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[vsnet-grb-info 42580] GRB 260504B: LCO z-band upper limit
by GCN Circulars 04 May '26

04 May '26

TITLE: GCN CIRCULAR NUMBER: 44456 SUBJECT: GRB 260504B: LCO z-band upper limit DATE: 26/05/04 10:38:06 GMT FROM: Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani(a)nbi.ku.dk> D. Turpin (CEA/Irfu), A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud), L. P. Xin (NAOC), Y. Wang (PMO,CAS; UCB), W. J. Xie (NAO,CAS), report on behalf of the SVOM mission team: We observed the field of the short GRB 260504B detected by SVOM (Saccardi et al., GCN 44454) with the LCO 1m telescope at Cerro Tololo equipped with the Sinistro instrument. Our observation started on 2026-05-04 at 09:40:18 UT (about 9 min after the trigger) and we obtained 3x200 s exposures in the Pan-STARRS z filter. No new source is detected within the ECLAIRs and MXT error circles, down to a limiting magnitude: z > 19.66 (AB, 5-sigma, mid-time 14.4 min after the SVOM trigger). This value was calibrated against the SkyMapper survey DR4 and is not corrected for Galactic extinction. This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/44456. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42579] SVOM GRB 260504B: MASTER-OAFA optical observations
by GCN Circulars 04 May '26

04 May '26

TITLE: GCN CIRCULAR NUMBER: 44455 SUBJECT: SVOM GRB 260504B: MASTER-OAFA optical observations DATE: 26/05/04 10:30:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> F.Podesta, M.J. Segura, C.Francile, R.Podesta, E. Gonzalez (OAFA, SJNU), A.Kuznetsov, V.Lipunov, I.Panchenko, P.Balanutsa, G.Antipov, N.Tiurina, K.Zhirkov, E.Gorbovskoy, V.Senik, A.Chasovnikov, Ya.Kechin, V.Topolev, D.Vlasenko,A.Sankovich, I.Gorbunov (Lomonosov MSU), N.Budnev, O.Gress (ISU), D.Buckley (SAAO), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich (Blagoveschensk Educational StateUniversity) 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) MASTER-OAFA robotic telescope of MASTER Global Robotic Net [1-4] was pointed to the SVOM GRB260504.40 (trigger No 1777887197,23h 24m 54.98s, -80d 21m 09.7s, R=0.0491, Saccardi et al. GCN 44454 ) errorbox 434 sec after trigger time at 2026-05-04 09:40:30 UT, with upper limit up to 19.7 mag. The observations began at zenith distance = 54 deg. The sun altitude was -18.8 deg. The galactic latitude b = -36 deg., longitude l = 307 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3291780 MASTER upper limits: Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment 489 | 2026-05-04 09:40:30 | MASTER-OAFA | (23h 23m 41.35s , -81d 33m 14.0s) | C | 110 | 18.9 | 634 | 2026-05-04 09:40:30 | MASTER-OAFA | (23h 23m 41.33s , -81d 33m 14.1s) | C | 400 | 19.7 | Coadd 615 | 2026-05-04 09:42:26 | MASTER-OAFA | (23h 23m 41.51s , -81d 33m 07.2s) | C | 130 | 19.1 | 767 | 2026-05-04 09:44:43 | MASTER-OAFA | (23h 23m 41.18s , -81d 33m 00.8s) | C | 160 | 19.2 | 883 | 2026-05-04 09:47:29 | MASTER-OAFA | (23h 23m 40.81s , -81d 32m 56.0s) | C | 60 | 18.8 | 943 | 2026-05-04 09:47:29 | MASTER-OAFA | (23h 23m 40.80s , -81d 32m 56.1s) | C | 180 | 19.5 | Coadd 948 | 2026-05-04 09:48:35 | MASTER-OAFA | (23h 23m 40.67s , -81d 32m 53.0s) | C | 60 | 18.8 | 1014 | 2026-05-04 09:49:40 | MASTER-OAFA | (23h 23m 40.42s , -81d 32m 50.2s) | C | 60 | 18.8 | 1080 | 2026-05-04 09:50:46 | MASTER-OAFA | (23h 23m 40.47s , -81d 32m 47.6s) | C | 60 | 18.9 | 1140 | 2026-05-04 09:50:46 | MASTER-OAFA | (23h 23m 40.46s , -81d 32m 47.6s) | C | 180 | 19.6 | Coadd 1145 | 2026-05-04 09:51:51 | MASTER-OAFA | (23h 23m 40.03s , -81d 32m 44.5s) | C | 60 | 18.7 | 1211 | 2026-05-04 09:52:57 | MASTER-OAFA | (23h 23m 39.95s , -81d 32m 41.8s) | C | 60 | 18.8 | 1277 | 2026-05-04 09:54:03 | MASTER-OAFA | (23h 23m 39.77s , -81d 32m 39.0s) | C | 60 | 18.8 | 1342 | 2026-05-04 09:55:09 | MASTER-OAFA | (23h 23m 39.54s , -81d 32m 36.0s) | C | 60 | 18.7 | 1408 | 2026-05-04 09:56:14 | MASTER-OAFA | (23h 23m 39.36s , -81d 32m 33.3s) | C | 60 | 18.7 | 1474 | 2026-05-04 09:57:21 | MASTER-OAFA | (23h 23m 39.24s , -81d 32m 30.3s) | C | 60 | 18.8 | 1540 | 2026-05-04 09:58:26 | MASTER-OAFA | (23h 23m 39.00s , -81d 32m 27.3s) | C | 60 | 18.9 | Filter C is a clear (unfiltred) band. 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/44455. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42578] GRB 260504B: SVOM detection of a short burst
by GCN Circulars 04 May '26

04 May '26

TITLE: GCN CIRCULAR NUMBER: 44454 SUBJECT: GRB 260504B: SVOM detection of a short burst DATE: 26/05/04 10:00:59 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> A. Saccardi (CEA/Irfu), D. Adrien (CEA/Irfu), F. Piron (LUPM), D. Gotz (CEA/Irfu), P. Maggi (ObAS), C. W. Wang (IHEP), Y. Wang (PMO,CAS; UCB), W. J. Xie (NAO,CAS), report on behalf of the SVOM mission team: At 2026-05-04T09:31:19 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260504B (SVOM burst-id sb26050402). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was only detected by the Count-Rate Trigger (CRT), which produced a sequence of 6 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 17.15 in the [8-120] keV energy band over a time window of 0.30 seconds starting at 2026-05-04T09:31:19. The localization of the best alert is R.A., Dec. 351.2451, -80.3291 degrees (J2000) with a 90% confidence level (C.L.) radius of 4.91 arcmin (including systematic error of 2 arcmin added in quadrature). The SVOM/ECLAIRs light curve shows a single narrow peak structure with a T90 duration of 0.5 +/- 0.1 s (5-120 keV). This burst also triggered SVOM/GRM at 2026-05-04T09:31:19 on a timescale of 0.10 seconds with an SNR of 31.30. The SVOM/GRM light curve shows a single narrow peak structure with a T90 duration of 0.22 +/- 0.02 s (8-1100 keV). The SVOM/GRM light curve can be found here： https://www.bursthub.cn//admin/static/svgrb260504B.png SVOM slewed to the burst. SVOM/MXT began observing the field at 2026-05-04T09:33:16 UTC, 117 seconds after T0. Using onboard processed data we found a possible uncatalogued X-ray source located at R.A., Dec. 351.285, -80.383 degrees: R.A. (J2000) = 23h25m08s Dec. (J2000) = -80d22m69s with a 90% C.L. radius of 167 arcseconds. This location is 3.2 arcminutes from the ECLAIRs onboard position. This position may be improved as more data is received. VT began observing the field after the slew. The analysis of the data will be published in a future circular. 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. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE. The Burst Advocate (BA) on shift for this alert is Yun Wang: wangyun(a)pmo.ac.cn. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/44454. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42577] Fermi GRB 260504A: Global MASTER-Net observations report
by GCN Circulars 04 May '26

04 May '26

TITLE: GCN CIRCULAR NUMBER: 44453 SUBJECT: Fermi GRB 260504A: Global MASTER-Net observations report DATE: 26/05/04 09:46:26 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260504A ( Fermi GBM team, GCN 44452) errorbox 578 sec after notice time and 612 sec after trigger time at 2026-05-04 09:23:10 UT, with upper limit up to 16.5 mag. The observations began at zenith distance = 79 deg. The sun altitude is -22.5 deg. The galactic latitude b = 5 deg., longitude l = 86 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3291732 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 672 | 2026-05-04 09:23:10 | MASTER-OAFA | (20h 30m 50.42s , +46d 55m 36.5s) | C | 120 | 16.4 | 813 | 2026-05-04 09:25:16 | MASTER-OAFA | (20h 30m 48.57s , +46d 55m 44.3s) | C | 150 | 16.1 | 924 | 2026-05-04 09:27:52 | MASTER-OAFA | (20h 30m 47.07s , +46d 55m 48.4s) | C | 60 | 16.4 | 990 | 2026-05-04 09:28:58 | MASTER-OAFA | (20h 30m 46.11s , +46d 55m 50.2s) | C | 60 | 16.5 | 1056 | 2026-05-04 09:30:03 | MASTER-OAFA | (20h 30m 45.24s , +46d 55m 54.1s) | C | 60 | 16.4 | 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/44453. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42576] GRB 260504A: Fermi GBM Final Real-time Localization
by GCN Circulars 04 May '26

04 May '26

TITLE: GCN CIRCULAR NUMBER: 44452 SUBJECT: GRB 260504A: Fermi GBM Final Real-time Localization DATE: 26/05/04 09:21:13 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 09:12:58 UT on 4 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260504A (trigger 799578783.057988 / 260504384). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 308.8, Dec = 48.4 (J2000 degrees, equivalent to J2000 20h 35m, 48d 23'), with a statistical uncertainty of 5.0 degrees. The angle from the Fermi LAT boresight is 44.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260504384/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260504384/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260504384/… View this GCN Circular online at https://gcn.nasa.gov/circulars/44452. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42575] GRB 260503A: Fermi GBM Final Real-time Localization
by GCN Circulars 03 May '26

03 May '26

TITLE: GCN CIRCULAR NUMBER: 44451 SUBJECT: GRB 260503A: Fermi GBM Final Real-time Localization DATE: 26/05/03 20:50:53 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 20:40:17 UT on 3 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260503A (trigger 799533622.581348 / 260503861). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 287.1, Dec = -2.0 (J2000 degrees, equivalent to J2000 19h 08m, -2d 00'), with a statistical uncertainty of 2.6 degrees. The angle from the Fermi LAT boresight is 30.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260503861/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260503861/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260503861/… View this GCN Circular online at https://gcn.nasa.gov/circulars/44451. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42574] SVOM/GRM observation of a bright burst from SGR 1E1841-045
by GCN Circulars 03 May '26

03 May '26

TITLE: GCN CIRCULAR NUMBER: 44450 SUBJECT: SVOM/GRM observation of a bright burst from SGR 1E1841-045 DATE: 26/05/03 16:26:46 GMT FROM: xueyuan zao <zaoxueyuan(a)gmail.com> SVOM/GRM team: Xue-Yuan Zao, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Hui Yang, Sebastien Guillot (IRAP) Report on behalf of the SVOM team: SVOM/GRM detected a bright burst from SGR 1E1841-045 at 2026-05-02T05:39:51.950 UTC (T0), which is also detected by Konus-Wind (A. Ridnaia el at., GCN#44448). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a single pulse with a T90 of 0.08 +0.08/-0.02 s in the 15-5000 keV band. All the signal is detected below 100 keV. The SVOM/GRM light curve can be found here： https://www.bursthub.cn//admin/static/svsgr_260502_053951.png In addition, the localization of SGR 1E1841-045 is located at about 94 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. The time-averaged spectrum from T0-0.04 to T0+0.07 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -0.49 +0.28/-0.27 and the cutoff energy, parameterized as Epeak, is 37.08 +1.88/-2.12 keV. The event fluence (10-1000 keV) in this time interval is (7.29 +0.32/-0.31) E-07 erg/cm^2. 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. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM/GRM point of contact for this burst is: Xue-Yuan Zao (IHEP) (zaoxy(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/44450. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42573] GRB 260502A: GECAM-B observation of a short burst
by GCN Circulars 03 May '26

03 May '26

TITLE: GCN CIRCULAR NUMBER: 44449 SUBJECT: GRB 260502A: GECAM-B observation of a short burst DATE: 26/05/03 15:58:17 GMT FROM: Xinghao Luo at IHEP <2952704891(a)qq.com> Xing-Hao Luo, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight by GRB 260502A, at 2026-05-02T05:01:00.300 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #44447). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of a single pulse pulses with a duration (T90) of 0.40 +0.14/-0.08 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecambgrb260502A.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/44449. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42572] IPN triangulation of a bright burst from SGR 1E1841-045
by GCN Circulars 03 May '26

03 May '26

TITLE: GCN CIRCULAR NUMBER: 44448 SUBJECT: IPN triangulation of a bright burst from SGR 1E1841-045 DATE: 26/05/03 15:05:53 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, C. Wang (IHEP), S. Xiong (IHEP), S. Zhang (IHEP), J. Wei (NAOC), B. Cordier (CEA) on behalf of the SVOM-GRM team, and E. Burns on behalf of the IPN, report: A bright, short-duration, soft burst was detected by Konus-Wind and SVOM (GRM) at about 20396 s UT (05:39:56) on May 2. We have triangulated it to a Konus-GRM annulus centered at RA(2000)=243.691 deg (16h 14m 46s) Dec(2000)=-21.870 deg (-21d 52' 12"), whose radius is 39.329 +/- 0.068 deg (3 sigma). Among known SGRs, only the position of SGR 1E1841-045 is inside the annulus. Given the positional coincidence of this burst with SGR 1E1841-045, its time history, and softness of its spectrum (as observed by Konus-Wind), we conclude this burst likely originated from SGR 1E1841-045. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/260502_T20396/IPN/ The time history and spectrum will be given in forthcoming GCN circulars. View this GCN Circular online at https://gcn.nasa.gov/circulars/44448. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42571] GRB 260502A: Fermi GBM Final Localization
by GCN Circulars 03 May '26

03 May '26

TITLE: GCN CIRCULAR NUMBER: 44447 SUBJECT: GRB 260502A: Fermi GBM Final Localization DATE: 26/05/03 05:20:13 GMT FROM: Rushikesh Sonawane at IISER TVM <rushikesh23(a)iisertvm.ac.in> The Fermi GBM team reports the detection of a likely SHORT GRB "At 05:01:00.25 UT on 05 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260502A (trigger 799390865/260502209). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 283.76, Dec = 57.62 (J2000 degrees, equivalent to J2000 18h 55m, +57d 37′), with a statistical uncertainty of 13.77 degrees. The angle from the Fermi LAT boresight is 23 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260502209/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260502209/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260502209/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/44447. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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