | C | 60 | 20.5 | 14095 | MASTER-Tunka | C | 90 | 19.9 | 14201 | MASTER-Tunka | C | 60 | 20.5 | 14261 | MASTER-Tunka | C | 180 | 21.2 | Coadd 14288 | MASTER-Tunka | C | 60 | 20.5 | 14377 | MASTER-Tunka | C | 60 | 20.5 | 14463 | MASTER-Tunka | C | 60 | 15.6 | 14463 | MASTER-Tunka | C | 60 | 20.5 | 14523 | MASTER-Tunka | C | 180 | 21.1 | Coadd 14548 | MASTER-Tunka | C | 60 | 20.5 | 14633 | MASTER-Tunka | C | 60 | 20.5 | 14717 | MASTER-Tunka | C | 60 | 15.5 | 14718 | MASTER-Tunka | C | 60 | 20.5 | 14778 | MASTER-Tunka | C | 180 | 21.2 | Coadd 14805 | MASTER-Tunka | C | 60 | 20.6 | 14885 | MASTER-Tunka | C | 60 | 20.6 | 14973 | MASTER-Tunka | C | 60 | 20.6 | 15033 | MASTER-Tunka | C | 180 | 21.3 | Coadd 15060 | MASTER-Tunka | C | 60 | 15.4 | 15061 | MASTER-Tunka | C | 60 | 20.6 | 15147 | MASTER-Tunka | C | 60 | 20.6 | 15233 | MASTER-Tunka | C | 60 | 15.6 | 15233 | MASTER-Tunka | C | 60 | 20.5 | 15293 | MASTER-Tunka | C | 180 | 21.1 | Coadd 15381 | MASTER-Tunka | C | 180 | 20.6 | 15533 | MASTER-Tunka | C | 60 | 20.5 | 15620 | MASTER-Tunka | C | 60 | 20.5 | 15705 | MASTER-Tunka | C | 60 | 20.3 | 15765 | MASTER-Tunka | C | 180 | 20.8 | Coadd 15796 | MASTER-Tunka | C | 60 | 20.3 | 15885 | MASTER-Tunka | C | 60 | 20.4 | 15966 | MASTER-Tunka | C | 60 | 20.4 | 16051 | MASTER-Tunka | C | 60 | 14.6 | 16051 | MASTER-Tunka | C | 60 | 20.3 | Filter C is a clear (unfiltred) band. Real time updated cover map and actual upper limits list available here: https://master.sai.msu.ru/site/master2/observ.php?id=2306494 The observations began at zenith distance = 47 deg. The sun altitude is -57.5 deg. The galactic latitude b = 41 deg., longitude l = 141 deg. The message may be cited.