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

[vsnet-grb-info 37598] EP250304a: TRT optical counterpart detection
by GCN Circulars 04 Mar '25

04 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39583 SUBJECT: EP250304a: TRT optical counterpart detection DATE: 25/03/04 08:17:49 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> X. Liu, J. An, N.C. Sun (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), S.Q. Jiang, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, Y.N. Wang (NAOC) report on behalf of a large collaboration: We observed the field of EP250304a (Chen et al, GCN 39580), using the 0.7-m telescope of the Thai Robotic Telescope … [View More]

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[vsnet-grb-info 37597] LIGO/Virgo/KAGRA S250304cb: Identification of a GW compact binary merger candidate
by GCN Circulars 04 Mar '25

04 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39582 SUBJECT: LIGO/Virgo/KAGRA S250304cb: Identification of a GW compact binary merger candidate DATE: 25/03/04 06:58:51 GMT FROM: Pan Guo at KAGRA <panguocas(a)gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250304cb during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo … [View More]Observatory (V1) at 2025-03-04 06:22:45.568 UTC (GPS time: 1425104583.568). The candidate was found by the GstLAL [1] and MBTA [2] analysis pipelines. S250304cb is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.6e-08 Hz, or about one in 6 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250304cb The classification of the GW signal, in order of descending probability, is BBH (96%), Terrestrial (4%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 2%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1569 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1768 +/- 541 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] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39582. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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[vsnet-grb-info 37596] EP250304a: Global MASTER-Net observations report
by GCN Circulars 04 Mar '25

04 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39581 SUBJECT: EP250304a: Global MASTER-Net observations report DATE: 25/03/04 03:00:51 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.… [View More]

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[vsnet-grb-info 37595] EP250304a: Einstein Probe detection of an X-ray transient
by GCN Circulars 04 Mar '25

04 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39580 SUBJECT: EP250304a: Einstein Probe detection of an X-ray transient DATE: 25/03/04 02:35:25 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> W. Chen, W. X. Wang (NAO, CAS), Y. J. Zhang (THU), C. Y. Dai (NJU), Y.Liu (NAO, CAS) report on behalf of the Einstein Probe team: We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP250304a. The transient … [View More]

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[vsnet-grb-info 37594] The EP-WXT trigger 01709132212 is not a real source
by GCN Circulars 04 Mar '25

04 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39579 SUBJECT: The EP-WXT trigger 01709132212 is not a real source DATE: 25/03/04 02:18:44 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> J. W. Hu, M. H. Zhang (NAOC, CAS), C. Y. Dai (NJU), Y. Q. Zhao (USTC, PRIC), W. D. Zhang (NAOC, CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709132212 at 16:00:13 UTC on 3th March 2025, is not a real source. View this GCN Circular online at https://gcn.nasa.gov/circulars/39579. --- To … [View More]

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[vsnet-grb-info 37593] EP250302a: SVOM/VT optical observation
by GCN Circulars 04 Mar '25

04 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39578 SUBJECT: EP250302a: SVOM/VT optical observation DATE: 25/03/04 02:15:58 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> C. Wu, D. H. Zhao, Y. N. Ma, L. P. Xin, Y. L. Qiu, H. L. Li, Z. H. Yao, Y. Xu, P. P. Zhang, W. J. Xie, J. Wang, X. H. Han, Y. J. Xiao, H. B. Cai, J. Y. Wei(NAOC), J. T. Palmerio(CEA/Irfu) report on behalf of the SVOM team: The SVOM/VT conducted a ToO follow-up observations of the EP250302a (Zhu et al., GCN 39550) in VT_B … [View More]

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[vsnet-grb-info 37592] LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Swift/UVOT Upper Limits
by GCN Circulars 03 Mar '25

03 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39577 SUBJECT: LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Swift/UVOT Upper Limits DATE: 25/03/03 19:55:29 GMT FROM: noelklin(a)umbc.edu Noel Klingler (NASA-GSFC / UMBC / CRESST II), Sam Shilling (Lancaster U.), P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.B. Cenko (NASA/GSFC), R.A.J. Eyles-Ferris (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld … [View More]

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[vsnet-grb-info 37591] EP250302a: SAO RAS optical observations
by GCN Circulars 03 Mar '25

03 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39576 SUBJECT: EP250302a: SAO RAS optical observations DATE: 25/03/03 16:32:59 GMT FROM: Moskvitin Alexander at SAO RAS <mosk(a)sao.ru> A. S. Moskvitin, O. A. Maslennikova (SAO RAS), A. Pozanenko (IKI) and N. Pankov (HSE, IKI) report on behalf of larger collaboration. We observed the field of the X-ray transient EP250302a (Dai et al., GCN 39556; Page et al., GCN 39557) with SAO RAS 1-m telescope Zeiss-1000 equipped with CCD-photometer under … [View More]

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[vsnet-grb-info 37590] EP250302a : GIT optical follow-up
by GCN Circulars 03 Mar '25

03 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39575 SUBJECT: EP250302a : GIT optical follow-up DATE: 25/03/03 16:09:43 GMT FROM: V. Swain at IIT Bombay <vishwajeet.s(a)iitb.ac.in> D. Eappachen (IIA), V. Swain (IITB), A.P. Saikia (IITB), V. Bhalerao (IITB), G.C. Anupama (IIA), S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team: We observed the field of EP250302a (Dai et al., GCN 39556) with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2025-03-02 20:51:47 UT, … [View More]

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[vsnet-grb-info 37589] EP250302a: VLT/X-shooter redshift confirmation
by GCN Circulars 03 Mar '25

03 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39574 SUBJECT: EP250302a: VLT/X-shooter redshift confirmation DATE: 25/03/03 15:53:51 GMT FROM: Yu-Han Yang at University of Rome Tor Vergata <yyang(a)roma2.infn.it> Yu-Han Yang (U Rome), Eleonora Troja (U Rome), and Rosa Becerra (U Rome) report on behalf of the ERC BHianca team: A further analysis was performed on the VLT/X-shooter spectrum reported by Yang et al. (GCN 39561). Whereas no significant features are visible in the VIS and NIR arms, we … [View More]

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