LIGO/Virgo/KAGRA S241231bg
GCN Circular 38737
Subject
LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
Date
2024-12-31T07:07:06Z (6 months ago)
From
Jyotirmaya Mohanta at University of Tsukuba <s2430161@u.tsukuba.ac.jp>
Via
Web form
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
GCN Circular 38742
Subject
LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
Date
2024-12-31T16:52:00Z (6 months ago)
From
David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu>
Via
Web form
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).
GCN Circular 38744
Subject
LIGO/Virgo/KAGRA S241231bg: Updated Sky localization and EM Bright Classification
Date
2024-12-31T17:08:00Z (6 months ago)
From
Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org>
Via
Web form
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
GCN Circular 38745
Subject
LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
Date
2024-12-31T17:14:54Z (6 months ago)
From
David Cook at Caltech/IPAC-NED <dcook@ipac.caltech.edu>
Via
Web form
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).