TITLE: GCN CIRCULAR NUMBER: 38465 SUBJECT: GRB 241207C: MASTER optical observations DATE: 24/12/08 03:02:31 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs lipunov@xray.sai.msu.ru

C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), V.Lipunov, I.Panchenko, A.Kuznetsov, K.Zhirkov, E.Gorbovskoy, N.Tiurina,D.Vlasenko, A.Chasovnikov, V.Topolev, P.Balanutsa, G.Antipov, A.Sankovich,M.Gulyaev, Ya.Kechin, V.Senik (Lomonosov MSU), A.Sosnovskij (CrAO RAS), O.Gress, N.Budnev(ISU), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez,J.Martinez,A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),

MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the MAXI GRB241207C error-box (trigger No 2412072220, GCN #38462, notice time 2024-12-08T00:13:03UT ) 8462 sec after trigger time at 2024-12-08 00:41:09 UT,with upper limit up to 18.6 mag. Observations started at twilight.

The observations began at zenith distance = 61 deg. The sun altitude is -13.9 deg. Distance to Moon is 34deg., distance to Sun is 47deg. The galactic latitude b = -31 deg., longitude l = 21 deg.

Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2700028

We obtain the following upper limits.

Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|_________________________________|_____|_______|_______|_

8475 | 2024-12-08 00:41:09 | MASTER-OAFA | (20h 36m 54.99s -22d 53m 32.3s) | C | 25 | 16.6 | 8500 | 2024-12-08 00:41:09 | MASTER-OAFA | (20h 36m 54.99s -22d 53m 32.3s) | C | 75 | 17.3 | Coadd 8486 | 2024-12-08 00:41:09 | MASTER-OAFA | (20h 27m 07.85s -23d 14m 22.0s) | C | 45 | 17.9 | 8531 | 2024-12-08 00:41:09 | MASTER-OAFA | (20h 27m 07.85s -23d 14m 22.0s) | C | 345 | 19.0 | Coadd 8537 | 2024-12-08 00:42:11 | MASTER-OAFA | (20h 37m 00.75s -22d 54m 33.0s) | C | 25 | 16.6 | 8547 | 2024-12-08 00:42:11 | MASTER-OAFA | (20h 27m 13.60s -23d 15m 22.0s) | C | 45 | 18.1 | 8601 | 2024-12-08 00:43:14 | MASTER-OAFA | (20h 36m 55.72s -22d 55m 33.7s) | C | 25 | 16.8 | 8611 | 2024-12-08 00:43:15 | MASTER-OAFA | (20h 27m 08.52s -23d 16m 21.9s) | C | 45 | 18.1 | 8661 | 2024-12-08 00:44:15 | MASTER-OAFA | (20h 37m 01.73s -22d 55m 30.7s) | C | 25 | 16.8 | 8672 | 2024-12-08 00:44:15 | MASTER-OAFA | (20h 27m 14.60s -23d 16m 18.7s) | C | 45 | 18.0 | 8724 | 2024-12-08 00:45:18 | MASTER-OAFA | (20h 36m 58.39s -22d 53m 48.8s) | C | 25 | 16.9 | 8734 | 2024-12-08 00:45:18 | MASTER-OAFA | (20h 27m 11.43s -23d 14m 36.5s) | C | 45 | 18.2 | 8822 | 2024-12-08 00:46:18 | MASTER-OAFA | (20h 36m 58.46s -22d 55m 16.4s) | C | 100 | 17.7 | 8792 | 2024-12-08 00:46:19 | MASTER-OAFA | (20h 27m 11.44s -23d 16m 03.0s) | C | 40 | 18.2 | 8838 | 2024-12-08 00:47:05 | MASTER-OAFA | (20h 27m 11.45s -23d 16m 03.3s) | C | 40 | 18.2 | 8884 | 2024-12-08 00:47:50 | MASTER-OAFA | (20h 27m 11.44s -23d 16m 03.5s) | C | 40 | 18.2 | 8943 | 2024-12-08 00:48:49 | MASTER-OAFA | (20h 37m 01.58s -22d 54m 05.1s) | C | 40 | 17.4 | 8953 | 2024-12-08 00:48:50 | MASTER-OAFA | (20h 27m 14.72s -23d 14m 51.6s) | C | 60 | 18.5 | 9020 | 2024-12-08 00:50:07 | MASTER-OAFA | (20h 36m 55.16s -22d 54m 38.4s) | C | 40 | 17.3 | 9031 | 2024-12-08 00:50:07 | MASTER-OAFA | (20h 27m 08.24s -23d 15m 24.4s) | C | 60 | 18.4 |

Filter C is a clear (unfiltred) band.

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