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

[vsnet-grb-info 36767] GRB 250101A: SAO RAS observations of optical brightening
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38765 SUBJECT: GRB 250101A: SAO RAS observations of optical brightening DATE: 25/01/01 22:57:03 GMT FROM: Moskvitin Alexander at SAO RAS <mosk(a)sao.ru> A. S. Moskvitin, O. I. Spiridonova (SAO RAS) and A. S. Pozanenko (IKI RAS) report on behalf of the GRB follow-up team. We continued follow-up observations of GRB 250101A OT (Page et al., GCN 38752; Li et al., GCN 38753; Mohan et al., GCN 38754; Zhu et al., GCN 38755, GCN 38759; Budnev et al., GCN 38756; Wu et al., GCN 38758; Odeh and Guessoum, GCN 38763; Hu et al., GCN 38764) with the 1-m telescope of SAO RAS, Zeiss-1000 + CCD-photometer. After a steady decline in the afterglow light curve between 3.2 and 5.5 hours (see GCN 38762), we clearly observe an increase in the brightness of OT of R= 19.08 +/- 0.02 at 8.24 hours after the trigger. We encourage further observations of GRB 250101A. View this GCN Circular online at https://gcn.nasa.gov/circulars/38765. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36766] GRB 250101A: BOOTES-4/MET optical afterglow detection
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38764 SUBJECT: GRB 250101A: BOOTES-4/MET optical afterglow detection DATE: 25/01/01 22:09:03 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct(a)iaa.es> Y.-D. Hu (INAF-OAB, Brera), E. Fernandez-Garcia, I. Perez-Garcia, M. D. Caballero-Garcia, G. Garcia-Segura, S. Guziy, R. Sanchez-Ramirez, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), C. Perez del Pulgar, A. Castellon, I. M. Carrasco (Univ. de Malaga), M. Gritsevich (Univ. of Helsinki) and D. R. Xiong, J. M. Bai, Y. F. Fan, C. J. Wang, Y. X. Xin, X. H. Zhao, J. R. Mao, B. K. Lun, K. Ye (Yunnan Observatories/CAS, Kunming) on behalf of a larger collaboration, report: Following the detection of GRB 250101A by Swift (Page et al. GCNC 38752), the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical Observatory (China) automatically responded to this burst starting on Jan. 1, 13:26:58 UT (~248 s after trigger). Series of images in clear filter were gathered and the optical afterglow was detected within the enhanced Swift/XRT position (Goad et al. GCNC 38761), for which we measure a magnitude of 17.7 +- 0.3 on the first 5 s exposure image, which is consistent with the reported detections by UVOT (Page et al. GCNC 38752), GMG (Li et al. GCNC 38753), GIT (Mohan et al. GCNC 38754), Nanshan (Zhu et al. GCNC 38755), MASTER (Lipnov et al. GCNC 38756), C-GFT (Wu et al. GCNC 38758), Xinglong-2.16m (Zhu et al. GCNC 38759), SAO (Moskvitin et al. GCNC 38762) and AKO (Odeh et al. GCNC 38763). Further analysis of the additional images is ongoing. We thank the staff at Lijiang observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/38764. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36765] GRB 250101A: AKO Optical Afterglow Detection
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38763 SUBJECT: GRB 250101A: AKO Optical Afterglow Detection DATE: 25/01/01 19:23:00 GMT FROM: Mohammad Odeh at Al Khatim Observatory M44 <mshodeh(a)gmail.com> Mohammad Odeh (Al-Khatim Observatory, AKO, operated by the International Astronomical Center in Abu Dhabi, UAE), and Nidhal Guessoum (American University of Sharjah, UAE), report: We observed the field of GRB 250101A (Page et al., GCN 38752) using our 0.36m f/7.7 robotic telescope. The observation session began on 01 January 2025 at 15:52 UT and continued until 17:25 UT, with a midpoint at 16:40 UT, approximately 3.3 hours after the trigger. The weather conditions during the observation were partly cloudy. We obtained multiple 180-second exposures using the Ic filter. The optical afterglow was barely detected at: R.A. (J2000): 02:28:16.5 Dec. (J2000): +19:11:40.1 Our detection is consistent with the results of (Page et al., GCN 38752; 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). The following observation was calculated using Atlas catalogue as a reference: ---------------------------------------------------------------------------- - ObsTime (mid), Exposure (sec), Filter, Mag ---------------------------------------------------------------------------- - 2025-01-01T16:39:55Z, 25 x 180s (stacked), Ic, 17.8 +/- 0.9 ---------------------------------------------------------------------------- - The magnitude is not corrected for galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38763. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36764] GRB 250101A: SAO RAS optical observations
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38762 SUBJECT: GRB 250101A: SAO RAS optical observations DATE: 25/01/01 19:20:35 GMT FROM: Moskvitin Alexander at SAO RAS <mosk(a)sao.ru> A. S. Moskvitin and O. I. Spiridonova (SAO RAS), report on behalf of the GRB follow-up team. We observed the field of Swift GRB 250101A (Page et al., GCN 38752) with the 1-m telescope of SAO RAS, Zeiss-1000 + CCD-photometer. On January 1, 16:18:20--16:51:10 UT (t_mid - T0 = 3.1986 hours) we obtained first set of 6 x 300 sec. images in Rc band. At 18:43:29--18:59:33 UT (t_mid - T0 = 5.4781 hours) we obtained second set of data, 3 x 300 sec. images in Rc band. The OT (Page et. al., GCN 38752; Li et al., GCN 38753; Mohan et al., GCN 38754; Zhu et al., GCN 38755, GCN 38759; Budnev et al., GCN 38756; WU et al., GCN 38758) is clearly detected in our stacked frames with the brightness of R = 19.76 +/- 0.01 (t_mid - T0 = 3.1986 hours) and R = 19.84 +/- 0.02 (5.4781 hours), calibrated against nearby PS1 stars (magnitudes were converted with the Lupton 2005 equations and not corrected for the MW extinction). Observations are ongoing. View this GCN Circular online at https://gcn.nasa.gov/circulars/38762. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36763] GRB 250101A: Enhanced Swift-XRT position
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38761 SUBJECT: GRB 250101A: Enhanced Swift-XRT position DATE: 25/01/01 17:53:29 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 631 s of XRT Photon Counting mode data and 2 UVOT images for GRB 250101A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 37.06921, +19.19403 which is equivalent to: RA (J2000): 02h 28m 16.61s Dec (J2000): +19d 11' 38.5" with an uncertainty of 2.8 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38761. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36762] LIGO/Virgo/KAGRA S250101k: Updated Sky localization and Source Classification
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38760 SUBJECT: LIGO/Virgo/KAGRA S250101k: Updated Sky localization and Source Classification DATE: 25/01/01 17:21:16 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 S250101k (GCN Circular 38747). 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/S250101k The updated classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 455 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3231 +/- 945 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/38760. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36761] GRB 250101A: Xinglong-2.16m spectroscopic redshift
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38759 SUBJECT: GRB 250101A: Xinglong-2.16m spectroscopic redshift DATE: 25/01/01 16:33:10 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> Z.P. Zhu, S.Y. Fu, X. Liu, S.Q. Jiang, J. An, D. Xu (NAOC) report on behalf of a large collaboration: We carried out spectroscopy of the optical counterpart (e.g., Page et. al., GCN 38752; Li et al., GCN 38753; Mohan et al., GCN 38754; Zhu et al., GCN 38755) of GRB 250101A detected by Swift/BAT (Page et. al., GCN 38752), using the 2.16-m telescope located at Xinglong, Hebei, China. Our spectra cover the wavelength range 3800 - 9000 AA, and consist of 3 exposures of 1800 s each. The whole spectrum has a fairly low S/N, but absorption features are evident. From the detection of a Lya absorption feature at ~ 4240 AA and multiple absorption features, which interpreted as being due to Si II, O I, C IV, Fe II, and Cr II, we infer a common redshift of z = 2.49. We conclude this is the likely redshift of the burst. We acknowledge the expert support from the Xinglong-2.16m staff, in particular Yu Zhang, Junjun Jia, and Jie Zheng. View this GCN Circular online at https://gcn.nasa.gov/circulars/38759. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36760] GRB 250101A: SVOM/C-GFT early optical observations
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38758 SUBJECT: GRB 250101A: SVOM/C-GFT early optical observations DATE: 25/01/01 16:31:19 GMT FROM: Chao Wu at NAOC <cwu(a)nao.cas.cn> SVOM/C-GFT team: Chao WU (NAOC), Zhe Kang (CHO), Liping Xin(NAOC), Xuhui Han(NAOC), Pinpin Zhang (NAOC), Xiaomeng Lu (NAOC), Zhenwei Li (CHO), You Lv (CHO), Ruosong Zhang (NAOC), Yujie Xiao(NAOC) 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) We observed the field of GRB 250101A detected by Swift/BAT (Page et al., GCN 38752) on 2025-01-01T13:24:07 UT, ~ 77s after the trigger with C-GFT in the commissioning phase. A series of g, r and i band images were obtained with exposure time of 10s. The optical counterpart (Page et al. GCN 38752, Li et al. GCN 38753, Mohan et al. GCN 38754, Zhu et al. GCN 38755, Budnev et al., GCN 38756 ) was clearly detected in band g,r and i. The results are, (T-T0)_mid(s) mag mag_err band ------------------------------------- 82 18.38 +/- 0.26 i 172 17.37 +/- 0.08 g 262 16.83 +/- 0.05 r The photometry was calibrated with nearby PS1 star. Observations will be continued. We thank the observation assistant Guangsheng Zhang at Jilin observatory for their excellent support. Chinese Ground Follow-up Telescope of SVOM mission is located at Jilin, Changchun Observatory, National Astronomical Observatories, CAS. It has FOV of 1.28 deg x 1.28 deg with a 4k*4k CMOS detector mounted on the primary focus of 1.2-meter-aperure telescope. View this GCN Circular online at https://gcn.nasa.gov/circulars/38758. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36759] LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38757 SUBJECT: LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations DATE: 25/01/01 16:04:32 GMT FROM: Peter Veres at University of Alabama in Huntsville <veresp(a)gmail.com> P. Veres (UAH) reports on behalf of the Fermi-GBM Team: "For S250101k (GCN 38747) and using the initial bayestar skymap, Fermi-GBM was observing 100% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo/KAGRA (LVK) detection of GW trigger S250101k. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. We set upper limits on impulsive gamma-ray emission for the complete GW localization region. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 1.4 2.4 4.9 1.024 s: 0.55 0.9 2.2 8.192 s: 0.14 0.23 0.59 Assuming the median luminosity distance of 3057 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 2.5 3.7 12.0 1.024s: 0.98 1.4 5.7 8.192s: 0.25 0.36 1.5 View this GCN Circular online at https://gcn.nasa.gov/circulars/38757. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36758] GRB 250101A: MASTER earlier OT observations with SOSS emission features
by GCN Circulars 01 Jan '25

01 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38756 SUBJECT: GRB 250101A: MASTER earlier OT observations with SOSS emission features DATE: 25/01/01 15:23:19 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> N.Budnev (ISU, V.Lipunov, (Lomonosov MSU), O.Gress (ISU), I.Panchenko, A.Kuznetsov, P.Balanutsa, K.Zhirkov, V.Topolev, A.Chasovnikov, N.Tiurina, Ya.Kechin, G.Antipov, E.Gorbovskoy, D.Vlasenko, A.Sankovich, V.Senik (Lomonosov MSU), A.Sosnovskij (CrAO RAS), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), 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 Alvarez, J.Martinez,A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), MASTER Global robotic net (http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L) started observation (Lipunov et al. GCN 38751) of Swift GRB 240101A(Page et al. GCN 38752) 35 sec after notice time (86 sec after trigger time) at 2025-01-01 13:24:16 UT at MASTER-Tunka, see limits map https://master.sai.msu.ru/site/master2/observ.php?id=2730214 . There is MASTER OT J022816.52+191139.9 , discovered by Swift (GCN 38752) since 1st image. We see Smooth Optical Self-similar Emission of this Gamma-Ray Burst (SOSS-emission, Lipunov et al. 2017, ApJ, 845, id9 https://ui.adsabs.harvard.edu/abs/2017ApJ...845...52L/abstract ) Observations and reduction will be continued. View this GCN Circular online at https://gcn.nasa.gov/circulars/38756. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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