December 2024 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 36748] GRB 241229B: Continued CrAO ZTSh observations
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38746 SUBJECT: GRB 241229B: Continued CrAO ZTSh observations DATE: 24/12/31 23:03:47 GMT FROM: Alexei Pozanenko at IKI, Moscow <grb.alex(a)gmail.com> N. Pankov (HSE, IKI), A. Volnova (IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), report on behalf of the IKI-GRB-FuN collaboration: We observed the field of GRB 241229B (Fermi GBM Team, GCN 38698; D'Ai et al., GCN 38699) with 2.6-meter ZTSh telescope of CrAO. The observations started on 2024-12-30 (UT) 18:30, i.e. ~1.73 days since GBM trigger. The series of 30x120 s images were obtained using the CCD-photometer. The optical counterpart (SVOM/VT team, GCN 38729; Volnova et. al, GCN 38732) has been detected in a stacked image. Preliminary photometry is the following: Date UTstart T-T0 Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2024-12-30 18:13:33 1.73423 30x120 R 23.40 0.15 24.0 The photometry has been calibrated against nearby PS1 stars (see Volnova et. al, GCN 38732). View this GCN Circular online at https://gcn.nasa.gov/circulars/38746. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36747] LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38745 SUBJECT: LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume DATE: 24/12/31 17:14:54 GMT FROM: David Cook at Caltech/IPAC-NED <dcook(a)ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S241231bg-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 1003 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241231bg/4 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241231bg/4/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| |WISEA J034231.05+405421.8| 55.62946| 40.90622| G| 790.59| null| null| null| 13.733| 0.188| 10.196| 0.006|4.55e-08| 8.61e-10| |WISEA J040613.97+565212.5| 61.55829| 56.87019| G| 712.19| null| null| null| 12.904| 0.124| 10.162| 0.009|3.40e-08| 5.84e-10| | 4C +26.11| 48.34621| 26.42025| G| 800.52| null| null| null| 12.396| 0.088| 12.127| 0.008|1.67e-07| 5.51e-10| |WISEA J030248.50+220320.3| 45.70208| 22.05561| G| 547.28| null| null| null| 13.964| 0.231| 10.581| 0.006|8.10e-08| 5.27e-10| |WISEA J035334.16+461429.8| 58.39233| 46.24161| G| 963.44| null| null| null| 12.826| 0.095| 11.140| 0.007|3.87e-08| 4.83e-10| |WISEA J030333.55+225139.8| 45.88975| 22.86108| G| 739.90| null| null| null| 13.061| 0.119| 12.709| 0.021|2.99e-07| 4.79e-10| | 2MFGC 02843| 51.78196| 37.60861| G| 845.24| null| null| null| 13.350| 0.133| 10.690| 0.006|3.27e-08| 4.62e-10| |WISEA J031813.73+301528.5| 49.55725| 30.25797| G| 815.27| null| null| null| 13.068| 0.117| 12.402| 0.015|1.63e-07| 4.55e-10| |WISEA J030838.81+255248.2| 47.16175| 25.88006| G| 803.39| null| null| null| 13.168| 0.135| 12.965| 0.021|2.97e-07| 4.44e-10| |WISEA J031235.25+263108.2| 48.14696| 26.51889| G| 752.45| null| null| null| 13.702| 0.160| 12.548| 0.013|2.23e-07| 4.41e-10| |WISEA J030008.35+225108.5| 45.03471| 22.85222| G| 798.73| null| null| null| 13.505| 0.131| 12.881| 0.013|2.30e-07| 3.74e-10| |WISEA J031341.09+262414.6| 48.42129| 26.40403| G| 656.65| null| null| null| 12.770| 0.099| 12.061| 0.009|1.57e-07| 3.68e-10| |WISEA J030454.40+233721.7| 46.22667| 23.62269| G| 689.71| null| null| null| 13.227| 0.138| 12.742| 0.014|2.69e-07| 3.63e-10| |WISEA J030647.94+253530.0| 46.69975| 25.59167| G| 850.40| null| null| null| 13.584| 0.143| 13.062| 0.016|2.34e-07| 3.59e-10| |WISEA J031351.04+270053.6| 48.46296| 27.01464| G| 777.61| null| null| null| 13.214| 0.119| 12.771| 0.014|2.07e-07| 3.59e-10| |WISEA J025934.62+243010.3| 44.89425| 24.50328| G| 664.39| null| null| null| 13.347| 0.147| 10.609| 0.006|3.79e-08| 3.42e-10| |WISEA J030144.52+225829.0| 45.43550| 22.97472| G| 751.90| null| null| null| 13.301| 0.119| 13.065| 0.021|2.83e-07| 3.39e-10| |WISEA J034738.09+424129.1| 56.90888| 42.69147| G| 734.25| null| null| null| 13.856| 0.194| 10.919| 0.006|3.92e-08| 3.38e-10| |WISEA J030211.99+214836.9| 45.55008| 21.81031| G| 656.47| null| null| null| 13.113| 0.118| 12.558| 0.013|2.03e-07| 3.05e-10| |WISEA J030350.54+253907.0| 45.96079| 25.65142| IrS| 829.78| null| null| null| 12.879| 0.097| 12.378| 0.009|1.10e-07| 3.05e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241231bg sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1). View this GCN Circular online at https://gcn.nasa.gov/circulars/38745. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36746] LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38744 SUBJECT: LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification DATE: 24/12/31 17:08:00 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 S241231bg (GCN Circular 38737). 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/S241231bg Based on posterior support from parameter estimation [1], under the assumption that the candidate S241231bg is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] 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 <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 125 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 830 +/- 159 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 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe View this GCN Circular online at https://gcn.nasa.gov/circulars/38744. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36745] LIGO/Virgo/KAGRA S241230ev: Updated Sky localization
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38743 SUBJECT: LIGO/Virgo/KAGRA S241230ev: Updated Sky localization DATE: 24/12/31 17:00:25 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 S241230ev (GCN Circular 38735). 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/S241230ev For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 355 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2940 +/- 1041 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/38743. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36744] LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38742 SUBJECT: LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume DATE: 24/12/31 16:52:00 GMT FROM: David Cook at Caltech/IPAC-NED <dcook(a)ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S241231bg-3-Initial sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 2975 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241231bg/3 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241231bg/3/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| | 2MFGC 02843| 51.78196| 37.60861| G| 845.24| null| null| null| 13.350| 0.133| 10.690| 0.006|7.91e-08| 5.61e-10| |WISEA J034231.05+405421.8| 55.62946| 40.90622| G| 790.59| null| null| null| 13.733| 0.188| 10.196| 0.006|5.61e-08| 5.33e-10| |WISEA J172426.60-032531.3| 261.11071| -3.42564| G| 533.75| null| null| null| 12.327| 0.116| 8.965| 0.005|3.06e-08| 4.39e-10| |WISEA J033451.68+392802.3| 53.71533| 39.46742| G| 442.96| 0.75| null| null| 11.986| 0.112| 8.831| 0.005|4.12e-08| 4.23e-10| |WISEA J030248.50+220320.3| 45.70208| 22.05561| G| 547.28| null| null| null| 13.964| 0.231| 10.581| 0.006|9.55e-08| 3.12e-10| |WISEA J031324.39+301344.6| 48.35196| 30.22869| G| 852.37| null| null| null| 13.765| 0.147| 12.050| 0.010|1.20e-07| 2.44e-10| |WISEA J025934.62+243010.3| 44.89425| 24.50328| G| 664.39| null| null| null| 13.347| 0.147| 10.609| 0.006|5.32e-08| 2.42e-10| |WISEA J174249.63-112229.5| 265.70696| -11.37489| G| 672.81| null| null| null| 12.929| 0.184| 11.063| 0.011|6.98e-08| 2.30e-10| |WISEA J032905.13+404816.1| 52.27142| 40.80436| G| 863.24| null| null| null| 13.591| 0.184| 9.655| 0.006|1.21e-08| 2.22e-10| |WISEA J033553.60+401025.3| 53.97329| 40.17369| G| 695.33| null| null| null| 13.478| 0.172| 11.652| 0.007|1.17e-07| 2.22e-10| |WISEA J032706.63+373052.4| 51.77754| 37.51444| G| 782.22| null| null| null| 13.321| 0.135| 11.655| 0.008|8.92e-08| 2.21e-10| |WISEA J031813.73+301528.5| 49.55725| 30.25797| G| 815.27| null| null| null| 13.068| 0.117| 12.402| 0.015|1.54e-07| 2.16e-10| |WISEA J032545.43+340232.4| 51.43933| 34.04225| G| 532.67| null| null| null| 13.344| 0.127| 11.053| 0.007|9.38e-08| 1.81e-10| |WISEA J032009.05+312329.6| 50.03779| 31.39156| G| 714.64| null| null| null| 13.540| 0.147| 12.469| 0.014|1.82e-07| 1.80e-10| |WISEA J031455.80+301350.4| 48.73229| 30.23064| G| 755.36| null| null| null| 13.530| 0.144| 12.680| 0.014|2.00e-07| 1.79e-10| |WISEA J032347.98+340355.9| 50.94996| 34.06561| G| 912.69| null| null| null| 13.690| 0.157| 12.488| 0.014|1.17e-07| 1.77e-10| |WISEA J030957.19+280617.4| 47.48837| 28.10483| G| 660.86| null| null| null| 12.681| 0.104| 12.265| 0.009|1.77e-07| 1.77e-10| |WISEA J032105.14+340148.2| 50.27146| 34.03006| G| 705.64| null| null| null| 13.531| 0.167| 12.191| 0.009|1.47e-07| 1.74e-10| |WISEA J032328.08+323938.1| 50.86700| 32.66067| G| 859.20| null| null| null| 13.724| 0.159| 12.435| 0.011|1.16e-07| 1.69e-10| |WISEA J033300.46+402436.2| 53.25192| 40.41014| G| 954.15| null| null| null| 13.345| 0.135| 11.668| 0.009|4.40e-08| 1.55e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241231bg sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1). View this GCN Circular online at https://gcn.nasa.gov/circulars/38742. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36743] LIGO/Virgo/KAGRA S241230bd: Updated Sky localization
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38741 SUBJECT: LIGO/Virgo/KAGRA S241230bd: Updated Sky localization DATE: 24/12/31 16:50:25 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 Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S241230bd (GCN Circular 38722). 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/S241230bd For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 11129 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2811 +/- 842 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/38741. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36742] GRB 241229A: EP-FXT X-ray afterglow confirmation
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38740 SUBJECT: GRB 241229A: EP-FXT X-ray afterglow confirmation DATE: 24/12/31 10:22:37 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> S. Q. Jiang, J. W. Hu, H. Sun, W. J. Zhang, X. P. Xu (NAO, CAS), W. F. Wen (SZTU), J. H. Wu (GU), H.W. Pan, Z. X. Ling (NAO, CAS), B. Cordier (CEA) on behalf of Einstein Probe teams: We performed further follow-up observations of GRB 241229A (SVOM/ECLAIRs, Liang et al., GCN 38697) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The first epoch of the observation started at 2024-12-30T09:24:30 (T-TGRB ~ 1.39 days) with an exposure time of 2 ks, and a second epoch was performed at 2024-12-30T16:06:04 (T-TGRB ~ 1.67 days) with an exposure time of 5 ks. The flux of the first (EPF_J125139.4+315311) and the third (EPF_J125101.6+315007) sources reported in Jiang et al., GCN 38726 remained almost constant over all the observations. The second source EPF_J125129.3+314453, which is also detected by Swift/XRT (Williams et al., GCN 38728) shows a clear flux decay with a powerlaw index of ~ 0.8. The unabsorbed 0.5-10 keV flux given in the below table is calculated by assuming the same spectral index 1.86 and fixed with the Milky Way equivalent hydrogen column density nH of 1.43 x 10^20 cm^-2: Observation start time [UTC] | exposure time [s] | 0.5 - 10 keV unabsorbed flux [erg/s/cm2] 2024-12-29T14:11:35 | 2828 | 7.94 (+2.12 -1.53) x 10^(-13) 2024-12-30T09:24:30 | 2212 | 4.19 (+0.81 -0.72) x 10^(-13) 2024-12-30T16:06:04 | 4898 | 3.50 (+1.14 -0.77) x 10^(-13) Thus we claim that this source is very likely the afterglow of GRB 241229A. The above observation was made with the EP-FXT instrument. 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). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/38740. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36741] GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38739 SUBJECT: GRB 241228B: Multiband optical monitoring with 1.6m Mephisto DATE: 24/12/31 09:02:12 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh(a)ynu.edu.cn> Brajesh Kumar, Yuan Fang, Jianhui Lian, Qinhao Shao, Bo Wu, Yu Pan, Xingzhu Zou, Xinlei Chen, Jinghua Zhang, Guowang Du, Yuanpei Yang, Yehao Cheng, Xiangkun Liu, Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team: The 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory was triggered to perform monitoring of GRB 241228B discovered by (Fermi GBM team, GCN 38682, Scotton and Meegan, GCN 38714) and Swift (Evans, GCN 38688; Burrows et al., GCN 38713). Simultaneous uvgriz band observations were started at 15:38:16 UT 2024-12-28 (~11.4 hr after the trigger) at an altitude of ~32 deg in moderate sky conditions (seeing ~2”). The GOTO optical counterpart GOTO24jmz (Kumar et al., GCN 38684, GCN 38691; An et al. GCN 38687; Ortega-Casas et al., GCN 38692; Ghosh et al., GCN 38702; An et al., GCN 38704; Volnova et al., GCN 38709; Strobl and Jelinek, GCN 38715, Moskvitin et al., GCN 38733) is clearly detected in different bands in the stacked images. The monitoring of the GRB field was continued at different epochs between 2024-12-28 to 2024-12-30 each night and multiple sets of observations in vri bands were acquired. The preliminary photometry on the stacked i-band initial frames is 20.2 +/- 0.1 mag (15:53:03UT2024-12-28, ExpStart). Further analysis of our remaining data is in progress. -------------------------------------------------------------------------- Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21. -------------------------------------------------------------------------- View this GCN Circular online at https://gcn.nasa.gov/circulars/38739. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36740] GRB 241229B: SVOM/GRM observation
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38738 SUBJECT: GRB 241229B: SVOM/GRM observation DATE: 24/12/31 08:11:34 GMT FROM: Yue Wang <m18509381757(a)163.com> SVOM/GRM team: Yue Wang, Chen-Wei Wang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP), report on behalf of the SVOM team: The SVOM/GRM was triggered in-flight by GRB 241229B (SVOM trigger reference: sb24122902) at 2024-12-29T01:36:17.000 UT (T0), which was also observed by Fermi/GBM (Fermi GBM Team, GCN 38698) and Swift/BAT (A. D'Ai et al, GCN 38699). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of one main pulse with a T90 of 5.45 +0.76/-1.01 s This burst is located (from Swift/BAT) at about 57.10 degrees from the SVOM optical axis, and outside the ECLAIRs field of view. The GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb241229B.png The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Yue Wang (IHEP)(yuewang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/38738. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36739] LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
by GCN Circulars 31 Dec '24

31 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38737 SUBJECT: LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate DATE: 24/12/31 07:07:06 GMT FROM: Jyotirmaya Mohanta at University of Tsukuba <s2430161(a)u.tsukuba.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241231bg during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-12-31 05:41:33.606 UTC (GPS time: 1419658911.606). The candidate was found by the CWB [1], cWB BBH [2], GstLAL [3], MBTA [4], MLy [5], PyCBC Live [6], and SPIIR [7] analysis pipelines. S241231bg is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241231bg After parameter estimation by RapidPE-RIFT [8], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), 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%. [9] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [9] 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 7%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [10], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [10], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 217 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 802 +/- 184 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] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Skliris et al. (2020) arXiv:2009.14611 [6] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [7] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [8] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [9] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [10] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/38737. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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