GRB 260117A
GCN Circular 43456
Subject
GRB 260117A: Swift-XRT afterglow detection
Date
2026-01-19T20:06:20Z (2 months ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB),
D.N. Burrows (PSU), S. Lanava (PSU), S. Dichiara (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester)
reports on behalf of the Swift-XRT team:
Swift-XRT has conducted further observations of the field of the
SVOM/ECLAIRs-detected burst GRB 260117A. The observations now extend
from T0+12.5 ks to T0+153.1 ks and have a total exposure time of 5.7
ks.
Of the sources previously reported, "Source 1" is fading with >3-sigma
significance, and is therefore likely the GRB afterglow. Using 1064 s
of PC mode data and 1 UVOT image, we find an enhanced XRT position
(using the XRT-UVOT alignment and matching UVOT field sources to the
USNO-B1 catalogue): RA, Dec = 188.13864, +43.91274 which is equivalent
to:
RA (J2000): 12h 32m 33.27s
Dec(J2000): +43d 54' 45.9"
with an uncertainty of 4.9 arcsec (radius, 90% confidence). This
position is 2.5 arcmin from the SVOM/ECLAIRs position, and 0.2 arcsec
from the SVOM/VT optical candidate reported in GCN Circ. 43411. The
source is fading with alpha >0.2.
The results of the XRT-team automatic analysis are available at
https://www.swift.ac.uk/xrt_products/00021898.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021898.
This circular is an official product of the Swift-XRT team.
GCN Circular 43451
Subject
GRB 260117A: ZTSh optical upper limit
Date
2026-01-19T11:53:13Z (2 months ago)
From
Alina Volnova at IKI RAS <alinusss@gmail.com>
Via
Web form
A. A. Volnova (IKI), V. Rumyantsev (CrAO), N. Pankov (HSE, IKI), A. S. Pozanenko (IKI) report on behalf of IKI-GRB-FuN:
We observed the field of the SVOM GRB 260117A (Palmerio et al., GCN Circ. 43437) with the ZTSH telescope of CrAO starting on 2026-01-18 at 20:50:34 UT and taking several 120s exposures in R-band. At the position of the source detected by Swift/XRT (Salvaggio et al., GCN 43439; Evans et al., GCN 43438) we do not detect the optical source reported previously by SVOM/VT (Li et al., GCN Circ. 43441) and SVOM/COLIBRÍ (FM-GFT; Fortin et al., GCN 43445). Preliminary photometry is the following:
Date UT start t-T0 Exp. Filter Obj. Err. UL Site/Telescope
(mid,days) (n*s) (3sigma)
2026-01-18 20:50:34 1.07354 37*120 R n/d n/d 23.2 CrAO/ZTSh
The photometry is based on nearby stars from the USNO-B1 catalogue (R2 magnitudes) and is not corrected for the Galactic extinction.
GCN Circular 43445
Subject
GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
Date
2026-01-18T19:35:14Z (2 months ago)
From
Alan Watson at UNAM <alan@astro.unam.mx>
Via
Web form
Francis Fortin (IRAP), William H. Lee (UNAM), Benjamin Schneider (LAM), Noémie Globus (UNAM), Stéphane Basa (UAR Pytheas), Alan M. Watson (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), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Asuka Kuwata (UNAM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Antonio de Ugarte Postigo (LAM), J. T. Palmerio (CEA/Irfu) report:
We imaged the field of the SVOM GRB 260117A (Palmerio et al., GCN Circ. 43437) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-01-18 07:56 to 13:25 UTC (from 12.22 to 17.70 hours after the trigger) and obtained 240 minutes of simultaneous exposure in the r and z filters.
The data were reduced, coadded, calibrated, and analyzed with the COLIBRÍ ASU 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.
At the position of the source detected with Swift/XRT (Salvaggio et al., GCN 43439; Evans et al., GCN 43438) and SVOM/VT (Li et al., GCN Circ. 43441), we detect a source with preliminary magnitudes of
r = 24.27 +/- 0.12,
z > 23.7 (3 sigma).
It is not trivial to compare our results with SVOM/VT as our filters are different. Our r filter lies within VT_B and our z filter lies within VT_R. Nevertheless, our z upper limit does suggest that the source seen by Li et al. has faded and therefore is the afterglow.
We also note that in deep CFHT images from previous epochs, there is a source at this position with r = 24.41 ± 0.17. The source is also faintly visible in the PS1 r image. Therefore, we suggest that this source might be the host galaxy.
We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams.
COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico.
GCN Circular 43441
Subject
GRB 260117A: SVOM/VT optical candidate
Date
2026-01-18T08:09:33Z (2 months ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, C. Wu, Y. N. Ma, Y. L. Qiu, Z. H. Yao, L.P. Xin, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. R. Xu, J. S. Deng, J. Y. Wei (NAOC), J. T. Palmerio, D. Adrien(CEA/Irfu) report on behalf of the SVOM/VT team.
SVOM/VT performed ToO observation for the long faint burst GRB 260117A triggered by SVOM/ECLAIRs (sb26011705, Palmerio et al., GCN 43437). The observation started at 2026-01-17T22:14:53 UTC, i.e., 2.398 hours post trigger in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
An uncatalogued source was detected only in VT_R stacked images within the error box of EP/FXT and source 1 from Swift-XRT (Salvaggio et al., GCN 43439; Evans et al., GCN 43438), compared to the Legacy survey catalog. It is also located in the error box of ECLAIRs (Palmerio et al., GCN 43437). The position is at R.A., Dec. = 188.138564, 43.912747 degrees, equivalent to:
R.A. (J2000) = 12:32:33.25
Dec. (J2000) = +43:54:45.89
with an uncertainty of 0.5 arcsec.
The measurements in AB magnitudes are given below:
Mid_time Band Exposure Time Magnitude (AB)
4.36 hour VT_R 68*70 sec 22.98+/-0.25
4.36 hour VT_B 73*70 sec >23.8
Our photometry was not corrected for Galactic extinction.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS.
GCN Circular 43440
Subject
GRB 260117A: SVOM/C-GFT upper limit
Date
2026-01-18T05:54:34Z (2 months ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
C. Wu (NAOC), Z. Kang (CHO), L.P. Xin, X.H. Han, P.P. Zhang, X.M. Lu (NAOC), Z.W. Li, Y. Lv (CHO), R.S. Zhang, Y.J. Xiao, Y.L. Qiu, J. Wang, J.S. Deng, L. Huang, J.Y. Wei (NAOC), J. T. Palmerio, D. Adrien(CEA/Irfu) report on behalf of the SVOM/C-GFT team:
We observed the field of GRB 260117A (SVOM trigger: sb26011705) detected by SVOM/ECLAIRs (Palmerio et al., GCN 43437) with LATIOS on SVOM/C-GFT. Observations started at 2026-01-17T19:44:47 UTC, ~82 seconds after the trigger.
We obtained g, r, and i-band follow-up imaging. After preliminary analysis，no credible candidate was detected within the error box provided by EP/FXT and Swift/XRT (Evans et al., GCN 43438; Salvaggio et al., GCN 43439) in our images. The 3-upper limits in the early phase are:
| Mid_t - T0 (min) | Exposure Time (s) | Band | Upper Limit (AB) |
|---|---|---|---|
| 4.6 | 5×10 | i | 18.5 |
| 14.1 | 10×30 | g | 19.7 |
The photometry was calibrated against UCAC4 catalogue and no correction for Galactic dust extinction was applied.
We thank the observation assistants Bo-Wen Li and Hong-Xv Xue at Jilin observatory for their excellent support.
The Chinese Ground Follow-up Telescope (C-GFT) for the SVOM mission is located at Jilin Station, Changchun Observatory, National Astronomical Observatories, CAS. It features two instruments: (1) CATCH at the Cassegrain focus with a 21 arcsec x 21 arcsec FOV for simultaneous g/r/i-band imaging, and (2) LATIOS, a 4k x 4k CMOS camera at the prime focus with a 1.28 deg x 1.28 deg FOV that images in g, r, and i bands via filter switching.
GCN Circular 43439
Subject
GRB 260117A: Swift-XRT observations
Date
2026-01-18T04:47:03Z (2 months ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB),
D.N. Burrows (PSU), S. Lanava (PSU), S. Dichiara (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester)
reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
SVOM/ECLAIRs-detected burst GRB 260117A, collecting 2.9 ks of Photon
Counting (PC) mode data between T0+12.5 ks and T0+19.8 ks.
Two uncatalogued X-ray sources have been detected, however none of them
is above the RASS limit or shows definitive signs of fading. Therefore,
at the present time we cannot identify which, if any, is the afterglow.
Details of these sources are given below:
Source 1:
RA (J2000.0): 188.1380 = 12h 32m 33.12s
Dec (J2000.0): +43.9131 = +43d 54' 47.3"
Error: 5.3 arcsec (radius, 90% conf.)
Count-rate: (8.6 +/- 2.1)e-3 ct s^-1
Distance: 152 arcsec from SVOM/ECLAIRs position.
Flux: (3.90 +/- 0.93)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
Source 2:
RA (J2000.0): 188.3043 = 12h 33m 13.03s
Dec (J2000.0): +43.8449 = +43d 50' 41.7"
Error: 5.8 arcsec (radius, 90% conf.)
Count-rate: (4.0 [+1.7, -1.4])e-3 ct s^-1
Distance: 343 arcsec from SVOM/ECLAIRs position.
Flux: (1.29 [+0.56, -0.44])e-10 erg cm^-2 s^-1 (observed, 0.3-10 keV)
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/00021898.
This circular is an official product of the Swift-XRT team.
GCN Circular 43438
Subject
GRB 260117A: Swift ToO observations
Date
2026-01-17T23:10:27Z (2 months ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the SVOM/ECLAIRs-detected event
GRB 260117A. Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021898
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the SVOM/ECLAIRs event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular 43437
Subject
GRB 260117A: SVOM detection of a long faint burst
Date
2026-01-17T20:12:45Z (2 months ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
J. T. Palmerio, D. Adrien, S. Schanne, D. Turpin (CEA/Irfu), F. Piron (LUPM), report on behalf of the SVOM mission team:
At 2026-01-17T19:43:25 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260117A (SVOM burst-id sb26011705).
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 1 alert. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 8.05 in the [5-20] keV energy band over a time window of 20.48 seconds starting at 2026-01-17T19:43:05.
The localization of the best alert is R.A., Dec. 188.1895, 43.8927 degrees:
R.A. (J2000) = 12h32m45.49s
Dec. (J2000) = 43d53m33.87s
with a 90% confidence level (C.L.) radius of 9.77 arcmin (including systematic error of 2 arcmin added in quadrature).
This burst was also detected by SVOM/GRM with a significance of 8.90.
The SVOM/GRM light curve shows a double peak structure with a T90 duration of about 20 (-4 +5) seconds.
Due to the detection significance being below the slew threshold, no immediate slew was performed on this burst.
No X-ray observation could be performed by SVOM/MXT for the time being. No optical observation could be performed by SVOM/VT for the time being.
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 Jesse T. Palmerio: jesse.palmerio@cea.fr.
Please contact the BA by email if you require additional information.