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[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…

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[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…

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[vsnet-grb-info 43098] GRB 260614B: SVOM/VT optical observations
by GCN Circulars 14 Jun '26

14 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…

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[vsnet-grb-info 43097] GRB 260614B: Fermi GBM Observation
by GCN Circulars 14 Jun '26

14 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…

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[vsnet-grb-info 43096] GRB 260610B: ALMA detection
by GCN Circulars 14 Jun '26

14 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…

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[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…

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[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…

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[vsnet-grb-info 43093] GRB 260614B: SVOM detection of a burst
by GCN Circulars 14 Jun '26

14 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44938 SUBJECT: GRB 260614B: SVOM detection of a burst DATE: 26/06/14 14:17:03 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> O. Godet (IRAP), M. Pillas (IAP), D. Götz (CEA), F. Robinet (IJCLAB) report on behalf of the SVOM mission team: At 2026-06-14T13:49:55 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260614B (SVOM burst-id sb26061401), also detected by Fermi/GBM (GCN #44937). 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 15 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 40.78 in the [8-120] keV energy band over a time window of 20.48 seconds starting at 2026-06-14T13:49:52. The localization of the best alert is R.A., Dec. 353.940, -54.154 degrees: R.A. (J2000) = 23h35m45.60s Dec. (J2000) = -54d09m13.40s with a 90% confidence level (C.L.) radius of 2.75 arcmin (including systematic error of 2 arcmin added in quadrature). The SVOM/ECLAIRs light curve showed a multiple broad peak structure with a T90 duration of about 19.62 -2.19 / +5.93 s. This burst also triggered SVOM/GRM at 2026-06-14T13:49:47 on a timescale of 4 seconds with an SNR of 5.10. SVOM slewed to the burst. SVOM/MXT began observing the field at 2026-06-14T13:52:24.0 UTC. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec. 353.907, -54.1192 degrees with a 90% C.L. radius of 69 arcseconds. This location is 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 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/44938. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43092] GRB 260614B: Fermi GBM Final Real-time Localization
by GCN Circulars 14 Jun '26

14 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44937 SUBJECT: GRB 260614B: Fermi GBM Final Real-time Localization DATE: 26/06/14 13:57:42 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 13:49:53 UT on 14 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260614B (trigger 803137798.515116 / 260614576). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 2.5, Dec = -50.9 (J2000 degrees, equivalent to J2000 00h 10m, -50d 53'), with a statistical uncertainty of 2.7 degrees. The angle from the Fermi LAT boresight is 25.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260614576/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260614576/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260614576/… View this GCN Circular online at https://gcn.nasa.gov/circulars/44937. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43091] GRB 260611B: SVOM/GRM detection
by GCN Circulars 14 Jun '26

14 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44936 SUBJECT: GRB 260611B: SVOM/GRM detection DATE: 26/06/14 13:54:22 GMT FROM: zhangjinpeng(a)ihep.ac.cn SVOM/GRM team: Jin-Peng Zhang, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Marius Brunet (IRAP) Report on behalf of the SVOM team: SVOM/GRM detected GRB 260611B during the routine ground search at 2026-06-11T21:32:37.000 (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #44917) and CALET (Nakahira et al, GCN #44923). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst mainly consists of multiple pulses with a T90 of 26 +4/-2 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260611B.png In addition, the position of this burst, according to Fermi/GBM localization (RA = 13.3, Dec = 22.6, Fermi GBM Team, GCN #44917), is located at about 121 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-6 to T0+26 s is fitted by a power law function. The power law index is -2.14 +0.12/-0.12. The event fluence (10-1000 keV) in this time interval is (1.41 +0.13/-0.13)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/GRM point of contact for this burst is: Jin-Peng Zhang (IHEP) (zhangjinpeng(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/44936. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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