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[vsnet-grb-info 43740] GRB 260903A: J-band upper limit with WINTER
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45519 SUBJECT: GRB 260903A: J-band upper limit with WINTER DATE: 26/09/04 20:05:20 GMT FROM: tanishk.mohan(a)iitb.ac.in Tanishk Mohan (IITB), Geoffrey Mo (Caltech/Carnegie), Viraj Karambelkar (Columbia), Benjamin Schneider (LAM), Tomas Ahumada (NOIRLab), Robert Stein (UMD), Danielle Frostig (CfA), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report: We observed the field of GRB 260903A (Brunet et al., GCN 45499 and GCN 45517) in the near-infrared J band with the Palomar 1-m telescope, equipped with the 1.2-square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024). Observations began on 2026-09-04 at 05:43:17.936 UTC in the J band (17.1 hr after the SVOM/ECLAIRs trigger), consisting of 15*120 sec exposures. 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) We do not detect the source at the optical counterpart position (Li et al., GCN 45504; Saccardi et al., GCN 45505; Malesani et al., GCN 45508; Russeil et al., GCN 45509; Moskvitin el al., GCN 45515; Bochenek et al., GCN 45516) in our stacked image. We obtain the following 5-sigma upper limit: J = 19.07 mag (AB). 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/45519. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43739] EP Alert 260903.47: Global MASTER-Net observations report
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45518 SUBJECT: EP Alert 260903.47: Global MASTER-Net observations report DATE: 26/09/04 18:36:35 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 (Lomonosov MSU) D.Buckley (SAAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) A.Sosnovskij (CrAO RAS) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) R.Rebolo (The Instituto de Astrofisica de Canarias) O.Gress, N.Budnev(ISU) M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) MASTER-Tavrida robotic telescope [1] located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the EP Alert 260903.47 (trigger No 1788434279,19h 28m 00.96s , -21d 29m 38.4s, R=0.0433333) errorbox 35381 sec after notice time and 1 days 24713 sec after trigger time at 2026-09-04 18:09:52 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 66 deg. The sun altitude is -19.8 deg. The galactic latitude b = -18 deg., longitude l = 18 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3498862 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 111204 | 2026-09-04 18:09:52 | MASTER-Tavrida | (19h 27m 56.99s , -21d 32m 42.5s) | C | 180 | 17.5 | 111204 | 2026-09-04 18:09:53 | MASTER-Tavrida | (19h 27m 51.29s , -21d 33m 06.2s) | C | 180 | 18.0 | 111400 | 2026-09-04 18:13:09 | MASTER-Tavrida | (19h 27m 46.19s , -21d 33m 13.6s) | C | 180 | 18.0 | 111436 | 2026-09-04 18:13:45 | MASTER-Tavrida | (19h 27m 51.64s , -21d 32m 51.1s) | C | 180 | 17.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45518. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43738] GRB 260903A: SVOM/ECLAIRs refined analysis
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45517 SUBJECT: GRB 260903A: SVOM/ECLAIRs refined analysis DATE: 26/09/04 17:41:50 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> M. Brunet, H. Yang, O. Godet (IRAP) , W.-J. Xie (NAOC), R.-C. Chen (NJU), T. Xiao (GXU), report on behalf of the SVOM/ECLAIRs team: Using the event-by-event data downloaded through the X-band ground station, we report further analysis of SVOM/ECLAIRs observations of GRB 260903A (SVOM burst-id sb26090302 – GCN 45499, trigger time T0 = 2026-09-03T12:37:20 UTC). The burst that triggered ECLAIRs onboard shows a single peak lightcurve. The burst duration is T90 = 21 +6/-4 s in the 4-20 keV energy band. The time-averaged spectrum from T0-18.98 s to T0+1.13 s in the 5-120 keV energy range is best fitted by a powerlaw model, with alpha = -3.2/-0.5. With this model, the 4-120 keV fluence is (1.6 +0.3/-0.2)e-7 erg/cm^2 and the 4-120 keV photon flux is 0.70 +/-0.08 ph/cm^2/s. A blackbody model also gives a good fit with kT = 1.8 +/-0.2 keV. With this model, the 4-120 keV fluence is (1.2 +/-0.2)e-7 erg/cm^2 and the 4-120 keV photon flux is 0.54 +/-0.06 ph/cm^2/s. The spectral parameters show that this burst could be classified as an X-Ray Flash (XRF). All the quoted errors are at the 68% confidence level. The Space-based multi-band astronomical 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. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. The SVOM/ECLAIRs point of contact for this burst is: Marius Brunet (IRAP) (marius.brunet et utoulouse.fr) View this GCN Circular online at https://gcn.nasa.gov/circulars/45517. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43737] GRB260903A: Liverpool Telescope optical observations
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45516 SUBJECT: GRB260903A: Liverpool Telescope optical observations DATE: 26/09/04 16:39:14 GMT FROM: A. Bochenek at Liverpool John Moores University <a.m.bochenek(a)2023.ljmu.ac.uk> A. Bochenek, D. A. Perley (LJMU), report: We observed the field of GRB 260903A (Brunet et al., GCN 45499) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 6x120s exposures in SDSS gz filters and 12x120s in the SDSS r filter, starting at 2026-09-04 00:42:48 UT, approximately 12 hours after SVOM/ECLAIRS trigger. The obtained images were stacked after discarding bad quality exposures. We detect a source in the r-band stack at a counterpart position reported by Li et al. (GCN 45504), Saccardi et al. (GCN 45505), Malesani et al. (GCN 45508), Russeil et al. (GCN 45509), Li et al. (GCN 45510), and Moskvitin et al. (GCN 45115). We also report 3-sigma upper limits in other bands. MJD (mid) T_mid-T_0 Filter Mag. (AB) 61287.03369 12.2 h g > 22.37 61287.04889 12.6 h r 22.73 ± 0.26 61287.06252 12.9 h z > 21.38 The photometry is in the AB magnitude system, was calibrated using nearby PanSTARRS secondary standards and was not corrected for extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45516. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43736] GRB 260903A: SAO RAS optical observations
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45515 SUBJECT: GRB 260903A: SAO RAS optical observations DATE: 26/09/04 15:01:32 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Spiridonova (SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of the GRB 260903A discovered by the SVOM (Brunet et al., GCN 45499), also followed by EP (Li et al., GCN 45510) with the Zeiss-1000, 1-m SAO RAS telescope + new CCD photometer. A set of 16 x 300 sec images in Rc band were obtained on September 3, 19:58:07--21:32:51 (mid. time = 8.1358 hours). The OT (Li et al., GCN 45504; Saccardi et al., GCN 45505; Malesani et al., GCN 45508; Russeil et al., GCN 45509) is clearly detected in our stacked image. Details of the observation are the following. Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-09-03 19:58:07 0.33899 16*300 Rc 22.45 +/- 0.09 24.0 The preliminary photometry (Vega) is based on nearby SDSS stars (Lupton 2005 transformation) and not corrected for Galactic extinction. _____________________________________________ Alexander Sergeevich Moskvitin, Ph. D., researcher, Optical Transient Physics Laboratory (#523), SAO RAS, 369167, Nizhnij Arkhyz, Karachai-Cherkessia, Russia, +7(928)3946958, mosk(a)sao.ru View this GCN Circular online at https://gcn.nasa.gov/circulars/45515. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43735] GRB 260830A: GECAM-B detection of a burst
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45514 SUBJECT: GRB 260830A: GECAM-B detection of a burst DATE: 26/09/04 12:12:21 GMT FROM: yzh807926(a)163.com Zheng-Hang Yu, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight by a burst GRB 260830A at 2026-08-30T19:32:11.800 UTC (denoted as T0), which is also detected by NuSTAR (G. Waratkar et al., GCN #45483) and Insight-HXMT/HE (Yu et al., GCN #45511). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 11 +/-1 s. The on-ground localization of GECAM-B is: Ra: 245.5 deg Dec: -61.1 deg Err: 3.4 deg (1-sigma, statistical only) The GECAM-B light curve can be found here: https://www.bursthub.cn/gcn/2026/gecambgrb260830A.png The time-averaged spectrum from T0-5.0 to T0+10.0 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.13 +0.30/-0.28 and the cutoff energy, parameterized as Epeak, is 190 +23/-14 keV. The event fluence (10-1000 keV) in this time interval is (1.85 +0.25/-0.18) E-05 erg/cm^2. The localization of GRB 260830A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn/gcn/2026/gecambgrb260830A_amati.png Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS). View this GCN Circular online at https://gcn.nasa.gov/circulars/45514. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43734] EP260903a: EP-WXT detection of a fast X-ray transient
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45513 SUBJECT: EP260903a: EP-WXT detection of a fast X-ray transient DATE: 26/09/04 08:19:20 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Z.-M. Wang (BNU), R.-Z. Li (YNAO, CAS), R. Shi (PMO, CAS), H. Sun (NAO,CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of a fast X-ray transient, designated EP260903a (notice ID: 13600875138), by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The transient was identified in the telemetry data. The WXT light curve of the transient started at about 2026-09-03T11:17:59 (UTC) and lasted for approximately 200 s, exhibiting a double-peaked structure. The position of the transient is R.A. = 292.004 deg, Dec. = -21.494 (J2000), with an uncertainty radius of 2.6 arcmin in radius (90% confidence level, including both statistical and systematic uncertainties). The average WXT 0.5-4 keV spectrum can be fitted by an absorbed power-law model with a fixed Galactic hydrogen column density of 8.0×10^20 cm^-2 and a photon index of 1.67 (-0.54/+0.60). The derived average unabsorbed 0.5-4 keV flux is 7.41 (-2.21/+2.90) erg cm^-2 s^-1. The uncertainties are at the 90% confidence level for the above parameters. Follow-up observations by EP-FXT has be scheduled. The optical follow-up observation was performed by MASTER-Net (Gress et al., GCN 45512). Launched on 2024 January 9, Einstein Probe is a space-based X-ray observatory designed to monitor the dynamic X-ray sky and perform rapid follow-up observations of newly discovered transients (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45513. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43733] EP Alert 260903.62: Global MASTER-Net observations report
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45512 SUBJECT: EP Alert 260903.62: Global MASTER-Net observations report DATE: 26/09/04 06:54:44 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> O.Gress, N.Budnev(ISU) 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 (Lomonosov MSU) D.Buckley (SAAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) A.Sosnovskij (CrAO RAS) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) R.Rebolo (The Instituto de Astrofisica de Canarias) M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) MASTER-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the EP Alert 260903.62 (trigger No 1788446808,01h 42m 38.74s , +11d 22m 10.6s, R=0.5) errorbox 1399 sec after trigger time at 2026-09-03 15:10:07 UT, with upper limit up to 18.8 mag. The observations began at zenith distance = 70 deg. The sun altitude is -25.7 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the EP Alert 260903.62 errorbox 33005 sec after trigger time at 2026-09-03 23:56:53 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 34 deg. The sun altitude is -29.7 deg. The galactic latitude b = -49 deg., longitude l = 143 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3498859 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1429 | 2026-09-03 15:10:07 | MASTER-Tunka | (01h 39m 56.83s , +10d 45m 37.2s) | C | 60 | 13.9 | 1502 | 2026-09-03 15:11:19 | MASTER-Tunka | (01h 40m 02.09s , +10d 45m 48.3s) | C | 60 | 16.4 | 1577 | 2026-09-03 15:12:35 | MASTER-Tunka | (01h 39m 58.94s , +10d 47m 16.3s) | C | 60 | 16.9 | 1653 | 2026-09-03 15:13:51 | MASTER-Tunka | (01h 39m 59.00s , +10d 45m 42.4s) | C | 60 | 16.0 | 1727 | 2026-09-03 15:15:04 | MASTER-Tunka | (01h 40m 01.06s , +10d 47m 25.9s) | C | 60 | 16.3 | 1801 | 2026-09-03 15:16:19 | MASTER-Tunka | (01h 39m 55.32s , +10d 46m 25.1s) | C | 60 | 16.9 | 1908 | 2026-09-03 15:18:05 | MASTER-Tunka | (01h 39m 55.09s , +10d 47m 22.5s) | C | 60 | 16.9 | 1988 | 2026-09-03 15:19:25 | MASTER-Tunka | (01h 40m 02.37s , +10d 46m 21.1s) | C | 60 | 17.3 | 2065 | 2026-09-03 15:20:43 | MASTER-Tunka | (01h 39m 56.82s , +10d 45m 15.9s) | C | 60 | 16.5 | 2144 | 2026-09-03 15:22:01 | MASTER-Tunka | (01h 40m 01.29s , +10d 45m 27.8s) | C | 60 | 17.6 | 2190 | 2026-09-03 15:22:48 | MASTER-Tunka | (01h 39m 59.00s , +10d 46m 53.3s) | C | 60 | 18.0 | 2263 | 2026-09-03 15:24:01 | MASTER-Tunka | (01h 39m 58.96s , +10d 45m 21.6s) | C | 60 | 17.4 | 2338 | 2026-09-03 15:25:16 | MASTER-Tunka | (01h 40m 02.07s , +10d 47m 05.4s) | C | 60 | 17.2 | 2411 | 2026-09-03 15:26:28 | MASTER-Tunka | (01h 39m 55.16s , +10d 46m 05.9s) | C | 60 | 17.8 | 2484 | 2026-09-03 15:27:41 | MASTER-Tunka | (01h 39m 56.15s , +10d 47m 03.1s) | C | 60 | 17.1 | 2558 | 2026-09-03 15:28:56 | MASTER-Tunka | (01h 40m 02.39s , +10d 46m 01.4s) | C | 60 | 17.6 | 2631 | 2026-09-03 15:30:08 | MASTER-Tunka | (01h 39m 55.93s , +10d 44m 58.5s) | C | 60 | 17.2 | 2703 | 2026-09-03 15:31:21 | MASTER-Tunka | (01h 40m 00.97s , +10d 45m 24.5s) | C | 60 | 17.5 | 2778 | 2026-09-03 15:32:36 | MASTER-Tunka | (01h 39m 58.90s , +10d 46m 27.8s) | C | 60 | 18.3 | 2851 | 2026-09-03 15:33:49 | MASTER-Tunka | (01h 39m 58.86s , +10d 44m 58.2s) | C | 60 | 18.1 | 2924 | 2026-09-03 15:35:01 | MASTER-Tunka | (01h 40m 02.87s , +10d 46m 32.3s) | C | 60 | 17.0 | 3031 | 2026-09-03 15:36:48 | MASTER-Tunka | (01h 39m 55.80s , +10d 45m 47.7s) | C | 60 | 17.4 | 3110 | 2026-09-03 15:38:07 | MASTER-Tunka | (01h 39m 56.49s , +10d 46m 44.1s) | C | 60 | 18.1 | 3155 | 2026-09-03 15:38:53 | MASTER-Tunka | (01h 40m 01.47s , +10d 45m 43.1s) | C | 60 | 18.1 | 3263 | 2026-09-03 15:40:41 | MASTER-Tunka | (01h 39m 55.52s , +10d 44m 39.4s) | C | 60 | 18.2 | 3342 | 2026-09-03 15:41:59 | MASTER-Tunka | (01h 40m 02.63s , +10d 44m 49.8s) | C | 60 | 18.8 | 3420 | 2026-09-03 15:43:17 | MASTER-Tunka | (01h 39m 58.80s , +10d 46m 16.3s) | C | 60 | 18.3 | 3465 | 2026-09-03 15:44:03 | MASTER-Tunka | (01h 39m 58.83s , +10d 44m 53.9s) | C | 60 | 18.1 | 3536 | 2026-09-03 15:45:14 | MASTER-Tunka | (01h 40m 01.35s , +10d 46m 05.4s) | C | 60 | 18.3 | 3610 | 2026-09-03 15:46:28 | MASTER-Tunka | (01h 39m 55.82s , +10d 45m 27.4s) | C | 60 | 18.2 | 33036 | 2026-09-03 23:56:53 | MASTER-Tavrida | (01h 42m 02.94s , +11d 16m 34.4s) | C | 60 | 18.0 | 33036 | 2026-09-03 23:56:53 | MASTER-Tavrida | (01h 42m 06.31s , +11d 16m 21.4s) | C | 60 | 17.3 | 33106 | 2026-09-03 23:58:04 | MASTER-Tavrida | (01h 42m 04.01s , +11d 14m 30.9s) | C | 60 | 17.0 | 33128 | 2026-09-03 23:58:25 | MASTER-Tavrida | (01h 42m 07.38s , +11d 14m 16.8s) | C | 60 | 17.1 | 33179 | 2026-09-03 23:59:16 | MASTER-Tavrida | (01h 42m 10.39s , +11d 14m 53.9s) | C | 60 | 17.5 | 33846 | 2026-09-04 00:09:54 | MASTER-Tavrida | (01h 42m 07.05s , +11d 15m 32.1s) | C | 120 | 17.1 | 33846 | 2026-09-04 00:09:54 | MASTER-Tavrida | (01h 42m 10.32s , +11d 15m 17.4s) | C | 120 | 17.3 | 33978 | 2026-09-04 00:12:06 | MASTER-Tavrida | (01h 42m 07.15s , +11d 13m 55.6s) | C | 120 | 17.3 | 33978 | 2026-09-04 00:12:06 | MASTER-Tavrida | (01h 42m 10.36s , +11d 13m 41.1s) | C | 120 | 17.4 | 34184 | 2026-09-04 00:15:32 | MASTER-Tavrida | (01h 42m 03.25s , +11d 15m 47.0s) | C | 120 | 17.3 | 34184 | 2026-09-04 00:15:32 | MASTER-Tavrida | (01h 42m 06.48s , +11d 15m 33.0s) | C | 120 | 17.3 | 34318 | 2026-09-04 00:17:45 | MASTER-Tavrida | (01h 42m 10.82s , +11d 14m 41.8s) | C | 120 | 17.0 | 34318 | 2026-09-04 00:17:46 | MASTER-Tavrida | (01h 42m 14.05s , +11d 14m 27.8s) | C | 120 | 17.2 | 34451 | 2026-09-04 00:19:58 | MASTER-Tavrida | (01h 42m 13.92s , +11d 13m 41.7s) | C | 120 | 16.7 | 34444 | 2026-09-04 00:20:22 | MASTER-Tavrida | (01h 42m 10.69s , +11d 13m 56.4s) | C | 60 | 16.5 | 35075 | 2026-09-04 00:30:53 | MASTER-Tavrida | (01h 42m 07.42s , +11d 14m 45.6s) | C | 60 | 12.5 | 35075 | 2026-09-04 00:30:53 | MASTER-Tavrida | (01h 42m 10.60s , +11d 14m 31.5s) | C | 60 | 12.3 | 35147 | 2026-09-04 00:32:04 | MASTER-Tavrida | (01h 42m 10.36s , +11d 15m 00.9s) | C | 60 | 13.1 | 35167 | 2026-09-04 00:32:24 | MASTER-Tavrida | (01h 42m 13.57s , +11d 14m 46.8s) | C | 60 | 12.5 | 35218 | 2026-09-04 00:33:15 | MASTER-Tavrida | (01h 42m 04.87s , +11d 14m 05.6s) | C | 60 | 14.1 | 35847 | 2026-09-04 00:43:44 | MASTER-Tavrida | (01h 42m 05.14s , +11d 14m 40.7s) | C | 60 | 15.2 | 35847 | 2026-09-04 00:43:45 | MASTER-Tavrida | (01h 42m 08.34s , +11d 14m 27.5s) | C | 60 | 15.4 | 35920 | 2026-09-04 00:44:57 | MASTER-Tavrida | (01h 42m 08.26s , +11d 12m 23.9s) | C | 60 | 13.7 | 35941 | 2026-09-04 00:45:18 | MASTER-Tavrida | (01h 42m 05.04s , +11d 12m 36.7s) | C | 60 | 13.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45512. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43732] GRB 260830A: Insight-HXMT/HE detection
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45511 SUBJECT: GRB 260830A: Insight-HXMT/HE detection DATE: 26/09/04 06:53:59 GMT FROM: yzh807926(a)163.com Zheng-Hang Yu and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team: At 2026-08-30T19:32:13.02 (T0), Insight-HXMT/HE detected GRB 260830A, which is also detected by NuSTAR (G. Waratkar et al., GCN #45483). The Insight-HXMT/HE light curve mainly consists of multiple pulses with a T90 of 9 +7/-3 s. The 1 s peak rate, measured from T0+5.5 s, is 552 cnts/sec. Insight-HXMT/HE detected a total of 3815 counts from this burst. The Insight-HXMT/HE light curve can be found here: https://www.bursthub.cn/gcn/2026/hxmtgrb260830A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the Normal mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org View this GCN Circular online at https://gcn.nasa.gov/circulars/45511. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43731] GRB 260903A: EP-FXT follow-up observation
by GCN Circulars 04 Sep '26

04 Sep '26

TITLE: GCN CIRCULAR NUMBER: 45510 SUBJECT: GRB 260903A: EP-FXT follow-up observation DATE: 26/09/04 06:11:05 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.-Z. Li (YNAO, CAS), Z.-M. Wang (BNU), R. Shi (PMO), H. Sun (NAO,CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of GRB 260903A, detected by SVOM/ECLAIRs (sb26090302; Brunet et al., GCN 45499), at 2026-09-03 14:46:48 (UTC), about 2.16 hours after the SVOM/ECLAIRs trigger, with an exposure time of 6005 s. On-ground analysis of the EP-FXT data found an uncataloged fading X-ray source within the SVOM/VT error region (Li et al., GCN 45504). The preliminary results for the X-ray source are as follows: Source name: EPF_J014238.7+112211 R.A., Decl. (J2000) = 25.6614, 11.3696 deg Localization error radius = 10 arcsec 0.5-10 keV flux = 9.76e-13 erg/cm^ 2/s Flux error = 1.94e-13 erg/cm^2/s (1 sigma) Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45510. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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