January 2026 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 41399] Fermi GBM Sub-Threshold Detection of GRB 260102A
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43308 SUBJECT: Fermi GBM Sub-Threshold Detection of GRB 260102A DATE: 26/01/02 17:59:21 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA) reports on behalf of the Fermi-GBM Team: SVOM/ECLAIRs detected GRB 260102A on 2026-01-02 at 04:10:03 UTC (Xie et al 2026, GCN 43295). There was no Fermi-GBM onboard trigger around this event time. An automated, blind search for gamma-ray bursts below the onboard triggering threshold in Fermi-GBM identified no candidates. The GBM Targeted Search [1], the most sensitive coherent search for GRB-like signals in GBM, identified a transient starting approximately 33 seconds after the ECLAIRs best imaging SNR time at 2026-01-02T04:09:45 (Xie et al 2026, GCN 43295). The transient is detected most significantly on the 32.768 s timescale with a false alarm rate of 1.1e-05 Hz, using a "normal" spectrum (Band function with Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB. The Targeted Search localization is consistent with the ECLAIRs position. [1] Goldstein et al. 2019 arXiv:1903.12597 View this GCN Circular online at https://gcn.nasa.gov/circulars/43308. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41398] GRB 260102A: EP-FXT follow-up observation
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43307 SUBJECT: GRB 260102A: EP-FXT follow-up observation DATE: 26/01/02 15:50:27 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.-H. I. Yin (HKU), X. Mao (NAO, CAS), J. P. Chen (SYSU), and H. W. Pan (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of the SVOM/ECLAIRs-detected burst GRB 260102A (SVOM/sb26010201, Xie et al., GCN 43295) at 2026-01-02 05:43:47 (UTC), about 1.5 hours after the SVOM/ECLAIRs trigger, with an exposure time of 3523 s. One uncatalogued source is detected within the ECLAIRs error circle, and the source is spatially consistent with the counterpart reported in optical and X-ray bands, including detections (Evans et al., GCN 43298; Wu et al., GCN 43300; Bernardini et al., GCN 43304) and upper limits (Antier et al., GCN 43303; Saccardi et al., GCN 43305). Preliminary analysis on this source is automatically conducted, and details are listed as follows. EPF_J121547.6+481500 RA (J2000): 183.9483 Dec (J2000): 48.2501 Flux: 3.82 x 10^-13 erg/s/cm2 (observed, 0.5-10 keV) Flux_err: 4.60 x 10^-14 erg/s/cm2 (1 sigma) The position uncertainty of the source is about 10 arcsec in radius (90% C.L. statistical and systematic). Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/43307. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41397] EP260101a: Global MASTER-Net observations report
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43306 SUBJECT: EP260101a: Global MASTER-Net observations report DATE: 26/01/02 15:18:21 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> 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 EP260101a ( EP Team et al., GCN 43288) errorbox 1 days 27579 sec after notice time and 1 days 29347 sec after trigger time at 2026-01-02 14:44:49 UT, with upper limit up to 15.3 mag. Observations started at twilight. The observations began at zenith distance = 30 deg. The sun altitude is -10.3 deg. The galactic latitude b = -16 deg., longitude l = 150 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3092541 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 115778 | 2026-01-02 14:44:49 | MASTER-Kislovodsk | (03h 03m 11.45s , +39d 18m 40.8s) | C | 60 | 15.3 | 116532 | 2026-01-02 14:57:23 | MASTER-Kislovodsk | (03h 03m 11.69s , +39d 19m 18.4s) | C | 60 | 14.7 | 116631 | 2026-01-02 14:59:03 | MASTER-Kislovodsk | (03h 03m 05.44s , +39d 18m 20.6s) | C | 60 | 14.5 | 116730 | 2026-01-02 15:00:41 | MASTER-Kislovodsk | (03h 03m 10.27s , +39d 18m 43.9s) | C | 60 | 15.0 | 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/43306. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41396] GRB 260102A: LCO optical upper limits
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43305 SUBJECT: GRB 260102A: LCO optical upper limits DATE: 26/01/02 15:02:54 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> A. Saccardi (CEA/Irfu), C. Wu, W. Xie (NAOC), W. Tan (IHEP) report on behalf of the SVOM mission team: We observed the field of the SVOM GRB 260102A (Xie et al., GCN 43295) with the LCO 1m telescope at McDonald Observatory equipped with the Sinistro instrument. Our observation started on 2026-01-02 at 08:14:01 UT (about 4.06 hr after the trigger) and we obtained 3x200 s exposures in the Pan-STARRS z filter. In the stacked image, we do not detect any new source within the Swift/XRT source #2 error circle (Bernardini et al., GCN 43304) and at the position of the SVOM/VT optical counterpart (Wu et al., GCN 43300). We measure the following upper limit calibrated against the Pan-STARRS DR1 catalog, and not corrected for Galactic extinction: z > 20.1 AB (3-sigma, mid-time 4.13 hr after the trigger). This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/43305. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41395] GRB 260102A: Swift-XRT observations
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43304 SUBJECT: GRB 260102A: Swift-XRT observations DATE: 26/01/02 14:37:52 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> M.G. Bernardini (INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-OAR) 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 260102A, collecting 2.8 ks of Photon Counting (PC) mode data between T0+9.6 ks and T0+26.1 ks. One uncatalogued X-ray source has been detected within the estimated 3-sigma SVOM/ECLAIRs error region (502 arcsec), it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below: Source 2: RA (J2000.0): 183.9493 = 12h 15m 47.82s Dec (J2000.0): +48.2506 = +48d 15' 02.1" Error: 6.2 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: (6.3 [+2.2, -1.8])e-3 ct s^-1 Distance: 167 arcsec from SVOM/ECLAIRs position. Flux: (1.72 [+0.59, -0.48])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) SVOM/VT detected an optical counterpart consistent with this X-ray source (GCN Circ. 43300). An uncatalogued source was also detected, however this was too far from the GRB position to be the afterglow. 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/00021896. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/43304. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41394] GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43303 SUBJECT: GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations DATE: 26/01/02 14:09:15 GMT FROM: Dalya Akl at New York University Abu Dhabi <dka2010(a)nyu.edu> Sarah Antier (IJCLAB), William H. Lee (UNAM), Dalya Akl (NYUAD), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), 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), Nikos Mandarakas (LAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Wenjin Xie (NAOC), and Wenjun Tan (IHEP) report: We imaged the field of the SVOM GRB 260102A (Xie et al., GCN Circ. 43295) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-01-02 13:04 to 13:25 UTC (about 8.9 hours after the trigger) and obtained 18 minutes of simultaneous exposure in the r/z filters. The data were reduced and coadded with the COLIBRÍ ASU pipeline and 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 did not detect the optical counterpart reported by Wu et al. (GCN Circ. 43300) to preliminary 3-sigma magnitude limits of: r > 23.5 z > 22.8 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. View this GCN Circular online at https://gcn.nasa.gov/circulars/43303. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41393] Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43302 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB DATE: 26/01/02 13:09:36 GMT FROM: A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca(a)unitn.it> A. Holzmann Airasca (UniTrento and INFN Bari) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 789047602/260102495 at 11:53:17.07 UT on 02 January 2026, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to local particle activity." View this GCN Circular online at https://gcn.nasa.gov/circulars/43302. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41392] GRB 251230A / EP251230a: GECAM-B detection
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43301 SUBJECT: GRB 251230A / EP251230a: GECAM-B detection DATE: 26/01/02 13:08:59 GMT FROM: guohx(a)ihep.ac.cn Hao-Xuan Guo, Chen-Wei Wang, Zheng-Hang Yu, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight by GRB 251230A / EP251230a at 2025-12-30T01:21:44.050 UTC (denoted as T0), which is also detected by Swift (Lanava et al., GCN #43252), EP-WXT (Li et al., GCN #43255 and Wang et al., GCN #43272) and Insight-HXMT/HE (Guo et al., GCN #43299). According to the GECAM-B light curve in about 70-6000 keV, this burst mainly consists of multi-pulses with a duration (T90) of 71.2 +4.6/-8.2 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecambgrb251230A.png Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS). View this GCN Circular online at https://gcn.nasa.gov/circulars/43301. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41391] GRB 260102A: SVOM/VT optical counterpart
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43300 SUBJECT: GRB 260102A: SVOM/VT optical counterpart DATE: 26/01/02 12:45:56 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> C. Wu, H. L. Li, L. P. Xin, Y. L. Qiu, Y. N. Ma, Z. H. Yao, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, L. Lan, J. R. Xu, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), W. J. Tan (IHEP) report on behalf of the SVOM team. SVOM performed an automatic slew on the burst GRB 260102A triggered by SVOM/ECLAIRs (sb26010201, Xie et al., GCN 42295) in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. The observation began at 2026-01-02T04:13:40, i.e., 217 sec post trigger. An optical uncatalogued source was detected within errorbox of ECLAIRs (Xie et al., GCN 42295) and Swift-XRT source #2 (Evans et al., GCN 43298), compared to the Legacy survey catalog. The position is at R.A., Dec. = 183.95015, 48.25116 degrees, equivalent to: R.A. (J2000) = 12:15:48.03 Dec. (J2000) = 48:15:04.18 with an uncertainty of 0.5 arcsec. The magnitudes are: Mid_time Band Exposure Time Magnitude (AB) 242 sec VT_B 50 sec 19.98+/-0.06 242 sec VT_R 50 sec 18.46+/-0.03 872 sec VT_B 50 sec 21.40+/-0.16 872 sec VT_R 50 sec 20.21+/-0.10 Our photometry was not corrected for Galactic extinction. More follow-ups for this burst are encouraged. 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. View this GCN Circular online at https://gcn.nasa.gov/circulars/43300. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41390] GRB 251230A / EP251230a: Insight-HXMT/HE detection
by GCN Circulars 02 Jan '26

02 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43299 SUBJECT: GRB 251230A / EP251230a: Insight-HXMT/HE detection DATE: 26/01/02 12:17:17 GMT FROM: guohx(a)ihep.ac.cn Hao-Xuan Guo, Chen-Wei Wang, Cheng-Kui Li, Shao-Lin Xiong, and Chao Zheng (IHEP) report on behalf of the Insight-HXMT team: At 2025-12-30T01:22:22.000 (T0), Insight-HXMT/HE detected a burst, GRB 251230A / EP251230a, which is also detected by Swift (Lanava et al., GCN #43252) and EP-WXT (Li et al., GCN #43255 and Wang et al., GCN #43272). The Insight-HXMT/HE light curve mainly consists of multiple pulses with T90 of 54.4 +11.6/-8.4 s. The 1s peak rate, measured from T0-0.70 s, is 797 cnts/sec. Insight-HXMT/HE detected a total of 10,311 counts from this burst. The Insight-HXMT /HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb251230A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the Low-Gain mode with the energy range of about 300-3000 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org View this GCN Circular online at https://gcn.nasa.gov/circulars/43299. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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