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

[vsnet-grb-info 43103] GRB 260616A: Fermi GBM Final Real-time Localization
by GCN Circulars 16 Jun '26

16 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44948 SUBJECT: GRB 260616A: Fermi GBM Final Real-time Localization DATE: 26/06/16 03:34:02 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 03:21:54 UT on 16 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260616A (trigger 803272919.330008 / 260616140). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 95.0, Dec = -31.9 (J2000 degrees, equivalent to J2000 06h 19m, -31d 53'), with a statistical uncertainty of 1.4 degrees. The angle from the Fermi LAT boresight is 111.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260616140/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260616140/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260616140/… View this GCN Circular online at https://gcn.nasa.gov/circulars/44948. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43102] GRB 260614B: SVOM/ECLAIRs refined analysis
by GCN Circulars 16 Jun '26

16 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44947 SUBJECT: GRB 260614B: SVOM/ECLAIRs refined analysis DATE: 26/06/15 21:03:45 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> M. Brunet, O. Godet, S. Guillot (IRAP), M. Pillas (IAP) 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 SVOM/ECLAIRs observations of GRB 260614B (SVOM burst-id sb26061401 – GCN 44938, trigger time T0 = 2026-06-14T13:49:55 UTC), which was also detected by Fermi/GBM (GCN 44937, 44942) and GECAM-B (GCN 44945). The burst that triggered ECLAIRs onboard shows a multiple peak lightcurve. The burst duration is T90 = 88 +18/-9 s in the 4-120 keV energy band. The time-averaged spectrum before the slew from T0-4 s to T0+37 s in the 5-120 keV energy range is best fitted by a powerlaw model with a photon index of -1.04 +/- 0.03. With this model, the 4-120 keV fluence is (5.4 +/- 0.1)e-6 erg/cm^2 and the 4-120 keV photon flux is 2.50 +0.04/-0.06 ph/cm^2/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. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. The SVOM/ECLAIRs point of contact for this burst is: Marius Brunet (IRAP) (marius.brunet at utoulouse.fr). View this GCN Circular online at https://gcn.nasa.gov/circulars/44947. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43101] GRB 260610B: Terskol optical observations
by GCN Circulars 15 Jun '26

15 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44946 SUBJECT: GRB 260610B: Terskol optical observations DATE: 26/06/15 08:46:27 GMT FROM: Nicolai Pankov at IKI <colinsergesen(a)gmail.com> N. Pankov (IKI), A. Salakhotdinova (INASAN), A. Shein (INASAN), E. Postnikova (INASAN), A. Pozanenko (IKI), A. Moskvitin (SAO RAS), A. Volnova (IKI) report on behalf of IKI-GRB-FuN: We observed the field of GRB 260610B (The Fermi GBM team, GCN 44891; GCN 44901) with the Zeiss-2000 2-meter telescope of the Terskol Observatory on epochs 2026-06-11 and 2026-06-12. The R-band observations were carried out using the CCD-photometer. In the first epoch we acquired a series of 3x120+12x120 sec images, while in the latter epoch 9x120 sec images were obtained. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek & Perley, GCN 44932) is clearly detected in our co-add images. The observational properties and preliminary photometry are provided further: Date UTstart t-T0 Exp. Filter Mag Err UL (mid,d) (n*s) (3-sigma) 2026-06-11 21:33:51 1.48481 3x120+12x90 R 19.81 0.06 22.4 2026-06-12 19:46:19 2.40802 9x120 R 20.70 0.13 22.3 The photometry is based on nearby SDSS stars (R-magnitudes obtained via Lupton 2005 transformation equations; Moskvitin et al., GCN 44918) and not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44946. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43100] GRB 260614B: GECAM-B observation
by GCN Circulars 15 Jun '26

15 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44945 SUBJECT: GRB 260614B: GECAM-B observation DATE: 26/06/15 08:39:27 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 260614B, at 2026-06-14T13:49:54.950 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #44937), and SVOM/ECLAIRs (O. Godet et.al., GCN#44938). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 43 +/-7 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecambgrb260614B.png In addition, the position of this burst is determined by SVOM/VT (RA=353.90883 , DEC=-54.11628, with an uncertainty of 0.50 arcsec, J.T. Palmerio et.al., GCN #44939). With this localization, the time-averaged spectrum from T0-19.5 to T0+22.5 s is best fitted by a power law function. The power law index is -1.58 +0.08/-0.09. The event fluence (10-1000keV) in this time interval is (2.43 +0.17/-0.16)E-05 erg/cm^2. 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/44945. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43099] GRB 260610B: SVOM/GRM observation
by GCN Circulars 15 Jun '26

15 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44944 SUBJECT: GRB 260610B: SVOM/GRM observation DATE: 26/06/15 08:36:29 GMT FROM: yzh807926(a)163.com SVOM/GRM team: Zheng-Hang Yu, Chen-Wei Wang, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Marius Brunet (IRAP) Report on behalf of the SVOM team: SVOM/GRM was triggered on-ground by a burst GRB 260610B at 2026-06-10T23:46:14.100 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #44901). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a main episode with two peaks a T90 of 65.0 +/-8.0 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260610B.png In addition, the position of this burst, as determined by Fermi/GBM (RA= 218.66 deg, DEC= 23.94 deg, ERR=2.77 deg, GCN#44901), is located at about 74 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-10 to T0+60 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.59 +0.18/-0.22 and the cutoff energy, parameterized as Epeak, is 34 +6/-8 keV. The event fluence (10-1000 keV) in this time interval is (9.48 +0.50/-0.47)E-06 erg/cm^2. The 1s peak spectrum, measured from T0+1.9 to T0+2.9 s, if fitted by a power law function with an exponential high-energy cutoff, the power law index is -1.62 +0.16/-0.32 and the cutoff energy, parameterized as Epeak, is 25 +8/-7 keV. The flux (10-1000 keV) in this time interval is (3.98 +0.41/-0.37)E-07 erg/cm^2/s. With the measured redshift z=0.473 (D. O'Neill et al., GCN#44914), we calculate the isotropic energy Eiso is about 8.8E51 erg. Thus GRB 260610B is well consistent with Type II GRBs in the 'Amati' relation diagram, as shown at: https://www.bursthub.cn//admin/static/svgrb260610B_amati.png The localization of GRB 260421B in the 'Yonetoku' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb260610B_yonetoku.png 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: Zheng-Hang Yu(IHEP)(zhyu(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/44944. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43098] GRB 260614B: SVOM/VT optical observations
by GCN Circulars 15 Jun '26

15 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44943 SUBJECT: GRB 260614B: SVOM/VT optical observations DATE: 26/06/15 01:08:34 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H. L. Li, L. P. Xin, Y. L. Qiu, C. Wu, J. R. Xu, Y. N. Ma, Z. H. Yao, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. T. Palmerio (CEA/Irfu), O. Godet (IRAP) and M. Pillas (IAP) report on behalf of the SVOM/VT team. SVOM/VT performed observations with an automatic slew of GRB 260614B triggered by SVOM/ECLAIRs (sb26061401, Godet et al., GCN 44938), which was also detected by SVOM/GRM (Godet et al., GCN 44938) and Fermi GBM (the Fermi GBM team, GCN 44937; Palafox, GCN 44942). The observation started at 2026-06-14T13:52:36 UTC, i.e., 186 seconds post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously. The optical counterpart identified via VT VHF data (Palmerio et al., GCN 44939) within the error box of SVOM/ECLAIRs and SVOM/MXT (Godet et al., GCN 44938) is clearly detected in both channels. The following measurements are in the AB magnitude and are not corrected for Galactic extinction: Mid time | Band | Exposure Time | Brightness 186 s VT_B 50 s 18.28 +/-0.05 mag 186 s VT_R 50 s 15.56 +/-0.04 mag 3.16 h VT_B 20*100 s 23.0 +/-0.2 mag 3.10 h VT_R 16*100 s 20.3 +/-0.1 mag The source showed a fading slope of about -1.2 during the observations above. 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/44943. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43097] GRB 260614B: Fermi GBM Observation
by GCN Circulars 15 Jun '26

15 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44942 SUBJECT: GRB 260614B: Fermi GBM Observation DATE: 26/06/14 21:57:48 GMT FROM: Eva M. Palafox at INAOE <eva.palafox(a)gmail.com> E. Palafox (INAOE-Mexico) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 13:49:53.52 UT on 14 June 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260614B (trigger 803137798/260614576). which was also detected by SVOM/ECLAIRs (Godet et al. 2026, GCN 44938). The Fermi GBM on-ground location is consistent with the SVOM/ECLAIRs position. The angle from the Fermi LAT boresight is 31 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 30 s (50-300 keV). The time-averaged spectrum from T0-13 to T0+34 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.78 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 510 +/- 10 keV. The event fluence (10-1000 keV) in this time interval is (2.20 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+13 s in the 10-1000 keV band is 5.7 +/- 0.2 ph/s/cm^2. 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/44942. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43096] GRB 260610B: ALMA detection
by GCN Circulars 15 Jun '26

15 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44941 SUBJECT: GRB 260610B: ALMA detection DATE: 26/06/14 21:57:00 GMT FROM: Tanmoy Laskar at U of Utah <tanmoylaskar(a)gmail.com> T. Laskar (Utah), B. P. Gompertz (Birmingham), G. E. Anderson (Curtin), A. Levan (Radboud and Warwick), Daniele Malesani (DAWN/NBI and Radboud), Steve Schulze (Weizmann), Nial Tanvir (Leicester), A. J. van der Horst (GWU) report on behalf of a larger collaboration: “We observed GRB 260610B (Fermi GBM team, GCN 44891; O'Neill et al., GCN 44903) with the Atacama Large Millimeter/Submillimeter Array (ALMA) at 43 GHz beginning on 2026 June 13 at 01:06 UT (2.62 days after the burst). Preliminary analysis reveals a mm source with flux density of ~ 0.3 mJy at position: RA (J2000) = 14:32:38.2 Dec (J2000) = +27:00:17.6 with an uncertainty of 0.2" in each coordinate. This is consistent with the optical position (O'Neill et al., GCN 44903). Further observations are planned. We thank the P2G, AoD, JAO staff, and the entire ALMA team for their help with these observations." View this GCN Circular online at https://gcn.nasa.gov/circulars/44941. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43095] GRB 260614A: GECAM-B observation
by GCN Circulars 14 Jun '26

14 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44940 SUBJECT: GRB 260614A: GECAM-B observation DATE: 26/06/14 16:14:12 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 on-ground by GRB 260614A, at 2026-06-14T10:06:15.950 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #44935). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 20 +/-6 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecambgrb260614A.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/44940. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 43094] GRB 260614B: SVOM/VT optical candidate from VHF data
by GCN Circulars 14 Jun '26

14 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44939 SUBJECT: GRB 260614B: SVOM/VT optical candidate from VHF data DATE: 26/06/14 15:06:45 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> J. T. Palmerio, A. Saccardi (CEA/Irfu), Y. L. Qiu, C. Wu, L. P. Xin (NAOC), M. Pillas (IAP) on behalf of the SVOM/VT team. After the trigger by SVOM/ECLAIRs at 2026-06-14T13:49:55 UTC (T0), SVOM performed an automatic slew on the burst location (Godet et al., GCN 44938). SVOM/VT began observing the field in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. From a preliminary analysis of the 1-bit subimage and source list downloaded via VHF network, at least one credible candidate is identified, the details of which are presented below. VT_ID 52: The position of this candidate is R.A., Dec. 353.90883, -54.11628 degrees, corresponding to: R.A. (J2000) = 23h35m38.1s Dec. (J2000) = -54d06m58.6s with an uncertainty of 0.50 arcsec. This candidate was detected in both VT_R and VT_Band was flagged as an uncatalogued source. The candidate's magnitudes are: | date-obs (UTC) | mid-time | exposure | VT_B mag(AB) | VT_R mag(AB) | | -------------------- | ----------- | --------- | ------------- | ------------- | | 2026-06-14T13:54:16 | 2026-06-14T13:56:46 | 6x50s | 19.25 ± 0.01 | 16.35 ± 0.01 | | 2026-06-14T13:59:16 | 2026-06-14T14:01:21 | 5x50s | – | 16.71 ± 0.01 | Magnitudes were not corrected for Galactic reddening. 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/VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. The Burst Advocate (BA) on shift for this alert is Marion Pillas: marion.pillas(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/44939. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0