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[vsnet-grb-info 42099] GRB 260310A / AT2026fgk : MASTER OT rebrightening during 7h observations
by GCN Circulars 13 Mar '26

13 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43978 SUBJECT: GRB 260310A / AT2026fgk : MASTER OT rebrightening during 7h observations DATE: 26/03/13 02:18:22 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov (Lomonosov MSU), N.Budnev, O.Gress (ISU), A.Kuznetsov, I.Panchenko, P.Balanutsa, G.Antipov, E.Gorbovskoy, N.Tiurina, Ya.Kechin, V.Senik, A.Chasovnikov, M.Shilova,V.Topolev, D.Vlasenko, A.Sankovich, Yu.Tselik (Lomonosov MSU), D.Svinkin (Ioffe Institute), M.J. Segura, 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), 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, J.Tanori, L. Villalobos, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) MASTER Global Robotic Net [1-4] started Fermi GRB 260310A observations (Fermi team GCN 43951) at MASTER-Tunka robotic telescope at 2026-03-10 16:01:36 UT (Lipunov et al. GCN 43954) Optical transient AT2026fgk, discovered by GOTO at 2026-03-10 05:14:30.624 (TNSC 1001, https://www.wis-tns.org/object/2026fgk ) was detected as MASTER OT J143716.19+715031.2 at our images at 2026-03-12 13:46:11UT with m_unfiltered~18.3. This OT was observed at 400 images with rebrigtening detection to 17.2 at 2026-03-12 21:02:59 UT. Observation and reduction will continue. [1] Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L [2] Lipunov et al. 2022, Universe, Vol. 8(5), id.271 [3] Lipunov et a. 2019, ARep, vol.63, 293 [4] Lipunov et al. 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics,Lomonosov MSU PRESS, 591pp. http://www.pereplet.ru/lipunov/625.html#625 View this GCN Circular online at https://gcn.nasa.gov/circulars/43978. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42098] GRB260310A / AT2026fgk: P200 Spectroscopy
by GCN Circulars 13 Mar '26

13 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43977 SUBJECT: GRB260310A / AT2026fgk: P200 Spectroscopy DATE: 26/03/13 00:27:51 GMT FROM: khinds(a)caltech.edu K-Ryan Hinds (Caltech), Daniel A. Perley (LJMU), Anna Y. Q. Ho (Cornell), Sam Rose (Caltech), Jillian Rastinejad (UMd), Robert Stein (UMd), Geoffrey Mo (Caltech), Mansi Kasliwal (Caltech), Jesper Sollerman (OKC), Xander J. Hall (CMU), Jacob Wise (LJMU), Rahul Jayaraman (Cornell), Aleksandra Bochenek (LJMU) We previously reported the optical transient AT 2026fgk (ID 294132) as an afterglow candidate based on its fast evolution, red color, and high implied luminosity (Hinds et al., AstroNote 2026-65). Konno et al. (GCN 43974) reported additional detections of AT 2026fgk using the Large Array Survey Telescope (LAST) whilst tiling the probability region for GRB 260310A (Fermi GBM Team, GCN 43951; Salunke et al., GCN 43958), and noted the temporal and spatial coincidence that identifies AT 2026fgk as the likely optical counterpart of this GRB. We observed GRB 260310A starting at 2026-03-12 10:23:42 UTC (~2.2 d after the Fermi GBM trigger time) with the Next Generation Palomar Spectrograph (NGPS; AstroNote 2024-340) on the Palomar 5.1m Hale Telescope (P200). The optical spectrum shows a featureless red continuum, although there is a strong, narrow emission line at 7566 Angstroms that we attribute to H-alpha from the candidate host galaxy at z = 0.153. If this is the redshift of the GRB, it would be among the closest long-duration bursts to date. For GRB 260310A, using a fluence of 5.8e-6 erg/cm^2 (10-1000 keV) reported by Hamburg et al. (GCN 43795) and assuming the redshift above, we find the gamma-ray E_iso is ~3.69e50 erg, characteristic of low-luminosity long-GRBs. The peak observed optical luminosity (from ATLAS forced photometry) is M_o ~ -22.7 mag at 7.2 hours post-trigger, more luminous than the equivalent value seen in most other nearby LLGRBs. An associated supernova similar to SN 1998bw would peak at an apparent magnitude of r = 19.7 at this redshift in the absence of host extinction. Further observations are encouraged. View this GCN Circular online at https://gcn.nasa.gov/circulars/43977. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42097] GRB 260312B: Glowbug gamma-ray detection
by GCN Circulars 12 Mar '26

12 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43976 SUBJECT: GRB 260312B: Glowbug gamma-ray detection DATE: 26/03/12 23:50:31 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report: The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 260312B, which was also detected by Fermi/GBM (GCN 43969, 43970). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-03-12 09:46:45.000 with a duration of 12.3 s and a total significance of about 43 sigma. The light curve comprises a faint peak at ~T0+1s and a primary peak at ~T0+7s. Note that data from ~T0+4.0s to +6.0s and ~T0+10.0s to +11.5s suffered from deadtime in various detectors. The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS. Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12. [1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959 [2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O [3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108 Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/43976. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42096] GRB 260310A: Fermi GBM Observation
by GCN Circulars 12 Mar '26

12 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43975 SUBJECT: GRB 260310A: Fermi GBM Observation DATE: 26/03/12 22:19:13 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 04:57:10.81 UT on 10 March 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260310A (trigger 794811435/260310206), which was also detected by AstroSat (Salunke et al. 2026, GCN 43958). This GRB has been reported to have a potential optical counterpart, AT2026fgk, which was discovered by GOTO (O'Neill et al. 2026, TNS Discovery Report 294132) and LAST (Konno et al. 2026, GCN 43974). AT2026fgk has a photometric redshift measurement of z = 0.11 (Hinds et al. 2026, AstroNote 2026-65). The angle from the Fermi LAT boresight is 124 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 60 s (50-300 keV). The time-averaged spectrum from T0-9.6 to T0+61.6 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.15 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 172 +/- 5 keV. The event fluence (10-1000 keV) in this time interval is (5.8 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+9.8 s in the 10-1000 keV band is 2.3 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/43975. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42095] GRB 260310A: potential optical counterpart
by GCN Circulars 12 Mar '26

12 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43974 SUBJECT: GRB 260310A: potential optical counterpart DATE: 26/03/12 19:11:47 GMT FROM: Ruslan Konno at Weizmann Institute of Science <ruslankonno(a)gmail.com> R. Konno (WIS), S. Garrappa (WIS), E. A. Zimmerman (WIS), A. Horowicz (WIS), E. O. Ofek (WIS), S. Ben-Ami (WIS), D. Polishook (WIS), O. Yaron (WIS), S. Fainer (WIS), A. Krassilchtchikov (WIS), Y. M. Shani (WIS), E. Segre (WIS), A. Gal-Yam (WIS), and S. Spitzer (WIS) report on behalf of the LAST Collaboration. We report observations of GRB 260310A, detected by Fermi/GBM (Fermi GBM Team, GCN 43951), as well as by AstroSat/CZTI (Salunke et al., GCN 43958). Observations were conducted with the Large Array Survey Telescope (LAST; Ofek et al. 2023, PASP 135, 5001; Ben-Ami et al. 2023, PASP 135, 5002). Observations of GRB 260310A were taken over several tiling epochs starting at 2026-03-10 16:37:45 UTC (T-T0 = 11.67 h), in clear band (similar to the Gaia Bp band) with 24 telescopes. Each epoch consists of 20x20s exposures per telescope. The follow-up covers an integrated localization probability of 97% as given within the HEALPix FITS file glg_healpix_all_bn260310206.fit (Fermi GBM Team, GCN 43951). Initially, we do not detect a credible counterpart within our automated pipeline due to incomplete reference coverage of the field. However, we note AT 2026fgk (discovered by GOTO; O'Neill et al. 2026, TNS Discovery Report 294132) as a potential counterpart. The transient was first detected at T-T0 = 1040 s, has an angular separation of about 7 deg from the best-fit Fermi/GBM position, and is shown to be highly variable (Hinds et al., AstroNote 2026-65). This transient is clearly detected within the LAST data and shows an initial rise and a subsequent steady decay, consistent with Hinds et al., AstroNote 2026-65. The LAST photometry is as follows | Tmid-T0 (h) | Mag (AB) | | ------------ | ------------ | | 14.05 | 17.18 +/- 0.04 | | 14.17 | 17.17 +/- 0.04 | | 14.30 | 17.09 +/- 0.04 | | 14.41 | 17.16 +/- 0.04 | | 14.54 | 17.10 +/- 0.04 | | 14.66 | 17.11 +/- 0.04 | | 17.97 | 17.23 +/- 0.04 | | 19.01 | 17.25 +/- 0.04 | | 20.05 | 17.19 +/- 0.04 | | 21.09 | 17.30 +/- 0.04 | | 22.02 | 17.32 +/- 0.04 | Furthermore, serendipitous LAST observations of the field prior to the GRB event time, up to 2026-03-10 02:51:01 UTC (T-T0 = -2.15 h), shows no detection up to a 5-sigma limiting magnitude of 20.74 (AB). We thus note this transient as a potential optical counterpart, and encourage further follow-up observations. LAST is a survey telescope array of the Weizmann Astrophysical Observatory (https://www.weizmann.ac.il/wao/) View this GCN Circular online at https://gcn.nasa.gov/circulars/43974. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42094] Fermi GRB 260312B: Global MASTER-Net observations report
by GCN Circulars 12 Mar '26

12 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43973 SUBJECT: Fermi GRB 260312B: Global MASTER-Net observations report DATE: 26/03/12 16:45:30 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 [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 260312B ( Fermi GBM team, GCN 43969) errorbox 24262 sec after notice time and 24340 sec after trigger time at 2026-03-12 16:32:26 UT, with upper limit up to 16.8 mag. Observations started at twilight. The observations began at zenith distance = 80 deg. The sun altitude is -15.4 deg. The galactic latitude b = -63 deg., longitude l = 154 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3182510 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 24370 | 2026-03-12 16:32:26 | MASTER-Kislovodsk | (01h 43m 41.60s , -02d 12m 39.7s) | C | 60 | 16.1 | 24472 | 2026-03-12 16:34:07 | MASTER-Kislovodsk | (01h 43m 29.55s , -00d 19m 40.6s) | C | 60 | 16.5 | 24577 | 2026-03-12 16:35:53 | MASTER-Kislovodsk | (01h 55m 57.24s , -04d 08m 01.4s) | C | 60 | 16.8 | 24677 | 2026-03-12 16:37:33 | MASTER-Kislovodsk | (01h 55m 42.13s , -02d 14m 03.2s) | C | 60 | 16.6 | 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/43973. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42093] Fermi GRB 260311B: Global MASTER-Net observations report
by GCN Circulars 12 Mar '26

12 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43972 SUBJECT: Fermi GRB 260311B: Global MASTER-Net observations report DATE: 26/03/12 12:32:31 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 [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 260311B ( Fermi GBM team, GCN 43964) errorbox 24516 sec after notice time and 24692 sec after trigger time at 2026-03-12 01:49:28 UT, with upper limit up to 15.6 mag. The observations began at zenith distance = 57 deg. The sun altitude is -18.9 deg. The galactic latitude b = 4 deg., longitude l = 32 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3181495 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 24723 | 2026-03-12 01:49:28 | MASTER-Kislovodsk | (19h 10m 01.93s , +04d 53m 01.1s) | C | 60 | 15.6 | 59805 | 2026-03-12 11:34:10 | MASTER- | (18h 18m 16.48s , +06d 44m 41.9s) | C | 60 | 17.4 | 59805 | 2026-03-12 11:34:10 | MASTER- | (18h 19m 31.23s , +06d 11m 34.9s) | C | 60 | 17.5 | 59876 | 2026-03-12 11:35:21 | MASTER- | (18h 26m 26.82s , +06d 44m 33.6s) | C | 60 | 17.2 | 59876 | 2026-03-12 11:35:21 | MASTER- | (18h 27m 41.28s , +06d 11m 25.0s) | C | 60 | 17.3 | 60391 | 2026-03-12 11:43:55 | MASTER- | (18h 18m 23.46s , +06d 44m 43.7s) | C | 60 | 17.2 | 60391 | 2026-03-12 11:43:55 | MASTER- | (18h 19m 38.47s , +06d 11m 36.0s) | C | 60 | 17.2 | 60478 | 2026-03-12 11:45:23 | MASTER- | (18h 26m 21.18s , +06d 44m 18.1s) | C | 60 | 17.3 | 60478 | 2026-03-12 11:45:23 | MASTER- | (18h 27m 36.03s , +06d 11m 09.5s) | C | 60 | 17.4 | 61508 | 2026-03-12 12:02:33 | MASTER- | (18h 18m 19.70s , +06d 44m 43.2s) | C | 60 | 17.5 | 61508 | 2026-03-12 12:02:33 | MASTER- | (18h 19m 35.99s , +06d 11m 38.1s) | C | 60 | 17.6 | 61579 | 2026-03-12 12:03:44 | MASTER- | (18h 26m 26.43s , +06d 45m 59.2s) | C | 60 | 17.5 | 61579 | 2026-03-12 12:03:44 | MASTER- | (18h 27m 42.44s , +06d 12m 52.6s) | C | 60 | 17.6 | 61657 | 2026-03-12 12:05:02 | MASTER- | (18h 02m 57.54s , +06d 46m 34.6s) | C | 60 | 17.4 | 61657 | 2026-03-12 12:05:02 | MASTER- | (18h 04m 14.17s , +06d 13m 30.5s) | C | 60 | 17.6 | 61729 | 2026-03-12 12:06:14 | MASTER- | (18h 12m 23.49s , +06d 12m 17.2s) | C | 60 | 17.5 | 61729 | 2026-03-12 12:06:14 | MASTER- | (18h 11m 06.96s , +06d 45m 21.9s) | C | 60 | 17.4 | 61810 | 2026-03-12 12:07:35 | MASTER- | (18h 23m 25.76s , +08d 38m 13.5s) | C | 60 | 17.5 | 61810 | 2026-03-12 12:07:35 | MASTER- | (18h 24m 42.43s , +08d 05m 07.3s) | C | 60 | 17.5 | 61890 | 2026-03-12 12:08:55 | MASTER- | (18h 31m 28.03s , +08d 39m 36.9s) | C | 60 | 16.7 | 61890 | 2026-03-12 12:08:55 | MASTER- | (18h 32m 44.52s , +08d 06m 30.1s) | C | 60 | 16.7 | 61964 | 2026-03-12 12:10:09 | MASTER- | (18h 08m 02.64s , +08d 40m 18.8s) | C | 60 | 17.5 | 61964 | 2026-03-12 12:10:09 | MASTER- | (18h 09m 19.69s , +08d 07m 14.2s) | C | 60 | 17.5 | 62053 | 2026-03-12 12:11:38 | MASTER- | (18h 16m 02.67s , +08d 39m 09.5s) | C | 60 | 17.8 | 62053 | 2026-03-12 12:11:38 | MASTER- | (18h 17m 19.59s , +08d 06m 04.4s) | C | 60 | 17.9 | 62137 | 2026-03-12 12:13:02 | MASTER- | (18h 19m 34.48s , +06d 13m 00.2s) | C | 60 | 17.5 | 62137 | 2026-03-12 12:13:02 | MASTER- | (18h 18m 17.96s , +06d 46m 05.6s) | C | 60 | 17.5 | 62213 | 2026-03-12 12:14:18 | MASTER- | (18h 27m 43.41s , +06d 11m 45.8s) | C | 60 | 17.6 | 62213 | 2026-03-12 12:14:18 | MASTER- | (18h 26m 27.07s , +06d 44m 51.9s) | C | 60 | 17.5 | 62289 | 2026-03-12 12:15:34 | MASTER- | (18h 04m 15.28s , +06d 11m 22.4s) | C | 60 | 17.8 | 62289 | 2026-03-12 12:15:34 | MASTER- | (18h 02m 58.43s , +06d 44m 26.1s) | C | 60 | 17.7 | 62361 | 2026-03-12 12:16:46 | MASTER- | (18h 11m 08.08s , +06d 44m 34.3s) | C | 60 | 17.5 | 62361 | 2026-03-12 12:16:46 | MASTER- | (18h 12m 24.83s , +06d 11m 29.9s) | C | 60 | 17.5 | 62435 | 2026-03-12 12:18:00 | MASTER- | (18h 24m 39.81s , +08d 06m 36.2s) | C | 60 | 17.6 | 62435 | 2026-03-12 12:18:00 | MASTER- | (18h 23m 22.92s , +08d 39m 41.6s) | C | 60 | 17.6 | 62534 | 2026-03-12 12:19:39 | MASTER- | (18h 31m 28.26s , +08d 38m 04.6s) | C | 60 | 16.7 | 62534 | 2026-03-12 12:19:39 | MASTER- | (18h 32m 45.03s , +08d 04m 58.7s) | C | 60 | 16.7 | 62607 | 2026-03-12 12:20:52 | MASTER- | (18h 09m 21.12s , +08d 06m 49.7s) | C | 60 | 17.5 | 62607 | 2026-03-12 12:20:52 | MASTER- | (18h 08m 03.80s , +08d 39m 53.7s) | C | 60 | 17.4 | 62679 | 2026-03-12 12:22:04 | MASTER- | (18h 17m 19.94s , +08d 05m 57.7s) | C | 60 | 18.0 | 62679 | 2026-03-12 12:22:04 | MASTER- | (18h 16m 02.75s , +08d 39m 01.9s) | C | 60 | 17.9 | 62750 | 2026-03-12 12:23:15 | MASTER- | (18h 19m 35.12s , +06d 12m 53.1s) | C | 60 | 17.8 | 62750 | 2026-03-12 12:23:15 | MASTER- | (18h 18m 18.36s , +06d 45m 57.6s) | C | 60 | 17.8 | 62825 | 2026-03-12 12:24:30 | MASTER- | (18h 27m 42.53s , +06d 11m 38.8s) | C | 60 | 17.7 | 62825 | 2026-03-12 12:24:30 | MASTER- | (18h 26m 25.94s , +06d 44m 44.0s) | C | 60 | 17.6 | 62898 | 2026-03-12 12:25:43 | MASTER- | (18h 04m 17.41s , +06d 11m 17.9s) | C | 60 | 17.9 | 62898 | 2026-03-12 12:25:43 | MASTER- | (18h 03m 00.33s , +06d 44m 20.9s) | C | 60 | 17.8 | 62970 | 2026-03-12 12:26:55 | MASTER- | (18h 12m 26.18s , +06d 11m 27.7s) | C | 60 | 17.6 | 62970 | 2026-03-12 12:26:55 | MASTER- | (18h 11m 09.22s , +06d 44m 31.3s) | C | 60 | 17.5 | 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/43972. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42092] Swift BAT trigger 1500148: A solar flare
by GCN Circulars 12 Mar '26

12 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43971 SUBJECT: Swift BAT trigger 1500148: A solar flare DATE: 26/03/12 10:45:18 GMT FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk> P. A. Evans (U Leicester), C. Gronwall (PSU), R. Gupta (NASA GSFC), A. Y. Lien (U Tampa) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: BAT trigger 1500148 is not a GRB, but was caused by a solar flare. Swift's automatic slews are currently disabled, so there will be no XRT or UVOT data for this trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/43971. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42091] GRB 260312B: BALROG localization (Fermi Trigger 795001611 / GRB 260312407)
by GCN Circulars 12 Mar '26

12 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43970 SUBJECT: GRB 260312B: BALROG localization (Fermi Trigger 795001611 / GRB 260312407) DATE: 26/03/12 10:16:35 GMT FROM: Jochen Greiner at MPE <jcgrog(a)mpe.mpg.de> T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 795001611 at 09:46:46 on 12 March 2026 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position is: RA(2000.0) = 26.3 deg Decl.(2000.0) = -8.3 deg The 1 sigma statistical error radius is 2.2 deg. We estimate an additional systematic error of 1 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB260312407/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB260312407/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB260312407/json View this GCN Circular online at https://gcn.nasa.gov/circulars/43970. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42090] GRB 260312B: Fermi GBM Final Real-time Localization
by GCN Circulars 12 Mar '26

12 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43969 SUBJECT: GRB 260312B: Fermi GBM Final Real-time Localization DATE: 26/03/12 09:57:18 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 09:46:46 UT on 12 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260312B (trigger 795001611.054834 / 260312407). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 25.9, Dec = -3.9 (J2000 degrees, equivalent to J2000 01h 43m, -3d 53'), with a statistical uncertainty of 1.9 degrees. The angle from the Fermi LAT boresight is 67.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260312407/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260312407/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260312407/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43969. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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