January 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 36977] Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
by GCN Circulars 17 Jan '25

17 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38969 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB DATE: 25/01/17 19:39:04 GMT FROM: oindabimukherjee(a)gmail.com O. Mukherjee (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 758829338/250117747 at 17:55:33.64 UT on 17 January 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to local particles." View this GCN Circular online at https://gcn.nasa.gov/circulars/38969. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36976] Konus-Wind detection of GRB 250116A
by GCN Circulars 17 Jan '25

17 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38968 SUBJECT: Konus-Wind detection of GRB 250116A DATE: 25/01/17 13:56:46 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration, bright GRB 250116A (Fermi/GBM detection: Bissaldi et al., GCN 38962; Fermi/LAT detection: Holzmann Airasca et al., GCN 38963; INTEGRAL/SPI-ACS and PICsIT detection: Barria et al., GCN 38965; GECAM-B detection: Wang et al., GCN 38967) triggered Konus-Wind at T0=45234.821 s UT (12:33:54.821). The burst light curve shows a bright initial multipeaked emission episode which starts at ~T0-0.3 s and has a total duration of ~24.2 s, followed by a weaker emission traced up to ~175 s. The emission is seen up to ~3 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250116_T45234/ As observed by Konus-Wind, the initial emission episode had a fluence of 1.05(-0.03,+0.03)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+15.344 s, of 1.77(-0.14,+0.14)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the initial episode (measured from T0 to T0+26.112 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.58(-0.04,+0.04), the high energy photon index beta = -3.21(-0.28,+0.18), the peak energy Ep = 382(-10,+11) keV (chi2 = 111/98 dof). A spectrum of the weaker emission tail (measured from T0+26.112 to T0+181.760 s) is best fit by a simple power-law (PL) function with the PL index of -2.13(-0.17,+0.19), chi2 = 97/100 dof. A 20 keV - 10 MeV fluence in this interval is estimated to 1.25(-0.29,+0.39)x10^-5 erg/cm2. All the quoted errors are at the 68% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/38968. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36975] GRB 250116A: GECAM-B detection of a long burst
by GCN Circulars 17 Jan '25

17 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38967 SUBJECT: GRB 250116A: GECAM-B detection of a long burst DATE: 25/01/17 09:54:30 GMT FROM: Yue Wang <m18509381757(a)163.com> Yue Wang, Shao-Lin Xiong, Chen-Wei Wang, Chao Zheng, Shi-Jie Zheng, Cheng-Kui Li, Wen-Long Zhang, Yan-Qiu Zhang report on behalf of the GECAM team: GECAM-B was triggered in-flight by a long burst, GRB 250116A, at 2025-01-16T12:33:59.550 UTC (T0), which was also observed by Fermi/GBM (GCN # 38962) and Fermi/LAT (GCN # 38963). According to the GECAM-B light curves in about 20-1000 keV, this burst mainly consists of multiple pulses with a duration (T90) of about 15.5（+0.4,-0.6）s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecamgrb250116A.png GECAM location is consistent with the Fermi/LAT position within the error. We notice that the location is close to the Galactic plane and the light curve pattern is somewhat atypical for GRB but more similar to SGR, though the duration is much longer than SGR. We note that these results are based on in-flight trigger data and thus very preliminary. Refined analysis will be reported later. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two microsatellites (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/38967. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36974] GRB 241217A / EP241217B: radio detection with the VLA
by GCN Circulars 17 Jan '25

17 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38966 SUBJECT: GRB 241217A / EP241217B: radio detection with the VLA DATE: 25/01/17 09:29:05 GMT FROM: Stefano Giarratana at INAF-OAB <s.giarratana(a)ira.inaf.it> S. Giarratana (INAF-OAB), M. Giroletti (INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.), N. Omodei (Stanford Univ.), O. S. Salafia (INAF-OAB) At 07:53:14 UT on 2024 Dec 22 (T_mid = 4.65 days post-burst) the Karl G. Jansky VLA observed the field of GRB 241217A / EP241217B (Brunet et al., GCN 38594; Williams et al., GCN 38599; Zhou et al., GCN 38606; Ravasio et al., GCN 38625) in three bands, with central frequencies of 6, 10 and 15 GHz. The standard 3C147 was used as bandpass and flux density calibrator, while J0530-2503 was used as phase calibrator. From a preliminary analysis, an unresolved radio source is tentatively detected at a position (J2000): RA: 05:36:36.321 +- 0.003 Dec: -25:17:49.39 +- 0.04 consistent with the X-ray (Williams et al., GCN 38599), optical (Qiu et al., GCN 38600; Freeburn et al., GCN 38642), and radio (An et al., GCN 38750) position of the transient. The preliminary analysis yields the following results: ================================================================ T_mid Freq Peak r.m.s. Beam PA [days] [GHz] [uJy/b] [uJy/b] [arcsec^2] [deg] ================================================================ 4.65 6 32 7 0.77x0.28 26 4.65 10 36 8 0.51x0.18 32 4.65 15 38 7 0.30x0.11 24 ================================================================ No source is detected with a >3sigma confidence at the aforementioned position in previous radio surveys (NVSS, VLASS, RACS), all of which have r.m.s. noise levels above 100 uJy/b. We would like to thank the staff of the VLA for approving, executing, and processing the observations. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. These observations were carried out as part of project SF171028, approved in the framework of the Fermi - NRAO joint program agreement. View this GCN Circular online at https://gcn.nasa.gov/circulars/38966. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36973] GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
by GCN Circulars 16 Jan '25

16 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38965 SUBJECT: GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection DATE: 25/01/16 22:28:51 GMT FROM: Aishwarya L Thakur at INAF-IAPS, Rome <aishth(a)outlook.com> Patrizia Barria(a,b), Giulia Gianfagna(a), James Craig Rodi(a), Aishwarya Linesh Thakur(a), Lorenzo Natalucci(a,b), Luigi Piro(a) report: GRB 250116A was discovered by Fermi/GBM (GCN 38962, seen also by Fermi/LAT GCN 38963) at time 2025-01-16T12:33:59.53 (UTC) with a duration of 16 s. We searched for any corresponding counterpart in the INTEGRAL/SPI-ACS and IBIS/PICsIT data. In a SPI/ACS light curve above 80 keV, we find a pulse temporally coincident with the GBM detection having an approximate duration of ~ 15 sec. This pulse is also seen in the PICsIT lightcurve above 212 keV, with a similar duration. The approximate peak count rate in SPI/ACS is 80,000 cts/s for E>80 keV, over a median background rate of 65,000 cts/s. After the GRB spike, we note that there is a second, stronger pulse in the light curves of both instruments. The association of this pulse to the GRB at this moment is unclear and is under investigation. This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany. ----- (a) INAF/IAPS-Rome (b) ICSC National Research Centre for High-Performance Computing View this GCN Circular online at https://gcn.nasa.gov/circulars/38965. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36972] GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
by GCN Circulars 16 Jan '25

16 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38965 SUBJECT: GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection DATE: 25/01/16 22:28:51 GMT FROM: Aishwarya L Thakur at INAF-IAPS, Rome <aishth(a)outlook.com> Patrizia Barria(a,b), Giulia Gianfagna(a), James Craig Rodi(a), Aishwarya Linesh Thakur(a), Lorenzo Natalucci(a,b), Luigi Piro(a) report: GRB 250116A was discovered by Fermi/GBM (GCN 38962, seen also by Fermi/LAT GCN 38963) at time 2025-01-16T12:33:59.53 (UTC) with a duration of 16 s. We searched for any corresponding counterpart in the INTEGRAL/SPI-ACS and IBIS/PICsIT data. In a SPI/ACS light curve above 80 keV, we find a pulse temporally coincident with the GBM detection having an approximate duration of ~ 15 sec. This pulse is also seen in the PICsIT lightcurve above 212 keV, with a similar duration. The approximate peak count rate in SPI/ACS is 80,000 cts/s for E>80 keV, over a median background rate of 65,000 cts/s. After the GRB spike, we note that there is a second, stronger pulse in the light curves of both instruments. The association of this pulse to the GRB at this moment is unclear and is under investigation. This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany. ----- (a) INAF/IAPS-Rome (b) ICSC National Research Centre for High-Performance Computing View this GCN Circular online at https://gcn.nasa.gov/circulars/38965. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36971] Swift Trigger 1282245 is not a GRB
by GCN Circulars 16 Jan '25

16 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38964 SUBJECT: Swift Trigger 1282245 is not a GRB DATE: 25/01/16 21:44:19 GMT FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk> C. Gronwall (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: Swift trigger 1282245 was caused by proximity to the South Atlantic Anomaly. It is not an astronomical source of interest. View this GCN Circular online at https://gcn.nasa.gov/circulars/38964. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36970] GRB 250116A: Fermi-LAT detection
by GCN Circulars 16 Jan '25

16 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38963 SUBJECT: GRB 250116A: Fermi-LAT detection DATE: 25/01/16 20:58:26 GMT FROM: A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca(a)unitn.it> A. Holzmann Airasca (UniTrento and INFN Bari), S. Lopez (CNRS / IN2P3), N. Di Lalla (Stanford University), T. Khalil (Johannesburg Univ) report on behalf of the Fermi-LAT Collaboration: On January 16, 2025, Fermi-LAT detected high-energy emission from GRB 250116A, which was also detected by Fermi-GBM (trigger 758723644/ 250116524, GCN 38962). The best LAT on-ground location is found to be: RA, Dec = 266.64, -19.36 (J2000) with an error radius of 0.13 deg (90 % containment, statistical error only). This was 53 deg from the LAT boresight at the time of the GBM trigger (T0 = 12:33:59.53 UT). The data from the Fermi-LAT shows a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0 - 1500 s after the GBM trigger is (4.0 ± 0.4) E-5 ph/cm2/s. The estimated photon index above 100 MeV is 2.3 ± 0.1. The highest-energy photon is a 3.9 GeV event which is observed 59 seconds after the GBM trigger. The Fermi-LAT point of contact for this burst is Chiara Bartolini (Chiara.Bartolini(a)ba.infn.it). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/38963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36969] GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
by GCN Circulars 16 Jan '25

16 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38962 SUBJECT: GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst DATE: 25/01/16 20:44:37 GMT FROM: Ava Myers at NASA GSFC <ava.myers(a)nasa.gov> E. Bissaldi (Politecnico and INFN Bari), A. Myers (NPP/GSFC), O.J. Roberts (USRA), and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 12:33:59.53 UT on 16 January 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250116A (trigger 758723644/250116524). The angle from the Fermi LAT boresight is 55 degrees. The GBM light curve consists of multiple peaks, with an apparent duration (T90) of 15.9 s (50-300 keV). However, there is low energy emission that extends longer than the T90 out to at least several hundred seconds after the trigger time. The Sun emerges from Earth occultation midway during this burst, and thus due to the spacecraft motion during this time and the localization being relative close to the Sun position, it is currently unknown whether this is part of a long duration C-class Solar Flare or afterglow emission from the Burst. Analysis is ongoing. The time-averaged spectrum from T0+0 to T0+21 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.71 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 462 +/- 6 keV. from T0+0 to T0+21 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.71 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 462 +/- 6 keV. The event fluence (10-1000 keV) in this time interval is (9.97 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+17 s in the 10-1000 keV band is 43.9 +/- 0.4 ph/s/cm^2. Multi-wavelength follow up of this Burst is strongly encouraged. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/38962. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36968] GRB 250114B: Swift-XRT afterglow detection
by GCN Circulars 16 Jan '25

16 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38961 SUBJECT: GRB 250114B: Swift-XRT afterglow detection DATE: 25/01/16 14:28:12 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> M. A. Williams (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB) 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 INTEGRAL-detected burst GRB 250114B. The observations now extend from T0+11.4 ks to T0+153.7 ks and have a total exposure time of 9.8 ks. . The source previously reported, "Source 2", is believed to be the afterglow. The position of this source is RA, Dec=48.8582, -2.2940 which is equivalent to: RA (J2000): 03:15:25.96 Dec(J2000): -02:17:38.2 with an uncertainty of 7.6 arcsec (radius, 90% confidence). This position is 81 arcsec from the INTEGRAL position and consistent with the reported optical counterpart (Sasada et al. GCN 38950). Comparison of individual observations show the source has faded. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021756. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021756. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38961. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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