TITLE: GCN CIRCULAR NUMBER: 36549 SUBJECT: LAT GRB240527.59: Global MASTER-Net observations report DATE: 24/05/27 21:11:31 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gress, N.M. Budnev, O.Ershova (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the LAT GRB240527.59 (trigger No 738511436,08h 32m 24.00s , -14d 28m 48.0s, R=0.19) errorbox 10372 sec after trigger time at 2024-05-27 16:56:44 UT, with upper limit up to 19.4 mag. Observations started at twilight. The observations began at zenith distance = 34 deg. The sun altitude is -15.4 deg. The galactic latitude b = 15 deg., longitude l = 239 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2473085 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 10403 | 2024-05-27 16:56:44 | MASTER-SAAO | (08h 32m 25.70s , -14d 04m 43.2s) | C | 60 | 19.2 | 10483 | 2024-05-27 16:58:04 | MASTER-SAAO | (08h 40m 34.75s , -14d 05m 43.1s) | C | 60 | 19.2 | 10803 | 2024-05-27 17:03:24 | MASTER-SAAO | (08h 24m 52.36s , -14d 03m 20.3s) | C | 60 | 19.2 | 11361 | 2024-05-27 17:12:42 | MASTER-SAAO | (08h 32m 22.70s , -14d 04m 02.7s) | C | 60 | 19.4 | 11441 | 2024-05-27 17:14:02 | MASTER-SAAO | (08h 40m 32.48s , -14d 05m 04.3s) | C | 60 | 19.4 | 11760 | 2024-05-27 17:19:21 | MASTER-SAAO | (08h 24m 53.78s , -14d 02m 57.9s) | C | 60 | 19.3 | 12238 | 2024-05-27 17:27:19 | MASTER-SAAO | (08h 29m 20.90s , -15d 58m 15.1s) | C | 60 | 19.2 | 12317 | 2024-05-27 17:28:38 | MASTER-SAAO | (08h 32m 19.29s , -14d 02m 28.2s) | C | 60 | 19.3 | 12397 | 2024-05-27 17:29:58 | MASTER-SAAO | (08h 40m 28.10s , -14d 03m 28.1s) | C | 60 | 19.4 | 12715 | 2024-05-27 17:35:16 | MASTER-SAAO | (08h 24m 49.37s , -14d 04m 02.0s) | C | 60 | 19.3 | 13194 | 2024-05-27 17:43:15 | MASTER-SAAO | (08h 29m 18.78s , -15d 56m 49.8s) | C | 60 | 19.1 | 13273 | 2024-05-27 17:44:34 | MASTER-SAAO | (08h 36m 50.31s , -15d 57m 42.1s) | C | 60 | 19.3 | 14434 | 2024-05-27 18:03:55 | MASTER-SAAO | (08h 29m 09.33s , -15d 54m 51.6s) | C | 60 | 19.1 | 14514 | 2024-05-27 18:05:15 | MASTER-SAAO | (08h 36m 39.92s , -15d 56m 46.8s) | C | 60 | 19.2 | 25080 | 2024-05-27 21:01:21 | MASTER-SAAO | (08h 32m 18.93s , -14d 24m 52.4s) | P/ | 60 | 15.1 | 25161 | 2024-05-27 21:02:42 | MASTER-SAAO | (08h 32m 17.88s , -14d 24m 36.1s) | P/ | 60 | 15.1 | 25241 | 2024-05-27 21:04:02 | MASTER-SAAO | (08h 32m 16.93s , -14d 24m 22.3s) | P/ | 60 | 15.1 | 25320 | 2024-05-27 21:05:21 | MASTER-SAAO | (08h 32m 15.96s , -14d 24m 09.4s) | P/ | 60 | 14.9 | 25400 | 2024-05-27 21:06:41 | MASTER-SAAO | (08h 32m 14.89s , -14d 23m 56.6s) | P/ | 60 | 14.9 | 25479 | 2024-05-27 21:08:00 | MASTER-SAAO | (08h 32m 13.88s , -14d 23m 43.6s) | P/ | 60 | 14.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.