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

[vsnet-grb-info 36847] GRB 250107A: Swift ToO observations
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38841 SUBJECT: GRB 250107A: Swift ToO observations DATE: 25/01/07 15:53:44 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the Swift/BAT GRB 250107A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021754 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 Swift/BAT 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. View this GCN Circular online at https://gcn.nasa.gov/circulars/38841. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36846] GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38840 SUBJECT: GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst DATE: 25/01/07 14:50:34 GMT FROM: Jimmy DeLaunay at Penn State <delauj2(a)gmail.com> James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT did not localize GRB 250107A onboard (T0: 2025-01-07T05:02:30.29 UTC, Fermi Trig 757918955). The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), detects the burst in a 16.384 s analysis time bin starting at T0 - 0.0 s with a sqrt(TS) of 21.8. An arcminute localization is found with DeltaLLHOut of 19.3 and a DeltaLLHPeak of 10.5. See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. The BAT position is RA, Dec = 302.52, 45.564 deg which is RA(J2000) = 20h 10m 04.80s Dec(J2000) = 45d 33' 50.4″ with an estimated uncertainty of 4 arcmin radius. XRT and UVOT follow-up has been requested. Results of follow-up observations will be reported in future circulars. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ View this GCN Circular online at https://gcn.nasa.gov/circulars/38840. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36845] GRB 250107B: Fermi GBM Final Real-time Localization
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38839 SUBJECT: GRB 250107B: Fermi GBM Final Real-time Localization DATE: 25/01/07 11:44:24 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely SHORT GRB At 11:34:04 UT on 7 Jan 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250107B (trigger 757942449.293284 / 250107482). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 110.8, Dec = 59.6 (J2000 degrees, equivalent to J2000 07h 23m, 59d 36'), with a statistical uncertainty of 25.9 degrees. The angle from the Fermi LAT boresight is 69.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107482/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107482/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107482/… View this GCN Circular online at https://gcn.nasa.gov/circulars/38839. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36844] GRB 250106A: SVOM/VT 2nd optical deep observation
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38838 SUBJECT: GRB 250106A: SVOM/VT 2nd optical deep observation DATE: 25/01/07 09:31:41 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> SVOM/VT commissioning team: Y. L. Qiu, H. L. Li, C. Wu, D. H. Zhao, L. P. Xin, X. H. Han, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. Deng, L. Lan, X. M. Lu, R. S. Zhang, Z. H. Yao (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) report on behalf of the SVOM team: The SVOM/VT conducted TOO observations of GRB 250106A (Zhao et al., GCN 38826) at 8.88 hr after the trigger. The observations were carried out in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously. The candidate reported by Qiu et al. (GCN 38829) were detected in both of stacked images of VT_B and VT_R. The brightness are, channel (t-T0)_mid(hr) exptime mag(AB) VT_B 13.25 149x100s 23.5 +/-0.2 VT_R 13.26 142x100s 22.4 +/-0.1 No definite fading was found compared to brightness reported (Qiu et al., GCN 38829). This observation is consistent with the result (Izzo et al. GCN 38834). Thus, this source is not a good candidate for the burst. A new source with a low S/N with a magnitude of VT_R~24.0 mag was tentatively detected near the errorbox of XRT source #1 (Osborne et al. GCN 38830), with a distance of 4.0 arcseconds from the XRT source #1. Its position is RA=117.2372, DEC=63.8132 deg, which is equivalent to: RA (J2000) : 07:48:56.93 Dec (J2000): +63:48:47.5 with an uncertainty of 0.5 arcsec. 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/38838. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36843] GRB 250101A: J band upper limit by SYSU 80cm telescope
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38837 SUBJECT: GRB 250101A: J band upper limit by SYSU 80cm telescope DATE: 25/01/07 06:20:55 GMT FROM: Jiaqi Lin <islinjiaqi(a)gmail.com> Jia-Qi Lin, Jin-Ji Li, Zhong-Nan Dong, Si-Yuan Zhu, Wei-Sen Huang, Pu Lin, Hao-Nan Yang, Yan Yu, Hao-Ran Zhang, Pak-Hin Thomas Tam, Bin Ma (Sun Yat-sen University) report on behalf of the SYSU 80cm telescope team: We observed the field of GRB 250101A (Page et al., GCN 38752), using the Sun Yat-sen University 80cm telescope, with 158 × 20 s exposures in J band. Our observations began at 2025-1-1 15:18:18 UTC, 1.92 hours after the BAT trigger. We did not detect any counterpart in the stacked images at the position of the optical afterglow (Li et al., GCN 38753; Mohan et al., GCN 38754; Zhu et al., GCN 38755; Budnev et al., GCN 38756; Wu et al., GCN 38758; Odeh et al., GCN Circular 38763), down to a 5-sigma depth of J ~ 18.0 Vega magnitudes. View this GCN Circular online at https://gcn.nasa.gov/circulars/38837. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36842] GRB 250107A: Fermi GBM Final Real-time Localization
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38836 SUBJECT: GRB 250107A: Fermi GBM Final Real-time Localization DATE: 25/01/07 05:12:57 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 05:02:30 UT on 7 Jan 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250107A (trigger 757918955.285842 / 250107210). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 309.4, Dec = 45.3 (J2000 degrees, equivalent to J2000 20h 37m, 45d 17'), with a statistical uncertainty of 3.5 degrees. The angle from the Fermi LAT boresight is 23.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/… View this GCN Circular online at https://gcn.nasa.gov/circulars/38836. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36841] EPWXT01709129925: Xinglong optical observations
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38835 SUBJECT: EPWXT01709129925: Xinglong optical observations DATE: 25/01/07 03:27:21 GMT FROM: Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong(a)nao.cas.cn> Yu-Zhang(NAOC), Jianfeng-Tian(NAOC), Ying-Wu(NAOC), Pengliang-Du(NAOC), Junjie-Jin(NAOC), Haiyang-Mu(NAOC), Yuguang-Sun(NAOC), Zheng-Jie (NAOC), Zhou-Fan(NAOC), Hong-Wu(NAOC) report on behalf of a large collaboration: In response to the detection of the likely flaring star 1RXS J060224.9-163451 by EP/WXT, an automatic trigger initiated follow-up observations using the 0.8-m telescope at Xinglong Observatory, Hebei, China. We obtained one 300-second exposure in both the g-band and r-band filters, with a median time of 2025-01-06T13:07:42, i.e., 16.2 hr after the EP trigger (ID 01709129925). For this target, we measured magnitudes of g ~ 12.82 mag and r ~ 11.48 mag, calibrated with the Pan-STARRS g-band and r-band field. View this GCN Circular online at https://gcn.nasa.gov/circulars/38835. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36840] GRB 250106A: NOT optical observations
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38834 SUBJECT: GRB 250106A: NOT optical observations DATE: 25/01/07 01:47:52 GMT FROM: Daniele B. Malesani at IMAPP / Radboud University <d.malesani(a)astro.ru.nl> L. Izzo (INAF/OACn and DARK/NBI), D. B. Malesani (DAWN/NBI and Radboud Univ.), D. Xu (NAOC), Z.P. Zhu (NAOC), X. Liu (NAOC), T. Pursimo (NOT), report on behalf of a larger collaboration: We observed the field of GRB 250106A (Zhao et al., GCN 38826) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera, using the SDSS z filter. The instrument was rotated in order to include XRT sources #1 and #2 (Osborne et al., GCN 38830), as well as the candidate SVOM/VT optical afterglow (which is consistent with the position of XRT source #2; Qiu et al., GCN 38829). The observation mid time was 2025 Jan 6.982 UT (10.13 hr after the SVOM trigger), and the exposure time was 2000 s. No source is detected within the localization circle of XRT source #1, down to a limiting magnitude z > 23.3 (AB). Two sources are detected within the localization circle of XRT source #2. Source A (coincident with the SVOM/VT optical candidate): RA = 07:49:29.04 Dec = +63:42:29.4 mag z = 22.23 +- 0.10 AB Source B: RA = 07:49:27.99 Dec = +63:42:31.5 mag z = 19.90 +- 0.02 AB At the locations of both sources, objects are visible in the Legacy Survey, for which we measure AB magnitudes z = 22.24 +- 0.11 and z = 19.84 +- 0.02 for sources A and B, respectively. Our measured values are thus fully consistent with those in the archival images. Source B is also detected by Gaia, which provides a QSO classification. This opens the question whether object B could be responsible for the X-ray emission detected by Swift/XRT. Source A could be the host galaxy of GRB 250106A, though we note that its archival r-band magnitude (r = 23) is only marginally fainter than the SVOM/VT magnitude (R = 22.5 +- 0.3 mag; Qiu et al., GCN 38829). We encourage further observations with both SVOM/VT and Swift/XRT in order to establish variability of both the optical and X-ray sources. View this GCN Circular online at https://gcn.nasa.gov/circulars/38834. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36839] GRB 210506A NOT GCN draft
by GCN Circulars 07 Jan '25

07 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38834 SUBJECT: GRB 210506A NOT GCN draft DATE: 25/01/07 01:47:52 GMT FROM: Daniele B. Malesani at IMAPP / Radboud University <d.malesani(a)astro.ru.nl> Hi. I doubt anyone is online, but here's the GCN draft for the NOT observations, which I'll submit soon. TLTR: no obvious candidate, one possible host galaxy, but I would hold spectroscopy until variability is confirmed by VT or XRT. d ============================== GRB 250106A: NOT optical observations L. Izzo (INAF/OACn and DARK/NBI), D. B. Malesani (DAWN/NBI and Radboud Univ.), D. Xu (NAOC), Z.P. Zhu (NAOC), X. Liu (NAOC), T. Pursimo (NOT), report on behalf of a larger collaboration: We observed the field of GRB 250106A (Zhao et al., GCN 38826) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera, using the SDSS z filter. The instrument was rotated in order to include XRT sources #1 and #2 (Osborne et al., GCN 38830), as well as the candidate SVOM/VT optical afterglow (which is consistent with the position of XRT source #2; Qiu et al., GCN 38829). The observation mid time was 2025 Jan 6.982 UT (10.13 hr after the SVOM trigger), and the exposure time was 2000 s. No source is detected within the localization circle of XRT source #1, down to a limiting magnitude z > 23.3 (AB). Two sources are detected within the localization circle of XRT source #2. Source A (coincident with the SVOM/VT optical candidate): RA = 07:49:29.04 Dec = +63:42:29.4 mag z = 22.23 +- 0.10 AB Source B: RA = 07:49:27.99 Dec = +63:42:31.5 mag z = 19.90 +- 0.02 AB At the locations of both sources, objects are visible in the Legacy Survey, for which we measure AB magnitudes z = 22.24 +- 0.11 and z = 19.84 +- 0.02 for sources A and B, respectively. Our measured values are thus fully consistent with those in the archival images. Source B is also detected by Gaia, which provides a QSO classification. This opens the question whether object B could be responsible for the X-ray emission detected by Swift/XRT. Source A could be the host galaxy of GRB 250106A, though we note that its archival r-band magnitude (r = 23) is only marginally fainter than the SVOM/VT magnitude (R = 22.5 +- 0.3 mag; Qiu et al., GCN 38829). We encourage further observations with both SVOM/VT and Swift/XRT in order to establish variability of both the optical and X-ray sources. View this GCN Circular online at https://gcn.nasa.gov/circulars/38834. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36838] LIGO/Virgo/KAGRA S250104v: Updated Sky localization
by GCN Circulars 06 Jan '25

06 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38833 SUBJECT: LIGO/Virgo/KAGRA S250104v: Updated Sky localization DATE: 25/01/06 21:54:46 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250104v (GCN Circular 38812). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250104v For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1514 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4932 +/- 1471 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 View this GCN Circular online at https://gcn.nasa.gov/circulars/38833. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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