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

[vsnet-grb-info 43301] The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45087 SUBJECT: The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare DATE: 26/07/06 14:39:25 GMT FROM: Weikang Zheng at UC Berkeley <weikang(a)berkeley.edu> WeiKang Zheng (UCB), Xuhui Han (NAOC), Pinpin Zhang (NAOC) and Alexei V. Filippenko (UCB) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, automatically responded to the EP-WXT trigger 01709274014 (Jiang et al. GCN 45086) starting at 09:52 UT, about 8 minutes after the trigger. A set of B, V, R, I and clear (roughly R) filter images were obtained and lasted for ~1.2 hours. We performed the photometry on the suggested flare star HD 183870B and see its brightness decreased in all bands, especially in B band decayed from ~13.6 mag to ~14.8 mag in about 1.2 hours, thus confirming the EP X-ray trigger is related to the stellar flare. View this GCN Circular online at https://gcn.nasa.gov/circulars/45087. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43300] The EP-WXT trigger 01709274014 is likely a flaring star
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45086 SUBJECT: The EP-WXT trigger 01709274014 is likely a flaring star DATE: 26/07/06 10:52:31 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> S. Q. Jiang (NAO, CAS), D. F. Hu (PMO, CAS), C.-K. Kan (HKU), X. Tian(GXU), H. W. Pan (NAO, CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709274014 at the time of 2026-07-06T09:44:54, is likely a stellar flare associated with the high proper motion star HD 183870B. The estimated flux of the flare is around 1.8 x 10^(-10) erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 6.73 x 10^(30) 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/45086. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43299] IceCube260704A: OHP/T193 optical observations
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45085 SUBJECT: IceCube260704A: OHP/T193 optical observations DATE: 26/07/06 10:52:28 GMT FROM: Christophe Adami at LAM <christophe.adami(a)lam.fr> C. Adami (LAM/Pytheas/AMU), S. Basa (LAM/OHP/Pytheas/AMU), E. Le Floc'h (CEA/Irfu), F. Schussler (CEA Paris-Saclay) report on behalf of a larger collaboration: We observed the WISEA J212302.62+340634.2 source (no available public spectroscopy in NED), at ~4.9arcmin from the mean coordinates of the IceCube event IceCube260704A (Zegarelli et al., GCN 45075), using the T193cm telescope at Observatoire de Haute-Provence (France) with the MISTRAL spectro-imager. We obtained 6 min of exposure in the r-band starting at 2026-07-05T02:04 UT (18.8h after the Zegarelli et al. trigger). In the preliminar stacked images, we do not detect significant magnitude change as compared to the PanStarrs r-band magnitude of r=18.05. We also observed in spectroscopic mode: - We obtained a total of 60 min of exposures (2 x 30min) with the MISTRAL spectroscopic blue setting from 4000 to 7800 AA, starting at 2026-07-05 00:18 UT (17h after the trigger). With a preliminar data reduction, we very clearly detect Halpha (apparently with a single peak) at a redshift of 0.1402. We also detect very clearly an intense double-peaked [NII]@6584A emission line. No other emission line are visible. We detect however Magnesium@5175A, CaFe@5269A and NaD@5892A in absorption. The log(Halpha/[NII]) is close to -0.1, likely placing this galaxy in the AGN/LINER region in a BPT diagram. The two peaks of the [NII] emission line are separated by ~300km/s. - We then obtained a second serie of 3 x 30min starting at 2026-07-05 23:13 UT (~40h after the trigger). With a preliminar data reduction, we still clearly detect Halpha with a single peak at the same redshift and with a similar intensity. The [NII]@6584A emission line may show a mild evolution: the flux is stronger and the two peaks are much less separated and proeminent. The photometric calibration was performed using nearby stars from the PanSTARRS catalog and the STDWeb/STDPipe tools (Karpov 2025), is in the AB system, and is not corrected for Galactic extinction. We acknowledge the excellent support from Observatoire de Haute-Provence and in particular Jean Pierre Troncin. View this GCN Circular online at https://gcn.nasa.gov/circulars/45085. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43298] GRB 260705A: LCO optical upper limits
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45084 SUBJECT: GRB 260705A: LCO optical upper limits DATE: 26/07/06 08:47:12 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Y.Y. Shi (GXU), A. Saccardi (CEA/Irfu), C. Wu (NAOC), L.P. Xin (NAOC), D. Turpin (CEA/Irfu), X. Tian (GXU), Z. Liu (GZNU) report on behalf of the SVOM mission team: We observed the field of GRB 260705A (SVOM burst-id sb26070502) detected by SVOM (Saccardi et al., GCN 45079) with the LCO 1m telescope at South African Astronomical Observatory equipped with the Sinistro instrument. Our observation started on 2026-07-06 at 03:52:16 UT (about 14.76 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r and 3x200 s exposures in the Pan-STARRS z filters. In the stacked image, we do not detect any new source within the SVOM/ECLAIRs error box. We measure the following upper limits calibrated against the DESI Legacy Imaging Surveys DR10 catalog, and not corrected for Galactic extinction: r > 20.9 AB (5-sigma, mid-time 14.85 h after the trigger); z > 19.9 AB (5-sigma, mid-time 15.06 h after the trigger). This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/45084. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43297] GRB 260704A: NOT optical upper limits
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45083 SUBJECT: GRB 260704A: NOT optical upper limits DATE: 26/07/06 06:20:45 GMT FROM: Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani(a)nbi.ku.dk> D. B. Malesani (DAWN/NBI and Radboud), G. Corcoran (UCD), A. Martin-Carrillo (UCD), A. Saccardi (CEA/Irfu), F. Mustafaj (NOT) report on behalf of a larger collaboration: We observed the field of GRB 260704A reported by SVOM/ECLAIRs (Xie et al., GCN 45072), using the ALFOSC camera mounted on the Nordic Optical Telescope (NOT). We obtained 9x120 s exposures in the SDSS i band at mid time 2026 Jul 5.116 UT (23.1 hr after the trigger). Our observations targeted the location of the X-ray source detected by SVOM/MXT (Xie et al., GCN 45072) and EP/FXT (Yin et al., GCN 45078). Within the EP/FXT error circle, we note the presence of a bright star (i = 15.46). Its magnitude in our image is consistent with the archival value. Its TESS light curve does not show historical variability either. This makes the star not likely related to the X-ray source. Furthermore, in the stack of our images, no new optical source is detected within the EP/FXT error region, down to the 3-sigma limiting AB magnitudes of i > 22.5 (calibrated against nearby stars from the Pan-STARRS catalog and not corrected for Galactic extinction). View this GCN Circular online at https://gcn.nasa.gov/circulars/45083. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43296] GRB 260705C: Fermi GBM Final Localization
by GCN Circulars 05 Jul '26

05 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45082 SUBJECT: GRB 260705C: Fermi GBM Final Localization DATE: 26/07/06 00:40:46 GMT FROM: rhamburg(a)usra.edu The Fermi GBM team reports the detection of a likely SHORT GRB "At 13:58:58.99 UT on 05 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260705C (trigger 804952743/260705583). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 251.67, Dec = 55.55 (J2000 degrees, equivalent to J2000 16h 46m, +55d 32'), with a statistical uncertainty of 11.60 degrees. The angle from the Fermi LAT boresight is 21 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/45082. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43295] GRB 260705B: Fermi GBM Final Real-time Localization
by GCN Circulars 05 Jul '26

05 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45081 SUBJECT: GRB 260705B: Fermi GBM Final Real-time Localization DATE: 26/07/06 00:19:12 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 22:46:36 UT on 5 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260705B (trigger 804984401.559966 / 260705949). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 68.5, Dec = -30.8 (J2000 degrees, equivalent to J2000 04h 33m, -30d 48'), with a statistical uncertainty of 3.0 degrees. The angle from the Fermi LAT boresight is 77.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705949/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705949/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705949/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45081. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43294] GRB 260705A: SVOM detection of a burst
by GCN Circulars 05 Jul '26

05 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45079 SUBJECT: GRB 260705A: SVOM detection of a burst DATE: 26/07/05 14:25:13 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> A. Saccardi (CEA/Irfu), N. Dagoneau (CEA/Irfu), D. Turpin (CEA/Irfu), X. Tian (GXU), Z. Liu (GZNU), report on behalf of the SVOM mission team: At 2026-07-05T13:06:46 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260705A (SVOM burst-id sb26070502). 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 16 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 11.38 in the [8-120] keV energy band over a time window of 40.96 seconds starting at 2026-07-05T13:06:28. The localization of the best alert is R.A., Dec. 58.2851, -31.6391 degrees: R.A. (J2000) = 3h53m08.43s Dec. (J2000) = -31d38m20.61s with a 90% confidence level (C.L.) radius of 7.06 arcmin (including systematic error of 2 arcmin added in quadrature). The SVOM/ECLAIRs light curve showed a broad peak structure with a T90 duration of about 18.387 (-3.43 +11.095). This burst was also detected by SVOM/GRM with a significance of 10.40. The SVOM/GRM light curve showed a broad peak structure with a T90 duration of about 33.216 (-8.32 +11.914). Due to sun constraint, no immediate slew was performed on this 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 Xiao Tian: tianxiao(a)st.gxu.edu.cn Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/45079. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43293] Fermi GBM Sub-Threshold Detection of GRB 250705A
by GCN Circulars 05 Jul '26

05 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45080 SUBJECT: Fermi GBM Sub-Threshold Detection of GRB 250705A DATE: 26/07/05 20:33:37 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA) and P. Veres (UAH) report on behalf of the Fermi-GBM Team: SVOM ECLAIRs detected GRB 250702A on 2026-07-05 at 13:06:46 UTC (Saccardi et al 2026; GCN 45079). There was no Fermi-GBM onboard trigger around this event time. An automated, blind search for gamma-ray bursts below the onboard triggering threshold in Fermi-GBM identified no candidates. The GBM Targeted Search [1], the most sensitive coherent search for GRB-like signals in GBM, identified a transient about 25 seconds after the SVOM ECLAIRs best SNR time of 2026-07-05 13:06:28 UTC. The Fermi-MET for this transient is 804949617.957 s. The transient is found most significantly on the 32 s timescale with a false alarm rate of 1.4e-04 Hz. The Targeted Search localization is found to be spatially consistent with the SVOM ECLAIRs localization. The GBM Targeted Search event was found with the highest significance using a "normal" spectrum (Band function with Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB. [1] Goldstein et al. 2019 arXiv:1903.12597 View this GCN Circular online at https://gcn.nasa.gov/circulars/45080. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43292] GRB 260704A: EP-FXT follow-up observation
by GCN Circulars 04 Jul '26

04 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45078 SUBJECT: GRB 260704A: EP-FXT follow-up observation DATE: 26/07/04 14:56:07 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.-H. I. Yin, C.-K. Kan (HKU), Y. H. Cheng (YNU), S.Y. Fu (HUST). Z. X. Ling (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed an automatically follow-up observation of GRB 260704A detected by SVOM/ECLAIRs (Xie et al., GCN 45072). The follow-up observation started at 2026-07-04T04:49:23 (UTC), about 1 hr after the SVOM trigger, with a total exposure time of around 2.6 ks. On-ground analysis of the FXT data found an uncatalogued source within the ECLAIRs and MXT error circles at R.A., Dec. = 318.7151, -25.5074 deg (J2000) with an uncertainty of about 10 arcsec (radius, 90% C.L. statistical and systematic). The derived average unabsorbed flux is 1.49 (-0.22/+0.26) 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/45078. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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