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

[vsnet-grb-info 43312] GRB 260706A: LCO optical upper limit
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45098 SUBJECT: GRB 260706A: LCO optical upper limit DATE: 26/07/07 09:30:30 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> A. Saccardi (CEA/Irfu), D. Turpin (CEA/Irfu), F. Daigne, M. Pillas (IAP), report on behalf of the SVOM mission team: We observed the field of GRB 260706A detected by SVOM/ECLAIRs (Alaux et al., GCN 45089) and Fermi/GBM (Fermi GBM team, GCN 45088; Trigg et al., GCN 45093), with the LCO 1m telescope at Cerro Tololo Observatory equipped with the Sinistro instrument. Our observation started on 2026-07-07 at 08:15:35 UT (about 16 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r filter. In the stacked image, we do not detect any new source within the EP/FXT error box (Liang et al., GCN 45097). We measure the following upper limit calibrated against the SkyMapper DR4 catalog, and not corrected for Galactic extinction: r > 22.3 AB (3-sigma, mid-time 16.14 hr after the trigger). This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/45098. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43311] GRB 260706A: EP-FXT follow-up observation
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45097 SUBJECT: GRB 260706A: EP-FXT follow-up observation DATE: 26/07/07 07:46:49 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.F. Liang, H. Zhou (PMO), K. R. Ni (CCNU), C.-K. Kan (HKU), H. Sun (NAOC) on behalf of the Einstein Probe (EP) team: EP-FXT performed an automatically follow-up observation of GRB 260706A detected by SVOM/ECLAIRs (Alaux et al., GCN 45089), which also triggered Fermi-GBM (Fermi GBM team, GCN 45088; Trigg et al., GCN 45093). The follow-up observation started at 2026-07-06 17:44:38 (UTC), about 1.5 hr after the SVOM trigger, with a total exposure time of around 5462 ks. On-ground analysis of the FXT data found an uncatalogued source within the ECLAIRs error circle at R.A., Dec. =33.8136, -49.1514 deg (J2000) with an uncertainty of about 10 arcsec (radius, 90% C.L. statistical and systematic). The derived average unabsorbed flux is 6.21 (-0.87/+1.03) x 10^(-12) 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/45097. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43310] GRB 260707A: Fermi GBM Final Real-time Localization
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45096 SUBJECT: GRB 260707A: Fermi GBM Final Real-time Localization DATE: 26/07/07 03:36:24 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 SHORT GRB At 03:25:09 UT on 7 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260707A (trigger 805087514.330134 / 260707142). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 283.4, Dec = -54.7 (J2000 degrees, equivalent to J2000 18h 53m, -54d 42'), with a statistical uncertainty of 13.3 degrees. The angle from the Fermi LAT boresight is 165.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260707142/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260707142/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260707142/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45096. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43309] The EP-WXT trigger 01709274151 is likely a flaring star
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45095 SUBJECT: The EP-WXT trigger 01709274151 is likely a flaring star DATE: 26/07/07 02:12:06 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y. F. Liang，H. Zhou (PMO)，K. R. Ni (CCNU), C.-K. Kan (HKU), H. Sun (NAO, CAS). on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709274151, detected at 2026-07-06T21:58:41, is likely associated with a stellar flare originating from one of two candidate stars within the FXT error circle: StKM 1-1292 or PM J15587+2351E. If the flare occurred on StKM 1-1292, the corresponding X-ray luminosity (0.5–4.0 keV) is estimated to be around 2.3 x 10^(31) erg/s. Alternatively, if it originated from PM J15587+2351E, the implied flare luminosity would be around 2.4 x 10^(31) erg/s. 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/45095. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43308] The EP-WXT trigger 01709274141 is likely a flaring star
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45094 SUBJECT: The EP-WXT trigger 01709274141 is likely a flaring star DATE: 26/07/07 02:07:57 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> K.R. Ni (CCNU), Y. F. Liang，H. Zhou (PMO)，C.-K. Kan (HKU), H. Sun (NAO, CAS). on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709274141 at the time of 2026-07-06 20:01:19, is likely a stellar flare associated with CD-25 16313. The estimated flux of the flare is around 2.1 x 10^-11 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 8.6 x 10^31 erg/s. 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/45094. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43307] GRB 260706A: Fermi GBM Observation
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45093 SUBJECT: GRB 260706A: Fermi GBM Observation DATE: 26/07/06 20:28:09 GMT FROM: atrigg2(a)lsu.edu A. C. Trigg (NPP ORAU, NASA MSFC) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 16:12:21.43 UT on 06 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260706A (trigger 805047146/260706675), which was also detected by SVOM/ECLAIRs (J. Alaux et al. 20026, GCN 45089). The Fermi GBM on-ground location is consistent with the SVOM/ELCAIRs position. The angle from the Fermi LAT boresight is 43 degrees. The GBM light curve displays two peaks with a duration (T90) of about 17 s (50-300 keV). The time-averaged spectrum from T0+0.001 to T0+30.616 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.13 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 47.1 +/- 0.6 keV. The event fluence (10-1000 keV) in this time interval is (3.18 +/- 0.08)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+15 s in the 10-1000 keV band is 5.3 +/- 0.3 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 39.1 +/- 0.5 keV, alpha = -0.71 +/- 0.01 and beta = -2.63 +/- 0.03. 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/45093. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43306] IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45092 SUBJECT: IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube DATE: 26/07/06 20:24:10 GMT FROM: Sam Hori at IceCube/U Wisc-Madison <sahori(a)wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-260704A (https://gcn.nasa.gov/circulars/45075) in a time range of 1000 seconds centered on the alert event time (2026-07-04 07:08:38.191 UTC to 2026-07-04 07:25:18.191 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-260704A. We report a p-value of 1.00 in this time window. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.4e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260704A in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 2e+02 GeV and 6e+04 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2026-07-03 07:16:58.191 UTC to 2026-07-05 07:16:58.191 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.6e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260704A in a 2 day time window. 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. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/45092. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43305] IPN triangulation of GRB 260627A
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45091 SUBJECT: IPN triangulation of GRB 260627A DATE: 26/07/06 19:33:12 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the MGNS/BepiColombo and HEND/Mars Odyssey teams, J. Benkhoff on behalf of the BepiColombo team, A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, E. Burns on behalf of the IPN, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 260627A was detected by Konus-Wind, Mars-Odyssey (HEND), and BepiColombo (MGNS), at about 6500 s UT (01:48:20). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 97.683 (06h 30m 44s) -11.018 (-11d 01' 04") Corners: 96.021 (06h 24m 05s) -10.787 (-10d 47' 15") 98.614 (06h 34m 27s) -12.214 (-12d 12' 51") 99.375 (06h 37m 30s) -11.186 (-11d 11' 10") 96.787 (06h 27m 09s) -9.778 ( -9d 46' 42") --------------------------------------------- The error box area is 3.6 sq. deg, and its maximum dimension is 3.3 deg (the minimum one is 1.2 deg). The Sun distance was 34 deg. This localization may be improved. A triangulation map and HEALPix FITS file are posted at https://www.ioffe.ru/LEA/GRBs/GRB260627_T06499/IPN/ The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. View this GCN Circular online at https://gcn.nasa.gov/circulars/45091. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43304] GRB 260705A: SVOM/ECLAIRs refined analysis
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45090 SUBJECT: GRB 260705A: SVOM/ECLAIRs refined analysis DATE: 26/07/06 17:19:11 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> N. Dagoneau, A. Saccardi (CEA), 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 ECLAIRs observations of GRB 260705A (SVOM burst-id sb26070502). The burst that triggered ECLAIRs onboard (GCN 45079) consists of a single broad peak lightcurve with a duration of T90 = 35.55 -9.04 / +6.05 (4-80 keV). The time-averaged spectrum (from T0-5.49 s to T0+29.72 s) in the energy range 5-120 keV is best fit by a powerlaw with an index of -1.68 ± 0.09. With this model, the 4-120 keV fluence is (1.053 ± 0.087)*E-6 erg/cm² and the 4-120 keV photon flux is 1.002 ± 0.059 ph/cm²/s. 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. The SVOM/ECLAIRs point of contact for this burst is: N. Dagoneau (nicolas.dagoneau at cea.fr) View this GCN Circular online at https://gcn.nasa.gov/circulars/45090. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43303] GRB 260706A: SVOM detection of a burst
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45089 SUBJECT: GRB 260706A: SVOM detection of a burst DATE: 26/07/06 16:50:02 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> J. Alaux, M. Brunet, S. Guillot, M. Boiziot (IRAP), F. Daigne, M. Pillas (IAP) report on behalf of the SVOM mission team: At 2026-07-06T16:12:23 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260706A (SVOM burst-id sb26070606), which is also detected by Fermi/GBM (GCN 45088). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 19 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 31.31 in the [8-120] keV energy band over a time window of 20.48 seconds starting at 2026-07-06T16:12:20. The localization of the best alert is R.A., Dec. 33.8323, -49.1375 degrees: R.A. (J2000) = 2h15m19.75s Dec. (J2000) = -49d08m15.14s with a 90% confidence level (C.L.) radius of 3.17 arcmin (including systematic error of 2 arcmin added in quadrature). The SVOM/ECLAIRs light curve showed a multiple peak structure. This burst also triggered SVOM/GRM at 2026-07-06T16:12:21 on a timescale of 1 second with an SNR of 9.50. The SVOM/GRM light curve showed a multiple peak structure with a T90 duration of about 22.9 -3.8/+10.5 seconds. SVOM slewed to the burst. No X-ray observation could be performed by SVOM/MXT for the time being. No optical observation could be performed by SVOM/VT for the time being. 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 Frédéric Daigne: daigne(a)iap.fr. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/45089. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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