GRB 260822A
GCN Circular 45444
Subject
GRB 260822A: SVOM/ECLAIRs refined analysis
Date
2026-08-26T08:53:15Z (7 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
H. Yang, O. Godet, S. Guillot (IRAP), S. Schanne, D. Turpin, D. Götz (CEA/Irfu)
report on behalf of the SVOM/ECLAIRs team:
Using the event-by-event data downloaded through the X-band ground station, we report further analysis of SVOM/ECLAIRs observations of the short burst GRB 260822A (SVOM burst-id sb26082201, GCN 45422, trigger time T0 = 2026-08-22T16:50:36.0 UTC).
The ECLAIRs lightcurve shows a multi-peaked structure, with T90(4-120 keV) = 0.18 +/- 0.05 s. No obvious extended emission has been detected.
The time-averaged spectrum from T0+ 0.637 s to T0 + 0.817 s in the 5-120 keV range, is well fitted by a power-law model with a photon index of -1.0 +/-0.1, a 4-120 keV photon flux of (6.9 +0.3/-1.4) photons/cm^2/s, and a corresponding 4-120 keV fluence of (6.5 +/-0.9)e-8 erg/cm^2.
All the quoted errors are at the 68% confidence level.
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. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC.
The SVOM/ECLAIRs point of contact for this burst is: Hui Yang (IRAP) (hui.yang@cnrs.fr).
GCN Circular 45442
Subject
GRB 260822A: SVOM/VT optical upper limits
Date
2026-08-25T18:13:04Z (8 days ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, L. P. Xin, C. Wu, Y. N. Ma, Y. L. Qiu, Z. H. Yao, J. R. Xu, 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) and J. T. Palmerio (CEA/Irfu) report on behalf of the SVOM/VT team.
SVOM/VT performed two additional ToO observations of GRB 260822A (sb26082201, Schanne et al., GCN 45422) at mid-times of 18.9 h and 23.8 h in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously.
No credible candidate was found in the stacked images of each epoch from both the earlier VT observations (Li et al., GCN 45430) and the present ToO observations, within the SVOM/ECLAIRs error box (Schanne et al., GCN 45422) and the Einstein Probe positions (Turpin et al., GCN 45436).
The typical 5-sigma upper limits are 23.0 mag in both channels. Our measurements are in AB magnitudes and are not corrected for Galactic extinction.
This non-detection is consistent with the reports from GOTO (O'Neill et al., GCN 45423), GROWTH-India (Saikia et al., GCN 45424), LCO (Turpin et al., GCN 45427) and PRIME (Durbak et al., GCN 45437).
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 45437
Subject
GRB 260822A: PRIME near-infrared upper limits from multiple epochs
Date
2026-08-25T05:45:24Z (8 days ago)
From
Joe Durbak at UMD <gcn.joedurbak@gmail.com>
Via
Web form
J. Durbak (UMD, NASA GSFC), O. Guiffreda (UMD, NASA GSFC), F. McDaniel (UMD, NASA GSFC), R. Hamada (UOsaka), N. Passaleva (U Rome), M. El Kabir (U Rome), E. Troja (U Rome), A. S. Kutyrev (NASA/GSFC), S. B. Cenko (NASA/GSFC)
Following the SVOM (GCN 45422) detection, we observed the transient field in J and H-filters with PRIME starting ~5.5 hours and ~30 hours after SVOM detection.
Within the localization region reported by SVOM (GCN 45422) and the regions of interest reported by Einstein Probe (GCN 45436), we find no significant varying sources during the 24 hour period between follow-up observations. The limiting magnitudes (SNR>6) for each filter and epoch are given below using Vista Hemispherical Survey (VHS) and UKIRT Infrared Deep Sky Survey Large Area Survey (UKIDSS LAS) stars for calibration.
| Epoch | Filter | Mag(AB) | Calibration Survey |
|---|---|---|---|
| 1 | J | > 21.4 | VHS |
| 1 | H | > 21.2 | UKIDSS LAS |
| 2 | J | > 21.7 | VHS |
| 2 | H | > 21.3 | VHS |
PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023, Durbak et al. 2024, Sumi et al. 2025).
We thank the University of Osaka observers at PRIME and the staff at SAAO for their support with these observations.
GCN Circular 45436
Subject
GRB 260822A: EP/FXT follow-up observations
Date
2026-08-24T15:20:24Z (9 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
D. Turpin, S. Schanne (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud) and J. P. Feng (USTC) report on behalf of the SVOM and Einstein Probe teams:
EP-FXT performed a follow-up observation of GRB 260822A detected by SVOM/ECLAIRs (Schanne et al., GCN 45422). The observation started at 2026-08-23T12:00:29.920 (UTC), about 19.2 hr after the SVOM trigger, with a total exposure time of around 5.8 ks.
On-ground analysis of the FXT data found several uncataloged sources inside the ECLAIRs error region.
Detected both in FXT A and B:
=============================================================
Name | RA | DEC | dist from ECL position | Flux [0.5-10keV]
| | | (arcmin) | (erg/cm^2/s)
=============================================================
EPF_J000959.8+012409 | 2.4997 | 1.4010 | 4.6072 | 1.2304e-13
EPF_J000926.2+012804 | 2.3576 | 1.4675 | 6.2141 | 7.2405e-14
Detected in FXT A only:
=============================================================
Name | RA | DEC | dist from ECL position | Flux [0.5-10keV]
| | | (arcmin) | (erg/cm^2/s)
=============================================================
EPF_J001001.7+011925 | 2.5071 | 1.3237 | 6.3032 | 5.673e-14
EPF_J000930.4+012950 | 2.3758 | 1.4964 | 7.1176 | 6.5814e-14
EPF_J001016.0+012360 | 2.5668 | 1.3999 | 8.5952 | 5.3425e-14
Detected in FXT B only:
=============================================================
Name | RA | DEC | dist from ECL position | Flux [0.5-10keV]
| | | (arcmin) | (erg/cm^2/s)
=============================================================
EPF_J000951.2+011738 | 2.4632 | 1.2940 | 6.1105 | 4.1612e-14
EPF_J001002.6+011947 | 2.5108 | 1.3271 | 6.3608 | 4.8955e-14
EPF_J000915.7+012111 | 2.3155 | 1.3529 | 6.8404 | 2.1891e-14
EPF_J000930.4+012948 | 2.3757 | 1.4971 | 7.1584 | 5.1928e-14
EPF_J000947.5+013106 | 2.4477 | 1.5183 | 7.9462 | 2.6114e-14
EPF_J000928.0+013037 | 2.3667 | 1.5103 | 8.1030 | 4.2864e-14
with uncertainties of 10 arcsec (radius, 90% C.L. statistical and systematic).
At this stage, we can not identify any significant flux variability from these sources. A second EP/FXT ToO has been requested in order to conclude about the association of the EP/FXT sources with GRB 260822A.
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).
GCN Circular 45435
Subject
GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
Date
2026-08-24T14:07:25Z (9 days ago)
From
Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani@nbi.ku.dk>
Via
Web form
L. Izzo (INAF/OAC), A. Saccardi (CEA/Irfu), G. Corcoran (UCD), A. Martin-Carrillo (UCD), A. J. Levan (Radboud and Warwick), D. O’Neill (Birmingham), A. L. Thakur (INAF/IAPS), D. B. Malesani (DAWN/NBI and Radboud), N. Globus (UNAM), S. Basa (UAR Pytheas), on behalf of the Stargate collaboration,
J. H. Gillanders (Oxford), K. W. Smith, S. J. Smartt (Oxford/QUB), M. Huber, K. C. Chambers (IfA, Univ. Hawaii), on behalf of the Pan-STARRS collaboration,
report:
We observed the candidate optical afterglow (Globus et al., GCN 45429; Li et al., GCN 45430) of the short GRB 260822A (Schanne et al., GCN 45422) using the ESO VLT UT4 (Yepun) equipped with the MUSE integral field unit spectrograph.
Observations began on 2026 August 23 at 09:31:23 UT (0.69 days after the SVOM/ECLAIRs trigger), and consisted of four observations of about 12 min exposure time each.
The optical transient lies close to a system of two galaxies, visible in both our data and in archival images. This could be plausibly the host system of the transient. We measure for them the following redshifts:
RA = 00:09:45.94, Dec = +01:23:29.8: z = 0.290 from Halpha, [N II], [O III], Hbeta;
RA = 00:09:45.91, Dec = +01:23:24.8: z = 0.296 from Halpha, [N II], [O III], Hbeta.
At the position of the candidate optical afterglow (Globus et al., GCN 45429), a faint source is detected. Following preliminary extraction and flux calibration, the transient spectrum shows a continuum with a number of broad undulations, typical of supernovae. Template matching via SNID (Blondin & Tonry 2007, doi:10.1086/520494), leaving the redshift free, provides a match with a type-Ia SN post peak at redshift z = 0.291 +- 0.010. Good matches to post-peak type-Ia SNe are also obtained using SNID-SAGE (Stoppa et al. 2026, doi:10.1093/mnras/stag1066). Given the timing of our observation, the SN exploded well before the SVOM/ECLAIRs trigger.
Examining recent data obtained during ordinary Pan-STARRS survey coverage (see Fulton et al. 2025, doi:10.1093/mnras/staf1165), we report the following archival detections of the transient:
| MJD | Filter | Magnitude (AB) |
| -------- | ------ | ------------------ |
| 61020.23 | w | >22.8 (3-sigma UL) |
| 61247.54 | i | 21.4 +/- 0.2 |
| 61263.54 | w | 22.5 +/- 0.4 |
These archival detections predate the GRB trigger (MJD 61274.7). Both the photometric and the spectroscopic data thus support the interpretation that this source is a pre-existing transient, unrelated to GRB 260822A.
We acknowledge expert support from the observing staff at Paranal, in particular Zahed Wahhaj, Thomas Szeifert and Marcelo Lopez.
The Pan-STARRS system comprises of two 1.8m telescope units located at the summit of Haleakala on the Hawaiian island of Maui, employing an SDSS-like filter system denoted as grizy, and a broad w-filter, which is a composite of the gri-filters (Chambers et al., 2016, ArXiv e-prints, 1612.05560) Images were processed with the Pan-STARRS pipeline. After astrometric and photometric calibration, reference images were subtracted from the target images (Magnier et al., 2020a, ApJS, 251, 3; Magnier et al., 2020b, ApJS, 251, 6; Waters et al., 2020, ApJS, 251, 4). Discoveries from this program are a byproduct of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) NEO survey observations. Operation of the Pan-STARRS1 and Pan-STARRS2 telescopes is primarily supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and Grant No. NNX14AM74G issued through the SSO Near-Earth Object Observations Program. Data are processed at Queen's University Belfast enabled through the STFC grants ST/P000312/1 and ST/T000198/1.
GCN Circular 45432
Subject
GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
Date
2026-08-23T22:49:28Z (10 days ago)
From
d.s.oneill@bham.ac.uk
Via
Web form
D. O'Neill on behalf of GOTO collaboration:
Upon further examination, the GOTO optical detection is approximately 6" offset from the optical counterpart reported by Globus et al., GCN 45429 and Li et al. GCN 45430. Using MPChecker (https://minorplanetcenter.net/cgi-bin/checkmp.cgi) we find that the optical detection is consistent with a known MP object 2016 CP289 which is estimated to have a brightness of 20.8 mag, consistent with the GOTO detection.
We apologise for any inconvenience caused.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research
Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester, the University of Birmingham and the Instituto de Astrofisica de Canarias (IAC).
GCN Circular 45431
Subject
GRB 260822A: GOTO optical counterpart detection
Date
2026-08-23T12:55:36Z (10 days ago)
From
d.s.oneill@bham.ac.uk
Via
Web form
D. O'Neill, S. Moran, M. Kennedy, R. Starling, B. Gompertz, K. Ackley, M. Dyer, G. Ramsay, J. Lyman, K. Ulaczyk, D. Steeghs, D. Galloway, V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. Breton, J. Casares, L. Nuttall, B. Godson, T. Killestein, A. Kumar, M. Pursiainen, on behalf of GOTO collaboration:
We report on optical observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) in response to the SVOM/ECLAIRS alert for GRB 260822A (Schanne et al.; GCN #45422).
Following the detection of an optical counterpart candidate of GRB 260822A (Globus et al., GCN #45429; Li et al., GCN #45430), we checked the position of the candidate in the targeted GOTO data (O'Neill et al. GCN #45423) and identify the counterpart at a 4-sigma level with magnitude L = 21.00 ± 0.25 AB mag at 2026-08-22 18:28:33 (+1.63h). We note an earlier non-detection with 3-sigma limiting magnitude L > 21.26 AB mag at 2026-08-22 17:21:22 (+0.51h).
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research
Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester, the University of Birmingham and the Instituto de Astrofisica de Canarias (IAC).
GCN Circular 45430
Subject
GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
Date
2026-08-23T10:27:10Z (10 days ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, L. P. Xin, C. Wu, Y. L. Qiu, Y. N. Ma, Z. H. Yao, J. R. Xu, J. Wang, X. H. Han, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. T. Palmerio, D. Turpin (CEA/Irfu) report on behalf of the SVOM/VT team.
SVOM/VT performed observations with automatic slew for GRB 260822A, which was triggered by SVOM/ECLAIRs (sb26082201, Schanne et al., GCN 45422). The observation started at 2026-08-22T17:37:09 UTC, about 47 minutes post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously.
The optical candidate reported by SVOM/COLIBRÍ (FM-GFT) (Globus et al., GCN 45429) was detected in both channels. The following measurements are in the AB magnitude and are not corrected for Galactic extinction:
Mid time | Exposure Time | Band | Brightness
1.17 h | 53*50 s | VT_B | 23.00 +/ -0.22 mag
1.17 h | 53*50 s | VT_R | 22.07 +/ -0.16 mag
Further VT ToO observation is scheduled.
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 45429
Subject
GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
Date
2026-08-23T09:16:01Z (10 days ago)
Edited On
2026-08-23T21:14:11Z (10 days ago)
From
Stephane Basa at UAR Pytheas/OHP, LAM <stephane.basa@lam.fr>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Stephane Basa at UAR Pytheas/OHP, LAM <stephane.basa@lam.fr>
Via
Web form
Noémie Globus (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García-García (UNAM), Ramandeep Gill (UNAM), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Alan M. Watson (UNAM) and Damien Turpin (CEA/Irfu) report:
We imaged the field of the SVOM GRB 260822A (Schanne et al., GCN Circ. 45422) using the DDRAGO two-channel wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-08-23 04:56 to 08:40 UTC (from 12.1 to 15.8 hours after the trigger) and obtained 82 minutes of simultaneous exposure in the r and z filters.
The data were reduced and coadded and analysed with the COLIBRÍ and ASU pipelines. The photometry was calibrated using nearby stars from the PanSTARRS DR2 catalog, is in the AB system, and is not corrected for Galactic extinction.
In the stacked image, we tentatively detected a faint, uncatalogued source in both bands, consistent with the SVOM/ECLAIRs error circle at:
RA (J2000) = 00:09:45.57 = 2.43988 deg
Dec (J2000) = +01:23:23.2 = 1.38978 deg,
with an estimated astrometric uncertainty of 0.5 arcsec.
The preliminary magnitude derived for that source was:
r = 22.88 ± 0.09
z = 22.08 ± 0.14
We encourage additional observations to confirm the nature of the source.
We thank the staff of the Observatorio Astronómico Nacional at Sierra de San Pedro Mártir, as well as the technical and engineering teams at CEA, CPPM, IRAP, LAM, OHP, OSU Pytheas, and UNAM.
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 45427
Subject
GRB 260822A: LCO optical upper limits
Date
2026-08-23T06:10:02Z (10 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
D. Turpin, A. Saccardi, J. T. Palmerio (CEA/Irfu), Y.Y. Shi (GXU), C. Wu, L.P. Xin (NAOC), report on behalf of the SVOM mission team:
We observed the field of GRB 260822A(SVOM burst-id sb26082201) detected by SVOM (Schanne et al., GCN 45422) with the LCO 1m telescope at Sutherland Observatory equipped with the Sinistro instrument.
Our observation started at 2026-08-22T20:20:17 about 3.49 hours after the SVOM/ECLAIRs trigger time. We obtained 3x200 s exposures in the SDSS r and PanSTARRS-z filters. In our stacked images, we did not detect any optical transient candidate consistent with GOTO (O'Neill et al., GCN 45423) and GROWTH-India (Saikia et al. GCN 45424) observations.
We measure the following upper limit magnitude calibrated against the PanSTARRS DR1 catalog, and not corrected for Galactic extinction:
r > 20.2 (AB) (5 sigma, Tmid - T0 = 3.6 hr);
z > 18.8 (AB) (5 sigma, Tmid - T0 = 3.6 hr).
This project is funded by the SVOM collaboration.
GCN Circular 45424
Subject
GRB 260822A: GROWTH-India Telescope Upper Limits
Date
2026-08-22T20:25:52Z (11 days ago)
From
Aditya Pawan Saikia at IIT Bombay <adityaps@iitb.ac.in>
Via
Web form
A. P. Saikia, V. Vijaykumar, V. Swain, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of SVOM GRB 260822A (Schanne et al., GCN 45422), with the 0.7m GROWTH-India Telescope (GIT). We started the observation at 2026-08-22 19:03:46 UT, i.e., 2.2 hours after the GRB trigger. We obtained multiple exposures in r' and g'. We did not detect the source in our stacked image within the SVOM localization region (Schanne et al., GCN 45422). The photometric upper limits are as follows:
| MJD (mid) | Filter | tmid-t0 (hr) | Exposure Time (sec) | Upper limit (AB) |
| ------------ | ------- | ------------ | ------------------- | ---------------- |
| 61274.800179 | r' | 2.36 | 3 x 300 | 21.6 |
| 61274.812419 | g' | 2.65 | 3 x 300 | 21.7 |
The measurement is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
The measurement is consistent with the reported optical measurements by O'Neill et al. (GCN 45423).
The GROWTH India Telescope (GIT; Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular 45423
Subject
GRB 260822A: GOTO optical upper limit
Date
2026-08-22T19:03:18Z (11 days ago)
From
d.s.oneill@bham.ac.uk
Via
Web form
D. O'Neill, S. Moran, G. Ramsay, R. Starling, B. Gompertz, K. Ackley, M. Dyer, J. Lyman, K. Ulaczyk, D. Steeghs, D. Galloway, V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. Breton, J. Casares, L. Nuttall, B. Godson, T. Killestein, A. Kumar, M. Pursiainen, on behalf of GOTO collaboration:
We report on optical observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) in response to the SVOM/ECLAIRS alert for GRB 260822A (Schanne et al.; GCN #45422).
Observations covering the localisation area were taken at 2026-08-22 17:21:22 UT, (+0.51h post trigger). Images consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using deeper template observations. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogs. Human vetting was carried out in real time on any candidates that passed the above checks (Lyman et al. 2026).
No new transients that could be credibly associated with GRB 260822A were detected down to an average 5-sigma depth of L > 20.7 AB mag.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research
Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester, the University of Birmingham and the Instituto de Astrofisica de Canarias (IAC).
GCN Circular 45422
Subject
GRB 260822A: SVOM detection of a short burst
Date
2026-08-22T17:21:32Z (11 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
S. Schanne, D. Turpin, D. Götz (CEA/Irfu) report on behalf of the SVOM mission team:
At 2026-08-22T16:50:36 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260822A (SVOM burst-id sb26082201).
The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.
The burst was only detected by the Count-Rate Trigger (CRT), which produced a sequence of 5 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 8.62 in the [8-120] keV energy band over a time window of 0.16 seconds starting at 2026-08-22T16:50:36.63 (Tb).
The localization of the best alert is R.A., Dec. 2.4240, 1.3876 degrees:
R.A. (J2000) = 0h09m41.75s
Dec. (J2000) = 1d23m15.50s
with a 90% confidence level (C.L.) radius of 9.15 arcmin (including systematic error of 2 arcmin added in quadrature).
The SVOM/ECLAIRs light curve showed a single narrow peak with a duration of about 100 ms.
This burst also triggered SVOM/GRM at 2026-08-22T16:50:36 on a timescale of 0.10 seconds with an SNR of 6.20.
The SVOM/GRM light curve showed a single narrow peak with a duration of about 100 ms.
SVOM slewed to the burst. At the time of the trigger, MXT was in Earth occultation. Observations performed by SVOM/MXT and SVOM/VT will be reported 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 Damien Turpin (damien.turpin@cea.fr).
Please contact the BA by email if you require additional information.