GRB 261113A
GCN Circular 46287
Subject
GRB 261113A: SVOM/GRM observation
Date
2026-11-15T04:22:24Z (2 hours ago)
From
xueyuan zao <zaoxueyuan@gmail.com>
Via
Web form
SVOM/GRM team: Xue-Yuan Zao, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Stéphane Schanne (CEA)
Report on behalf of the SVOM team:
SVOM/GRM was triggered in-flight by GRB 261113A at 2026-11-13T14:31:01 UTC (T0), which is also detected by SVOM/ECLAIRs (A. Saccardi et al., GCN #46244). The SVOM burst id is sb26111302.
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 duration of 7.2 +/-0.2 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn/gcn/2026/11/svgrb261113A.png
In addition, the position of this burst, as determined by SVOM/ECLAIRs (R.A.= 346.32 degrees, Dec.=5.14 degrees, ERR= 2.42 arcmins), is located at about 17.2 degrees from the SVOM optical axis.
With this localization, the time-averaged spectrum from T0-0.1 to T0+8.5 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -0.64 +/-0.08 and the cutoff energy, parameterized as Epeak, is 134 +8/-7 keV. The event fluence (10-1000 keV) in this time interval is (4.85 +0.19/-0.17) E-06 erg/cm^2.
The localization of GRB 261113A in the 'Amati' relation diagram is shown at:
https://www.bursthub.cn/gcn/2026/11/svgrb261113A_amati.png
The localization of GRB 261113A in the 'Yonetoku' relation diagram is shown at:
https://www.bursthub.cn/gcn/2026/11/svgrb261113A_yonetoku.png
The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS.
The SVOM point of contact for this burst is: Xue-Yuan Zao (IHEP)(zaoxy@ihep.ac.cn)
GCN Circular 46280
Subject
Optical Observations of GRB 261113A
Date
2026-11-14T23:50:26Z (7 hours ago)
From
J.H. Xu at AAVSO <hyena_eris@163.com>
Via
Web form
I observed the field of GRB 261113A (A. Saccardi et al., GCN 46244) with an 28cm SCT in Chengde, Hebei operated by the Interestar network, ~10 min after trigger and 7min after notice. Six 300s exposures were taken in the Luminance filter (approximately 400nm to 700nm), with a mid-time of 2026-11-13 14:59:40 UT (about 28 min after the trigger). The optical afterglow (Lin et al., GCN 46247) was detected in the stacked image, with an SNR of 14.8. I reduced the stacked image to a V band zeropoint using Tycho Tracker (Parrott, 2020), and measured the following Vega magnitude with hand-picked comp stars from the Atlas Star Catalog (Tonry et al., 2018).
Mid-time (UT) | Exp.time (s) | Mag | Mag error | Filter
14:59:40 | 6 x 300 | 19.52 | 0.1 | Luminance
The magnitudes were not corrected for Galactic extinction. The calibrated images are available on reasonable request.
GCN Circular 46279
Subject
GRB 261113A: AZT-20 Assy-Turgen optical observations
Date
2026-11-14T23:48:24Z (7 hours ago)
From
Alexander Moskvitin at SAO RAS <mosk@sao.ru>
Via
email
A. Moskvitin (SAO), A. Pozanenko (IKI), M. Krugov (FAI), A. Volnova (IKI),
N. Pankov (IKI), O. Spiridonova (SAO) report on behalf of IKI-GRB-FuN
and SAO GRB follow-up team.
We observed the field of the GRB 261113A (Saccardi et al., GCN 46244;
Frederiks et al., GCN 46268; Dagoneau et al., GCN 46270)
at the redshift of z = 3.580 (Saccardi et al., GCN 46261;
Perez-Garcia et al., GCN 46264) with the 1.5-m AZT-20 telescope
of the Assy-Turgen Observatory on 2026-11-14T13:09:44--
2026-11-14T14:15:32 UT (t_mid - T0 = 0.96639 days).
The OT (Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al.,
GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252; Zhao et al.,
GCN 46253; Li et al., GCN 46254; Saikia et al., GCN 46256; Adami et al.,
GCN 46257; Gress et al., GCN 46258; Izzo et al., GCN 46259; Saccardi et
al., GCN 46261; Maksut et al., GCN 46262; Moskvitin et al., GCN 46263;
Perez-Garcia et al., GCN 46264; de Ugarte Postigo et al., GCN 46265;
Dimple et al., GCN 46266; Jelinek et al., GCN 46271; Wei et al.,
GCN 46274; also observed in NIR: Lin et al., GCN 46247; Brivio et al.,
GCN 46260) is clearly detected in our stacked image.
The results are as follows.
Date UT start t-T0 Exp, Filter Obj Err UL
(mid,h) (n*s) (3sigma)
2026-11-14 13:09:44 23.1933 58*60 r-SDSS 23.26 +/- 0.12 24.4
The photometry was calibrated against nearby SDSS stars and
not corrected for Galactic extinction.
GCN Circular 46274
Subject
GRB 261113A: SVOM/GWAC bright optical counterpart
Date
2026-11-14T14:53:35Z (16 hours ago)
Edited On
2026-11-14T20:08:12Z (10 hours ago)
From
Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>
Edited By
K.L. Page at U Leicester <klp5@leicester.ac.uk> on behalf of Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
J. Y. Wei, L. P. Xin, Y. Xu, J. R. Xu, X. H. Han, H. L. Li, J. Wang, L. Huang, Y. L. Qiu, L.J. Wang, H. B. Cai, C. Wu, L. J. Chen, Y. T. Zheng, W. L. Dong, P. P. Zhang, Y. J. Xiao , Y. N. Ma , S., Jin, Z. R. Cui, W. J. Xie, J. S. Deng (NAOC), Z. G. Dai (USTC), X. Y. Wang (NJU), E. W. Liang (GXU), X. G. Wang (GXU) report on behalf of SVOM/GWAC team.
The field of GRB 261113A triggered by SVOM/Eclairs (sb26111302, Saccardi et al., GCN 46244, Dagoneau et al., GCN 46270) was monitored by GWAC system continuously during about 4 hrs before and 12 minutes post trigger. The exposure time for each frame is 3 sec.
The optical counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252; Zhao et al., GCN 46253; Li et al., GCN 46254; Saikia et al., GCN 46256; Adami et al., GCN 46257; Gress et al., GCN 46258; Izzo et al., GCN 46259; Brivio et al., GCN 46260; Maksut et al., GCN 46262; Moskvitin et al., GCN 46263; Perez-Garcia et al., 46264; Dimple et al., GCN 46266; Jelinek et al., GCN 46271) was clearly detected in single frames with a peak brightness of W~11 mag at around 10 seconds after the burst. The magnitude is calibrated to the GAIA G-band and not corrected for Galactic extinction.
GCN Circular 46271
Subject
GRB 261113A: Ondrejov D50 optical observations
Date
2026-11-14T12:25:30Z (18 hours ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
Via
email
M. Jelinek, J. Strobl, F. Novotny and R. Hudec (ASU CAS Ondrejov) report:
We observed the optical afterglow of the SVOM/ECLAIRs GRB 261113A (Saccardi
et al., GCN 46244; Lin et al., GCN 46247) with the D50 telescope of the
Astronomical Institute Ondrejov, near Prague, Czech Republic. Our
observations started at 16:48 UT on 2026 November 13, i.e. ~2.3 h after the
trigger, and continued until 22:17 UT, cycling through the SDSS r, g and
i filters.
The afterglow is detected in all filters. In the first combined r-band
image (mean time ~2.7 h after the trigger) we measure r = 20.51 +/- 0.09
(AB, calibrated against ATLAS-RefCat2, not corrected for Galactic
extinction).
Our multicolour sequence follows the afterglow decay up to ~7.8 h after
the trigger. The analysis is ongoing.
GCN Circular 46270
Subject
GRB 261113A: SVOM/ECLAIRs refined analysis
Date
2026-11-14T11:35:24Z (19 hours ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Authors: N. Dagoneau, A. Saccardi, S. Bisero (CEA) 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 GRB 261113A (SVOM burst-id sb26111302 - GCN 46244, trigger time T0 = 2026-11-13T14:31:02 UTC).
The burst that triggered ECLAIRs onboard shows a multiple narrow peak structure. The burst duration is T90 = 7.8 -0.1 / +0.1 in the 4-120 keV energy band.
The time-averaged spectrum from T0-0.68 s to T0+7.16 s in the 5-120 keV energy range is best fitted by a cutoff power law model with a power-law index alpha = -0.61 ± 0.05 and peak energy of 108 ± 10. With this model, the 4-120 keV fluence is (2.81 ± 0.09)e-6 erg/cm^2 and the 4-120 keV photon flux is 6.89 ± 0.15 ph/cm^2/s.
Assuming a redshift of z=3.580 (GCN 46261) and a standard cosmology with H_0 = 67.3 km/s/Mpc and Omega_M = 0.315 (Planck Collaboration, 2014), we estimate the following rest-frame parameters: the isotropic energy released Eiso is (1.10 +/- 0.09)e53 erg, and the rest-frame peak energy of the time-averaged spectrum Ep,z is 495 keV. With these estimates, GRB 261113A is consistent with the distribution of Type II (collapsar-like) GRBs on the Amati relation reported by Willingale et al. 2017.
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: Nicolas Dagoneau (CEA) (nicolas.dagoneau at cea.fr)
GCN Circular 46268
Subject
Konus-Wind detection of GRB 261113A
Date
2026-11-14T11:04:45Z (19 hours ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
Via
email
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
GRB 261113A (SVOM detection: Saccardi et al., GCN 46244)
triggered Konus-Wind (KW) at T0=52263.795 s UT (14:31:03.795).
The burst light curve shows a mult-peaked structure with the total duration of ~7 s.
The emission is seen up to ~700 keV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB261113_T52263/
As observed by Konus-Wind, the burst had the total fluence
of (3.51 ± 0.61)x10^-6 erg/cm^2 and a 16-ms peak energy flux,
measured from T0, of (1.36 ± 0.24)x10^-6 erg/cm^2/s
(both in the 20 keV - 10 MeV energy range).
The spectrum of the burst (measured from T0 to T0+8.448 s)
is best fitted in the 20 keV - 15 MeV range by a power law with exponential
cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.81 (-0.30, + 0.33) and Ep = 106(-9,+10) keV, PGstat = 49/60 dof.
Fitting this spectrum by a Band GRB function yields the same values
of alpha and Ep, and an upper limit on the high energy photon index beta of -3.1
Assuming the redshift z=3.580 (Saccardi et al., GCN 46261)
and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,
and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the burst isotropic energy release E_iso to (9.49 ± 1.65)x10^52 erg,
the isotropic peak luminosity L_iso to (1.68 ± 0.29)x10^53 erg/s, and
the rest-frame peak spectral energy Ep,z to (485 ± 43) keV.
With the obtained estimates, GRB 261113A is consistent with 68% prediction bands
for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs
with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021),
see http://www.ioffe.ru/LEA/GRBs/GRB261113_T52263/GRB261113A_rest_frame.pdf
All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.
GCN Circular 46266
Subject
GRB 261113A: Liverpool Telescope observations
Date
2026-11-14T09:41:38Z (21 hours ago)
From
Dimple at University of Birmingham <dimplepanchal96@gmail.com>
Via
Web form
Dimple (U. Birmingham), A. Martin-Carrillo (UCD), D. B. Malesani (DAWN/NBI and Radboud), D. O’Neill (U. Birmingham), and B. P. Gompertz (U. Birmingham) report on behalf of a larger collaboration:
We conducted the observations of GRB 261113A (Saccardi et al., GCN 46244), with the IO:O optical camera on the 2-m robotic Liverpool Telescope in the r, i, and z filters starting on 2026-11-13 at 22:25:40 UT (7.9 hr after the burst) and continued until 2026-11-14 at 00:33:14 UT. We clearly detected the optical counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252; Zhao et al., GCN 46253; Li et al., GCN 46254; Saikia et al., GCN 46256; Adami et al., GCN 46257; Gress et al., GCN 46258; Izzo et al., GCN 46259; Brivio et al., GCN 46260; Maksut et al., GCN 46262; Moskvitin et al., GCN 46263; Perez-Garcia et al., 46264) in all the bands with 21.59 +/- 0.05 and 21.74 +/- 0.34 in r and z, respectively.
Magnitudes are calibrated against nearby Pan-STARRS stars and are not corrected for Galactic extinction.
GCN Circular 46265
Subject
GRB 261113A: SVOM/COLIBRÍ (FM-GFT) optical observations
Date
2026-11-14T09:31:10Z (21 hours ago)
From
Antonio de Ugarte Postigo at LAM, CNRS <adeugartepostigo@gmail.com>
Via
email
Antonio de Ugarte Postigo (LAM), Ramandeep Gill (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), Noémie Globus (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), Alan M. Watson (UNAM), Andrea Saccardi (CEA/Irfu), Sofia Bisero (CEA/Irfu) report:
We imaged the field of the SVOM GRB 261113A (Saccardi et al., GCN Circ. 46244) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-11-14 07:13:39.794 to 2026-11-14 07:32:58.444 UTC (from 16.6739 - 16.9958 hours after the trigger) and obtained 16 minutes of exposure in the r filter.
The data were reduced and coadded and analyzed with the COLIBRÍ pipeline. The photometry was calibrated using nearby stars from the Legacy Survey, is in the AB system, and is not corrected for Galactic extinction.
We detected the optical counterpart reported by Lin et al., GCN Circ. 46247, at a preliminary magnitude of:
r = 22.80 +/- 0.25
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 46264
Subject
GRB 261113A: 10.4m GTC spectroscopic confirmation of z = 3.58
Date
2026-11-14T09:01:28Z (21 hours ago)
From
I. Perez-Garcia at Instituto de Astrofísica de Andalucía <ipg@iaa.es>
Via
Web form
I. Perez-Garcia (IAA-CSIC), Y.-D. Hu (GXU), A. J. Castro-Tirado (IAA-CSIC), C.-Y. Dai (NJU), M. D. Caballero-Garcia, E. Fernandez-Garcia, M. Gritsevich, S. Guziy (IAA-CSIC), A. M. Garcia Rodriguez (GRANTECAN, IAC), on behalf of a larger collaboration, report:
We observed the optical afterglow of GRB 261113A (SVOM/ECLAIRs trigger sb26111302; Saccardi et al., GCN 46244) with the OSIRIS+ spectrograph on the 10.4m Gran Telescopio Canarias (La Palma, Spain). Long-slit spectra with the R1000B and R1000R grisms (600 s each, 1.23" slit) started on 2026 November 13 at 22:02 and 22:13 UT, i.e. about 7.5 hr after the trigger, with the slit centred on the optical/NIR counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252; Zhao et al., GCN 46253; Li et al., GCN 46254; Saikia et al., GCN 46256; Adami et al., GCN 46257; Gress et al., GCN 46258; Izzo et al., GCN 46259; Brivio et al., GCN 46260; Maksut et al., GCN 46262; Moskvitin et al., GCN 46263).
The afterglow is clearly detected (~21.7 AB at 6250 A within the slit). The spectrum shows:
- a damped Lyman-alpha absorption with zero flux between 5530 and 5570 A; a preliminary fit to its red wing gives log N(HI) ~ 21.4;
- the Lyman-alpha forest blueward of it, and no flux below ~4200 A, which is the Lyman limit at this redshift;
- C II 1334 absorption (blended with C II* 1335) at 6113.5 A.
These features give a redshift of z = 3.58, which confirms the VLT/X-shooter value (z = 3.580; Saccardi et al., GCN 46261).
A detailed analysis is ongoing.
We thank the GTC staff for their excellent support.
GCN Circular 46263
Subject
GRB 261113A: Mondy and AbAO optical observations
Date
2026-11-14T06:17:27Z (a day ago)
From
Alexander Moskvitin at SAO RAS <mosk@sao.ru>
Via
email
A. Moskvitin (SAO), A. Pozanenko (IKI), E. Klunko (ISTP),
R. Ya. Inasaridze (AbAO), A. Volnova (IKI), N. Pankov (IKI),
O. Spiridonova (SAO) report on behalf of IKI-GRB-FuN
and SAO GRB follow-up team.
We observed the field of the GRB 261113A (Saccardi et al., GCN 46244)
at the redshift of z = 3.580 (Saccardi et al., GCN 46261)
with the 1.5-m telescope AZT-33IK of Sayan Solar Observatory (Mondy)
and AS-32 telescope of Abastumani Observatory (AbAO) started (UT)
2026-11-13T15:06:44 and 2026-11-13T17:37:43 respectively.
The OT (Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al.,
GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252; Zhao et al.,
GCN 46253; Li et al., GCN 46254; Saikia et al., GCN 46256; Adami et al.,
GCN 46257; Gress et al., GCN 46258; Izzo et al., GCN 46259; Saccardi et
al.,
GCN 46261; Maksut et al., GCN 46262; also observed in NIR: Lin et al.,
GCN 46247; Brivio et al., GCN 46260) is clearly detected in our stacked
images. The results of some stacked epochs are as follows.
Date UT start t-T0 Exp, Filter Obj Err UL Telescope
(mid,h) (n*s) (3sigma)
2026-11-13T15:06:44 0.67833 10*60 R 19.04 +/- 0.02 22.1 AZT-33IK
2026-11-13T15:26:45 1.01208 10*60 R 19.18 +/- 0.04 21.6 AZT-33IK
2026-11-13T15:46:56 1.34847 10*60 R 19.35 +/- 0.03 22.0 AZT-33IK
2026-11-13T16:09:31 1.72486 10*60 R 19.50 +/- 0.04 22.0 AZT-33IK
2026-11-13T16:29:33 2.06708 10*60 R 19.76 +/- 0.13 20.9 AZT-33IK
2026-11-13T16:50:35 2.40931 10*60 R 19.75 +/- 0.05 22.0 AZT-33IK
2026-11-13T17:37:43 3.63917 40*60 R 20.48 +/- 0.17 21.3 AS-32
This preliminary photometry (Vega) is based on nearby SDSS stars
(Lupton 2005 transformation) and not corrected for Galactic extinction.
Based on our data, it can be suggested that there is a jet break
in the light curve, occurring between 3 and 4 hours after the onset of the
burst.
GCN Circular 46262
Subject
GRB 261113A: GRANDMA/NUTTELA-TAO early optical observations
Date
2026-11-14T05:14:17Z (a day ago)
Edited On
2026-11-14T13:40:02Z (17 hours ago)
From
Zhanat Maksut at Nazarbayev University <zhanat.maksut@nu.edu.kz>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Zhanat Maksut at Nazarbayev University <zhanat.maksut@nu.edu.kz>
Via
Web form
Z. Maksut (NU), E. Abdikamalov (NU), T. Komesh (NU), D. Berdikhan (NU), M. Krugov (FAI), K. Baigarin (NU), M. Coughlin (UMN), P. Hello (IJCLAB), S. Antier (IJCLAB), M. Pillas (IAP), A. Simon (TShNU), N. Jamsin (IJCLab) and S. Karpov (FZU) on behalf of the GRANDMA/NUTTELA-TAO:
We observed the field of GRB 261113A (Saccardi et al., GCN 46244) with the 0.7 m NUTTelA-TAO telescope at the Assy-Turgen Astrophysical Observatory, starting on 2026-11-13 at 14:32:16 UT, 74 s after the SVOM/ECLAIRs trigger. Observations continued for two hours in the Sloan g′ and i′ bands.
We detected a rapidly fading optical counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Chen et al., GCN 46251; Wun et al., GCN 46252; Zhao et. al., GCN 46253; Li et. al., GCN 46254; Saikia et. al., GCN 46256; Adami et. al., GCN 46257; Izzo et. al., GCN 46259). We report the following photometry for selected epochs:
Date UT_mid i'(mag) err(mag) g’(mag) err(mag)
-------- ------ ------- --------
2026-11-13 14:33:56 16.3 0.07 17.2 0.08
The preliminary measurements are given in AB magnitudes and are not corrected for Galactic extinction. Observation will be continued.
The data were reduced by a data processing pipeline STDWeb (Karpov et al., 2022). Images obtained with the Sloan filters were calibrated using the PanSTARRS DR1 catalog.
This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP26103591). The NUTTELA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazakhstan. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
GCN Circular 46261
Subject
GRB 261113A: VLT/X-shooter spectroscopic redshift z = 3.580
Date
2026-11-14T03:36:08Z (a day ago)
From
Andrea Saccardi at CEA/Irfu <andrea.saccardi@cea.fr>
Via
Web form
A. Saccardi (CEA/Irfu), N. Habeeb (U. Leicester), D. B. Malesani (DAWN/NBI and Radboud), E. Le Floc’h (CEA/Irfu), H. Fausey (Baylor), S. D. Vergani (Observatoire de Paris/LUX), report on behalf of the Stargate collaboration:
We observed the optical/NIR counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252; Zhao et al., GCN 46253; Li et al., GCN 46254; Saikia et al., GCN 46256; Adami et al., GCN 46257; Gress et al. GCN 46258; Izzo et al., GCN 46259; Brivio et al., GCN 46260) of the SVOM/ECLAIRs GRB 261113A (Saccardi et. al., GCN 46244) using the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph.
In a 60 s r-band exposure taken with the acquisition camera (9.98 hr after the SVOM trigger), the counterpart is detected with a magnitude r = 22.00 +/- 0.06 (AB), calibrated against one nearby Pan-STARRS object, and not corrected for Galactic extinction.
A spectrum covering the wavelength range 3000-21000 AA was secured, with a total exposure time of 4x1200 s in each of the UVB, VIS, and NIR arms. Our observations started at 00:42:17 UT on 2026 Nov 14 (10.18 hr after the SVOM trigger).
In a preliminary reduction of the spectra, we clearly detect a continuum in each arm, down to ~4200 AA. A trough is visible at around ~5567 AA (which unfortunately lies at the intersection between the UVB and VIS arms), which we interpret as due to Lyman alpha at z ~ 3.58. At a consistent redshift, we also see the onset of the Lyman forest, as well as absorption due to Ly beta and the Lyman limit. Furthermore we detect several narrow metal absorption lines consistent with C II, Si II, C IV, and Fe II, which allow us to accurately measure the redshift z = 3.580.
We acknowledge excellent support from the ESO staff in Paranal, in particular Célia Desgrange, Marcela Espinoza, Aaron Labdon, and Alonso Luna.
GCN Circular 46260
Subject
GRB 261113A: TNG NIR afterglow detection
Date
2026-11-13T23:44:05Z (a day ago)
From
Riccardo Brivio at INAF-OAB <riccardo.brivio@inaf.it>
Via
Web form
R. Brivio, P. D'Avanzo (INAF-OAB), D.B. Malesani (DAWN/NBI and Radboud), A. Melandri (INAF-OAR), V. Lorenzi, H. Stoev (INAF-TNG) report on behalf of the CIBO collaboration:
We observed the field of GRB 261113A, detected by SVOM/ECLAIRs (Saccardi et. al., GCN 46244) with the Italian 3.6m TNG telescope equipped with the near-infrared camera NICS.
The observations were carried out in the J and K bands, started on 2026-11-13 at 19:07:27 UT (i.e. 4.6 hr after the burst), and lasted for about 1 hr.
From preliminary photometry, we detect the optical/NIR counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252; Zhao et al., GCN 46253; Li et al., GCN 46254; Saikia et al., GCN 46256; Adami et al., GCN 46257; Gress et al. GCN 46258; Izzo et al., GCN 46259) with the following magnitudes:
J = 19.2 +/- 0.1 (Vega; calibrated against the 2MASS catalogue),
at a mid-time of 5.4 hr after the trigger;
K = 18.1 +/- 0.2 (Vega; calibrated against the 2MASS catalogue),
at a mid-time of 4.9 hr after the trigger.
GCN Circular 46259
Subject
GRB 261113A: NOT optical observations
Date
2026-11-13T22:30:41Z (a day ago)
From
luca.izzo@inaf.it
Via
Web form
L. Izzo (INAF/OACN & DARK/NBI), B. Schneider (LAM), D. B. Malesani (DAWN/NBI and Radboud U.), A. Saccardi (CEA/Irfu), G. Corcoran, and A. Martin-Carrillo (UCD) report on behalf of a larger collaboration:
We observed the optical counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252; Zhao et al., GCN 46253; Li et al., GCN 46254; Saikia et al., GCN 46256; Adami et al., GCN 46257; Gress et al. GCN 46258) of the SVOM/ECLAIRs GRB 261113A (Saccardi et. al., GCN 46244) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC instrument. Observations were performed starting at 20:22:14 UT on 13 November 2026 (about 5.85 hr after the SVOM trigger), and consisted of 3x300 s in the SDSS-r band.
In our stacked image, we measure an AB magnitude:
r = 21.23 ± 0.07
This magnitude is calibrated using nearby objects from the Pan-STARRS catalog and is not corrected for Galactic extinction.
GCN Circular 46258
Subject
SVOM GRB261113.60: Global MASTER-Net OT detection
Date
2026-11-13T21:17:11Z (a day ago)
Edited On
2026-11-14T13:40:15Z (17 hours ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Vladimir Lipunov at Lomonosov Moscow State University, MASTER Global Robotic NET PI <lipunov2007@gmail.com>
Via
email
O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),
V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa,
A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov,
V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)
MASTER-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the GRB261113.60 16 sec after notice time and 74 sec after trigger time at 2026-11-13 14:32:14 UT. On our first (10s exposure) set we found 1 optical transient within SVOM error-box (ra=346.321 dec=5.14333 r=0.05) brighter than 17.9.
T-Tmid Date Time Expt. Ra Dec Mag
---------|---------------------|-------|-----------------|-----------------|-------
79 2026-11-13 14:32:14 10 (23h 05m 16.95s , +05d 10m 18.4s) 15.7
The 5-sigma upper limit has been about 17.9mag
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 46257
Subject
GRB 261113A: OHP/T193 optical detections of the afterglow
Date
2026-11-13T20:16:05Z (a day ago)
From
Christophe Adami at LAM <christophe.adami@lam.fr>
Via
Web form
C. Adami (LAM/Pytheas/AMU), B. Schneider (LAM), E. Le Floc’h (CEA/IRFU/DAp), S. Basa (LAM/OHP/Pytheas/AMU), report on behalf of the MISTRAL-GRB collaboration.
We observed the field of the SVOM/ECLAIRs GRB 261113A (Saccardi et al., GCN 46244) with the 1.93-m T193 telescope at the Observatoire de Haute-Provence (France), equipped with the MISTRAL spectro-imager.
We obtained 19 min, 30 min and 40 min of total integration times in the r, z, and g bands respectively, at mid-observing times of 2026-11-13 18:22UT, 2026-11-13 18:38UT and 2026-11-13 18:55UT.
In the preliminary stacked images, we detect in g, r and z bands the afterglow at the position of Gress et al. (GCN 46246), Lin et al. (GCN 46247), Lei et al. (GCN 46248), Li et al. (GCN 46249), Yin et al. (GCN 46250), Chen et al. (GCN 46251), Wu et al. (GCN 46252), Zhao et al. (GCN 46253), Li et al. (GCN 46254) and Saikia et al. (GCN 46256) with preliminary magnitudes of:
g = 22.08 +/- 0.21
r = 20.47 +/- 0.08
z = 20.16 +/- 0.08
The photometric calibration was performed using nearby stars from the Legacy Survey DR10 catalog (Dey et al. 2019) and the magnitudes are not corrected for Galactic extinction.
We acknowledge the excellent support from the Observatoire de Haute-Provence and in particular J. Balcaen. We also thank the SOPHIE observer: Neda Heidari.
GCN Circular 46256
Subject
GRB 261113A: GROWTH-India Telescope optical observations
Date
2026-11-13T19:46:50Z (a day ago)
From
Aditya Pawan Saikia at IIT Bombay <adityaps@iitb.ac.in>
Via
Web form
A.P. Saikia, A. Sarkar, Harshita, S. Patil, V. Swain, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and R. Norboo (IAO) report on behalf of the GIT team:
We observed the field of GRB 261113A by SVOM/ECLAIRs & SVOM/GRM (Saccardi et al., GCN 46244) with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2026-11-13 15:12:50 UT, i.e., 41.82 minutes after the SVOM GRM trigger. We obtained multiple exposures of 300 and 360 seconds in r' filter. We clearly detected the afterglow in our individual images at the positions given by Lin et. al., (GCN 46247). The photometry result follows as:
| MJD (mid) | t-t0 (hr) | Filter | Exposure Time (s) | Magnitude (AB) | Limiting Magnitude (5-sigma) |
|---|---|---|---|---|---|
| 61357.63565 | 0.74 | r' | 300 | 19.31 +/- 0.04 | 20.88 |
| 61357.68037 | 1.81 | r' | 360 | 20.00 +/- 0.09 | 20.57 |
Our result is consistent with Lin et al., (GCN 46247), Lei et al., (GCN 46248), Li et al., (GCN 46249), Yin et al., (GCN 46250), Chen et al., (GCN 46251), Xin et al., (GCN 46252), Zhao et al., (GCN 46253), Li et al., (GCN 46254).
The measurement is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
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 46254
Subject
GRB 261113A: SVOM/VT optical decay slope
Date
2026-11-13T19:00:06Z (a day ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, C. Wu, Y. L. Qiu, Y. N. Ma, L. P. Xin, L. J. Chen, 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), J. T. Palmerio, A. Saccardi, S. Bisero (CEA/Irfu) report on behalf of the SVOM/VT team.
SVOM/VT performed observation with automatic slew on the field of GRB 261113A detected by SVOM/ECLAIRs (sb26111302, Saccardi et al., GCN 46244). Our observation started on 2026:11:13T14:33:08 UT, 126.0 seconds in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously .
With the limited X-band data available, the optical counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Wu et al., GCN 46252; Zhao et al., GCN 46253 ) was clearly detected in single frame of both channels. It shows a decay with a slope index of -0.8 over our 1.5-hour observation span. The following measurements are in AB magnitudes and are not corrected for Galactic extinction:
Mid time | Band | Exposure Time | Brightness
133 s VT_B 15 s 17.16 +/- 0.07 mag
133 s VT_R 15 s 16.27 +/- 0.06 mag
More observations are 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 46253
Subject
GRB 261113A: Optical detection with 60cm Panzhihua Telescope
Date
2026-11-13T17:58:22Z (2 days ago)
From
Jiewei Zhao at SWIFAR, YNU <meow.jiewei.zhao@gmail.com>
Via
Web form
Jiewei Zhao, Xinchao Wang, Brajesh Kumar, Wenyu Li, Guowang Du, Yuanpei Yang (SWIFAR, YNU), Bin-Bin 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 261113A field detected by SVOM/ECLAIRs (Saccardi et al., GCN 46244). The observations were initiated at 2026-11-13T16:06:31.98 (~1.59 hours after the trigger) with the 60cm Panzhihua Telescope located at the Sichuan South Observatory (SSO), China. Several frames with 300s exposure each were acquired in L band.
We clearly detect the optical counterpart (Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Chen et al., GCN 46251; Wu et al., GCN 46252) in the stacked image. The L-band preliminary photometric magnitudes are following:
MJD (Exp_Start) MAG FILTER EXPTIME
61357.671203 20.18 +/- 0.13 L 5 x 300s
61357.690732 20.44 +/- 0.19 L 5 x 300s
Note that the expected Galactic extinction is not applied in our estimates.
GCN Circular 46252
Subject
GRB 261113A: SVOM/VT optical observation from VHF data
Date
2026-11-13T17:09:48Z (2 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
C. Wu, L. P. Xin, Y. L. Qiu (NAOC), J. T. Palmerio, A. Saccardi (CEA/Irfu), E. Arrigoni (INAF/IASF-Milano), S. Bisero (CEA/Irfu)
on behalf of the SVOM/VT team.
After the trigger by SVOM/ECLAIRs (sb26111302) at 2026-11-13T14:31:02 UTC (T0), SVOM performed an automatic slew on the burst location (Saccardi, GCN 46244). 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. 346.32057, 5.17185 degrees, corresponding to:
R.A. (J2000) = 23h05m16.93s
Dec. (J2000) = +05d10m18.6s
with an uncertainty of 0.50 arcsec. This location is consistent with the optical afterglow reported by Lin et al. (GCN 46247), Lei et al. (GCN 46248), Li et al. (GCN 46249), and Yin et al. (GCN 46250). 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) |
|---|---|---|---|---|
| 2026-11-13T15:34:03 | 63.0 min | 6*70 sec | 20.38 +/- 0.02 | 19.31 +/- 0.02 |
| 2026-11-13T16:12:33 | 101.5 min | 5*70 sec | 20.94 +/- 0.04 | 19.66 +/- 0.03 |
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 46251
Subject
GRB 261113A: Xinglong 2.16m optical afterglow detection
Date
2026-11-13T17:06:29Z (2 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
L. J. Chen, C. Wu, L. P. Xin, H.L. Li, Y. N. Ma, Y. L. Qiu, J. Wang, X. H. Han, P. P. Zhang, J. Zheng, J. J. Jia, Z. Fan, J. Y. Wei (NAOC), Q. Zhao report on behalf of SVOM follow-up team:
We observed the field of GRB 261113A triggered by SVOM/ECLAIRs (sb26111302, Saccardi et al., GCN 46244) using the 2.16m telescope located at Xinglong observatory, China, equipped with the BFOSC camera. We obtained 6*60s frames in R-band, starting at 15:07:13 UT on 2026-11-13, about 36 min after the trigger.
The optical counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250) was well detected in our R-band image.
We measure a magnitude of R ~ 18.9 for the optical afterglow.
We thank the staff at Xinglong observatory for their excellent support.
GCN Circular 46250
Subject
GRB 261113A : SVOM/GWAC-F60 optical afterglow detection
Date
2026-11-13T16:49:43Z (2 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
S.J. Yin (GXU), Y.X. Guan,C. Wu, L.P. Xin, L.J. Chen, X.H. Han, P.P. Zhang, J.L. Wang (NAOC), Y.Y. Shi, E.W. Liang, X.G. Wang(GXU) report on behalf of the SVOM follow-up team:
We observed the field of GRB261113A detected by SVOM/ECLAIRs (A. Saccardi et al., GCN 46244), with the GWAC-F60 at Xinglong Observatory, China. F60 started observing 2026-11-13 from 14:32:41.4 to 14:51:35.7 UTC.
We found a candidate at RA, DEC = 346.32051 , 5.17192 degrees:
R.A. (J2000) = 23h05m16.92s
Dec. (J2000) = +05d10m18.91s
with an uncertainty of ~ 0.5 arcsec.
The coordinates are consistent with those provided by the SYSU 80cm (Lin et al., GCN 46247）.The optical counterpart faded from 16.1 to 18.5 mag over a time span of ~ 19 min（Lei et al., GCN 46248; Li et al., GCN 46249).
We measure the following magnitudes calibrated against the USNO-B1.0 catalog, and not corrected for Galactic extinction.
Two 60cm GWAC-F60(A/B) are operated by Guangxi University and NAOC, CAS, at Xinglong Observatory, China. The field of view is 19*19 arcmin.
GCN Circular 46249
Subject
GRB 261113A: GMG Optical Observation
Date
2026-11-13T16:36:35Z (2 days ago)
From
Rui-Zhi Li at Yunnan Observatories, CAS <liruizhi@ynao.ac.cn>
Via
Web form
R.-Z. Li, B.-T. Wang, F.-F. Song, J. Mao, J.-G. Wang and B. Wang (YNAO, CAS) report:
We observed the field of GRB 261113A (Saccardi et al., GCN 46244, T0 at 2026-11-13T14:31:02) using the GMG-2.4m telescope at the Lijiang Observatory.
The observation began at 2026-11-13T15:23:45, about 0.88 hours after the trigger.
The optical counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248) was well detected in our r-band image.
The preliminary analysis results are shown as follows:
Start time [UTC] Exposure [s] Tmid-T0 [h] Filter AB Magnitude 5-sigma U.L.
----------------------- -------------- ------------- -------- -------------- --------------
2026-11-13 15:23:45.073 300 0.92 r 19.39 ± 0.02 22.3
The given magnitudes are derived based on calibration against Pan-STARRS field stars, and are not corrected for the expected Galactic foreground extinction, corresponding to a reddening of E(B-V) = 0.052 mag in the direction of the optical counterpart (Schlafly & Finkbeiner 2011).
GCN Circular 46248
Subject
GRB 261113A: JinShan optical afterglow detection
Date
2026-11-13T15:57:38Z (2 days ago)
From
liuxing@nao.cas.cn
Via
Web form
L. Lei (HUST), X. Liu, D. Xu, J. An, L.B. He, S.Q. Jiang, Z.P. Zhu (NAOC), A.D. Zhu (HUST) report:
We observed the field of GRB 261113A detected by SVOM/ECLAIRs (GCN 46244) using the 100A and 100C telescopes of the JinShan project locate at Altay, Xinjiang, China. A series of Sloan r-band frames were obtained.
An uncatalogued and varying optical source is detected within the SVOM/ECLAIRs error circle at coordinates
R.A. (J2000) = 23:05:16.96
Dec. (J2000) = +5:10:18.65
with an uncertainty of ~1 arcsec. The source has r = 19.14 +/- 0.05 mag at a median time of 0.5 hr post-trigger, calibrated with nearby PanSTARRS stars.
We thus think the source is the optical afterglow of GRB 261113A.
GCN Circular 46247
Subject
GRB 261113A: K-band infrared counterpart candidate by the SYSU 80cm infrared telescope
Date
2026-11-13T15:48:25Z (2 days ago)
From
linp@mail2.sysu.edu.cn
Via
Web form
Pu Lin, Jing-Kai Sun, Zhong-Nan Dong, Jin-Ji Li, Yun Shi, Rui-Chen Gao, Jia-Qi Lin, Hao-Nan Yang, Hao-Ran Zhang, Jian-Hong Cao, Shu-Quan Bai, Si-Rui Huang, Lu-Yao Wen, Zhi-Xiang Tan, 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 261113A, detected by SVOM/ECLAIRs (A. Saccardi et al., GCN 46244), using the Sun Yat-sen University (SYSU) 80 cm infrared telescope in the K band. Our observations were carried out on 2026-11-13 from 14:37:32 to 15:09:43 UT (from ~6.5 to ~38.7 minutes after the SVOM/ECLAIRs trigger), using stacked images in the K band (73 x 20 s, 1460 s total exposure).
In the stacked image, we detect a point-like near-infrared source at the following coordinates (J2000):
RA = 23:05:16.94 (346.320585)
Dec = +05:10:19.27 (+5.172020)
The source is located approximately 65 arcsec from the reported SVOM/ECLAIRs position (A. Saccardi et al., GCN 46244), slightly outside the quoted 47 arcsec error radius, and we measure a magnitude of:
K = 16.49 +/- 0.083 mag (Vega).
Further observations are ongoing.
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 46246
Subject
SVOM GRB261113.60: Global MASTER-Net observations report
Date
2026-11-13T15:28:27Z (2 days ago)
Edited On
2026-11-14T05:38:45Z (a day ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Edited By
K.L. Page at U Leicester <klp5@leicester.ac.uk> on behalf of Vladimir Lipunov at Lomonosov Moscow State University, MASTER Global Robotic NET PI <lipunov2007@gmail.com>
Via
email
O.Gress, N.Budnev(ISU)
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 (Lomonosov MSU)
D.Buckley (SAAO),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
A.Sosnovskij (Lomonosov MSU)
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory)
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
R.Rebolo (The Instituto de Astrofisica de Canarias)
M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)
MASTER-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the SVOM GRB261113.60 (trigger No 1794580260,23h 05m 17.23s , +05d 08m 36.2s, R=0.0403) errorbox 13 sec after notice time and 74 sec after trigger time at 2026-11-13 14:32:14 UT, with upper limit up to 18.3 mag. The observations began at zenith distance = 52 deg. The sun altitude is -46.6 deg.
The galactic latitude b = -49 deg., longitude l = 81 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3532578
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
79 | 2026-11-13 14:32:14 | MASTER-Tunka | (23h 03m 12.73s , +04d 46m 34.0s) | C | 10 | 18.3 |
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 46244
Subject
GRB 261113A: SVOM detection of a bright burst
Date
2026-11-13T14:52:18Z (2 days ago)
Edited On
2026-11-13T15:28:59Z (2 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Edited By
K.L. Page at U Leicester <klp5@leicester.ac.uk> on behalf of SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
A. Saccardi (CEA/Irfu), E. Arrigoni (INAF/IASF-Milano), S. Bisero, N. Dagoneau, D. Gotz, S. Schanne, B. Cordier (CEA/Irfu), report on behalf of the SVOM mission team:
At 2026-11-13T14:31:02 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 261113A (SVOM burst-id sb26111302).
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 19 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 56.88 in the [8-120] keV energy band over a time window of 10.20 seconds starting at 2026-11-13T14:30:59.
The localization of the best alert is R.A., Dec. 346.3218, 5.1434 degrees (J2000) with a 90% confidence level (C.L.) radius of 2.42 arcmin (including systematic error of 2 arcmin added in quadrature).
The SVOM/ECLAIRs light curve showed a multiple narrow peak structure with a T90 duration of about 7.447 (-0.084 +0.121) s.
This burst also triggered SVOM/GRM at 2026-11-13T14:31:01 on a timescale of 0.10 seconds with an SNR of 6.90. The SVOM/GRM light curve showed a multiple narrow peak structure with a T90 duration of about 10 s.
SVOM slewed to the burst.
SVOM/MXT began observing the field at 2026-11-13T14:33:13 UTC, 131 seconds after T0. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec. 346.3133, 5.1560 degrees:
R.A. (J2000) = 23h05m15s
Dec. (J2000) = 5d09m21s
with a 90% C.L. radius of 47 arcseconds.
This location is 0.91 arcminutes from the ECLAIRs onboard position. This position may be improved as more data is received.
VT began observing the field after the slew. The analysis of the data will be published 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 Sofia Bisero: sofia.bisero@cea.fr.
Please contact the BA by email if you require additional information.