GRB 251129A
GCN Circular 42900
Subject
GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
Date
2025-11-29T20:56:25Z (2 days ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Via
email
R. Sanchez-Ramirez, A. J. Castro-Tirado, S. Guziy, M.D. Caballero-Garcia, I. Perez-Garcia, E. Fernandez-Garcia and S. Wu (IAA-CSIC), A.M. Garcia Rodriguez (IAC), D. Gonzalez (GTC), C. Hernandez (GTC), M. Gritsevich (Univ. of Helsinki), Y.-D. Hu (GXI) and L. Piro (INAF), on behalf of a larger collaboration, report:
Following the detection of GRB 251129A by SVOM/ECLAIRs (Tan et al., GCN 42877, GCN 42879), Einstein Probe (EP Team et al., GCN 42884), and by additional Swift ToO observations (Evans, GCN 42888), we observed the optical afterglow detected by Angulo et al. (GCN 42880) and further reported (Watson, GCN 42883, Wu et al., GCN 42882, Masi, GCN 42885, Li et al., GCN 42887, Lipunov et al. GCN 42892, Moskvitin et al., GCN 42897 and Guziy et al., GCN 42899), with the 10.4m GTC telescope, at the Spanish Roque de los Muchachos Observatory, on the island of La Palma, equipped with the OSIRIS+ instrument.
The spectroscopic data consisted of 900s exposures using grisms R1000B and R2500I, covering the spectral range between 3,600 and 10,000 A. The observations started on Nov 29, 05:32 UT (i.e. 3.01 h after the burst trigger), and were carried out at high airmass (X~2). From a preliminary reduction, we find a highly absorbed continuum, showing several metal absorption with complex velocity structure. We interpret these lines as coming from CrII, FeII, FeII*, MgII, NiII, SiII, ZnII, all at z=1.460. The detection of iron fine structure lines links this system to the GRB.
GCN Circular 42899
Subject
GRB 251129A / EP251129a: OSN and CAHA optical follow-up
Date
2025-11-29T20:25:20Z (2 days ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Via
email
S. Guziy, A. Sota, M.D. Caballero-Garcia, R. Sanchez-Ramirez, I. Olivares, I. Perez-Garcia, E. Fernandez-Garcia, S. Wu and A.J. Castro-Tirado (IAA-CSIC), J.I. Vico Linares, A. Fernandez-Martin and J. Flores-Martin (CAHA), E. Gomez, B. Rodriguez, J.P. Lopez, N. Morant Juan, I. Castillo, A. Lozano-Fernandez, F. Lopez-Martinez, M. Salah-Martinez and R. Ardon-Leon (VIU, Valencia), M. Gritsevich (Univ. of Helsinki) and Y.-D. Hu (GXI), on behalf of a larger collaboration, report:
Following the detection of GRB 251129A/EP251129a by SVOM (Tan et al. GCNC 42879) and EP (Wu et al. GCNC 42884) we imaged the gamma-ray burst error box with both the 0.9 and 1.5m telescopes at Sierra Nevada Observatory. In addition to them, we also used the 1.23m and 2.2m telescopes at the nearby Calar Alto Observatory.
We clearly detect the optical afterglow discovered by Angulo et al. (GCNC 42880), also reported by Wu et al. (GCNC 42882), Masi (GCNC 42885), Li et al. (GCNC 42887), Lipunov et al. (GCNC 42892) and Moskvitin et al. (GCNC 42897). At both Sierra Nevada and Calar Alto observatories we measure R = 19.8 +/- 0.2 and i = 19.9 +/- 0.3 respectively (2.47 h and 2.90 h after the burst onset time).
This preliminary photometry is based on nearby stars from the USNO-B1 catalogue (R2 magnitudes) and SDSS and is not corrected for the Galactic extinction.
GCN Circular 42897
Subject
GRB 251129A / EP251129a: SAO RAS optical observations
Date
2025-11-29T17:59:49Z (3 days ago)
From
Alexander Moskvitin at SAO RAS <mosk@sao.ru>
Via
Web form
A. S. Moskvitin and O. I. Spiridonova (SAO RAS)
report on behalf of GRB follow-up team.
We observed the field of the SVOM GRB 251129A (Tan et al., GCN 42877)
also detected by Einstein Probe as EP251129a (Wu et al., GCN 42884)
and Swift (Evans, GCN 42888; Page et al., GCN 42891)
with the Zeiss-1000 1m telescope of the SAO RAS on November 29,
15:27:01--16:00:22 UT (t_mid - T0 = 0.54973 days). We obtained
6 * 300 sec images in Rc band.
The optical afterglow (Angulo et al., GCN 42880; Wu et al., GCN 42882;
Watson, GCN 42883; Masi, GCN 42885; Li et al., GCN 42887;
Lipunov et al., GCN 42892) is clearly detected in the stacked frame
with the following brightness.
Date UT start t-T0 Exp. Filter OT Err. UL
(mid,days) (n*s) (3sigma)
2025-11-29 15:27:01 0.54973 6*300 Rc 21.00 0.07 22.8
This preliminary photometry is based on nearby stars from the USNO-B1
catalogue (R2 magnitudes) and is not corrected for the Galactic
extinction.
GCN Circular 42892
Subject
SVOM GRB 251129A : MASTER optical counterpart detection
Date
2025-11-29T14:26:34Z (3 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
V.M. Lipunov, A.Kuznetsov, I.Panchenko, E.Gorbovskoy, G.Antipov, P.Balanutsa, V.Senik, N. Tiurina, K.Zhirkov, Ya.Kechin, A.Chasovnikov, D.Vlasenko, Yu. Tselik(Lomonosov MSU, SAI, Moscow),
O.A.Gress, N.M.Budnev, O.Ershova (Irkutsk State University),
R. Podesta, C.Francile, F. Podesta, E. Gonzalez (OAFA, San Juan Uni.,Argentina);
D. Buckley (SAAO, South Africa),
A. Sosnovskij (CrAO RAS),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino, J.Martinez, A.R.Corella,L.H.Rodriguez (INAOE, Guillermo Haro Astrophysic Observatory, Mexico)
V.M.Pillet, R.Rebolo Lopez (The Instituto de Astrofisica de Canarias,Spain),
MASTER-Kislovodsk robotic telescope (Global MASTER-Net [1-4], http://observ.pereplet.ru)
started inspect (Lipunov et al. GCN 42878) of SVOM GRB 251129A ( GCN 42877)
9 sec after notice time (997 sec after trigger time) at 2025-11-29 02:48:01 UT
There is optical counterpart with unfiltered m_OT=18.7(auto-detection) at 2025-11-25 02:48:01UT,
that was discovered by SVOM/COLIBRÍ (Angulo et al. GCN 42880)
at 2025-11-29 02:51:22UT and also observed by SVOM/VT (Wu et al. GCN 42882, Li et al. GCN 42887), VT (Maxi et al. GCN 42885).
Real time updated cover map and OT position are available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3054567
[1] Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L
[2] Lipunov et al. 2022, Universe, Vol. 8(5), id.271
[3] Lipunov et a. 2019, ARep, vol.63, 293
[4] Lipunov V., Kornilov V., Gorbovskoy E., Tiurina N., Kuznetsov A. 2023,
Astronomical Robotic Networks and Operative Multichanel Astrophysics,Lomonosov MSU PRESS, 591pp.
http://www.pereplet.ru/lipunov/625.html#625
GCN Circular 42891
Subject
GRB 251129A: Swift-XRT afterglow detection
Date
2025-11-29T12:29:18Z (3 days ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
K.L. Page (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti
(INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU), S. Lanava (PSU),
A.P. Beardmore (U. Leicester), J.P. Osborne (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 251129A. We searched for X-ray sources
in 732 s of Photon Counting (PC) mode data. The total exposure at the
position of the afterglow (see below) is 2.3 ks, obtained between
T0+16.5 ks and T0+28.5 ks.
An uncatalogued X-ray source is detected within the estimated 3-sigma
SVOM/ECLAIRs error region (49 arcsec) and is above the RASS 3-sigma
upper limit at this position, and is therefore likely the GRB
afterglow. Using 2336 s of PC mode data and 4 UVOT images, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 224.33074, +79.29312
which is equivalent to:
RA (J2000): 14h 57m 19.38s
Dec(J2000): +79d 17' 35.2"
with an uncertainty of 2.1 arcsec (radius, 90% confidence). This
position is 26 arcsec from the SVOM/ECLAIRs position. The position is
consistent with the optical afterglow (GCNs 42880, 42882, 42883, 42885,
42887) and the EP X-ray transient (GCN 42884).
The light curve can be modelled can be modelled with a power-law decay
with a decay index of alpha=6.23 (+0.32, -0.29).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.71 (+0.22, -0.20). The
best-fitting absorption column is 7.3 (+3.7, -3.3) x 10^20 cm^-2, in
excess of the Galactic value of 2.9 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 2.6 x 10^-11 (3.7 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 7.3 (+3.7, -3.3) x 10^20 cm^-2
Galactic foreground: 2.9 x 10^20 cm^-2
Excess significance: 2.2 sigma
Photon index: 2.71 (+0.22, -0.20)
If the light curve continues to decay with a power-law decay index of
6.2, the count rate at T+24 hours will be 1.1 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.0 x
10^-15 (4.2 x 10^-15) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
https://www.swift.ac.uk/xrt_products/00021892.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021892.
This circular is an official product of the Swift-XRT team.
GCN Circular 42888
Subject
GRB 251129A: Swift ToO observations
Date
2025-11-29T07:05:48Z (3 days 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 251129A. Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021892
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 42887
Subject
GRB 251129A / EP251129a: SVOM/VT optical fading
Date
2025-11-29T05:41:54Z (3 days ago)
Edited On
2025-12-01T04:53:50Z (a day ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li , L. P. Xin, Y. L. Qiu, C. Wu, Z. H. Yao, Y. N. Ma, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. R. Xu, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), W. J. Tan (IHEP), D. F. Kong (GXU) report on behalf of the SVOM/VT team.
SVOM/VT performed an automatic slew to GRB 251129A/EP251129a triggered by SVOM/ECL (sb25112901, Tan et al., GCN 42879). The burst was also triggered by EP (Wu et al., GCN 42884). SVOM/VT began the observation at 2025-11-29T02:43:03 UTC, i.e., 658 seconds post trigger in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
With the downloaded early X band data, the optical counterpart (Angulo et al. GCN 42880; Watson, GCN 42883; Wu et al., GCN 42882; Masi et al. GCN 42885) was clearly detected in both channels. The measurements are given below:
Mid_time Band Exposure Time Magnitude (AB)
12.43 min VT_B 50 sec 18.16+/-0.03 mag
12.43 min VT_R 50 sec 17.89+/-0.03 mag
44.96 min VT_B 50 sec 19.11+/-0.04 mag
44.96 min VT_R 50 sec 18.80+/-0.03 mag
It was fading with a slope of about 0.7 with a single power law.
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 42885
Subject
GRB 251129A: Optical Observations via Virtual Telescope Project, Italy
Date
2025-11-29T05:27:43Z (3 days ago)
From
Gianluca Masi at Virtual Telescope Project <gianluca@bellatrixobservatory.org>
Via
Web form
Gianluca Masi, Virtual Telescope Project (Italy), reports:
We attempted to observe the optical counterpart of GRB 251129A (Wenjun et al., GCN 42877) with the 14” robotic unit available at the Virtual Telescope Project facility in Manciano, Italy, equipped with a KAF-3200E based CCD camera, its QE peaking (90%) in the red part of the spectrum.
We collected five, 300-second unfiltered exposures, then we averaged them. The central time of the resulting stack was 29 Nov., 04:54:23 UTC, that is about 2.4 hours after the burst.
We detected a bright object at the following position (J2000.0):
R.A.: 14 57 18.81
Decl.: +79 17 34.6
mean residuals < 0.1” on both axes
R= 19.5 (assuming R-mags from Gaia DR2 for the reference stars).
This position is consistent with Angulo et al. (GCN 42880). The source is not present in the PanSTARRS DR1 dataset.
GCN Circular 42883
Subject
GRB 251129A: Correction to the position of the optical counterpar
Date
2025-11-29T04:48:59Z (3 days ago)
From
Alan Watson at UNAM <alan@astro.unam.mx>
Via
Web form
Alan Watson (UNAM) reports:
The position of the optical counterpart given by Angulo et al. (GCN 42880) was not given completely correctly. The position was given correctly in sexagesimal but not in degrees. The correct position is:
RA(J2000) = 14:57:18.88 = 224.3286 degrees
Dec(J2000) = +79:17:34.8 = 79.2930 degrees
We apologize for this error. We thank Huali Li for bringing this mistake to our attention.
GCN Circular 42882
Subject
GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
Date
2025-11-29T04:12:26Z (3 days ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
C. Wu, H. L. Li, L.P. Xin, Y. L. Qiu (NAOC), J. T. Palmerio (CEA), W. J. Tan (IHEP), D. F. Kong (GXU) report on behalf of the SVOM team.
After the trigger by SVOM/ECLAIRs at 2025-11-29T02:32:05 UTC (T0), SVOM/VT performed an automatic slew to the burst GRB 251129A (sb25112901, Tan et al., GCN 42879). The observation began at 2025-11-29T02:43:03, 658 seconds after T0, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
The optical counterpart reported (Angulo et al., GCN 42880) was clearly detected in the 1-bit subimages and source lists downloaded via VHF network in both channels.
The magnitudes are :
Mid_time Band Magnitude (AB)
808 sec VT_B 18.63+/-0.01 mag
808 sec VT_R 18.02+/-0.01 mag
Our photometry was derived in AB magnitude and not corrected for Galactic extinction.
Given the VT color, it is likely a low redshift GRB.
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 42880
Subject
GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
Date
2025-11-29T03:38:10Z (3 days ago)
From
Camila Angulo Valdez at UNAM <camiangulo@astro.unam.mx>
Via
Web form
Camila Angulo (UNAM), Nikos Mandarakas (LAM), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), N. A. Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Wenjun Tan (IHEP), Defeng Kong (GXU), Wenjin Xie (NAOC), Donghua Zhao (NAOC), Hatsune Goto (Kanazawa Univ.) report:
We imaged the field of the SVOM GRB 251129A (Tan et al., GCN Circ. 42877) using the DDRAGO two-channel wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2025-11-29 02:51:22 to 02:57:11 UTC (from 20.0 to 25.8 minutes after the trigger) and obtained 5 minutes of simultaneous exposure in the r and z filters.
The data were reduced, coadded, and analyzed with the 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.
We detect an uncatalogued source just outside the MXT error circle at:
RA(J2000) = 14:57:18.88 = 224.2949 degrees
Dec(J2000) = +79:17:34.8= 79.3050 degrees
with an uncertainty of 0.5 arcsec.
The preliminary magnitude derived for that source is:
r = 18.30 +/- 0.01
z = 18.03 +/- 0.01
Further observations are ongoing.
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 42879
Subject
GRB 251129A: SVOM detection of a burst
Date
2025-11-29T03:15:27Z (3 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Wenjun Tan (IHEP), Defeng Kong (GXU), Wenjin Xie, Donghua Zhao (NAOC), Hatsune Goto (Kanazawa Univ.) report on behalf of the SVOM mission team:
At 2025-11-29T02:32:05 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251129A (SVOM burst-id sb25112901).
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 5 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 8.82 in the [8-50] keV energy band over a time window of 81.92 seconds starting at 2025-11-29T02:31:24.
The localization of the best alert is R.A., Dec. 224.5380, 79.4287 degrees (J2000) with a 90% confidence level (C.L.) radius of 8.96 arcmin (including systematic error of 2 arcmin added in quadrature).
SVOM slewed to the burst.
SVOM/MXT began observing the field at 2025-11-29T02:45:53 UTC, 828 seconds after T0. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec. 224.3258, 79.3004 degrees:
R.A. (J2000) = 14h57m01.94s
Dec. (J2000) = 79d18m32.94s
with a 90% C.L. radius of 25.08 arcseconds.
This location is 7.82 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 Wenjun Tan: tanwj@ihep.ac.cn
Please contact the BA by email if you require additional information.
GCN Circular 42878
Subject
SVOM GRB251129A: Global MASTER-Net observations report
Date
2025-11-29T03:14:31Z (3 days ago)
Edited On
2025-12-01T14:36:50Z (16 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>
Via
email
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, I. Gorbunov (Lomonosov MSU),
O.Gress, N.Budnev (ISU),
C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A.Sosnovskij (CrAO),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity),
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the SVOM GRB251129.11 (trigger No 1764383485,14h 58m 09.12s , +79d 25m 43.3s, R=0.1493) errorbox 9 sec after notice time and 997 sec after trigger time at 2025-11-29 02:48:01 UT, with upper limit up to 18.9 mag. Observations started at twilight. The observations began at zenith distance = 45 deg. The sun altitude is -16.3 deg.
The galactic latitude b = 36 deg., longitude l = 116 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3054567
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
1057 | 2025-11-29 02:48:01 | MASTER-Kislovodsk | (14h 59m 33.58s , +79d 37m 30.3s) | C | 120 | 18.3 |
1177 | 2025-11-29 02:48:01 | MASTER-Kislovodsk | (14h 59m 33.58s , +79d 37m 30.3s) | C | 360 | 18.9 | Coadd
1057 | 2025-11-29 02:48:01 | MASTER-Kislovodsk | (15h 21m 37.07s , +79d 09m 16.3s) | C | 120 | 18.4 |
1197 | 2025-11-29 02:50:21 | MASTER-Kislovodsk | (14h 59m 33.13s , +79d 37m 36.2s) | C | 120 | 18.0 |
1197 | 2025-11-29 02:50:21 | MASTER-Kislovodsk | (15h 21m 37.81s , +79d 09m 22.5s) | C | 120 | 18.2 |
1337 | 2025-11-29 02:52:41 | MASTER-Kislovodsk | (14h 59m 32.62s , +79d 37m 42.8s) | C | 120 | 18.0 |
1337 | 2025-11-29 02:52:41 | MASTER-Kislovodsk | (15h 21m 38.00s , +79d 09m 30.4s) | C | 120 | 18.0 |
1487 | 2025-11-29 02:55:11 | MASTER-Kislovodsk | (14h 59m 32.17s , +79d 37m 50.0s) | C | 120 | 17.8 |
1607 | 2025-11-29 02:55:11 | MASTER-Kislovodsk | (14h 59m 32.18s , +79d 37m 50.0s) | C | 360 | 18.3 | Coadd
1487 | 2025-11-29 02:55:11 | MASTER-Kislovodsk | (15h 21m 37.94s , +79d 09m 39.5s) | C | 120 | 18.0 |
1627 | 2025-11-29 02:57:31 | MASTER-Kislovodsk | (14h 59m 31.42s , +79d 37m 57.4s) | C | 120 | 17.6 |
1627 | 2025-11-29 02:57:31 | MASTER-Kislovodsk | (15h 21m 37.84s , +79d 09m 49.2s) | C | 120 | 17.7 |
1766 | 2025-11-29 02:59:50 | MASTER-Kislovodsk | (14h 59m 30.65s , +79d 38m 04.2s) | C | 120 | 17.5 |
1766 | 2025-11-29 02:59:50 | MASTER-Kislovodsk | (15h 21m 37.58s , +79d 09m 57.9s) | C | 120 | 17.8 |
1906 | 2025-11-29 03:02:10 | MASTER-Kislovodsk | (14h 59m 29.69s , +79d 38m 11.3s) | C | 120 | 17.6 |
1906 | 2025-11-29 03:02:10 | MASTER-Kislovodsk | (15h 21m 37.28s , +79d 10m 06.9s) | C | 120 | 17.9 |
2046 | 2025-11-29 03:04:31 | MASTER-Kislovodsk | (14h 59m 28.84s , +79d 38m 19.5s) | C | 120 | 17.7 |
2046 | 2025-11-29 03:04:31 | MASTER-Kislovodsk | (15h 21m 37.01s , +79d 10m 17.3s) | C | 120 | 17.9 |
2186 | 2025-11-29 03:06:50 | MASTER-Kislovodsk | (14h 59m 27.87s , +79d 38m 27.5s) | C | 120 | 17.7 |
2186 | 2025-11-29 03:06:50 | MASTER-Kislovodsk | (15h 21m 36.63s , +79d 10m 27.4s) | C | 120 | 17.9 |
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 42877
Subject
GRB 251129A: SVOM detection of a burst
Date
2025-11-29T03:14:08Z (3 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Wenjun Tan (IHEP), Defeng Kong (GXU), Wenjin Xie, Donghua Zhao (NAOC), Hatsune Goto (Kanazawa univ.) report on behalf of the SVOM mission team:
At 2025-11-29T02:32:05 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251129A (SVOM burst-id sb25112901).
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 5 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 8.82 in the [8-50] keV energy band over a time window of 81.92 seconds starting at 2025-11-29T02:31:24.
The localization of the best alert is R.A., Dec. 224.5380, 79.4287 degrees (J2000) with a 90% confidence level (C.L.) radius of 8.96 arcmin (including systematic error of 2 arcmin added in quadrature).
SVOM slewed to the burst.
SVOM/MXT began observing the field at 2025-11-29T02:45:53 UTC, 828 seconds after T0. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec. 224.3258, 79.3004 degrees:
R.A. (J2000) = 14h57m01.94s
Dec. (J2000) = 79d18m32.94s
with a 90% C.L. radius of 25.08 arcseconds.
This location is 7.82 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 Wenjun Tan: tanwj@ihep.ac.cn
Please contact the BA by email if you require additional information.