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[vsnet-grb-info 43512] SN 2026stf / GRB 260708A: ATLAS forced photometry
by GCN Circulars 06 Aug '26

06 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45295 SUBJECT: SN 2026stf / GRB 260708A: ATLAS forced photometry DATE: 26/08/06 00:07:04 GMT FROM: Ismael Perez-Fournon at Instituto de Astrofisica de Canarias <ipf(a)iac.es> I. Pérez-Fournon (IAC and ULL), F. Poidevin (IAC and ULL), A. López-Oramas (IAC and ULL), D. Aguado (IAC and ULL), N. Abreu García (ULL), D. Cano-Morales (ULL), I. Correa-Plasencia (ULL), A.E. Hernández-Díaz (ULL), E. Lekaroz-Urriza (ULL), M. Magdalena-Rodríguez (ULL), M. Quintana-Ansaldo (ULL), D. Rodríguez-Fernández (ULL), and J. Uríbarri-Dermit (ULL) We report results of ATLAS forced photometry of the type Ic-BL SN 2026stf at z = 0.055 (Corcoran et al., GCN 45283) which appears associated with the LONG GRB 260708A detected by Fermi-GBM, Fermi-LAT, GECAM, and Glowbug (Fermi-GBM Team, GCN 45115; Holzmann Airasca et al., GCN 45117; Malacaria, GCN 45124; Ren et al., GCN 45126; Cheung et al., GCN 45130) and EP/FXT (Li et al., GCN 45150). The optical counterpart (AT 2026stf, MASTER OT J150237.02-435307.7) was discovered by MASTER (Shilova et al., GCN 45123; and Zhirkov et al., TNS Astronomical Transient Report No. 313535), with other reported optical detections (Freeberg et al., GCN 45127, Shi et al., GCN 45140, Sheng et al. GCN 45147, Shi et al., GCN 45280, Corcoran et al., GCN 45283, and O'Neill et al., TNS photometry report). Using the ATLAS forced-photometry server (Shingles et al. 2021, Transient Name Server AstroNote 2021-7), we find four detections of the fading afterglow in the ATLAS orange filter starting on MJD = 61230.82579, at about 1.40 days after the Fermi trigger, at an ATLAS orange magnitud of o = 18.567 +/- 0.106, and more detections close to the minimum of the light curve and in 10 more epochs that include the rebrightening in the SN Ic-BL phase. The last ATLAS non detection was on MJD = 61228.84782, about 0.58 days before the Fermi trigger. The following table gives the ATLAS forced photometry since MJD = 61200. We note that according to the methods of the ATLAS forced photometry, if the flux is negative, then a magnitude is still quoted and denoted with a negative sign (see https://fallingstar-data.com/forcedphot/resultdesc/) Magnitudes are in the AB system and are not corrected for interstellar medium absorption. Fluxes are in uJy. MJD. | mag | e_mag |flux |e_flux| filter| observation ---------------------------------------------------------------------------------------------- 61203.257379 18.634 0.491 128.0 63 o 04a61203o0384o 61203.260575 -18.648 0.712 -126.0 90 o 04a61203o0391o 61203.285519 20.077 0.581 34.0 20 o 04a61203o0444o 61203.29178 20.792 1.566 18.0 27 o 04a61203o0457o 61206.11809 21.107 4.412 13.0 58 o 04a61206o0248o 61206.12176 -18.955 0.647 -95.0 62 o 04a61206o0256o 61206.127177 -19.91 1.685 -39.0 66 o 04a61206o0268o 61206.137231 -18.837 0.787 -106.0 83 o 04a61206o0290o 61208.003738 -21.432 0.984 -10.0 10 c 03a61208o0094c 61208.006902 21.842 1.825 7.0 12 c 03a61208o0101c 61208.03234 -22.219 2.429 -5.0 11 c 03a61208o0156c 61208.037748 -23.402 7.111 -2.0 11 c 03a61208o0168c 61215.101062 20.405 0.87 25.0 22 o 04a61215o0341o 61215.106041 -20.875 1.571 -16.0 26 o 04a61215o0352o 61215.109687 21.063 1.366 14.0 19 o 04a61215o0360o 61215.116029 20.644 1.086 20.0 22 o 04a61215o0374o 61215.125947 23.114 8.294 2.0 17 o 04a61215o0396o 61220.18041 20.739 2.089 18.0 38 o 04a61220o0405o 61220.212007 -19.219 0.46 -74.0 34 o 04a61220o0473o 61220.215569 -20.976 2.384 -15.0 35 o 04a61220o0480o 61220.244229 -20.8 2.407 -17.0 42 o 04a61220o0541o 61221.106872 -20.685 1.464 -19.0 28 o 04a61221o0347o 61221.110508 19.599 0.571 52.0 30 o 04a61221o0355o 61221.114247 19.799 0.677 44.0 30 o 04a61221o0363o 61221.119822 19.554 0.429 55.0 24 o 04a61221o0375o 61221.129752 20.192 1.137 30.0 35 o 04a61221o0394o 61224.134068 17.646 2.756 317.0 875 o 04a61224o0172o 61224.137394 17.479 1.786 370.0 661 o 04a61224o0179o 61224.143895 -18.04 2.122 -221.0 468 o 04a61224o0193o 61224.153723 14.528 0.353 5608.0 1982 o 04a61224o0214o 61224.850689 -22.279 2.743 -4.0 12 o 03a61225o0364o 61224.854295 20.341 0.58 26.0 15 o 03a61225o0372o 61224.860177 20.367 0.6 26.0 16 o 03a61225o0385o 61224.870545 -21.838 2.262 -7.0 15 o 03a61225o0408o 61225.953387 -23.99 15.857 -1.0 15 o 03a61226o0036o 61225.957069 21.685 1.891 8.0 14 o 03a61226o0044o 61225.962523 20.444 0.561 24.0 14 o 03a61226o0056o 61225.982975 20.19 0.653 30.0 20 o 03a61226o0100o 61227.828562 21.292 0.881 11.0 10 o 03a61228o0314o 61227.831716 22.195 2.425 5.0 12 o 03a61228o0321o 61227.837861 21.672 1.562 8.0 12 o 03a61228o0334o 61227.847773 0.0 21.251 -0.0 12 o 03a61228o0356o 61228.828314 20.573 0.548 21.0 12 o 03a61229o0313o 61228.831947 23.404 7.462 2.0 12 o 03a61229o0321o 61228.837418 -21.735 1.435 -7.0 10 o 03a61229o0333o 61228.847822 23.144 4.533 2.0 9 o 03a61229o0356o 61230.825786 18.567 0.106 136.0 14 o 03a61231o0303o 61230.829421 18.463 0.089 150.0 13 o 03a61231o0311o 61230.83483 18.536 0.1 140.0 14 o 03a61231o0323o 61230.847461 18.6 0.098 132.0 13 o 03a61231o0351o 61233.132315 19.314 0.21 68.0 14 o 04a61233o0234o 61233.152559 19.689 0.312 48.0 15 o 04a61233o0277o 61233.155718 19.645 0.277 50.0 14 o 04a61233o0284o 61233.168334 19.367 0.185 65.0 12 o 04a61233o0311o 61234.819699 19.127 0.166 81.0 14 o 03a61235o0253o 61234.822959 19.42 0.243 62.0 15 o 03a61235o0260o 61234.828055 19.497 0.231 58.0 13 o 03a61235o0271o 61234.840874 19.112 0.161 82.0 13 o 03a61235o0299o 61236.79229 18.959 0.239 95.0 23 o 03a61237o0226o 61236.795085 19.905 0.853 40.0 34 o 03a61237o0232o 61236.801591 19.14 0.382 80.0 31 o 03a61237o0245o 61236.811886 18.648 0.173 126.0 22 o 03a61237o0267o 61237.809594 19.061 0.123 86.0 11 o 03a61238o0262o 61237.812764 19.156 0.163 79.0 13 o 03a61238o0269o 61237.8201 19.148 0.147 80.0 12 o 03a61238o0285o 61237.830145 19.069 0.121 86.0 10 o 03a61238o0307o 61240.79296 19.048 0.147 87.0 13 o 03a61241o0092o 61240.796119 19.057 0.157 86.0 14 o 03a61241o0099o 61240.801526 18.923 0.138 98.0 14 o 03a61241o0111o 61240.835558 19.297 0.213 69.0 15 o 03a61241o0184o 61242.787705 18.836 0.173 106.0 18 o 03a61243o0213o 61242.793772 18.852 0.164 104.0 17 o 03a61243o0226o 61242.796932 18.821 0.185 108.0 20 o 03a61243o0233o 61242.807162 18.875 0.223 102.0 23 o 03a61243o0255o 61243.802909 18.507 0.214 144.0 31 o 03a61244o0135o 61243.851004 18.728 0.234 117.0 28 o 03a61244o0151o 61243.856046 18.883 0.273 102.0 28 o 03a61244o0162o 61243.868817 18.547 0.206 138.0 28 o 03a61244o0190o 61245.908433 19.092 0.268 84.0 22 o 03a61246o0447o 61245.929595 18.977 0.271 93.0 25 o 03a61246o0492o 61245.935043 19.026 0.263 89.0 23 o 03a61246o0504o 61245.959763 19.081 0.37 85.0 31 o 03a61246o0558o 61247.804195 19.022 0.28 89.0 25 o 03a61248o0239o 61247.807349 18.81 0.239 109.0 26 o 03a61248o0246o 61247.812913 18.911 0.292 99.0 29 o 03a61248o0258o 61247.823386 19.47 0.493 59.0 29 o 03a61248o0281o 61249.247796 19.688 0.712 48.0 34 o 01a61249o0018o 61249.251905 18.651 0.255 126.0 32 o 01a61249o0027o 61249.2583 18.647 0.246 126.0 31 o 01a61249o0041o 61249.274816 18.898 0.294 100.0 29 o 01a61249o0077o 61253.787954 18.938 0.185 96.0 18 o 03a61254o0205o 61253.791569 18.882 0.144 102.0 15 o 03a61254o0213o 61253.797995 18.984 0.164 92.0 15 o 03a61254o0227o 61253.807829 19.042 0.217 88.0 19 o 03a61254o0248o 61256.862169 -20.237 10.875 -29.0 317 o 03a61257o0091o 61256.871251 -16.142 1.031 -1268.0 1308 o 03a61257o0111o This work is part of grant CEX2025-001609-S, awarded to the Instituto de Astrofísica de Canarias under the Severo Ochoa Centre of Excellence program and funded by MICIU/AEI/10.13039/501100011033. This work made use of the Astro-COLIBRI platform (P. Reichherzer et al. 2021, ApJS, 256, 5). View this GCN Circular online at https://gcn.nasa.gov/circulars/45295. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43511] IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 06 Aug '26

06 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45294 SUBJECT: IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 26/08/06 00:02:49 GMT FROM: mvelazquez(a)icecube.wisc.edu The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 26-08-05 at 14:01:39.70 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_BRONZE alert stream. Documentation regarding the alert streams and their astrophysical purity can be found here: https://gcn.nasa.gov/missions/icecube. This alert has an estimated false alarm rate of 1.449 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/142956_64385264.amon) more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 26-08-05 Time: 14:01:39.70 UT RA: 60.47 (+0.91/-0.8 deg 90% PSF containment) J2000 Dec: 26.07 (+0.54/-0.56 deg 90% PSF containment) J2000 As announced in GCN Circular 43419 (https://gcn.nasa.gov/circulars/43419) IceCube alert notices for high-energy track alerts are now also streamed via Kafka. IceCube Gold/Bronze track alerts are available on the Kafka topic 'gcn.notices.icecube.gold_bronze_track_alerts'. The probability distribution of the true neutrino direction, allowing the extraction of precise 90% containment regions around the best-fit direction, is now available for revised reconstruction of high-energy track alerts. The corresponding sky map is distributed as a FITS file and follows the explicit naming convention IceCube-YYMMDDX, where YYMMDD indicates the date of the event and X is a letter distinguishing multiple alerts on the same day. The download link is provided through the GCN schema distributed via Kafka. Detailed documentation describing the alert distribution, schemas, and probability maps is available at: https://gcn.nasa.gov/missions/icecube. One gamma-ray source from the Fermi FL16Y catalog is located within the 90% uncertainty region of this event: FL16Y J0402.5+2615, at RA = 60.647° and Dec = 26.267° (J2000), with an angular separation of 0.254° from the best-fit event position. We report here sources within the 90% confidence contour available in the multi-order probability map, rather than those selected using the simplified rectangular error-box reported in this Circular. 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/45294. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43510] GRB 260730B: Glowbug gamma-ray detection
by GCN Circulars 05 Aug '26

05 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45293 SUBJECT: GRB 260730B: Glowbug gamma-ray detection DATE: 26/08/05 22:36:31 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 260730B, which was also detected by NuSTAR (GCN 45262), AstroSat (GCN 45265), and CALET (GCN 45284). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-07-30 13:13:49.456 with a duration of 8.2 s and a total significance of about 21.8 sigma. The light curve comprises a multi-peaked structure corresponding to the brightest portion of the burst seen in the CALET light curve (GCN 45284). 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/45293. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43509] GRB 260805C: Glowbug gamma-ray detection
by GCN Circulars 05 Aug '26

05 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45292 SUBJECT: GRB 260805C: Glowbug gamma-ray detection DATE: 26/08/05 21:24:48 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 260805C. Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-08-05 07:27:39.496 with a duration of ~12 s and a total significance of about 36 sigma. The light curve comprises a single FRED-shaped pulse. Additional lower-level emission up to ~T0+22s may be present in the Glowbug light curve at low significance. 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/45292. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43508] GRB 260805B: Glowbug gamma-ray detection
by GCN Circulars 05 Aug '26

05 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45291 SUBJECT: GRB 260805B: Glowbug gamma-ray detection DATE: 26/08/05 19:41:57 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 260805B, which was also detected by Fermi/GBM (GCN 45287, 45289). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-08-05 11:36:49.640 with a duration of 14.6 s and a total significance of about 20.3 sigma. The light curve comprises a broad emission profile similar to that observed by Fermi/GBM. 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/45291. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43507] Fermi GRB 260805A: Global MASTER-Net observations report
by GCN Circulars 05 Aug '26

05 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45290 SUBJECT: Fermi GRB 260805A: Global MASTER-Net observations report DATE: 26/08/05 18:16:07 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), M. Segura, 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-SAAO robotic telescope [1] located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 260805A ( Fermi GBM team, GCN 45286) errorbox 26848 sec after notice time and 26944 sec after trigger time at 2026-08-05 16:47:37 UT, with upper limit up to 18.3 mag. Observations started at twilight. The observations began at zenith distance = 73 deg. The sun altitude is -10.3 deg. The galactic latitude b = 38 deg., longitude l = 61 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3458691 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 26974 | 2026-08-05 16:47:37 | MASTER-SAAO | (16h 46m 23.79s , +37d 05m 59.0s) | C | 60 | 16.2 | 27079 | 2026-08-05 16:49:21 | MASTER-SAAO | (16h 46m 20.13s , +37d 05m 05.7s) | C | 60 | 16.5 | 27177 | 2026-08-05 16:51:00 | MASTER-SAAO | (16h 53m 24.94s , +39d 00m 48.3s) | C | 60 | 16.7 | 27274 | 2026-08-05 16:52:37 | MASTER-SAAO | (16h 33m 55.61s , +39d 00m 11.2s) | C | 60 | 17.1 | 27371 | 2026-08-05 16:54:13 | MASTER-SAAO | (16h 40m 42.58s , +35d 13m 18.4s) | C | 60 | 17.3 | 27468 | 2026-08-05 16:55:51 | MASTER-SAAO | (16h 42m 02.63s , +40d 54m 37.3s) | C | 60 | 17.1 | 27565 | 2026-08-05 16:57:28 | MASTER-SAAO | (16h 59m 16.29s , +35d 12m 25.7s) | C | 60 | 17.4 | 27662 | 2026-08-05 16:59:05 | MASTER-SAAO | (16h 27m 13.66s , +37d 07m 26.1s) | C | 60 | 17.8 | 27763 | 2026-08-05 17:00:46 | MASTER-SAAO | (17h 02m 11.79s , +40d 53m 02.6s) | C | 60 | 17.5 | 27865 | 2026-08-05 17:02:28 | MASTER-SAAO | (16h 54m 27.27s , +33d 17m 55.3s) | C | 60 | 17.9 | 27965 | 2026-08-05 17:04:07 | MASTER-SAAO | (17h 05m 29.88s , +37d 04m 27.6s) | C | 60 | 17.8 | 28066 | 2026-08-05 17:05:49 | MASTER-SAAO | (16h 36m 16.59s , +33d 18m 58.1s) | C | 60 | 18.2 | 28172 | 2026-08-05 17:07:35 | MASTER-SAAO | (16h 21m 54.26s , +40d 56m 57.8s) | C | 60 | 18.2 | 28273 | 2026-08-05 17:09:16 | MASTER-SAAO | (16h 22m 01.69s , +35d 14m 54.4s) | C | 60 | 18.3 | 28369 | 2026-08-05 17:10:52 | MASTER-SAAO | (16h 22m 02.96s , +35d 12m 55.3s) | C | 60 | 18.3 | 28476 | 2026-08-05 17:12:39 | MASTER-SAAO | (16h 51m 41.89s , +42d 49m 29.3s) | C | 60 | 17.9 | 28576 | 2026-08-05 17:14:19 | MASTER-SAAO | (17h 13m 05.13s , +39d 00m 07.2s) | C | 60 | 18.3 | 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/45290. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43506] GRB 260805B: Fermi GBM Final Localization
by GCN Circulars 05 Aug '26

05 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45289 SUBJECT: GRB 260805B: Fermi GBM Final Localization DATE: 26/08/05 15:19:19 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> The Fermi GBM team reports the detection of a likely LONG GRB "At 11:36:52.81 UT on 05 August 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260805B (trigger 807622617/260805484). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 259.42, Dec = 64.59 (J2000 degrees, equivalent to J2000 17h 17m, +64d 35'), with a statistical uncertainty of 2.15 degrees. The angle from the Fermi LAT boresight is 31 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260805484/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260805484/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260805484/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/45289. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43505] GRB 260804A: Glowbug gamma-ray detection
by GCN Circulars 05 Aug '26

05 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45288 SUBJECT: GRB 260804A: Glowbug gamma-ray detection DATE: 26/08/05 13:56:11 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 260804A, which was also detected by Fermi/GBM (GCN 45281). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-08-04 03:07:09.160 with a duration of 19.7 s and a total significance of about 23.6 sigma. The light curve comprises a faint peak at ~T0, multi-peaked emission from ~T0+11s to +16s, and the brightest peak at ~T0+18s. Note that data from ~T0+8s to +12s 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/45288. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43504] GRB 260805B: BALROG localization (Fermi Trigger 807622617 / GRB 260805484)
by GCN Circulars 05 Aug '26

05 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45287 SUBJECT: GRB 260805B: BALROG localization (Fermi Trigger 807622617 / GRB 260805484) DATE: 26/08/05 12:19:46 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 807622617 at 11:36:52 on 05 Aug. 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) = 255.8 deg Decl.(2000.0) = 67.9 deg The 1 sigma statistical error radius is 2.9 deg. We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB260805484/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB260805484/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB260805484/json View this GCN Circular online at https://gcn.nasa.gov/circulars/45287. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43503] GRB 260805A: Fermi GBM Final Localization
by GCN Circulars 05 Aug '26

05 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45286 SUBJECT: GRB 260805A: Fermi GBM Final Localization DATE: 26/08/05 11:02:33 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> The Fermi GBM team reports the detection of a likely LONG GRB "At 09:18:33.28 UT on 05 August 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260805A (trigger 807614318/260805388). This trigger was initially classified as Distant Particles by the flight software, but is in fact a GRB. The on-ground calculated location, using the Fermi GBM trigger data, is RA = 252.53, Dec = 34.93 (J2000 degrees, equivalent to J2000 16h 50m, +34d 56'), with a statistical uncertainty of 3.11 degrees. The angle from the Fermi LAT boresight is 112 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260805388/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260805388/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260805388/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/45286. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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