GRB 260619A
GCN Circular 45041
Subject
GRB 260619A: SVOM/ECLAIRs refined analysis
Date
2026-06-24T20:31:19Z (4 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Nicolas Dagoneau (CEA), Marius Brunet (IRAP), Wenjin Xie (NAOC)
Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of GRB 260619A (SVOM burst-id sb26061901).
The burst that triggered ECLAIRs onboard (GCN 44985) consists of a faint single peak lightcurve with a duration of about 40 sec in the 8-50 keV energy band.
The time-averaged spectrum (from T0-40.96 s to T0) in the energy range 5-120 keV is best fit by a blackbody model with a temperature kT = 6.6 -1.3/+1.6 keV. With this model, the 4-120 keV fluence is (2.03 +/- 0.63)*E-7 erg/cm² and the 4-120 keV photon flux is (2.02 +/- 0.33)*E-1 ph/cm²/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.
The SVOM/ECLAIRs point of contact for this burst is: N. Dagoneau (nicolas.dagoneau at cea.fr)
GCN Circular 45015
Subject
GRB 260619A: NOT optical observations
Date
2026-06-20T13:36:17Z (8 days ago)
From
Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani@nbi.ku.dk>
Via
Web form
D. B. Malesani (DAWN/NBI and Radboud), A. Martin-Carrillo (UCD), A. Saccardi (CEA/Irfu), G. Corcoran (UCD), B. Schneider (LAM), report on behalf of a larger collaboration:
We observed the optical afterglow (Ducoin et al., GCN 44999; Li et al., GCN 45003; He et al., GCN 45008) of the SVOM GRB 260619A (Goto et al., GCN 44985) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations were carried out in the SDSS i band and consisted of 4x300 s exposures.
The optical afterglow is detected with an AB magnitude i = 22.26 +- 0.08 at the mean epoch Jun 20.207 UT (1.114 days after trigger), calibrated against nearby stars from the Pan-STARRS catalog, and not corrected for Galactic extinction.
We note that our measurement indicates little evolution of the counterpart brightness compared to previously reported flux values. We encourage further follow-up to better understand the nature of this object.
GCN Circular 45008
Subject
GRB 260619A: TRT optical counterpart confirmation
Date
2026-06-19T16:30:48Z (9 days ago)
From
L. B. He at NAOC <helb@bao.ac.cn>
Via
Web form
L.B. He (NAOC), K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), S.Y. Fu (HUST), J. An, X. Liu, Z.P. Zhu, S.Q. Jiang, D. Xu (NAOC) report:
We observed the field of GRB 260619A detected by SVOM/ECLAIRs (Goto et al., GCN 44985) using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Cerro Tololo Inter-American Observatory, Chile (CTO).
The previously reported optical counterpart (Ducoin et al., GCN 44999; Li et al., GCN 45003) is detected in our stacked images with a brightness of r~21.4 at a median time of 3.95 hrs post-trigger, calibrated with Pan-STARRS DR2 stars in the field and not corrected for Galactic extinction.
GCN Circular 45003
Subject
GRB 260619A: SVOM/VT optical counterpart confirmation
Date
2026-06-19T14:30:00Z (9 days ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, L. P. Xin, Y. L. Qiu, C. Wu, Y. N. Ma, 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. Palmerio (CEA/Irfu), Kuan Liu (GXU), Zhiyong Liu (GZNU) report on behalf of the SVOM/VT team.
SVOM/VT performed ToO observations of GRB260619A triggered by SVOM/ECLAIRs (sb26061901, Goto et al., GCN 44985). The observation started at 2026-06-19T05:54:32 UTC, approximately 3.71 hours post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously.
The optical candidate (Ducoin et al., GCN 44999) was detected in both channels. The following measurements are in the AB magnitude and are not corrected for Galactic extinction:
Mid time | Band | Exposure Time | Brightness
6.13 h VT_B 14*70 s 22.56 +/- 0.15 mag
6.14 h VT_R 13*70 s 22.63 +/- 0.18 mag
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 44999
Subject
GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
Date
2026-06-19T13:01:35Z (9 days ago)
From
J.-G. Ducoin at CPPM <ducoin@cppm.in2p3.fr>
Via
Web form
Jean-Grégoire Ducoin (CPPM), Rosa L. Becerra (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Leonardo García-García (UNAM), Ramandeep Gill (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), Antonio de Ugarte Postigo (LAM), Alan M. Watson (UNAM), Hatsune Goto (RIKEN), Jun Yang (ZZU), Kuan Liu (GXU), Zhiyong Liu (GZNU) report:
We imaged the field of the SVOM GRB 260619A (Goto et al., GCN Circ. 44985) using the DDRAGO two-channel wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-06-19 09:49:05 to 11:11:49 UTC (from 7.62 to 9.01 hours after the trigger) and obtained 61 minutes of simultaneous exposure in the r and z filters.
The data were reduced, coadded and analysed with the COLIBRÍ ASU pipeline and cross-analyzed with STDWeb/STDPipe (Karpov 2025). 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) consistent with the ECLAIRs 11.33 arcmin error circle (Goto et al., GCN Circ. 44985) at:
RA(J2000) = 23:56:24.46 = 359.10192 degrees
Dec(J2000) = -15:27:41.0 = -15.46140 degrees
with an uncertainty of 0.5 arcsec.
The preliminary unsubtracted magnitude derived for that source is:
r = 22.13 +/- 0.05
z = 21.91 +/- 0.14
The lack of clear evidence for variability, prevents a firm confirmation that this source is the optical afterglow of GRB 260619A.
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 44992
Subject
GRB 260619A: Kilonova-Catcher optical upper limit
Date
2026-06-19T09:54:36Z (9 days ago)
From
Damien Turpin at CEA-Saclay <dturpin-astro@hotmail.com>
Via
Web form
R. Hellot (KNC), D. Turpin (CEA-Saclay/Irfu), C. Andrade(UMN), S. Antier (IJCLab), M. Coughlin (UMN), S. Karpov (FZU), P. Hello (IJCLAB), M. Pillas (IAP) on behalf of the GRANDMA/Kilonova-Catcher collaboration:
We observed the field of GRB 260619A detected by SVOM/ECLAIRs (Goto et al., GCN 44985) with the GRANDMA citizen science project Kilonova-catcher (KNC). Our observations were performed with a CDK17 telescope located at AITP San Pedro Chile Observatory and operated by R. Hellot. Our observations started at TGRB+4.0 hours and were taken with the sdssr filter.
In our stacked frames, subtracted from the PanSTARRS DR2 template image, we do not detect any optical uncatalogued source inside the SVOM/ECLAIRs error box.
We report our follow-up results in the table below:
| Tmid-TGRB (hr) | Exp (s) | Filter | Magnitude | Instrument |
|---|---|---|---|---|
| 4.29 | 12 x 300s | r (AB) | 20.3 (5 sigma) | AITP |
All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained with the Sloan filters were calibrated using the PanSTARRS DR1 catalog.
We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023).
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 44985
Subject
GRB 260619A: SVOM possible detection of a faint burst
Date
2026-06-19T03:10:53Z (9 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Hatsune Goto (RIKEN), Jun Yang (ZZU), Kuan Liu (GXU), Zhiyong Liu (GZNU) report on behalf of the SVOM mission team:
At 2026-06-19T02:12:40 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260619A (SVOM burst-id sb26061901).
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 Image Trigger (IMT), which produced a sequence of 1 alert. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 6.90 in the [8-50] keV energy band over a time window of 40.96 seconds starting at 2026-06-19T02:11:59.
The localization of the best alert is R.A., Dec. 359.0538, -15.3917 degrees:
R.A. (J2000) = 23h56m12.91s
Dec. (J2000) = -15d23m30.15s
with a 90% confidence level (C.L.) radius of 11.33 arcmin (including systematic error of 2 arcmin added in quadrature).
There’re 3 High Proper Motion Stars in the ECLAIRs error box:
LP 764-29
GR* 276
BD-16 6388
These sources may cause this trigger.
Due to the detection significance being below the slew threshold, no immediate slew was performed on this burst.
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 Kuan Liu: liuk@st.gxu.edu.cn.
Please contact the BA by email if you require additional information.