GRB 260207B
GCN Circular 43712
Subject
Konus-Wind detection of GRB 260207B
Date
2026-02-12T14:06:38Z (4 months ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
A. Tsvetkova, M. Ulanov, and T. Cline
on behalf of the Konus-Wind team, report:
The short-duration GRB with extended emission (EE) GRB 260207B
(Fermi-GBM detection: Fermi GBM team, GCN 43629;
Sonawane & Bala, GCN 43634;
GECAM-B detection: Zao et al., GCN 43644;
AstroSat-CZTI detection: Goyal et al., GCN 43680;
IPN triangulation: Kozyrev et al., GCN 43691;
GRID detection: Zeng et al., GCN 43710)
triggered Konus-Wind at T0=47529.467 s UT (13:12:09.467).
The burst light curve shows a short initial pulse,
which starts at ~T0-40 ms and has a duration of ~220 ms.
The initial pulse is followed by a weaker extended emission (EE),
starting at ~T0+9 s, peaking at ~T0+43 s, and lasting up to ~T0+95 s.
The emission in the initial pulse is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB260207_T47529/
As observed by Konus-Wind, the initial pulse
had the fluence of 2.66(-0.19,+0.20)x10^-6 erg/cm2,
and the 16-ms peak flux, measured from T0+0.104 s,
of 4.41(-0.54,+0.58)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the initial pulse
(measured from T0 to T0+0.192 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.99(-0.08,+0.08)
and Ep = 495(-60,+72) keV (chi2 = 44/43 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.1
(chi2 = 44/42 dof).
The time-averaged spectrum of the EE
(measured from T0+8.448 s to T0+73.984 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
with alpha = -1.67(-0.21,+0.24)
and Ep = 44 (-19,+11) keV (chi2 = 93/98 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.0
(chi2 = 93/97 dof).
From this spectrum, the total EE fluence is 5.02(-0.4,+0.4)x10^-6 erg/cm2,
a factor of ~2 higher than that of the initial pulse.
All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.
GCN Circular 43710
Subject
GRID detection of GRB 260207B
Date
2026-02-12T08:33:36Z (4 months ago)
Edited On
2026-02-12T13:48:02Z (4 months ago)
From
GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn>
Via
Web form
Ming Zeng, Chenyu Wang, Longhao Li, Zirui Yang report on behalf of the GRID Collaboration:
GRID reports the detection of GRB 260207B, which was also observed by Fermi-GBM (Fermi GBM team, GCN 43629; Sonawane & Bala, GCN 43634), GECAM-B (Zao et al., GCN 43644), and AstroSat CZTI (Goyal et al., GCN 43680).
The event triggered GRID-09B, GRID-10B, and GRID-11B at T0 = 2026-02-07 13:12:10 UTC. This burst was simultaneously detected by three GRID nanosatellites, marking the first event jointly observed by three GRID satellites.
Temporal analysis of the main emission yields a duration of T90 = 0.42 ± 0.08 s in the 30–2000 keV energy range. Although extended emission appears to be present, the limited sensitivity of GRID does not allow for a detailed characterization of this component. At the trigger time, GRID-10B was operating in 1 s bin mode, which prevents a refined localization. Nevertheless, the reconstructed direction is consistent with the position reported by Fermi-GBM.
At present, only the GRID light curve is available. Spectral analysis is not yet reported. The GRID light curve of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB260207B/GRID_GRB260207B_ltcv.pdf
GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to: https://doi.org/10.1007/s10686-019-09636-w, https://doi.org/10.1007/s10686-021-09819-4.
GCN Circular 43691
Subject
IPN triangulation of GRB 260207B (short/hard with EE)
Date
2026-02-10T20:33:53Z (4 months ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
Via
Web form
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars Odyssey team,
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
and
W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:
The short-duration GRB with extended emission GRB 260207B
(Fermi-GBM detection: Fermi GBM team, GCN 43629;
Sonawane & Bala, GCN 43634;
GECAM-B observation: Zao et al., GCN 43644;
AstroSat CZTI detection: Goyal et al., GCN 43680)
was detected by Fermi (GBM trigger 792162735),
Konus-Wind, GECAM-B, AstroSat (CZTI), and
Mars-Odyssey (HEND) at about 47531 s UT (13:12:11).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
283.695 (18h 54m 47s) +51.643 (+51d 38' 34")
Corners:
284.134 (18h 56m 32s) +51.778 (+51d 46' 39")
283.959 (18h 55m 50s) +51.758 (+51d 45' 29")
283.258 (18h 53m 02s) +51.506 (+51d 30' 22")
283.432 (18h 53m 44s) +51.527 (+51d 31' 36")
---------------------------------------------
The error box area is 67 sq. arcmin, and its maximum
dimension is 36 arcmin (the minimum one is 2 arcmin).
The Sun distance was 74 deg.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB260207_T47529/IPN
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.
The Konus-Wind time history and spectrum will be given
in a forthcoming GCN Circular.
GCN Circular 43680
Subject
GRB 260207B: AstroSat CZTI detection
Date
2026-02-10T11:47:42Z (4 months ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
Web form
A. Goyal (IITB), A. Arya (IITB), S. Salunke (IUCAA), Harsha K. H. (IUCAA), M. Tembhurnikar (IUCAA), 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 short GRB 260207B which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 43629) and GECAM (Zao et. al., GCN Circ. 43644).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2026-02-07 13:12:07 UTC. The measured peak count rate associated with the burst is 1402 (+767, -219) counts/s above the background in the combined data of all four quadrants, with a total of 82 (+26, -21) counts. The local mean background count rate was 269 (+12, -45) counts/s. Using cumulative rates, we measure a T90 of 0.09 (+0.06, -0.03) s. We only observed the main emission (ME) part of the burst.
The source was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-02-07 13:12:07 UTC. The measured peak count rate associated with the burst is 446 (+68, -75) counts/s above the background in the combined data of all quadrants, with a total of 630 (+143, -162) counts. The local mean background count rate was 1340 (+7, -8) counts/s. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 for our detection.
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 43644
Subject
GRB 260207B: GECAM-B observation
Date
2026-02-08T14:58:40Z (4 months ago)
From
xueyuan zao <zaoxueyuan@gmail.com>
Via
Web form
Xue-Yuan Zao, Xing-Hao Luo, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered in-flight and on-ground by GRB 260207B, at 2026-02-07T13:12:10.850 UTC, which is also detected by Fermi/GBM (Fermi GBM team, GCN #43629).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of a short spike (Main Emission, ME) followed by an extended emission (EE) with a total duration (T90) of 65 +23/-9.5 s.
The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb260207B.png
The ME from T0 - 0.07 to T0 + 0.19 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.15 +0.29/-0.32 and the cutoff energy, parameterized as Epeak, is 345 +151/-70 keV. The event fluence (10-1000 keV) in this time interval is (2.04 +/-0.22)E-06 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 43634
Subject
GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission
Date
2026-02-08T04:24:37Z (4 months ago)
From
Rushikesh Sonawane at IISER, TVM <rushikesh23@iisertvm.ac.in>
Via
Web form
R. Sonawane (IISER, TVM) and S. Bala (USRA) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 13:12:10.83 UT on 07 February 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 260207B (trigger 792162735/260207550).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 292.87, Dec = 50.03 (J2000 degrees, equivalent to
J2000 19h 31m, +50d 1'), with a statistical uncertainty of 2.81 degrees.
(radius, 1-sigma containment, statistical only; there is additionally a
systematic error which we have characterized as a mixture of two Gaussians,
one with a radius of 1.8 degrees (52% contribution) and one with a radius
of 4.1 degrees (47% contribution) [A. Goldstein et al. 2020, ApJ, 895, 1]).
The angle from the Fermi LAT boresight is 45 degrees.
The GBM light curve consists of a short spike (Main Emission, ME)
followed by an extended emission (EE) with a total duration (T90) of about 56 s (50-300 keV).
The ME from T0-1 to T0+5 s is best fit by a power law function with an
exponential high-energy cutoff. The power law index is -1.18 +/- 0.07 and the
cutoff energy, parameterized as Epeak, is 350 +/- 65 keV. The total fluence (10-1000 keV)
in this time interval is (2.7 +/- 0.1)E-06 erg/cm^2.
The EE from T0+10 to T0+89 s, is best fit by a Band function with
Epeak= 32 +/- 4 keV, alpha = -1.7 +/- 0.1 and beta = -2.4 +/- 0.1.
The total fluence (10-1000 keV) during this time interval is (7.5 +/- 0.4)E-06 erg/cm^2.
The time-averaged (ME+EE) spectrum from T0-2 to T0+89 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.83 +/- 0.05 and the cutoff energy,
parameterized as Epeak, is 67 +/- 9 keV. A Band function fits this interval equally
well with Epeak= 52 +/- 10 keV, alpha = -1.7 +/- 0.1 and beta = -2.2 +/- 0.1.
The event fluence (10-1000 keV) in this time interval is (9.6 +/- 0.5)E-06 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+0.0024 s in the 10-1000 keV band
is 16.6 +/- 0.3 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/"
GCN Circular 43631
Subject
Fermi GRB 260207B: Global MASTER-Net observations report
Date
2026-02-07T15:30:40Z (4 months ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko,
G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU),
O.Gress, N.Budnev (ISU),
C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A.Sosnovskij (CrAO),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity),
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 260207B ( Fermi GBM team, GCN 43629) errorbox 7553 sec after notice time and 7584 sec after trigger time at 2026-02-07 15:18:35 UT, with upper limit up to 13.0 mag. Observations started at twilight. The observations began at zenith distance = 74 deg. The sun altitude is -9.3 deg.
The galactic latitude b = 14 deg., longitude l = 82 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3125301
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
7614 | 2026-02-07 15:18:35 | MASTER-Kislovodsk | (19h 15m 56.41s , +48d 54m 29.6s) | C | 60 | 13.0 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
[1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.
http : // www.pereplet.ru/lipunov/625.html
GCN Circular 43629
Subject
GRB 260207B: Fermi GBM Final Real-time Localization
Date
2026-02-07T13:22:56Z (4 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 13:12:10 UT on 7 Feb 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260207B (trigger 792162735.829288 / 260207550).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 292.9, Dec = 50.0 (J2000 degrees, equivalent to J2000 19h 31m, 50d 00'), with a statistical uncertainty of 2.8 degrees.
The angle from the Fermi LAT boresight is 45.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260207550/quicklook/glg_skymap_all_bn260207550.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/bn260207550/quicklook/glg_healpix_all_bn260207550.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260207550/quicklook/glg_lc_medres34_bn260207550.gif