GRB 260710A — All Circulars

SVOM/GRM team: Xue-Yuan Zao, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)

SVOM/ECLAIRs team: Olivier Godet, Sebastien Guillot (IRAP)

Report on behalf of the SVOM team:

SVOM/GRM was triggered on-ground and in-flight by GRB 260710A at 2026-07-10T12:58:43.450 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45131 and M. Dafcikova et al., GCN #45138).

With the event-by-event data downloaded through the X-band ground station, we conducted the standard analysis pipeline of GRB 260710A. The GRM light curve shows that this burst consists of a single pulse with a T90 of 2.60 +1.00/-0.60 s in the 15-5000 keV band. 

The SVOM/GRM light curve can be found here：
https://www.bursthub.cn/gcn/2026/svgrb260710A.png

In addition, the position of this burst, as determined by Fermi/GBM (RA= 5.6, DEC=-85.0, ERR= 1.8 degrees, GCN #45131), is located at about 60 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view.

With this localization, the time-averaged spectrum from T0-0.25 to T0+2.75 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.27 +/-0.12 and the cutoff energy, parameterized as Epeak, is 161 +41/-25 keV. The event fluence (10-1000 keV) in this time interval is (2.26 +0.21/-0.17) E-06- erg/cm^2. 

The 1s peak spectrum, measured from T0-0.05 to T0+0.95 s, is also fitted by a power law function with an exponential high-energy cutoff, the power law index is -0.91 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 153 +16/-12 keV. The flux (10-1000 keV) in this time interval is (1.74 +0.09/-0.08) E-06 erg/cm^2/s.

The localization of GRB 260710A in the 'Amati' relation diagram is shown at: 
https://www.bursthub.cn/gcn/2026/svgrb260710A_amati.png

The localization of GRB 260710A in the 'Yonetoku' relation diagram is shown at: 
https://www.bursthub.cn/gcn/2026/svgrb260710A_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/GRM point of contact for this burst is: Xue-Yuan Zao (IHEP) (zaoxy@ihep.ac.cn)

A. Arya (IITB), A. Goyal (IITB), S. Salunke(IUCAA), Harsha K. H. (IUCAA), G. Waratkar (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 short duration GRB 260710A which was also detected by Fermi (Fermi GBM team, GCN Circ. 45131), and Insight-HXMT/HE (Xing-Hao Luo et.al., GCN Circ. 45144).

The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-07-10 12:58:43.56 UTC. The measured peak count rate associated with the burst is 331 (+50, -55) counts/s above the background in the combined data of all quadrants, with a total of 426 (+150, -166) counts. The local mean background count rate was 616 (+6, -6) counts/s. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 for our detection.

The source was also faintly detected in the CZT detectors in the 20-200 keV energy range. 

CZTI data products like interactive and downloadable light curves for this GRB can be found at:https://astrosat.iucaa.in/cift/cift_products/ET20260710T125843/ET20260710T125843_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

Xing-Hao Luo, Chen-Wei Wang, Chao Zheng, and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team:

At 2026-07-10T12:56:43.800 (T0), Insight-HXMT/HE detected the GRB 260710A, which is also detected by Fermi/GBM (Fermi GBM Team, GCN #45131).
	
The Insight-HXMT/HE light curve mainly consists of a single pulse with a T90 of 1.2 +1.2/-0.4 s. The 1s peak rate, measured from T0-0.3 s, is 727 cnts/sec. Insight-HXMT/HE detected a total of 841 counts from this burst.

The HXMT/HE light curve can be found here:
https://www.bursthub.cn/gcn/2026/hxmtgrb260710A.png

All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://hxmten.ihep.ac.cn/

M. Dafcikova (MUNI) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 12:58:43.52 UT on 10 July 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 260710A (trigger 805381128/260710541).
The Final real-time localization was reported in GCN 45131.

The GBM light curve consists of a single peak with a duration (T90)
of about 1.9 s (50-300 keV). The time-averaged spectrum
from T0-0.16 to T0+1.94 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.93 +/- 0.03 and the cutoff energy,
parameterized as Epeak, is 139 +/- 3 keV.

The event fluence (10-1000 keV) in this time interval is
(2.17 +/- 0.09)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.38 s in the 10-1000 keV band is 30 +/- 3 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 98 +/- 3 keV, alpha = -0.71 +/- 0.02 and beta = -2.00 +/- 0.07.

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/"

The Fermi GBM team reports the detection of a likely LONG GRB

At 12:58:43 UT on 10 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260710A (trigger 805381128.521136 / 260710541).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 5.6, Dec = -85.0 (J2000 degrees, equivalent to J2000 00h 22m, -85d 00'), with a statistical uncertainty of 1.8 degrees.

The angle from the Fermi LAT boresight is 135.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260710541/quicklook/glg_skymap_all_bn260710541.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/bn260710541/quicklook/glg_healpix_all_bn260710541.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260710541/quicklook/glg_lc_medres34_bn260710541.gif