July 2026 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 43331] GRB 260708A: Fermi-LAT detection
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45117 SUBJECT: GRB 260708A: Fermi-LAT detection DATE: 26/07/08 17:20:47 GMT FROM: A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca(a)unitn.it> A. Holzmann Airasca (UniTrento and INFN Bari), D. Depalo (Politecnico and INFN Bari) and P. Loizzo (UniTrento and INFN Bari) report on behalf of the Fermi-LAT collaboration: At 10:11:16.89 UT on July 8th, 2026, Fermi-LAT detected high-energy emission from GRB 260708A, which was also detected by Fermi-GBM (trigger 805198281/260708424, GCN #45115). The best LAT on-ground location is found to be RA, Dec = 225.61, -44.07 (J2000) with an error radius of 0.27 deg (90 % containment, statistical error only). This was 43 deg from the LAT boresight at the time of the trigger. The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance. The photon flux above 100 MeV in the time interval 0 - 400 s after the GBM trigger is (1.9 ± 0.4)E-5 ph/cm2/s. The estimated photon index above 100 MeV is -2.5 ± 0.3. The highest energy photon has an energy of 2.1 GeV and occurs at 65.8 s after trigger time. The Fermi-LAT point of contact for this burst is Pierpaolo Loizzo (pierpaolo.loizzo(a)ba.infn.it) The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/45117. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43330] GRB 260705B: SVOM/GRM observation
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45116 SUBJECT: GRB 260705B: SVOM/GRM observation DATE: 26/07/08 16:19:53 GMT FROM: Xinghao Luo at IHEP <2952704891(a)qq.com> SVOM/GRM team: Xing-Hao Luo, Chen-Wei Wang, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Nicolas Dagoneau (CEA) Report on behalf of the SVOM team: SVOM/GRM was triggered on-ground by GRB 260705B at 2026-07-05T22:46:39.000 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45081). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple pulses with a T90 of 99 +12/-9 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260705B.png In addition, the position of this burst, as determined by Fermi/GBM (RA=68.5 , DEC=-30.8, with a statistical uncertainty of 3.0 degrees, Fermi GBM team, GCN #5081), is located at about 74 degrees form the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-24 to T0+75 s is best fitted by a power law function. The power law index is -1.84 +/-0.06. The event fluence (10-1000keV) in this time interval is (1.11 +0.19/-0.16)E-05 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 point of contact for this burst is: Xing-Hao Luo (luoxh(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/45116. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43329] GRB 260708A: Fermi-GBM detection
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45115 SUBJECT: GRB 260708A: Fermi-GBM detection DATE: 26/07/08 14:17:47 GMT FROM: Christian Malacaria at INAF-OAR <cmalacaria.astro(a)gmail.com> The Fermi GBM team reports the detection of a likely LONG GRB "At 10:11:16.89 UT on 08 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260708A (trigger 805198281/260708424). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 227.4, Dec = -44.5 (J2000 degrees, equivalent to J2000 15h 09m, -44d 30'), with a statistical uncertainty of 1.6 degrees. The angle from the Fermi LAT boresight is 43 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260708424/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260708424/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260708424/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/45115. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43328] GRB 260706A: Further EP-FXT follow-up observation
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45114 SUBJECT: GRB 260706A: Further EP-FXT follow-up observation DATE: 26/07/08 13:58:49 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> M. Pillas (IAP), F. Daigne (IAP), Y.F. Liang (PMO), report on behalf of the SVOM and EP collaborations: EP-FXT performed an additional follow-up observation of GRB 260706A detected by SVOM/ECLAIRs (Alaux et al., GCN 45089) and Fermi/GBM (Fermi GBM Team, GCN 45088). This second follow-up observation epoch started on 2026-07-07 at 19:16:49 (UTC), about 27.1 hr after the SVOM trigger, with a total exposure time of 3 ks. On-ground analysis of the FXT data still detected an uncatalogued source consistent with the previous EP/FXT detection (Liang et al., GCN 45097). The derived average unabsorbed flux is (2.5+/- 0.5) x 10^(-13) erg/s/cm^2 (0.5-10 keV; 1-sigma uncertainty). 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/45114. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43327] GRB 260706A: SVOM/VT optical upper limits
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45113 SUBJECT: GRB 260706A: SVOM/VT optical upper limits DATE: 26/07/08 09:45:48 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H. L. Li, L. P. Xin, C. Wu, Y. L. Qiu, Y. N. Ma, J. R. Xu, Z. H. Yao, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), F. Daigne (IAP) and M. Pillas (IAP) report on behalf of the SVOM/VT team. SVOM/VT performed ToO observation to GRB 260706A detected by SVOM/Eclairs (sb26070606, Alaux et al., GCN 45089; Guillot et al., GCN 45103). This burst was also detected by SVOM/GRM (Alaux et al., GCN 45089; Wang et al., GCN 45101) and Fermi/GBM (the Fermi GBM team, GCN 45088; Trigg et al., GCN 45093). The observation started at 2026-07-07T07:42:10 UTC, about 15.506 hours after trigger in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. No credible sources are detected in stacked images within error box of SVOM/Eclairs (Alaux et al., GCN 45089) and EP-FXT (Liang et al., GCN 45097) down to 10-sigma upper limits of 22.0 mag in both channels at the midtime of 17.43 hr post trigger. The magnitudes are in the AB system and are not corrected for Galactic extinction. Our non-detection is consistent with observations from LCO (Saccardi et al., GCN 45098) and REM (Brivio et al., GCN 45100). The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/45113. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43326] EP260707a (by EP-FXT): NOT optical upper limit
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45112 SUBJECT: EP260707a (by EP-FXT): NOT optical upper limit DATE: 26/07/08 04:41:03 GMT FROM: sqjiang at NAOC <sqjiang(a)bao.ac.cn> X. Liu, S.Q. Jiang, Z.P. Zhu, J. An, L.B. He, D. Xu (NAOC), S.Y. Fu (HUST), J.P.U. Fynbo (DAWN/NBI), F. Mustafaj (NOT) report: We observed the field of the uncatalogued X-ray source detected by EP-FXT (Zhou et al., GCNs 45107 & 45111), located within the EP-WXT error circle of the very likely fake event of EP260707a, using the 2.56m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observation started at 2026-07-08 01:09:50.53 UT, i.e., 8.41 hr post-burst, and a series of r-band frames were obtained. No new optical transient is detected in the stacked image within the EP-FXT error circle (GCN 45107), down to a 5-sigma limiting magnitude of r ~ 23.0 (AB), calibrated with Pan-STARRS DR2 stars in the field and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45112. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43325] EP260707a is not a real source
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45111 SUBJECT: EP260707a is not a real source DATE: 26/07/08 02:34:57 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> H. Zhou, Y. F. Liang (PMO), K. R. Ni (CCNU), C.-K. Kan (HKU), H. Sun (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the follow-up analysis of the X-ray transient candidate EP260707a, initially triggered the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission (Zhou et al. GCN 45107) also followed by optical telescopes (Liu et al. GCN 45109, Strausbaugh et al. GCN 45110) Following the analysis of the telemetry data, we found that the EP260707a is not a real transient. The uncatalogued X-ray source subsequently detected by the Follow-up X-ray Telescope (FXT) within the WXT error circle is considered as a coincidental alignment, rather than a counterpart to a real transient. We apologize for any inconvenience caused to the community. 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/45111. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43324] EP260707a: LCOGT Optical Upper Limit
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45110 SUBJECT: EP260707a: LCOGT Optical Upper Limit DATE: 26/07/07 21:12:22 GMT FROM: Robert Strausbaugh at Eastern Illinois University <rstrausbaugh(a)eiu.edu> R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the EP260707a field (Zhou et al., GCN 45107) with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory site, on July 7, from 20:02 to 20:35 UT (corresponding to 3.28 to 3.83 hours after the trigger time) with the SDSS r and i filters. We performed a series of 3x300s exposures in i-band and r-band. We do not detect an uncatalogued source in the FXT error region, consistent with other optical upper limits (Liu et al., GCN 45109). The following magnitudes are calculated using the PanSTARRS catalog as reference: r > 22.1 i > 21.6 These magnitudes are not corrected for galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45110. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43323] EP260707a: TRT optical upper limit
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45109 SUBJECT: EP260707a: TRT optical upper limit DATE: 26/07/07 19:33:31 GMT FROM: liuxing(a)nao.cas.cn X. Liu (NAOC), K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), S.Y. Fu (HUST), S.Q. Jiang, J. An, L.B. He, Z.P. Zhu, D. Xu (NAOC) report: We observed the field of EP260707a detected by EP (Zhou et al., GCN 45107) using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at New South Wales, Australia (SBO). 4x300s frames in the R-band were obtained at a median time of 1.52 hr post-trigger. No uncatalogued optical transient is detected in the stacked image within the EP/FXT error circle (Zhou et al., GCN 45107), down to a 5-sigma limiting magnitude of R ~ 21.0 (Vega), calibrated with Pan-STARRS DR2 stars in the field converted using Lupton (2005) equations and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45109. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43322] Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45108 SUBJECT: Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB DATE: 26/07/07 19:31:42 GMT FROM: Suman Bala at USRA <sumanbala2210(a)gmail.com> S. Bala (USRA) reports report on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 805087514/260707142 at 03:25:09.33 UT on 07 July 2026, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to Terrestrial Gamma-ray Flash (TGF)." View this GCN Circular online at https://gcn.nasa.gov/circulars/45108. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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