GRB 260709A
GCN Circular 45297
Subject
GRB 260709A: cubesat Avion detection
Date
2026-08-06T08:49:20Z (3 months ago)
From
Andrey Bogomolov at Moscow State University <aabboogg@srd.sinp.msu.ru>
Via
email
From Andrey Bogomolov at Moscow State University <aabboogg@srd.sinp.msu.ru>
At 2026-07-09 ~01:07:32 UT the long-duration GRB 260709A (Fermi/GBM detection: GCN #45121, GECAM-B detection: GCN #45136, SVOM/GRM detection: GCN #45137, AstroSat detection: GCN #45164) was detected by the DeCoR-1 and DeCoR-3 instruments on the cubesat Avion of the Moscow University project “Sozvezdie-270” [1].
Total amount of photons detected by Avion is 100 (energy band >40 keV), it corresponds to a fluence of ~4.5*10^(-7) erg/cm^2 in the range 40-500 keV.
LC in the energy range of 40-500 keV consists of several peaks of various intensity, a maximum flux is ~2 phot/(cm^2*s) at the central peak at 01:07:32 UT.
А total duration (T90) of the burst is ~18 s.
The light curve obtained by Avion is available here:
https://swx.sinp.msu.ru/models/grb_cat/data/pictures/GRB260709A_LC_Avion.png
Parameters of GRB 260709A as well as other GRBs detected by Moscow University cubesats are listed at: https://swx.sinp.msu.ru/models/grb_cat/grb.php?lang=en
Avion is one of 5 cubesats of the Moscow University project “Sozvezdie-270” [1] launched on 2023 June 27. The payload of Avion is a set of scintillation gamma-ray detectors DeCoR [2], the energy range is >30 keV, the time resolution is 0.5s.
[1] Svertilov et al. 2023 https://link.springer.com/chapter/10.1007/978-3-031-50248-4_21
[2] Bogomolov et al. 2026 Cosmic Research 64, 262 https://link.springer.com/article/10.1134/S0010952526600071
GCN Circular 45164
Subject
GRB 260709A: AstroSat CZTI detection
Date
2026-07-15T07:35:09Z (3 months ago)
Edited On
2026-07-15T13:28:22Z (3 months ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
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S.Salunke (IUCAA), Harsha K. H. (IUCAA), A. Goyal (IITB), A. Arya (IITB), G. Waratkar (Caltech/IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 260709A which was also detected by Fermi (Fermi GBM team, GCN Circ. 45121), VOM/GRM (SVOM/GRM team, GCN Circ. 45137).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2026-07-09 01:07:50.62 UTC. The measured peak count rate associated with the burst is 108 (+32, -14) counts/s above the background in the combined data of three quadrants (out of four), with a total of 1034 (+278, -266) counts. The local mean background count rate was 207 (+2, -3) counts/s. We measure a T90 of 26 (+10, -8) s from the cumulative CZT light curve. We note that the burst is relatively weak, hence theT90 measurement has a larger uncertainty than usual.
CZTI data products like interactive and downloadable light curves for this GRB can be found at:https://astrosat.iucaa.in/cift/cift_products/ET20260709T010732/ET20260709T010732_details.html
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 45137
Subject
GRB 260709A: SVOM/GRM detection
Date
2026-07-11T05:58:51Z (3 months ago)
From
zhangjinpeng@ihep.ac.cn
Via
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SVOM/GRM team: Jin-Peng Zhang, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Sebastien Guillot (IRAP)
Report on behalf of the SVOM team:
SVOM/GRM detected GRB 260709A during the routine ground search at 2026-07-09T01:07:50.900 (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #45121).
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 63 +9/-9 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn/gcn/2026/svgrb260709A.png
In addition, the position of this burst, according to Fermi/GBM localization (RA = 84.1, Dec = 74.0, Fermi GBM Team, GCN #45121), is located at about 119 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view.
With this localization, the time-averaged spectrum from T0-25 to T0+25 s is fitted by a power law function. The power law index is -2.87 +0.16/-0.09. The event fluence (10-1000 keV) in this time interval is (3.0 +1.0/-1.2)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@ihep.ac.cn)
GCN Circular 45136
Subject
GRB 260709A: GECAM-B observation
Date
2026-07-11T05:57:32Z (3 months ago)
From
zhangjinpeng@ihep.ac.cn
Via
Web form
Jin-Peng Zhang, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered in-flight by GRB 260709A, at 2026-07-09T01:07:32.000 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45121).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of several pulses, with a duration (T90) of 56 +5/-4 s.
The GECAM-B light curve can be found here:
https://www.bursthub.cn/gcn/2026/gecambgrb260709A.png
The time-averaged spectrum from T0 - 5 to T0 + 50 s (photon energy > 70 keV) is fitted by a power law function. The power law index is -2.38 +0.25/-0.25. The event fluence (10-1000 keV) in this time interval is (1.5 +0.5/-0.3)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).
GCN Circular 45121
Subject
GRB 260709A: Fermi GBM Final Real-time Localization
Date
2026-07-09T01:18:22Z (3 months ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 01:07:32 UT on 9 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260709A (trigger 805252057.543312 / 260709047).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 84.1, Dec = 74.0 (J2000 degrees, equivalent to J2000 05h 36m, 74d 00'), with a statistical uncertainty of 4.0 degrees.
The angle from the Fermi LAT boresight is 106.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260709047/quicklook/glg_skymap_all_bn260709047.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260709047/quicklook/glg_healpix_all_bn260709047.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260709047/quicklook/glg_lc_medres34_bn260709047.gif