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

[vsnet-grb-info 36728] Konus-Wind detection of GRB 241228A
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38727 SUBJECT: Konus-Wind detection of GRB 241228A DATE: 24/12/30 11:44:36 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 GRB 241228A (Swift-BAT detection: D'Elia et al., GCN 38681; Sadaula et al., GCN 38701; Fermi-GBM detection: Scotton & Meegan, GCN 38695) triggered Konus-Wind at T0=14233.924 s UT (03:57:13.924). The burst light curve shows a two-peak structure which starts at ~T0-0.2 s and has a total duration of ~5.1 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB241228_T14233/ As observed by Konus-Wind, the burst had a fluence of 3.35(-0.17,+0.18)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+1.760 s, of 1.74(-0.01,+0.01)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.88(-0.24,+0.26) and Ep = 75(-5,+5) keV (chi2 = 96/81 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 96/80 dof). 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/38727. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36727] GRB 241229A: EP-FXT afterglow candidates
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38726 SUBJECT: GRB 241229A: EP-FXT afterglow candidates DATE: 24/12/30 11:41:58 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> S.Q. Jiang, J. W. Hu, 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 a follow-up observation 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 observation started at 2024-12-29 14:11:35 (T-TGRB ~ 14.1 hr) for about 3 ks of exposure in total. Three uncatalogued X-ray sources are detected by both FXT-A and FXT-B within the 7.6 arcmin error circle of SVOM/ECLAIRs (Liang et al., GCN 38697). We list the sources in the following table, with the seperations from the ECLAIRs source given. The observed 0.5-10 keV flux given in the table is a rough estimate assuming the same spectral paramters, and is not corrected for absorption. | FXT source | R.A. (deg, J2000) | DEC (deg, J2000) | Sep. (arcmin) | Flux (erg/s/cm^2) | | EPF_J125139.4+315311 | 192.9133 | 31.8867 | 2.06 | 6.82 x 10^(-14) | | EPF_J125129.3+314453* | 192.8715 | 31.7484 | 6.61 | 7.73 x 10^(-13) | | EPF_J125101.6+315007 | 192.7572 | 31.8356 | 7.04 | 9.25 x 10^(-14) | * sources also detected by Swift/XRT (Evans et al., GCN 38711) Further follow-up observation will be performed by the EP-FXT to confirm 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/38726. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36726] EP240702a: 7DT Optical upper limits
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38725 SUBJECT: EP240702a: 7DT Optical upper limits DATE: 24/12/30 10:47:28 GMT FROM: Gregory Paek at Seoul National University <gregorypaek94(a)gmail.com> Gregory S.H. Paek (SNU ARC/SNU), Myungshin Im (SNU ARC/SNU), Hyeonho Choi (SNU ARC/SNU), Seo-Won Chang (SNU ARC/SNU), and Ji Hoon Kim (SNU ARC/SNU) report on behalf of the 7-Dimensional Telescope collaboration We searched for the optical counterpart of a fast X-ray transient, EP240702a (Chen et al., GCN #36801) using the 7-Dimensional Telescopes (7DT). Approximately 26 hours following the initial detection (2024-07-02T00:50:05 UTC), we targeted the localization center provided by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission at RA, Dec = 328.203 deg, -38.980 deg with an uncertainty of 3 arcmins. Observations were made with eleven 7DT units in twenty medium-band filters, denoted as m400, m425, then through m875, in which the numeric values indicate their central wavelengths in nanometers. Each medium-band filter has a bandwidth of 25nm. No significant transient event was identified in the preliminary result. Photometric flux calibration was performed using synthetic photometries derived from the Gaia DR3 XP catalog (Gaia Collaboration et al. 2022) within the AB magnitude system. The 5-sigma upper limits (AB) range from 16.3 to 19.6 mag in the medium-band filters. To improve the depth for detection, we combined all images taken with the medium-band filters from m400 to m875. The combined image was treated as an r-band equivalent, and photometric measurements were performed. This approach yielded a 5-sigma upper limit of 20.2 AB magnitudes. Despite the increased depth, no significant transient detection was identified. Observations were conducted under suboptimal conditions, potentially limiting our search sensitivity. ------ Filter Date-obs[UT] Exp.time[s] Depth(5sigma) m400 2024-07-03T03:01:13.000 300 19.181 m425 2024-07-03T03:06:51.000 300 19.510 m450 2024-07-03T03:01:15.000 300 19.643 m475 2024-07-03T03:06:45.000 300 18.943 m500 2024-07-03T03:01:13.000 300 19.643 m525 2024-07-03T03:06:42.000 300 19.497 m550 2024-07-03T03:01:13.000 300 18.947 m575 2024-07-03T03:06:41.000 300 19.092 m600 2024-07-03T03:01:19.000 300 19.009 m625 2024-07-03T03:06:53.000 300 18.688 m650 2024-07-03T03:01:14.000 300 18.777 m675 2024-07-03T03:06:42.000 300 18.853 m700 2024-07-03T03:01:08.000 300 18.502 m725 2024-07-03T03:06:34.000 300 18.062 m750 2024-07-03T03:01:15.000 300 17.998 m775 2024-07-03T03:06:43.000 300 17.450 m800 2024-07-03T03:01:19.000 300 17.131 m825 2024-07-03T03:06:44.000 300 16.989 m850 2024-07-03T03:01:15.000 300 16.692 m875 2024-07-03T03:06:42.000 300 16.306 The 7-Dimensional Telescope (7DT), located in Chile and comprising 20 wide-field telescopes equipped with 40 medium-bandwidth (~25nm) filters, aims to detect optical counterparts of GW sources and conduct the 7-Dimensional Sky Survey (7DS) of the Southern Hemisphere. Further information about the 7DT is available at http://gwuniverse.snu.ac.kr/. View this GCN Circular online at https://gcn.nasa.gov/circulars/38725. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36725] GRB 240606B: 7DT Optical upper limits
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38724 SUBJECT: GRB 240606B: 7DT Optical upper limits DATE: 24/12/30 10:45:36 GMT FROM: Gregory Paek at Seoul National University <gregorypaek94(a)gmail.com> Gregory S.H. Paek (SNU ARC/SNU), Myungshin Im (SNU ARC/SNU), Hyeonho Choi (SNU ARC/SNU), Seo-Won Chang (SNU ARC/SNU), and Ji Hoon Kim (SNU ARC/SNU) report on behalf of the 7-Dimensional Telescope collaboration We searched for the optical counterpart of the GRB, GRB 240606B (DeLaunay et al., GCN #36628) using the 7-Dimensional Telescopes (7DT). Approximately 20.2 hours following the initial detection (2024-06-06T13:33:06.5 UTC), we targeted the localization center provided by the Swift XRT at RA, Dec = 40.29507 deg, -60.61201 deg with an uncertainty of 2.4 arcsecs (Osborne et al., GCN #36631). Observations were made with eleven 7DT units in eight medium-band filters, denoted as m450, m500, m550, m650, m700, m750, m800, and m850, in which the numeric values indicate their central wavelengths in nanometers. Each medium-band filter has a bandwidth of 25nm. No significant transient event was identified in the preliminary result. Photometric flux calibration was performed using synthetic photometries derived from the Gaia DR3 XP catalog (Gaia Collaboration et al. 2022) within the AB magnitude system. The 5-sigma upper limits (AB) range from 17.8 to 21.0 mag in the medium-band filters. To improve the depth for detection, we combined all images taken with the medium-band filters from m400 to m875. The combined image was treated as an r-band equivalent, and photometric measurements were performed. This approach yielded a 5-sigma upper limit of 20.9 AB magnitudes. Despite the increased depth, no significant transient detection was identified. Observations were conducted under suboptimal conditions, potentially limiting our search sensitivity. Filter Date-obs[UT] Exp.time[s] Depth(5sigma) m450 2024-06-07T09:47:55 1200 20.7 m500 2024-06-07T09:47:23 1200 21.0 m550 2024-06-07T09:47:22 1200 20.1 m650 2024-06-07T09:46:09 1200 20.1 m700 2024-06-07T09:47:20 1200 19.6 m750 2024-06-07T09:47:16 1200 19.2 m800 2024-06-07T09:47:21 1200 18.0 m850 2024-06-07T09:47:18 1200 17.8 The 7-Dimensional Telescope (7DT), located in Chile and comprising 20 wide-field telescopes equipped with 40 medium-bandwidth (~25nm) filters, aims to detect optical counterparts of GW sources and conduct the 7-Dimensional Sky Survey (7DS) of the Southern Hemisphere. Further information about the 7DT is available at http://gwuniverse.snu.ac.kr/. View this GCN Circular online at https://gcn.nasa.gov/circulars/38724. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36724] Fermi trigger No 757231333: Global MASTER-Net observations report
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38723 SUBJECT: Fermi trigger No 757231333: Global MASTER-Net observations report DATE: 24/12/30 09:45:52 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.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB241230.25 (trigger No 757231333,16h 38m 24.00s , -63d 12m 00.0s, R=29.63) errorbox 975 sec after notice time and 984 sec after trigger time at 2024-12-30 06:18:33 UT, with upper limit up to 18.6 mag. The observations began at zenith distance = 45 deg. The sun altitude is -30.6 deg. The galactic latitude b = -11 deg., longitude l = 326 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2726669 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1015 | 2024-12-30 06:18:33 | MASTER-OAFA | (11h 29m 50.20s , -65d 17m 29.7s) | C | 60 | 18.4 | 1093 | 2024-12-30 06:19:51 | MASTER-OAFA | (11h 29m 47.79s , -65d 15m 59.2s) | C | 60 | 18.5 | 1168 | 2024-12-30 06:21:06 | MASTER-OAFA | (11h 29m 47.74s , -65d 17m 22.1s) | C | 60 | 18.5 | 2540 | 2024-12-30 06:43:58 | MASTER-OAFA | (11h 29m 48.44s , -65d 15m 03.2s) | C | 60 | 18.6 | 2617 | 2024-12-30 06:45:15 | MASTER-OAFA | (11h 29m 48.52s , -65d 16m 32.4s) | C | 60 | 18.6 | 2694 | 2024-12-30 06:46:32 | MASTER-OAFA | (11h 29m 51.22s , -65d 14m 54.9s) | C | 60 | 18.6 | 4887 | 2024-12-30 07:23:05 | MASTER-OAFA | (11h 29m 49.76s , -65d 13m 17.7s) | C | 60 | 18.5 | 5662 | 2024-12-30 07:36:00 | MASTER-OAFA | (11h 29m 52.28s , -65d 14m 43.1s) | C | 60 | 18.5 | 6199 | 2024-12-30 07:45:08 | MASTER-OAFA | (12h 58m 04.26s , -58d 09m 12.0s) | C | 40 | 17.4 | 6210 | 2024-12-30 07:45:08 | MASTER-OAFA | (13h 15m 06.22s , -57d 42m 12.6s) | C | 60 | 18.3 | 6277 | 2024-12-30 07:46:25 | MASTER-OAFA | (12h 57m 58.18s , -58d 10m 08.2s) | C | 40 | 17.4 | 6287 | 2024-12-30 07:46:25 | MASTER-OAFA | (13h 15m 00.51s , -57d 43m 09.3s) | C | 60 | 18.4 | 6698 | 2024-12-30 07:53:26 | MASTER-OAFA | (12h 58m 03.82s , -58d 09m 47.1s) | C | 40 | 17.4 | 6708 | 2024-12-30 07:53:26 | MASTER-OAFA | (13h 15m 06.11s , -57d 42m 43.2s) | C | 60 | 18.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38723. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36723] LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38722 SUBJECT: LIGO/Virgo/KAGRA S241230bd: Identification of a GW compact binary merger candidate DATE: 24/12/30 09:32:45 GMT FROM: martina.delaurentis(a)ligo.org The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S241230bd during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2024-12-30 08:45:04.540 UTC (GPS time: 1419583522.540). The candidate was found by the GstLAL [1] analysis pipeline. S241230bd is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.2e-14 Hz, or about one in 1e6 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S241230bd 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%. [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%. 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 [3], distributed via GCN notice about 25 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], 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 10806 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2719 +/- 776 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] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/38722. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36722] GRB 241229B: Swift-BAT refined analysis
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38721 SUBJECT: GRB 241229B: Swift-BAT refined analysis DATE: 24/12/30 05:50:24 GMT FROM: Amy <yarleen(a)gmail.com> S. D. Barthelmy (GSFC), D'Ai (INAF-IASFPA), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 241229B (trigger #1277428) (D'Ai et al., GCN Circ. 38699). The BAT ground-calculated position is RA, Dec = 274.140, 74.694 deg which is RA(J2000) = 18h 16m 33.5s Dec(J2000) = +74d 41' 39.5" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve shows several overlapping pulses that start at ~T-3 s and end at ~T+3 s. The main peak occurs at ~T+0.5 s, T90 (15-350 keV) is 5.05 +- 0.65 sec (estimated error including systematics). The time-averaged spectrum from T-2.62 to T+3.38 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.93 +- 0.50, and Epeak of 68.3 +- 22.6 keV (chi squared 47.78 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 7.0 +- 0.6 x 10^-07 erg/cm2 and the 1-sec peak flux measured from T-0.06 sec in the 15-150 keV band is 4.0 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.70 +- 0.11 (chi squared 55.86 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1277428 View this GCN Circular online at https://gcn.nasa.gov/circulars/38721. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36721] LIGO/Virgo/KAGRA S241225v: Updated Sky localization
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38720 SUBJECT: LIGO/Virgo/KAGRA S241225v: Updated Sky localization DATE: 24/12/30 05:09:07 GMT FROM: jgolomb(a)caltech.edu The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S241225v (GCN Circular 38670). 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/S241225v For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1192 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2008 +/- 695 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/38720. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36720] LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38719 SUBJECT: LIGO/Virgo/KAGRA S241225c: Updated Sky localization and EM Bright Classification DATE: 24/12/30 04:44:48 GMT FROM: jgolomb(a)caltech.edu 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 S241225c (GCN Circular 38666). 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/S241225c Based on posterior support from parameter estimation [1], under the assumption that the candidate S241225c 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 2264 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 666 +/- 137 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/38719. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36719] Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB
by GCN Circulars 30 Dec '24

30 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38718 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB DATE: 24/12/30 00:22:47 GMT FROM: Ava Myers at NASA GSFC <ava.myers(a)nasa.gov> A. Myers (NPP/GSFC) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 757207662/241229978 at 23:27:37.34 UT on 29 December 2024, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to a solar flare." View this GCN Circular online at https://gcn.nasa.gov/circulars/38718. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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