GRB 260223A
GCN Circular 43871
Subject
GRID detection of GRB 260223A
Date
2026-02-28T04:46:33Z (20 days ago)
From
GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn>
Via
Web form
GRID detection of GRB 260223A
Longhao Li, Xinyu Liu, Chenyu Wang report on behalf of the GRID Collaboration:
GRID-11B reports the detection of the long-duration GRB 260223A, which was also detected by Fermi GBM (GCN Circular 43808), MASTER-OAFA (GCN Circular 43809), BALROG (GCN Circular 43810), DDOTI (GCN Circular 43811), COLIBRÍ(GCN Circular 43812), SVOM (GCN Circular 43815), Glowbug (GCN Circular 43824)
The event was triggered with GRID on 2026-02-23 at 04:11:09 UTC. The measured burst duration (T90) in the 30-2000 keV range is approximately 22.2 +/- 3.0 seconds.
The GRID light curve of this event can be found at GRID_GRB260223A_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 the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4.
GCN Circular 43863
Subject
GRB 260223A: 7DT detection and Medium-band SED of Afterglow
Date
2026-02-27T12:05:22Z (20 days ago)
From
YoungPyo Hong at Seoul National University <evan77333@gmail.com>
Via
Web form
YoungPyo Hong (SNU ARC/SNU), Myungshin Im (SNU ARC/SNU), Donggeun Tak (SNU ARC/SNU), Hyeonho Choi (SNU ARC/SNU), Donghwan Hyun (SNU ARC/SNU), Gregory S.H. Paek (IfA, SNU ARC/SNU), Seo-Won Chang (SNU ARC/SNU), Ji Hoon Kim (SNU ARC/SNU), and Won-Hyeong Lee (SNU ARC/SNU), report on behalf of the 7 Dimensional Telescope (7DT) team:
We report optical follow-up observations of GRB26023A (GCN 43808; GCN 43809), conducted with the 7-Dimensional Telescope (7DT), located in Chile.
The 7DT follow-up began at 04:44:14 UTC on 2026-02-23, corresponding to T0 + 33 minutes, pointing to a region covering the target localization provided by Fermi (GCN 43808) at RA, DEC = 110.5 deg, -29.4 deg with an uncertainty of 1.7 degree.
Initial observations were made with 15, units in 19 medium-band filters as well as r-band filters (20 filters in total).
The following table summarizes the observations and the derived 5-sigma upper limits:
Filter Mag Mag_err Exposure Date Time
----------------------------------------------------------------------------------------------------
r 19.05 0.08 300.0 2026-02-23T04:49:44.000
m400 >19.02 N/A 300.0 2026-02-23T04:44:14.000
m425 19.28 0.16 300.0 2026-02-23T04:44:31.667
m450 19.48 0.24 300.0 2026-02-23T04:44:16.667
m475 18.97 0.12 300.0 2026-02-23T04:44:15.000
m500 19.62 0.27 300.0 2026-02-23T04:44:20.667
m525 19.48 0.24 300.0 2026-02-23T04:44:23.000
m550 >19.29 N/A 300.0 2026-02-23T04:49:38.000
m575 18.95 0.14 300.0 2026-02-23T04:51:58.000
m600 18.92 0.20 300.0 2026-02-23T04:49:39.333
m625 18.79 0.22 300.0 2026-02-23T04:49:37.000
m650 18.66 0.22 300.0 2026-02-23T04:44:38.000
m675 >18.95 N/A 300.0 2026-02-23T04:44:23.000
m700 18.13 0.18 300.0 2026-02-23T04:44:18.000
m725 >18.46 N/A 300.0 2026-02-23T04:44:23.000
m750 18.23 0.22 300.0 2026-02-23T04:44:20.667
m775 17.99 0.31 300.0 2026-02-23T04:44:43.333
m800 >17.52 N/A 300.0 2026-02-23T04:44:21.667
m825 >17.41 N/A 300.0 2026-02-23T04:44:21.333
m850 >17.05 N/A 300.0 2026-02-23T04:44:21.000
----------------------------------------------------------------------------------------------------
* Upper limits (marked with '>') are 5-sigma limits
The optical counterpart was detected in most filters.
Photometric flux calibration was performed using synthetic photometry based on the Gaia DR3 XP catalog (Gaia Collaboration et al. 2022) within the AB magnitude system. Note that no extinction correction has been applied.
The 7-Dimensional Telescope (7DT), located in Chile and comprising 20 wide-field telescopes equipped with 40 medium-bandwidth (~25nm) filters, aims to detect optical counterparts of GW sources and conduct the 7-Dimensional Sky Survey (7DS) of the Southern Hemisphere. Further information about the 7DT is available at https://7ds.snu.ac.kr/ and http://gwuniverse.snu.ac.kr/.
GCN Circular 43835
Subject
GRB 260223A: Fermi GBM Observation
Date
2026-02-25T17:16:57Z (22 days ago)
From
Peter Veres at University of Alabama in Huntsville <veresp@gmail.com>
Via
Web form
P. Veres (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 04:11:09.81 UT on 23 February 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 260223A (trigger 793512674/260223174),
which was also detected by
DDOTI (Becerra et al. 2026, GCN 43811),
COLIBRI (de Ugarte Postigo et al. 2026, GCNs 43812, 43814 & 43820),
SVOM/GRM (Wang et al. 2026, GCN 43815),
SVOM/VT (Li et al. 2026, GCN 43816) and
Glowbug (Woolf et al. 2026, GCN 43824).
The Fermi GBM on-ground location (GCN 43808) is consistent with the DDOTI position.
The angle from the Fermi LAT boresight is 33 degrees.
The GBM light curve consists of a single emission episode with a duration (T90)
of about 39 s (50-300 keV). The time-averaged spectrum
from T0-9.2 to T0+51.2 s is best fit by
a Band function with Epeak = 70 +/- 6 keV,
alpha = -0.76 +/- 0.09, and beta = -1.91 +/- 0.02.
The event fluence (10-1000 keV) in this time interval is
(2.16 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+18 s in the 10-1000 keV band is 10.4 +/- 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 43824
Subject
GRB 260223A: Glowbug gamma-ray detection
Date
2026-02-25T05:26:59Z (22 days ago)
From
Richard S. Woolf at US Naval Research Laboratory <richard.s.woolf.civ@us.navy.mil>
Via
Web form
R. Woolf, C.C. Cheung, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 260223A, which was also detected by Fermi GBM (GCN 43808) and SVOM/GRM (GCN 43815).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-02-23 04:11:09.520 with a duration of 20.5 s and a total significance of about 48.4 sigma. Following the initial event onset, the light curve comprises two main peaks at ~T0+11s and +18s. Note that data from ~T0+15s to T0+17s suffered from deadtime in various detectors.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108
Distribution Statement A: Approved for public release. Distribution is unlimited.
GCN Circular 43820
Subject
GRB 260223A: COLIBRÍ optical afterglow decay confirmation
Date
2026-02-24T09:24:20Z (23 days ago)
From
Antonio de Ugarte Postigo at LAM, CNRS <adeugartepostigo@gmail.com>
Via
email
Antonio de Ugarte Postigo (LAM), Fredd Sánchez Álvarez (UNAM), Alan M. Watson (UNAM), Rosa L. Becerra (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Edilberto Aguilar-Ruiz (UNAM), Dalya Akl (NYUAD), Camila Angulo (UNAM), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Nikos Mandarakas (LAM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), and Benjamin Schneider (LAM) report:
We continued to observe the field of the Fermi GRB 260223A (Fermi GBM team et al., GCN Circ. 43808) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed in two epochs between 2026-02-24 02:23:16 and 07:15:39 UTC (between 22.20 and 27.07 hours after the trigger) obtaining images in the grizy filters on the first and rz on the second.
The data were reduced, coadded, calibrated, and analysed with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR2, is in the AB system, and is not corrected for Galactic extinction.
The optical counterpart reported by Becerra et al. (GCN Circ. 43811) and confirmed by our earlier observations (de Ugarte Postigo et al. GCN Circ 43812) has decayed after the early rebrightnening (de Ugarte Postigo et al. GCN Circ 43814). On our latest stack, we detect the afterglow of GRB 260223A at r = 20.93 +/- 0.07 mag. Between our last observation obtained yesterday and today’s observations, we measure a decay slope of alpha ~ -1.1 (where F_nu ~ t ^ alpha). This is consistent with the observations obtained by SVOM/VT a few hours before (Li et al. GCN Circ. 43816) and serves to confirm that this object is indeed the afterglow of GRB 260223A.
We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams.
COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico.
GCN Circular 43816
Subject
GRB 260223A: SVOM/VT optical observation
Date
2026-02-24T03:00:50Z (24 days ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, Y. N. Ma, L. P. Xin, Y. L. Qiu, C. Wu, Z. H. Yao, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. R. Xu, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA) report on behalf of the SVOM/VT team.
SVOM/VT performed a Target of Opportunity observation of GRB 260223A detected by Fermi (Fermi GBM team et al., GCN 43808; Preis et al., GCN 43810) and SVOM/GRM (sb26022301, Wang et al., GCN 43815). The observation started on 2026-02-23T15:26:24 UTC, i.e. about 11.26 hours after the trigger time of GBM, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
The optical counterpart (Becerra et al., GCN 43811; Postigo et al., GCN 43812; Postigo et al., GCN 43814) were detected in both channels. The measurements in AB magnitude are derived as follows:
Mid time | Band | Exposure Time | Magnitude (AB)
14.893 hours VT_R 27*70 sec 19.66 +/- 0.06 mag
14.864 hours VT_B 28*70 sec 20.50 +/- 0.08 mag
The counterpart showed a power-law decay with the index of -1.1 during our observation from 11.40 hours to 15.14 hours.
Our photometry was not corrected for Galactic extinction.
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.
GCN Circular 43815
Subject
GRB 260223A: SVOM/GRM observation
Date
2026-02-23T17:10:56Z (24 days ago)
From
Chenwei Wang at IHEP <cwwang@ihep.ac.cn>
Via
Web form
SVOM/GRM team: Yue Wang, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Nicolas Dagoneau (CEA)
Report on behalf of the SVOM team:
SVOM/GRM was triggered in-flight by GRB 260223A (SVOM trigger reference: sb26022301) at 2026-02-23T04:11:28.000 (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #43808).
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple pulses with a T90 of 26 +8/-4 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb260223A.png
In addition, the position of this burst, as determined by Fermi/GBM (RA = 110.5, Dec = -29.4, Error = 1.7, GCN #43808), is located at about 96 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. ECLAIRs was not collecting data at the time of this burst.
With this localization, the time-averaged spectrum from T0-23 to T0+15 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.29 +0.10/-0.11 and the cutoff energy, parameterized as Epeak, is 194 +33/-25 keV. The event fluence (10-1000 keV) in this time interval is (2.27 +0.13/-0.13)E-05 erg/cm^2.
The 1s peak spectrum, measured from T0-0 to T0+1 s, if fitted by a power law function with an exponential high-energy cutoff, the power law index is -1.39 +0.10/-0.11 and the cutoff energy, parameterized as Epeak, is 741 +456/-228 keV. The flux (10-1000 keV) in this time interval is (3.03 +0.18/-0.18)E-06 erg/cm^2/s.
The localization of GRB 260223A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb260223A_amati.png
The localization of GRB 260223A in the 'Yonetoku' relation diagram is shown at:
https://www.bursthub.cn//admin/static/svgrb260223A_yonetoku.png
The SVOM/VT ToO has been performed.
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: Yue Wang (IHEP) (yuewang@ihep.ac.cn)
GCN Circular 43814
Subject
GRB 260223A: COLIBRÍ further optical observations and a brightening
Date
2026-02-23T14:15:07Z (24 days ago)
From
Alan Watson at UNAM <alan@astro.unam.mx>
Via
Web form
Antonio de Ugarte Postigo (LAM), Leonardo García García (UNAM), Rosa L. Becerra (UNAM), Jean-Grégoire Ducoin (CPPM), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Edilberto Aguilar-Ruiz (UNAM), Dalya Akl (NYUAD), Camila Angulo (UNAM), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), and Benjamin Schneider (LAM) report:
We continued to observe the field of the Fermi GRB 260223A (Fermi GBM team et al., GCN Circ. 43808) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-02-23 06:16 to 07:48 UTC (from 2.08 to 3.67 hours after the trigger) and obtained near-continuous, alternating 60-second exposures in the grizy filters.
The data were reduced, coadded, calibrated, and analysed with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR2, is in the AB system, and is not corrected for Galactic extinction (A_V = 0.68, Schlafly et al. 2011).
The optical counterpart reported by Becerra et al. (GCN Circ. 43811) and confirmed by our earlier observations (de Ugarte Postiga et al. GCN Circ 43812) is observed to brighten continuously during our extended observations, rising from i = 18.55 at the start of our observations to i = 18.15 at the end. Similar behaviour is seen in the other bands.
We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams.
COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico.
GCN Circular 43812
Subject
GRB 260223A: COLIBRÍ optical observations
Date
2026-02-23T08:22:07Z (24 days ago)
From
Antonio de Ugarte Postigo at LAM, CNRS <adeugartepostigo@gmail.com>
Via
email
Antonio de Ugarte Postigo (LAM), Leonardo García García (UNAM), Rosa L. Becerra (UNAM), Jean-Grégoire Ducoin (CPPM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), and Benjamin Schneider (LAM) report:
We imaged the field of the Fermi GRB 260223A (Fermi GBM team et al., GCN Circ. 43808) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-02-23 06:16:02 to 06:26:30 UTC (from 2.081 to 2.256 hours after the trigger) and obtained 3x60 s of simultaneous exposure in the grizy filters.
The data were reduced, coadded and analysed with the COLIBRÍ pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR2, is in the AB system, and is not corrected for Galactic extinction (A_V = 0.68, Schlafly et al. 2011).
We detected the optical counterpart reported by Becerra et al., GCN Circ. 43811, at preliminary magnitudes of:
g = 19.44 +/- 0.06
r = 18.92 +/- 0.04
i = 18.52 +/- 0.05
z = 18.27 +/- 0.04
y = 18.23 +/- 0.07
Further observations are ongoing.
We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams.
COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico.
GCN Circular 43811
Subject
GRB 260223A: DDOTI Optical Candidate
Date
2026-02-23T05:44:22Z (24 days ago)
From
Rosa Leticia Becerra Godínez at Instituto de Astronomía, UNAM <rbecerra@astro.unam.mx>
Via
Web form
Rosa L. Becerra (UNAM), Alan M. Watson (UNAM), Camila Angulo Valdez (UNAM), Nat Butler (ASU), Simone Dichiara (Penn State University), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl López (UNAM), Margarita Pereyra (UNAM) and Eleonora Troja (U Roma) report:
We observe the field of GRB 260223A (Fermi Team, GCN Circ. 43808) with the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir (http://ddoti.astroscu.unam.mx) on the night of 2026-02-23 UTC. DDOTI observed from 04:26 UTC to 04:36 UTC (T+14.9 minutes to T+25.3 minutes after the trigger), with a total exposure time of 8 minutes.
Comparing our observations with the USNO-B1 and Pan-STARRS PS1 DR2 catalogues, we detect an uncatalogued fading source at:
RA = 07:24:21.20 (111.0883 deg)
DEC = -29:25:04.4 (-29.4179 deg)
at a preliminary AB magnitude of:
w = 18.30 +/- 0.13
at T + 14.9 minutes. From our observations, we estimate a temporal decay of approximately −0.6. We suggest that this source is the optical counterpart of GRB 260223A and encourage follow-up observations.
We thank the staff of the Observatorio Astronómico Nacional on the Sierra of San Pedro Mártir.
GCN Circular 43810
Subject
GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
Date
2026-02-23T05:37:50Z (24 days ago)
From
Jochen Greiner at MPE <jcgrog@mpe.mpg.de>
Via
email
T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
793512674 at 04:11:09 on 23 Feb. 2026 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position is:
RA(2000.0) = 109.5 deg
Decl.(2000.0) = -28.9 deg
The 1 sigma statistical error radius is 1.7 deg.
We estimate an additional systematic error of 1 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB260223174/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB260223174/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB260223174/json
GCN Circular 43809
Subject
Fermi GRB 260223A: Global MASTER-Net observations report
Date
2026-02-23T05:15:25Z (24 days 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260223A ( Fermi GBM team, GCN 43808) errorbox 123 sec after notice time and 154 sec after trigger time at 2026-02-23 04:13:44 UT, with upper limit up to 19.8 mag. The observations began at zenith distance = 32 deg. The sun altitude is -48.2 deg.
The galactic latitude b = -7 deg., longitude l = 243 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3152151
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
170 | 2026-02-23 04:13:44 | MASTER-OAFA | (07h 21m 14.73s , -29d 00m 58.9s) | C | 30 | 19.3 |
210 | 2026-02-23 04:14:20 | MASTER-OAFA | (07h 21m 14.73s , -29d 00m 58.0s) | C | 40 | 19.5 |
262 | 2026-02-23 04:15:07 | MASTER-OAFA | (07h 21m 14.77s , -29d 00m 57.4s) | C | 50 | 19.6 |
324 | 2026-02-23 04:16:03 | MASTER-OAFA | (07h 21m 14.79s , -29d 00m 56.9s) | C | 60 | 18.9 |
395 | 2026-02-23 04:17:09 | MASTER-OAFA | (07h 21m 14.83s , -29d 00m 56.3s) | C | 70 | 19.8 |
603 | 2026-02-23 04:20:17 | MASTER-OAFA | (07h 22m 38.12s , -29d 04m 33.0s) | C | 110 | 19.3 |
730 | 2026-02-23 04:22:15 | MASTER-OAFA | (07h 22m 38.17s , -29d 04m 33.2s) | C | 130 | 19.4 |
882 | 2026-02-23 04:24:31 | MASTER-OAFA | (07h 22m 38.28s , -29d 04m 33.1s) | C | 160 | 19.5 |
998 | 2026-02-23 04:27:17 | MASTER-OAFA | (07h 22m 38.38s , -29d 04m 32.8s) | C | 60 | 18.9 |
1063 | 2026-02-23 04:28:23 | MASTER-OAFA | (07h 22m 38.43s , -29d 04m 32.7s) | C | 60 | 19.2 |
1129 | 2026-02-23 04:29:29 | MASTER-OAFA | (07h 22m 38.49s , -29d 04m 32.7s) | C | 60 | 19.1 |
1196 | 2026-02-23 04:30:35 | MASTER-OAFA | (07h 22m 38.53s , -29d 04m 32.7s) | C | 60 | 19.1 |
1261 | 2026-02-23 04:31:40 | MASTER-OAFA | (07h 22m 38.57s , -29d 04m 32.8s) | C | 60 | 18.9 |
1326 | 2026-02-23 04:32:46 | MASTER-OAFA | (07h 22m 38.61s , -29d 04m 33.1s) | C | 60 | 18.9 |
1393 | 2026-02-23 04:33:52 | MASTER-OAFA | (07h 22m 38.66s , -29d 04m 33.1s) | C | 60 | 19.0 |
1458 | 2026-02-23 04:34:58 | MASTER-OAFA | (07h 22m 38.71s , -29d 04m 33.0s) | C | 60 | 18.8 |
1524 | 2026-02-23 04:36:04 | MASTER-OAFA | (07h 22m 38.76s , -29d 04m 33.3s) | C | 60 | 19.2 |
1591 | 2026-02-23 04:37:10 | MASTER-OAFA | (07h 22m 38.81s , -29d 04m 33.5s) | C | 60 | 19.2 |
1656 | 2026-02-23 04:38:15 | MASTER-OAFA | (07h 22m 38.85s , -29d 04m 33.5s) | C | 60 | 19.2 |
1721 | 2026-02-23 04:39:21 | MASTER-OAFA | (07h 22m 38.89s , -29d 04m 33.7s) | C | 60 | 19.1 |
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 43808
Subject
GRB 260223A: Fermi GBM Final Real-time Localization
Date
2026-02-23T04:20:24Z (25 days 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 04:11:09 UT on 23 Feb 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260223A (trigger 793512674.810552 / 260223174).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 110.5, Dec = -29.4 (J2000 degrees, equivalent to J2000 07h 21m, -29d 23'), with a statistical uncertainty of 1.7 degrees.
The angle from the Fermi LAT boresight is 33.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260223174/quicklook/glg_skymap_all_bn260223174.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/bn260223174/quicklook/glg_healpix_all_bn260223174.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260223174/quicklook/glg_lc_medres34_bn260223174.gif