August 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 39436] GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41375 SUBJECT: GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope DATE: 25/08/14 18:24:24 GMT FROM: Janet Chen at National Central University <janetstars(a)gmail.com> L. E. Salazar Manzano (Umich), H.-W. Lin (UMich), A. Aryan, T.-W. Chen (both NCU), and S. Yang (HNAS) report: We observed the field of the GRB 250814A (Fermi GBM team, GCN41357) using the 2.4m Hiltner telescope (HT) at the Michigan-Dartmouth-MIT (MDM) Observatory in Arizona, United States. The Swift-XRT detection of GRB 250814A was proposed to be temporally and spatially coincident with the subthreshold GW trigger S250814bg, which occurred 6 s after the BAT trigger (Caputo et al., GCN41358). The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration, with the Fermi GBM team and Swift team, reported the identification of a GW candidate possibly associated with this GRB (GCN41364). The first epoch of observations started at 10:22 UTC on the 14th of August 2025 (MJD = 60901.432), 2.79 hr after the Swift trigger. We do not find any credible evidence of a new and uncataloged source in the difference images (subtraction using the Pan-STARRS1 template images) within the 2.2 arcseconds uncertainty circle of Swift-XRT localization. We utilized the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform template subtraction using the 'hotpants' (Becker A., 2015, ascl.soft. ascl:1504.004) algorithm and perform the PSF photometry. The details of the observations and the measured 3-sigma upper limits (in the AB system) are as follows: Telescope | Filter | MJD (start) | t-t0 (hr) | Exposure (s) | Magnitude | avg. Seeing 2.4m HT | g | 60901.432 | 2.79 | 300 * 5 | > 22.03 | 1".32 2.4m HT | r | 60901.436 | 2.88 | 300 * 7 | > 22.98 | 0".99 2.4m HT | i | 60901.462 | 3.51 | 300 * 4 | > 21.96 | 1".21 Our (detection) limits are consistent with those reported by Becerra et al. (GCN41362), Postigo et al. (GCN41367), and Karambelkar et al. (GCN41372). The presented magnitudes are calibrated using the field stars from the PanStarrs1 catalog and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of A_g = 3.5 mag, A_r = 2.4 mag, and A_i = 1.8 mag in the direction of the transient (Schlafly & Finkbeiner 2011). View this GCN Circular online at https://gcn.nasa.gov/circulars/41375. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39435] Fermi trigger No 776818276: Global MASTER-Net observations report
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41374 SUBJECT: Fermi trigger No 776818276: Global MASTER-Net observations report DATE: 25/08/14 16:14:45 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB250813.95 (trigger No 776818276,22h 11m 00.00s , +19d 13m 58.8s, R=7.28) errorbox 2746 sec after notice time and 2777 sec after trigger time at 2025-08-13 23:37:29 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 34 deg. The sun altitude is -24.0 deg. The galactic latitude b = -30 deg., longitude l = 79 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2967904 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 2808 | 2025-08-13 23:37:29 | MASTER-Kislovodsk | (22h 08m 10.03s , +18d 25m 11.7s) | C | 60 | 17.7 | 2808 | 2025-08-13 23:37:29 | MASTER- | (22h 03m 28.88s , +18d 46m 39.1s) | C | 60 | 14.8 | 2984 | 2025-08-13 23:40:25 | MASTER-Kislovodsk | (22h 07m 29.43s , +20d 20m 47.2s) | C | 60 | 17.8 | 2984 | 2025-08-13 23:40:25 | MASTER- | (22h 02m 44.88s , +20d 42m 11.9s) | C | 60 | 14.9 | 3156 | 2025-08-13 23:43:17 | MASTER-Kislovodsk | (22h 10m 24.38s , +16d 32m 57.3s) | C | 60 | 17.5 | 3157 | 2025-08-13 23:43:17 | MASTER- | (22h 05m 45.98s , +16d 54m 29.9s) | C | 60 | 14.6 | 3339 | 2025-08-13 23:46:19 | MASTER-Kislovodsk | (22h 24m 10.71s , +18d 27m 26.3s) | C | 60 | 17.5 | 3339 | 2025-08-13 23:46:19 | MASTER- | (22h 19m 27.90s , +18d 49m 00.7s) | C | 60 | 14.5 | 3418 | 2025-08-13 23:47:39 | MASTER-Kislovodsk | (22h 08m 15.78s , +18d 25m 52.8s) | C | 60 | 17.9 | 3418 | 2025-08-13 23:47:39 | MASTER- | (22h 03m 36.62s , +18d 47m 14.6s) | C | 60 | 14.8 | 3591 | 2025-08-13 23:50:32 | MASTER-Kislovodsk | (22h 07m 30.54s , +20d 19m 04.2s) | C | 60 | 17.7 | 3591 | 2025-08-13 23:50:32 | MASTER- | (22h 02m 47.85s , +20d 40m 34.3s) | C | 60 | 14.7 | 3773 | 2025-08-13 23:53:33 | MASTER-Kislovodsk | (22h 10m 21.49s , +16d 31m 09.9s) | C | 60 | 17.6 | 3773 | 2025-08-13 23:53:33 | MASTER- | (22h 05m 44.59s , +16d 52m 43.6s) | C | 60 | 14.5 | 3853 | 2025-08-13 23:54:53 | MASTER-Kislovodsk | (22h 23m 41.95s , +20d 20m 32.4s) | C | 60 | 17.8 | 3853 | 2025-08-13 23:54:53 | MASTER- | (22h 18m 59.12s , +20d 42m 15.9s) | C | 60 | 14.7 | 3933 | 2025-08-13 23:56:13 | MASTER-Kislovodsk | (22h 08m 08.08s , +22d 13m 26.1s) | C | 60 | 17.7 | 3933 | 2025-08-13 23:56:13 | MASTER- | (22h 03m 21.71s , +22d 35m 08.2s) | C | 60 | 14.6 | 4012 | 2025-08-13 23:57:33 | MASTER-Kislovodsk | (22h 24m 09.79s , +18d 26m 53.9s) | C | 60 | 17.7 | 4012 | 2025-08-13 23:57:33 | MASTER- | (22h 19m 30.00s , +18d 48m 52.6s) | C | 60 | 14.4 | 4092 | 2025-08-13 23:58:53 | MASTER-Kislovodsk | (22h 08m 13.06s , +18d 25m 21.0s) | C | 60 | 17.9 | 4092 | 2025-08-13 23:58:53 | MASTER- | (22h 03m 32.84s , +18d 46m 59.0s) | C | 60 | 15.1 | 4172 | 2025-08-14 00:00:13 | MASTER-Kislovodsk | (22h 13m 51.74s , +14d 36m 31.5s) | C | 60 | 18.0 | 4172 | 2025-08-14 00:00:13 | MASTER- | (22h 09m 21.28s , +14d 57m 54.6s) | C | 60 | 14.4 | 4252 | 2025-08-14 00:01:33 | MASTER-Kislovodsk | (22h 07m 28.98s , +20d 18m 32.7s) | C | 60 | 17.8 | 4252 | 2025-08-14 00:01:33 | MASTER- | (22h 02m 45.07s , +20d 40m 23.5s) | C | 60 | 14.8 | 4332 | 2025-08-14 00:02:52 | MASTER-Kislovodsk | (22h 26m 12.78s , +16d 32m 27.6s) | C | 60 | 17.7 | 4332 | 2025-08-14 00:02:52 | MASTER- | (22h 21m 35.76s , +16d 54m 11.5s) | C | 60 | 14.6 | 5035 | 2025-08-14 00:14:36 | MASTER-Kislovodsk | (22h 10m 18.04s , +16d 32m 03.7s) | C | 60 | 17.6 | 5035 | 2025-08-14 00:14:36 | MASTER- | (22h 05m 43.29s , +16d 53m 37.3s) | C | 60 | 14.4 | 5115 | 2025-08-14 00:15:56 | MASTER-Kislovodsk | (22h 23m 41.08s , +20d 19m 17.0s) | C | 60 | 17.7 | 5115 | 2025-08-14 00:15:56 | MASTER- | (22h 18m 57.71s , +20d 41m 09.0s) | C | 60 | 14.7 | 5195 | 2025-08-14 00:17:15 | MASTER-Kislovodsk | (22h 08m 06.96s , +22d 11m 39.9s) | C | 60 | 17.6 | 5195 | 2025-08-14 00:17:15 | MASTER- | (22h 03m 22.97s , +22d 33m 19.9s) | C | 60 | 14.4 | 5275 | 2025-08-14 00:18:35 | MASTER-Kislovodsk | (22h 24m 14.86s , +18d 24m 30.7s) | C | 60 | 17.6 | 5275 | 2025-08-14 00:18:35 | MASTER- | (22h 19m 35.72s , +18d 46m 14.2s) | C | 60 | 14.6 | 5354 | 2025-08-14 00:19:55 | MASTER-Kislovodsk | (22h 08m 10.37s , +18d 25m 29.3s) | C | 60 | 17.8 | 5354 | 2025-08-14 00:19:55 | MASTER- | (22h 03m 35.00s , +18d 46m 54.5s) | C | 60 | 14.7 | 5434 | 2025-08-14 00:21:15 | MASTER-Kislovodsk | (22h 13m 55.03s , +14d 36m 10.9s) | C | 60 | 17.8 | 5434 | 2025-08-14 00:21:15 | MASTER- | (22h 09m 26.62s , +14d 57m 29.9s) | C | 60 | 14.4 | 5514 | 2025-08-14 00:22:35 | MASTER-Kislovodsk | (22h 07m 30.65s , +20d 19m 20.6s) | C | 60 | 17.8 | 5514 | 2025-08-14 00:22:35 | MASTER- | (22h 02m 51.61s , +20d 40m 54.7s) | C | 60 | 14.9 | 5594 | 2025-08-14 00:23:55 | MASTER-Kislovodsk | (22h 26m 09.86s , +16d 31m 01.7s) | C | 60 | 17.6 | 5594 | 2025-08-14 00:23:55 | MASTER- | (22h 21m 34.79s , +16d 52m 40.2s) | C | 60 | 14.6 | 5673 | 2025-08-14 00:25:14 | MASTER-Kislovodsk | (22h 10m 17.52s , +16d 31m 26.8s) | C | 60 | 17.7 | 5673 | 2025-08-14 00:25:14 | MASTER- | (22h 05m 43.53s , +16d 52m 58.7s) | C | 60 | 14.4 | 5753 | 2025-08-14 00:26:34 | MASTER-Kislovodsk | (22h 23m 41.53s , +20d 18m 44.5s) | C | 60 | 17.8 | 5753 | 2025-08-14 00:26:34 | MASTER- | (22h 19m 01.61s , +20d 40m 23.1s) | C | 60 | 14.8 | 5833 | 2025-08-14 00:27:53 | MASTER-Kislovodsk | (22h 08m 06.39s , +22d 11m 07.6s) | C | 60 | 17.7 | 5833 | 2025-08-14 00:27:53 | MASTER- | (22h 03m 23.24s , +22d 32m 45.0s) | C | 60 | 14.6 | 5913 | 2025-08-14 00:29:13 | MASTER-Kislovodsk | (22h 24m 14.63s , +18d 24m 10.0s) | C | 60 | 17.7 | 5913 | 2025-08-14 00:29:13 | MASTER- | (22h 19m 36.26s , +18d 45m 52.2s) | C | 60 | 14.5 | 5992 | 2025-08-14 00:30:33 | MASTER-Kislovodsk | (22h 08m 11.02s , +18d 24m 45.7s) | C | 60 | 17.9 | 5992 | 2025-08-14 00:30:33 | MASTER- | (22h 03m 36.46s , +18d 46m 08.9s) | C | 60 | 14.7 | 6072 | 2025-08-14 00:31:53 | MASTER-Kislovodsk | (22h 13m 55.87s , +14d 35m 37.3s) | C | 60 | 17.8 | 6072 | 2025-08-14 00:31:53 | MASTER- | (22h 09m 28.10s , +14d 56m 52.3s) | C | 60 | 14.4 | 6152 | 2025-08-14 00:33:12 | MASTER-Kislovodsk | (22h 07m 29.61s , +20d 18m 28.1s) | C | 60 | 17.8 | 6152 | 2025-08-14 00:33:13 | MASTER- | (22h 02m 51.28s , +20d 39m 56.7s) | C | 60 | 15.0 | 6232 | 2025-08-14 00:34:32 | MASTER-Kislovodsk | (22h 26m 07.82s , +16d 30m 36.5s) | C | 60 | 17.7 | 6232 | 2025-08-14 00:34:32 | MASTER- | (22h 21m 34.79s , +16d 52m 23.4s) | C | 60 | 14.3 | 6312 | 2025-08-14 00:35:53 | MASTER-Kislovodsk | (22h 10m 18.37s , +16d 30m 59.9s) | C | 60 | 17.8 | 6312 | 2025-08-14 00:35:53 | MASTER- | (22h 05m 47.66s , +16d 52m 15.6s) | C | 60 | 14.4 | 6392 | 2025-08-14 00:37:13 | MASTER-Kislovodsk | (22h 23m 40.10s , +20d 18m 20.1s) | C | 60 | 17.8 | 6392 | 2025-08-14 00:37:13 | MASTER- | (22h 18m 58.10s , +20d 40m 04.6s) | C | 60 | 14.9 | 6472 | 2025-08-14 00:38:32 | MASTER-Kislovodsk | (22h 08m 06.07s , +22d 10m 41.2s) | C | 60 | 17.7 | 6472 | 2025-08-14 00:38:32 | MASTER- | (22h 03m 21.72s , +22d 31m 59.9s) | C | 60 | 14.4 | 6552 | 2025-08-14 00:39:53 | MASTER-Kislovodsk | (22h 24m 15.13s , +18d 23m 33.6s) | C | 60 | 17.7 | 6552 | 2025-08-14 00:39:53 | MASTER- | (22h 19m 38.79s , +18d 45m 23.9s) | C | 60 | 14.0 | 6632 | 2025-08-14 00:41:13 | MASTER-Kislovodsk | (22h 08m 09.79s , +18d 24m 27.6s) | C | 60 | 17.9 | 6632 | 2025-08-14 00:41:13 | MASTER- | (22h 03m 35.86s , +18d 45m 46.2s) | C | 60 | 14.8 | 6712 | 2025-08-14 00:42:33 | MASTER-Kislovodsk | (22h 13m 55.82s , +14d 35m 22.4s) | C | 60 | 17.9 | 6712 | 2025-08-14 00:42:33 | MASTER- | (22h 09m 28.63s , +14d 56m 38.2s) | C | 60 | 14.3 | 6792 | 2025-08-14 00:43:53 | MASTER-Kislovodsk | (22h 07m 28.23s , +20d 18m 24.3s) | C | 60 | 17.9 | 6792 | 2025-08-14 00:43:53 | MASTER- | (22h 02m 50.64s , +20d 39m 51.8s) | C | 60 | 14.8 | 6872 | 2025-08-14 00:45:13 | MASTER-Kislovodsk | (22h 26m 07.62s , +16d 30m 11.5s) | C | 60 | 17.6 | 6872 | 2025-08-14 00:45:13 | MASTER- | (22h 21m 33.88s , +16d 51m 45.9s) | C | 60 | 14.6 | 6952 | 2025-08-14 00:46:33 | MASTER-Kislovodsk | (22h 10m 18.06s , +16d 30m 32.1s) | C | 60 | 17.6 | 6952 | 2025-08-14 00:46:33 | MASTER- | (22h 05m 45.53s , +16d 52m 01.0s) | C | 60 | 14.6 | 7032 | 2025-08-14 00:47:53 | MASTER-Kislovodsk | (22h 23m 40.75s , +20d 17m 53.8s) | C | 60 | 17.8 | 7032 | 2025-08-14 00:47:53 | MASTER- | (22h 18m 59.61s , +20d 39m 37.5s) | C | 60 | 14.8 | 7112 | 2025-08-14 00:49:13 | MASTER-Kislovodsk | (22h 08m 05.53s , +22d 10m 12.6s) | C | 60 | 17.6 | 7112 | 2025-08-14 00:49:13 | MASTER- | (22h 03m 23.89s , +22d 31m 42.7s) | C | 60 | 14.6 | 7192 | 2025-08-14 00:50:33 | MASTER-Kislovodsk | (22h 24m 13.75s , +18d 23m 04.7s) | C | 60 | 17.7 | 7192 | 2025-08-14 00:50:33 | MASTER- | (22h 19m 36.81s , +18d 44m 41.7s) | C | 60 | 14.8 | 7272 | 2025-08-14 00:51:53 | MASTER-Kislovodsk | (21h 58m 11.91s , +14d 35m 47.6s) | C | 60 | 17.1 | 7272 | 2025-08-14 00:51:53 | MASTER- | (21h 53m 44.26s , +14d 57m 09.2s) | C | 60 | 14.3 | 7352 | 2025-08-14 00:53:13 | MASTER-Kislovodsk | (22h 13m 54.38s , +14d 34m 46.8s) | C | 60 | 17.9 | 7352 | 2025-08-14 00:53:13 | MASTER- | (22h 09m 28.22s , +14d 56m 01.7s) | C | 60 | 14.3 | 7432 | 2025-08-14 00:54:32 | MASTER-Kislovodsk | (21h 51m 13.95s , +20d 16m 59.8s) | C | 60 | 17.4 | 7432 | 2025-08-14 00:54:32 | MASTER- | (21h 46m 38.71s , +20d 38m 21.3s) | C | 60 | 14.6 | 7512 | 2025-08-14 00:55:53 | MASTER-Kislovodsk | (22h 26m 08.99s , +16d 29m 45.1s) | C | 60 | 17.6 | 7512 | 2025-08-14 00:55:53 | MASTER- | (22h 21m 36.15s , +16d 51m 19.2s) | C | 60 | 14.4 | 7592 | 2025-08-14 00:57:13 | MASTER-Kislovodsk | (22h 24m 29.76s , +22d 12m 32.8s) | C | 60 | 17.7 | 7592 | 2025-08-14 00:57:13 | MASTER- | (22h 19m 44.77s , +22d 34m 21.0s) | C | 60 | 14.7 | 7672 | 2025-08-14 00:58:33 | MASTER-Kislovodsk | (22h 23m 39.23s , +20d 17m 28.4s) | C | 60 | 17.6 | 7672 | 2025-08-14 00:58:33 | MASTER- | (22h 19m 01.43s , +20d 38m 58.8s) | C | 60 | 14.6 | 7753 | 2025-08-14 00:59:54 | MASTER-Kislovodsk | (22h 08m 04.95s , +22d 09m 44.1s) | C | 60 | 17.5 | 7753 | 2025-08-14 00:59:54 | MASTER- | (22h 03m 24.14s , +22d 31m 12.8s) | C | 60 | 14.4 | 7833 | 2025-08-14 01:01:13 | MASTER-Kislovodsk | (22h 10m 22.60s , +24d 03m 48.3s) | C | 60 | 17.5 | 7833 | 2025-08-14 01:01:13 | MASTER- | (22h 05m 34.23s , +24d 25m 32.9s) | C | 60 | 14.4 | 7913 | 2025-08-14 01:02:33 | MASTER- | (21h 53m 44.89s , +14d 56m 38.4s) | C | 60 | 14.1 | 7913 | 2025-08-14 01:02:33 | MASTER-Kislovodsk | (21h 58m 11.67s , +14d 35m 15.6s) | C | 60 | 17.0 | 7994 | 2025-08-14 01:03:55 | MASTER- | (22h 09m 28.81s , +14d 55m 32.4s) | C | 60 | 13.9 | 7994 | 2025-08-14 01:03:55 | MASTER-Kislovodsk | (22h 13m 54.14s , +14d 34m 16.2s) | C | 60 | 17.5 | 8074 | 2025-08-14 01:05:15 | MASTER- | (21h 46m 41.03s , +20d 37m 52.8s) | C | 60 | 14.3 | 8074 | 2025-08-14 01:05:15 | MASTER-Kislovodsk | (21h 51m 15.27s , +20d 16m 32.0s) | C | 60 | 17.1 | 8154 | 2025-08-14 01:06:34 | MASTER- | (22h 21m 35.69s , +16d 50m 51.6s) | C | 60 | 14.1 | 8154 | 2025-08-14 01:06:34 | MASTER-Kislovodsk | (22h 26m 07.61s , +16d 29m 17.7s) | C | 60 | 17.4 | 8234 | 2025-08-14 01:07:55 | MASTER-Kislovodsk | (22h 24m 28.05s , +22d 12m 04.6s) | C | 60 | 17.3 | 8234 | 2025-08-14 01:07:55 | MASTER- | (22h 19m 46.63s , +22d 33m 41.3s) | C | 60 | 14.3 | 8314 | 2025-08-14 01:09:14 | MASTER-Kislovodsk | (21h 51m 45.60s , +22d 09m 33.8s) | C | 60 | 17.0 | 8314 | 2025-08-14 01:09:14 | MASTER- | (21h 47m 05.50s , +22d 31m 20.4s) | C | 60 | 13.6 | 8394 | 2025-08-14 01:10:34 | MASTER-Kislovodsk | (21h 52m 05.11s , +18d 20m 33.4s) | C | 60 | 16.8 | 8394 | 2025-08-14 01:10:34 | MASTER- | (21h 47m 32.62s , +18d 41m 59.4s) | C | 60 | 13.9 | 8474 | 2025-08-14 01:11:54 | MASTER-Kislovodsk | (22h 10m 22.92s , +24d 03m 22.1s) | C | 60 | 17.0 | 8474 | 2025-08-14 01:11:54 | MASTER- | (22h 05m 38.34s , +24d 24m 55.7s) | C | 60 | 14.1 | 8553 | 2025-08-14 01:13:14 | MASTER- | (21h 53m 45.59s , +14d 55m 58.9s) | C | 60 | 13.6 | 8553 | 2025-08-14 01:13:14 | MASTER-Kislovodsk | (21h 58m 11.28s , +14d 34m 35.2s) | C | 60 | 16.3 | 8633 | 2025-08-14 01:14:34 | MASTER-Kislovodsk | (21h 54m 27.28s , +16d 26m 39.4s) | C | 60 | 16.2 | 8633 | 2025-08-14 01:14:34 | MASTER- | (21h 49m 58.89s , +16d 48m 04.0s) | C | 60 | 13.6 | 8713 | 2025-08-14 01:15:54 | MASTER- | (21h 46m 40.88s , +20d 37m 02.6s) | C | 60 | 13.6 | 8713 | 2025-08-14 01:15:54 | MASTER-Kislovodsk | (21h 51m 13.90s , +20d 15m 43.3s) | C | 60 | 16.4 | 8793 | 2025-08-14 01:17:14 | MASTER-Kislovodsk | (22h 40m 07.00s , +18d 23m 20.2s) | C | 60 | 16.7 | 8793 | 2025-08-14 01:17:14 | MASTER- | (22h 35m 33.87s , +18d 44m 52.4s) | C | 60 | 13.4 | 8873 | 2025-08-14 01:18:34 | MASTER- | (22h 19m 45.64s , +22d 33m 33.4s) | C | 60 | 12.9 | 8873 | 2025-08-14 01:18:34 | MASTER-Kislovodsk | (22h 24m 27.35s , +22d 11m 33.6s) | C | 60 | 16.5 | 8953 | 2025-08-14 01:19:54 | MASTER-Kislovodsk | (21h 51m 43.82s , +22d 08m 58.9s) | C | 60 | 16.2 | 8953 | 2025-08-14 01:19:54 | MASTER- | (21h 47m 06.12s , +22d 30m 11.7s) | C | 60 | 13.2 | 9032 | 2025-08-14 01:21:13 | MASTER-Kislovodsk | (21h 52m 03.47s , +18d 19m 58.8s) | C | 60 | 16.0 | 9032 | 2025-08-14 01:21:13 | MASTER- | (21h 47m 34.22s , +18d 41m 19.5s) | C | 60 | 13.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/41374. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39434] Swift GRB250814.32: Global MASTER-Net observations report
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41373 SUBJECT: Swift GRB250814.32: Global MASTER-Net observations report DATE: 25/08/14 16:14:43 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), 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-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 Swift GRB250814.32 (trigger No 1342439,20h 25m 18.96s , +48d 23m 27.6s, R=0.05) errorbox 28681 sec after notice time and 28770 sec after trigger time at 2025-08-14 15:34:30 UT, with upper limit up to 16.4 mag. The observations began at zenith distance = 6 deg. The sun altitude is -21.4 deg. The galactic latitude b = 6 deg., longitude l = 85 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2968157 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 28860 | MASTER-Tunka | C | 180 | 16.4 | 28860 | MASTER- | C | 180 | 16.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/41373. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39433] GRB 250814A: J-band upper limit from WINTER
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41372 SUBJECT: GRB 250814A: J-band upper limit from WINTER DATE: 25/08/14 15:52:22 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197(a)gmail.com> Viraj Karambelkar (Caltech), Tomas Ahumada (Caltech), Benjamin Schneider (LAM), Robert Stein (UMD), Geoffrey Mo (MIT), Danielle Frostig (CfA), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report: We observed the field of the Fermi and Swift GRB 250814A (Fermi team, GCN Circ. 41357, Caputo et al. GCN Circ. 41358) coincident with the sub-threshold GW trigger S250814bg (GCN Circ. 41364) in the near-infrared with the Palomar 1-m telescope, equipped with the 1-square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024). Observations started on 2025-08-14 at 07:49:52 UT (15 min after the trigger) and consisted of 15 exposures of 120 s in the J-band. In the stacked image, we do not detect any new source at the X-ray afterglow position reported by Caputo et al, GCN 41358 down to the following 5-sigma AB magnitude: J > 19.3 The images were processed using the WINTER data reduction pipeline implemented with mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565) The photometric calibration was performed using nearby stars from the 2MASS catalog and the magnitude is not corrected for Galactic extinction. WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/41372. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39432] IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41371 SUBJECT: IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube DATE: 25/08/14 13:42:34 GMT FROM: Alicia Mand at IceCube/UW-Madison <aemand(a)wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-250813A (https://gcn.nasa.gov/circulars/41338) in a time range of 1000 seconds centered on the alert event time (2025-08-13 03:12:49.690 UTC to 2025-08-13 03:29:29.690 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-250813A. We report a p-value of 1.00 in this time window. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-250813A is 1.3e-01 GeV cm^-2 in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 2e+02 GeV and 1e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2025-08-12 03:21:09.690 UTC to 2025-08-14 03:21:09.690 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-250813A is 1.5e-01 GeV cm^-2 in a 2 day time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/41371. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39431] GRB 250813B: NOT observations of the optical afterglow
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41370 SUBJECT: GRB 250813B: NOT observations of the optical afterglow DATE: 25/08/14 12:18:54 GMT FROM: Antonio Martin-Carrillo at UCD,Space Science Group <antonio.martin-carrillo(a)ucd.ie> G. Corcoran (UCD), A. Martin-Carrillo (UCD), D. B. Malesani (DAWN/NBI and Radboud), B. Schneider (LAM), B. P. Gompertz (Birmingham), V. Vuolteenaho (Univ. of Oulu), report on behalf of a larger collaboration: We observed the field of the SVOM/ECLAIRs GRB 250813B (Xie et al., GCN 41352; Xie et al., GCN 42354), using the ALFOSC camera mounted on the Nordic Optical Telescope (NOT). We obtained 6x150 s exposures in the r-band and 5x200 s in the z-band, starting at 2025-08-14 00:05:04 UT (1.231 hr after the trigger). The optical afterglow reported by Jelinek et al. (GCN 41355), de Ugarte Postigo et al. (GCN 41356), Schneider et al. (GCN 41363) and Xin et al. (GCN 41369) is well detected with a preliminary magnitude of r = 21.00 +/- 0.08 (AB, mid-time 1.379 hr after trigger); z = 20.04 +/- 0.09 (AB, mid-time 1.689 hr after trigger). The photometric calibration was performed using nearby stars from the Pan-STARRS catalog and the magnitudes are not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/41370. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39430] GRB 250813B: SVOM/VT optical observations
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41369 SUBJECT: GRB 250813B: SVOM/VT optical observations DATE: 25/08/14 12:16:34 GMT FROM: Liping Xin at NAOC, SVOM <xlp(a)nao.cas.cn> L. P. Xin, H. L. Li, Y. L. Qiu, C. Wu, Y. N. Ma, Z. H. Yao, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), B. T. Wang (YNAO) report on behalf of the SVOM/VT team. SVOM performed an automatic slew on the burst GRB 250813B triggered by SVOM/ECLAIRs (Xie et al., GCN 41354). SVOM/VT start the observations at 278 seconds after the burst, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. The optical counterpart (Jelinek et al., GCN 41353 & GCN 41355; Schneider et al., GCN 41363; de Ugarte Postigo et al., GCN 41356) at the position consistent with the locations of Swift/XRT (Page et al., GCN 41359), EP/FXT (Wu et al., GCN 41361) and SVOM/MXT(Xie et al., GCN 41354, Gotz et al., GCN 41368), was clearly detected in both VT_R and VT_B. During the X-band data available, the brightness was fading from VT_R=16.61+/0.02 mag and VT_B=17.73+/-0.03 mag at 303 seconds post the burst to VT_R=20.9+/-0.1 mag and VT_B=22.1+/-0.2 mag at 4.27 hours after the burst. Our photometry was not corrected for Galactic extinction. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. The SVOM point of contact for this burst is Wenjin Xie (xiewj(a)bao.ac.cn) Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst. View this GCN Circular online at https://gcn.nasa.gov/circulars/41369. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39429] Subject GRB 250813B: SVOM/MXT refined analysis
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41368 SUBJECT: Subject GRB 250813B: SVOM/MXT refined analysis DATE: 25/08/14 11:45:54 GMT FROM: Diego Gotz at CEA <diego.gotz(a)cea.fr> D. Götz (CEA), F. Robinet (IJCLab), P. Maggi (ObAS), H. Goto (Kanazawa Univ./CEA), M. Moita (CEA), C. Plasse (CEA), , C. Van Hove (IJCLab) report of behalf of the SVOM/MXT Team: GRB 250813B (Xie et al. GCN 41352/41354) was observed by SVOM/MXT after an automatic SVOM slew, starting at T0 = 2025-08-13T22:54:01, 169 s after trigger time Tb. MXT observed for the remainder of the orbit, cumulating 188 s of useful data before entering Earth occultation. Using the full X-band dataset of the first orbit, the position of the MXT afterglow is refined to: R.A. (J2000) = 22h26m58.6s Dec (J2000) = +12d27m08s with a 90% C.L. radius of 54 arc sec (including 25 arcseconds systematic error added in quadrature). This position is at 47 arc sec from the optical counterpart reported in GCN 41353. The light curve exhibits an initial fast fading with temporal decay of -2.3+/-0.5. We analysed the early time (first orbit) spectrum and modelled it with a redshifted (z=1.75 GCN 41363) absorbed power-law, a photon index Gamma 1.4+-/0.3 at 90% C.L and a redshifted absorbing column of NH = <0.8x1e22 cm^-2 on top of a Galactic NH = 4.86x10^20 cm^-2. The source is still detected on the subsequent orbit between Tb+3900 and Tb+6100 s but not after. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. MXT was developed jointly by CEA, CNES, University of Leicester, IJCLab and MPE. The SVOM point of contact for this burst is Wenjin Xie (xiewj(a)bao.ac.cn) Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst. View this GCN Circular online at https://gcn.nasa.gov/circulars/41368. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39428] GRB 250814A: COLIBRÍ optical upper limit
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41367 SUBJECT: GRB 250814A: COLIBRÍ optical upper limit DATE: 25/08/14 11:04:35 GMT FROM: Antonio de Ugarte Postigo at LAM, CNRS <adeugartepostigo(a)gmail.com> Antonio de Ugarte Postigo (LAM), Ramandeep Gill (UNAM), Jean-Grégoire Ducoin (CPPM), Rosa L. Becerra (U Roma), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Fredd Alvarez (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (OCA), Nathaniel R. Butler (ASU) , Damien Dornic (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Benjamin Schneider (LAM): We imaged the field of the Fermi and Swift GRB 250814A (Fermi team, GCN Circ. 41357, Caputo et al. GCN Circ. 41358) using the DDRAGO wide-field imager on the COLIBRÍ telescope. We observed from 2025-08-14 07:48 to 08:07 UTC (from 13.9 to 33.0 minutes after the trigger) and obtained 16 minutes of exposure in the i filter. The data were reduced and coadded with the COLIBRÍ pipeline and analysed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. In the stacked image, we do not detect any new source at the XRT source position (Caputo et al. GCN Circ. 41358) down to the following 3-sigma limit: i > 22.9 This upper limit is consistent with the one reported by Becerra et al. (GCN Circ. 41362). We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/41367. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39427] GRB 250814B: Fermi GBM Final Real-time Localization
by GCN Circulars 14 Aug '25

14 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41366 SUBJECT: GRB 250814B: Fermi GBM Final Real-time Localization DATE: 25/08/14 10:32:39 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 10:22:10 UT on 14 Aug 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250814B (trigger 776859735.510984 / 250814432). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 80.1, Dec = 24.6 (J2000 degrees, equivalent to J2000 05h 20m, 24d 36'), with a statistical uncertainty of 4.6 degrees. The angle from the Fermi LAT boresight is 132.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250814432/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250814432/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250814432/… View this GCN Circular online at https://gcn.nasa.gov/circulars/41366. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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