GRB 261026A
GCN Circular 46068
Subject
GRB 261026A: SVOM/ECLAIRs refined analysis
Date
2026-10-28T15:31:41Z (5 hours ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
GRB 261026A: SVOM/ECLAIRs refined analysis
W. Xie (NAOC), N. Dagoneau (CEA), M. Brunet (IRAP), H. Goto (RIKEN/CEA), C. Plasse (HKU), C. Wu (NAOC), C. Wang (IHEP) report on behalf 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 GRB 261026A (SVOM burst-id sb26102601 – GCN 46030, trigger time T0 = 2026-10-26T06:09:37.68 UTC).
The burst that triggered ECLAIRs onboard shows a broad bump lightcurve. The burst duration is T90 = 26.7 +1.5/-1.6 s in the 4-120 keV energy band.
The time-averaged spectrum from T0-8.3 s to T0+18.4 s in the 4-120 keV energy range is well fitted by a powerlaw model with alpha = -1.82 +/- 0.18. With this model, the 4-120 keV fluence is (1.37 ± 0.18)e-6 erg/cm^2 and the 4-120 keV photon flux is 2.03 ± 0.13 ph/cm^2/s.
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: Wenjin Xie (NAOC) (xiewj@bao.ac.cn)
GCN Circular 46064
Subject
GRB261026A: Infrared detection with MDM/MIRAGE
Date
2026-10-27T23:02:35Z (21 hours ago)
From
Stella Lucine Manyan <sld2197@columbia.edu>
Via
Web form
Stella Manyan (Columbia U), K. De (Columbia U), G. Mo (Caltech/Carnegie), V. Karambelkar (Columbia U), D. Schiminovich (Columbia U) report:
We observed the field of GRB 261026A discovered by SVOM (Goto et al., GCN 46030), also detected by EP-FXT (Jiang et al., GCN 46058) in the near-infrared J and Hs band with the MDM InfraRed Astronomy inGaas Experiment (MIRAGE) instrument on the MDM 1.3m telescope.
A near-infrared counterpart was detected in J band by WINTER (J = 18.55 +/- 0.1 AB mag at T0+12.6 min; Mohan et al., GCN 46041), which faded to 20.28 mag over ~6 hours as reported by the SYSU 80cm infrared telescope (Shi et al., GCN 46047). Several optical detections have also been reported by other facilities (Zheng et al., GCN 46034; Morín-González et al., GCN 46048; Zhao et al., GCN 46056).
Observations began at 2026-10-27T01:31:05 (19.4 hours after SVOM trigger) in the J band lasting 1620 s, and 2026-10-27 02:06:03 (19.9 hours after trigger) in the Hs band lasting 2160 s. We detect a faint infrared source in Hs band at ~ 2.5 sigma significance at Hs = 20.484 ± 0.486 AB mag, while we obtain an upper limit in the J band with J > 19.83 AB mag.
MIRAGE is a new robotic YJHs-band near infrared imager for the MDM 1.3 m telescope. We thank the Mt Cuba astronomical foundation for supporting development of MIRAGE and MDM Observatory staff for supporting the observations
GCN Circular 46063
Subject
GRB 261026A: SVOM/VT optical blue bump
Date
2026-10-27T17:33:52Z (a day ago)
Edited On
2026-10-28T00:11:52Z (20 hours ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, Y. L. Qiu, C. Wu, J. Wang, Y. N. Ma, L. P. Xin, Z. H. Yao, J. R. Xu, L. J. Chen, X. H. Han, 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 continuous observations for GRB 261026A (sb26102601, Goto et al., GCN 46030). The ToO observation started at 2026-10-26T16:05:47 UTC, about 9.9 hr post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously.
Combining earlier observations with automatic-slew data (Wu et al., GCN 46035; Li et al., GCN 46046), the afterglow (Dornic et al., GCN 46033; Zheng et al., GCN 46034; Wu et al., GCN 46035; Li et al., GCN 46046; Mohan et al., GCN 46041; Shi et al., GCN 46047; Morín-González et al., GCN 46048; Novotny et al., GCN 46049; Coyo et al., GCN 46054; Zhao et al., GCN 46056; Jiang et al., GCN 46058; Moskvitin et al., GCN 46062) exhibits a broad blue bump in the VT_B band at ~10-30 ks, with an amplitude of 0.3±0.1 mag peaking at a mid-time of approximately 5.3 hr post trigger. Preliminary analysis did not reveal a significant bump in the VT_R band at the corresponding epoch (amplitude<0.1 mag). The following measurements are in AB magnitudes and are not corrected for Galactic extinction:
Mid time | Band | Exposure Time | Brightness
28.03 h VT_B 70*34 s 22.8 +/- 0.2 mag
28.02 h VT_R 70*30 s 22.5 +/- 0.2 mag
The physical origin of this feature is currently unclear. Continuous monitoring is ongoing.
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 46062
Subject
GRB 261026A: SAO RAS optical observations
Date
2026-10-27T16:49:43Z (a day ago)
From
Alexander Moskvitin at SAO RAS <mosk@sao.ru>
Via
email
A. Moskvitin (SAO), V. Goranskij (SAI MSU, SAO), V. Vlasyuk (SAO),
A. Volnova (IKI), N. Pankov (IKI), A. Pozanenko (IKI),
on behalf of the SAO GRB follow-up team and the IKI-GRB-FuN report.
We observed the field of GRB 261026A discovered by SVOM (Goto et al.,
GCN 46030), also detected by EP-FXT (Jiang et al., GCN 46058)
with the SAO RAS 1-m Zeiss-1000 and 0.5-m AS-500(2) telescopes
on October 26.
The OT (Dornic et al., GCN 46033; Zheng et al., GCN 46034; Wu et al.,
GCN 46035; Li et al., GCN 46046; Morín-González et al., GCN 46048;
Coyo et al., GCN 46054; also observed in NIR, Mohan et al., GCN 46041;
Shi et al., GCN 46047) is detected only in the Zeiss-1000 stacked frame.
Details of the observation are the following.
Date UT start t-T0 Exp, Filter Obj Err UL
Telescope
(mid,days) (n*s) (3sigma)
2026-10-26 20:11:58 0.59342 4*300 Rc 21.5 +/- 0.2 22.1
Zeiss-1000
2026-10-26 20:41:16 0.61058 30*30 R n/d n/d 20.5 AS-500
(2)
This preliminary photometry (Vega) is based on nearby SDSS stars
(Lupton 2005 transformation) and not corrected for Galactic extinction.
GCN Circular 46058
Subject
GRB 261026A: EP-FXT follow-up observation
Date
2026-10-27T10:57:10Z (a day ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
S. Q. Jiang, J. W. Hu, C. L. Guo, B. B. Zhang, K. Ao (NAO, CAS), A. D. Zhu (HUST), Z. X. Ling (NAO, CAS) on behalf of the Einstein Probe (EP) team:
EP-FXT performed a follow-up observation of GRB 261026A, detected by SVOM/ECLAIRs (Goto et al., GCN 46030), which was also observed in optical by SVOM/COLIBRÍ (Dornic et al., GCN 46033), KAIT (Zheng et al., GCN 46034), SVOM/VT (Wu et al., GCN 46035; Li et al., GCN 46046), WINTER ( Mohan et al., GCN 46041), SYSU 80cm telescope (Shi et al., GCN 46047), ULL-ASTRO-MASTER (Morín-González et al., GCN 46048), Ondrejov D50 (Novotny et al., GCN 46049), OHP/T120 (Coyo et al., GCN 46054) and 60cm Panzhihua Telescope (Zhao et al., GCN 46056). The observation started at 2026-10-26 06:59:08 (UTC), about 49.52 mins after the SVOM/ECLAIRs trigger, with an exposure time of 5791 s.
On-ground analysis of the EP-FXT data found an uncataloged X-ray source within the SVOM/ECLAIRs error region (Goto et al., GCN 46030). The position of the source is consistent with that of the optical counterpart candidate, and its X-ray flux shows a declining trend. The preliminary result for the X-ray source are as follow:
R.A., Decl. (J2000) = 337.3535, 27.0268 deg
Localization error radius = 10 arcsec
0.5-10 keV flux = 2.80e-12 erg/cm^ 2/s
Flux error = 1.83e-13 erg/cm^2/s (1 sigma)
Separation = 1.76 arcmin
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 46056
Subject
GRB 261026A: Upper Limit with 60cm Panzhihua Telescope
Date
2026-10-27T06:04:05Z (2 days ago)
From
Jiewei Zhao at SWIFAR, YNU <meow.jiewei.zhao@gmail.com>
Via
Web form
Jiewei Zhao, Wenyu Li, Brajesh Kumar, Xinchao Wang, Guowang Du, Yuanpei Yang (SWIFAR, YNU), Binbin Zhang, Kamil Nadaf (NJU), Kai Liao, Xinyu Wang, Xing Yao, Yang Zeng and Chunlai Zhang (SSO) report on behalf of a larger collaboration:
We observed the GRB 261026A field detected by SVOM/ECLAIRs and SVOM/GRM (Goto et al., GCN 46030). The observations were initiated at 2026-10-26T12:01:07.78 (~5.86 hours after the trigger) with the 60cm Panzhihua Telescope located at the Sichuan South Observatory (SSO), China. A total of 8 frames with 180s exposure each were acquired in L band. We did not detect the optical counterpart (Dornic et al., GCN 46033; Zheng et al., GCN 46034; Wu et al., GCN 46035; Mohan et al., GCN 46041; Li et al., GCN 46046; Shi et al., GCN 46047; Morín-González et al., GCN 46048; Coyo et al., GCN 46054) in the stacked image. The 3-sigma upper limit is 20.54 mag (The expected Galactic extinction is not applied in our estimates).
GCN Circular 46054
Subject
GRB 261026A: OHP/T120 optical imaging
Date
2026-10-27T03:56:39Z (2 days ago)
From
Christophe Adami at LAM <christophe.adami@lam.fr>
Via
Web form
L. Coyo (SUPAERO), L. Sename (SUPAERO), G. Bassetto Fernandes (SUPAERO), M. Blet--Dufauret (SUPAERO), S. Doudeau--Pera (SUPAERO), A. Heraud (SUPAERO), M. Matilla (SUPAERO), T. Piat (SUPAERO), D. Russeil (LAM/Pytheas/AMU), C. Adami (LAM/Pytheas/AMU), S. Basa (UAR Pytheas), Damien Laurent (Pytheas/OHP), N. Andre (SUPAERO/IRAP):
We performed observations of the optical counterpart of GRB 261026A (Dornic et al, GCN 46033; Zheng et al., GCN 46034; Wu et al., GCN 46035; Mohan et al, GCN 46041; Li et al., GCN 46046; Shi et al., GCN 46047; Perez-Fournon et al., GCN 46048; Novotny et al., GCN 46049) using the T120cm telescope at Observatoire de Haute-Provence (France). We obtained 15 exposures of 400s in the R-band at a mean time of 19:00 UT on 2026-10-26 (12.85 hours after the trigger). The afterglow is detected with a preliminary magnitude of:
r = 21.4 +/- 0.2 mag (AB)
The photometric calibration was performed using nearby stars from the PanSTARRS catalog and the magnitudes are not corrected for Galactic extinction.
We acknowledge the excellent support from the Observatoire de Haute-Provence.
GCN Circular 46049
Subject
GRB 261026A: Ondrejov D50 optical limit
Date
2026-10-26T21:27:28Z (2 days ago)
From
Filip Novotný at Masaryk University <filip.novotny@talentovani.cz>
Via
Web form
F. Novotny, J. Strobl, M. Jelinek and R. Hudec (ASU CAS Ondrejov) report:
We observed the position of GRB 261026A, detected by SVOM/ECLAIRs and
SVOM/GRM (Goto et al., GCN 46030), with the D50 telescope of the
Astronomical Institute Ondrejov, near Prague, Czech Republic. We obtained
a series of 60s Sloan i'-band exposures between 17:05 and 20:58 UT on
2026 October 26, i.e. 10.9-14.8 h after the trigger. Part of the series
was affected by clouds; 192 frames with good transparency were combined.
We do not detect the optical counterpart at the SVOM/VT position
(RA, Dec = 337.35317, +27.02623; Wu et al., GCN 46035), neither in single
images (3-sigma limit i'>17.3-18.8) nor in the combined 11520 s image
(mean epoch T0+13.13 h, 3-sigma limit i'>20.6).
Photometry is calibrated in Sloan i' (AB system) against ATLAS-RefCat2
field stars, not corrected for Galactic extinction.
GCN Circular 46048
Subject
GRB 261026A: ULL-ASTRO-MASTER optical detection with LCO 40-cm telescope at Haleakalā Observatory
Date
2026-10-26T18:54:54Z (2 days ago)
From
Ismael Perez-Fournon at Instituto de Astrofisica de Canarias <ipf@iac.es>
Via
Web form
H. Morín-González, S. Abad Gómez, K.N. Alvez Báez, G. de la Mata Núñez, J. Díaz-Miguel Font, A. Fernández-Roselló, L. García Rodríguez, S. M. Holtham, R. Jiménez Rioja, L. Ortega-Barcenilla, C. Pasamontes-Duarte, M. Ríos-Jiménez, S.J. Riquelme-Salinas, L. Rodríguez-Torres, A. Rosendo Pato, E. Ruiz-Laguna, I. Ruiz-Pérez, D. Zazo-Callejas (all ULL), S. R. Berlanas (IAC and ULL), and I. Pérez-Fournon (IAC and ULL)
We report on observations of the optical counterpart of GRB 261026A detected by SVOM/ECLAIRs and SVOM/GRM (Goto et al., GCN 46030).
We observed the field of GRB 261026A with a Las Cumbres Observatory (LCO) 40-cm telescope located at the LCO node at the Haleakalā High Altitude Observatory (HO), Maui, Hawaii. The observation,a single 500-sec exposure in the SDSS i' filter, started on 2026-10-26 at 08:03:57 UT (about 1.906 hr after the SVOM trigger).
The optical counterpart first reported by SVOM/COLIBRÍ (FM-GFT) (Dornic et al., GCN 46033) is detected in our LCO image. We measure an AB magnitude of i' = 19.74 +/- 0.33, calibrated against PanSTARRS-1 DR2 stars and not corrected for Galactic extinction. This result is consistent with other optical and near-infrared observations (Dornic et al., GCN 46033; Zheng et al., GCN 46034; Wu et al., GCN 46035; Mohan et al., GCN 46041; Li et al., GCN 46046; and Shi et al., GCN 46047).
Based on observations made with the Las Cumbres Observatory’s education network telescopes that
were upgraded through generous support from the Gordon and Betty Moore Foundation (LCO program IAC2026B-010).
These observations are part of a course in Astrophysical Techniques of the Master in Astrophysics of
the Astrophysics Department of the University of La Laguna in collaboration with the Instituto de Astrofísica de Canarias (La Laguna, Tenerife, Canary Islands, Spain).
GCN Circular 46047
Subject
GRB 261026A: J-band observations by the SYSU 80cm infrared telescope
Date
2026-10-26T16:43:15Z (2 days ago)
From
shiy228@mail2.sysu.edu.cn
Via
Web form
Yun Shi, Jin-Ji Li, Shu-Quan Bai, Jian-Hong Cao, Zhong-Nan Dong, Rui-Chen Gao, Si-Rui Huang, Jia-Qi Lin, Pu Lin, Jing-Kai Sun, Zhi-Xiang Tan, Lu-Yao Wen, Hao-Nan Yang, Hao-Ran Zhang, P. H. Thomas Tam, Rong-Feng Shen, and Bin Ma (Sun Yat-sen University) report on behalf of the SYSU 80cm infrared telescope team:
We observed the field of GRB 261026A, detected by SVOM/ECLAIRs (Goto et al., GCN 46030), using the Sun Yat-sen University (SYSU) 80 cm infrared telescope in the J band. Our observations were carried out on 2026 Oct 26 from 11:50:00 to 12:50:00 UT (from ~5.67 to ~6.67 hours after the SVOM/ECLAIRs trigger), using stacked images in the J band (165 x 20 s, 3300 s total exposure).
We clearly detect the near-infrared afterglow at the position of the previously reported optical counterpart (Dornic et al., GCN 46033; Zheng et al., GCN 46034; Mohan et al., GCN 46041; Li et al., GCN 46046), and we measure a magnitude of:
J = 19.37 +/- 0.14 mag (Vega), at a mid-time of ~6.17 hours post-trigger.
Assuming a standard J-band conversion of J (AB) = J (Vega) + 0.91, our measurement corresponds to J ~ 20.28 mag (AB). Comparing this with the early J-band detection by WINTER (J = 18.55 +/- 0.1 mag, AB, at T0+12.6 min; Mohan et al., GCN 46041), our result indicates a significant fading of ~1.73 mag over ~6 hours.
The photometry was calibrated against nearby stars from the 2MASS catalog and is reported in the Vega system, without correction for Galactic extinction.
The SYSU 80 cm infrared telescope is operated and managed by the Department of Astronomy, Sun Yat-sen University.
GCN Circular 46046
Subject
GRB 261026A: SVOM/VT optical observations
Date
2026-10-26T15:16:38Z (2 days ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, C. Wu, Y. N. Ma, L. P. Xin, Y. L. Qiu, Z. H. Yao, J. R. Xu, L. J. Chen, 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), J. T. Palmerio (CEA/Irfu), C. W. Wang (IHEP) report on behalf of the SVOM/VT team.
SVOM/VT performed an automatic slew toward the position of GRB 261026A, triggered by SVOM/ECLAIRs (sb26102601, Goto et al., GCN 46030) and also detected by SVOM/GRM (Goto et al., GCN 46030). The observation started at 2026-10-26T06:20:29 UTC, about 10.8 minutes post trigger in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
The optical counterpart (Dornic et al., GCN 46033; Zheng et al., GCN 46034; Wu et al., GCN 46035; Mohan et al., GCN 46041) was clearly detected in both channels, showing a power-law temporal decay index of -0.6 during our observation. The following measurements are in AB magnitudes and are not corrected for Galactic extinction:
Mid time | Band | Exposure Time | Brightness
677 s VT_B 50 s 19.0 +/- 0.1
677 s VT_R 50 s 18.6 +/- 0.1
5.74 h VT_B 100 s 20.95 +/- 0.15
5.74 h VT_R 100 s 20.52 +/- 0.13
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 46041
Subject
GRB 261026A: WINTER J-band observations
Date
2026-10-26T10:19:45Z (2 days ago)
From
tanishk.mohan@iitb.ac.in
Via
Web form
Tanishk Mohan (IITB), Geoffrey Mo (Caltech/Carnegie), Benjamin Schneider (LAM), Viraj Karambelkar (Columbia), Tomas Ahumada (NOIRLab), Robert Stein (UMD), Danielle Frostig (CfA), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report:
We observed the field of GRB 261026A (Goto et al., GCN 46030) in the near-infrared J band with the Palomar 1-m telescope, equipped with the 1.2-square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024).
Observations began on 2026-10-26 at 06:22:15.440 UTC in the J band (12.6 min after the SVOM/ECLAIRs trigger), consisting of 15*120 sec exposures. The images were processed using the WINTER data reduction pipeline implemented with mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565).
We detect a source present at the optical counterpart position in our stacked image and obtain the following magnitude: J = 18.55 +- 0.1 mag (AB) in our stacked image. Optical counterpart is also detected by Dornic et al., GCN 46033; Zheng et al., GCN 46034; Wu et al., GCN 46035.
WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research.
GCN Circular 46035
Subject
GRB 261026A: SVOM/VT optical observation from VHF data
Date
2026-10-26T08:08:42Z (2 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
C. Wu (NAOC), J. T. Palmerio (CEA/Irfu), A. Saccardi, D. Turpin (CEA/Irfu), Y. L. Qiu, L. P. Xin (NAOC), Chenwei Wang (IHEP) on behalf of the SVOM/VT team.
After the trigger by SVOM/ECLAIRs (sb26102601) at 2026-10-26T06:09:37 UTC (T0), SVOM performed an automatic slew on the burst location (Goto et al., GCN 46030).
From a preliminary analysis of the 1-bit subimage and source list downloaded via VHF network, one credible candidate is identified, the details of which are presented below.
The position of this candidate is R.A., Dec. 337.35317 27.02623 degrees, corresponding to:
R.A. (J2000) = 22h29m24.76s
Dec. (J2000) = +27d01m34.4s
with an uncertainty of 0.50 arcsec. This location is consistent with the optical afterglow reported by Dornic et al.(GCN 46033).
This candidate was detected in both VT_R and VT_B band of the VT observations. The candidate's magnitudes are:
| date-obs (UTC) | mid-time | exposure | VT_B mag(AB) | VT_R mag(AB) |
|---|---|---|---|---|
| 2026-10-26T06:19:39 | 12.53 min | 6*50 sec | 19.47 ± 0.02 | 18.70 ± 0.01 |
Magnitudes were not corrected for Galactic reddening.
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/VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS.
GCN Circular 46034
Subject
GRB 261026A: KAIT optical observations
Date
2026-10-26T08:03:03Z (3 days ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
Via
email
WeiKang Zheng (UCB), Yun Wang (UCB), Xuhui Han (NAOC),
Pinpin Zhang (NAOC), Yun Wang (UCB) and Alexei V. Filippenko (UCB)
report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, observed the field of SVOM GRB 261026A (Goto
et al., GCN 46030) starting at 06:11:44 UT, 127 seconds after SVOM
trigger. Observations were performed in 3 x 3 tiling mode, and a
set of clear (roughly R) filter images were obtained. In one of
the fields, we detected the uncatalogued source reported by Dornic
et al. (GCN 46033) with a mag of 18.1 +/- 0.1 mag at 290 seconds
after the burst. The object continued fading in our follow up
observations, we therefore confirm it to be the optical counterpart
of GRB 261026A. Observations are on going.
GCN Circular 46033
Subject
GRB 261026A: SVOM/COLIBRÍ (FM-GFT) optical observations
Date
2026-10-26T07:32:39Z (3 days ago)
From
damien dornic <damiendornic@gmail.com>
Via
Web form
Damien Dornic (CPPM), Diego López-Cámara (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Camila Angulo (UNAM), Jean-Luc Atteia (IRAP), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García-García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), 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), Hatsune Goto (RIKEN/CEA), Clara Plasse (HKU), Wenjin Xie (NAOC), Chao WU (NAOC), Chenwei Wang (IHEP) report:
We imaged the field of the SVOM GRB 261026A (Goto et al., GCN Circ. 46030) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-10-26T06:11:22.748 to 2026-10-26T06:23:45.890 UTC (from 115 to 858 seconds after the trigger) and obtained 100 seconds of exposure in the r filter.
The data were reduced and coadded with the COLIBRI pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction.
We detect an uncatalogued source revealed by image subtraction using Legacy Survey as template and consistent with the ECLAIRs error circle (Goto et al., GCN Circ. 46030) at:
RA(J2000) = 22:29:24.760 = 337.3531676 degrees
Dec(J2000) = +27:01:34.600 = 27.0262778 degrees
with an uncertainty of 0.5 arcsec.
The preliminary magnitude derived for that source is:
r = 18.79 +/- 0.05
We encourage further observations.
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 46030
Subject
GRB 261026A: SVOM detection of a burst
Date
2026-10-26T06:36:32Z (3 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Hatsune Goto (RIKEN/CEA), Clara Plasse (HKU), Wenjin Xie, Chao WU (NAOC), Chenwei Wang (IHEP) report on behalf of the SVOM mission team:
At 2026-10-26T06:09:37 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 261026A (SVOM burst-id sb26102601).
The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.
The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 8 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 11.10 in the [5-20] keV energy band over a time window of 20.40 seconds starting at 2026-10-26T06:09:27.
The localization of the best alert is R.A., Dec. 337.3314, 27.0485 degrees:
R.A. (J2000) = 22h29m19.52s
Dec. (J2000) = 27d02m54.66s
with a 90% confidence level (C.L.) radius of 7.22 arcmin (including systematic error of 2 arcmin added in quadrature).
This burst was also detected by SVOM/GRM with a significance of 11.20.
SVOM slewed to the burst.
SVOM/MXT and VT began observing the field after the slew. The analysis of the data will be published in future circulars.
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 Chao WU: cwu@nao.cas.cn. Please contact the BA by email if you require additional information.