LIGO/Virgo/KAGRA S241127aj
GCN Circular 38336
Subject
LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
Date
2024-11-27T06:48:14Z (6 months ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We identified the compact binary merger candidate S241127aj during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-11-27 06:10:08.230 UTC (GPS time: 1416723026.230). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines.
S241127aj is an event of interest because its false alarm rate, as estimated by the online analysis, is 6.5e-39 Hz, or about one in 1e31 years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S241127aj
The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%).
There was a noise transient (glitch) in the Virgo detector near the event time which may affect the localization of the candidate.
Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. 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 [8], distributed via GCN notice about 29 seconds after the candidate event time.
* bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], 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 80 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 729 +/- 181 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] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a
[6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023
[7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe
[8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
GCN Circular 38348
Subject
LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
Date
2024-11-27T14:52:53Z (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 S241127aj-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 375 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/S241127aj/3
Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S241127aj/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|
|-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------|
|WISEA J132117.98-700426.4| 200.32579| -70.07392| G| 720.76| null| null| null| 12.998| 0.187| 11.042| 0.020|6.83e-08| 1.34e-09|
|WISEA J123225.10-303341.2| 188.10458| -30.56150| G| 551.29| null| null| null| 13.457| 0.173| 10.413| 0.006|5.71e-08| 1.13e-09|
| WKK 1683| 195.50746| -69.54883| G| 411.98| null| null| null| 12.500| 0.178| 9.939| 0.007|5.95e-08| 1.07e-09|
| WKK 1959| 198.11004| -68.33072| G| 315.84| 0.55| null| null| 11.470| 0.130| 10.224| 0.012|8.09e-08| 6.51e-10|
|WISEA J125433.99-390111.9| 193.64171| -39.02006| G| 840.17| null| null| null| 13.589| 0.176| 10.727| 0.006|1.59e-08| 5.47e-10|
|WISEA J124847.18-695639.9| 192.19642| -69.94439| G| 646.47| null| null| null| 13.521| 0.234| 11.863| 0.029|7.38e-08| 5.47e-10|
|WISEA J123747.24-313850.1| 189.44683| -31.64747| G| 781.89| 0.49| null| null| 12.754| 0.134| 12.631| 0.017|9.45e-08| 4.88e-10|
|WISEA J124706.30-364934.8| 191.77629| -36.82636| G| 830.06| null| null| null| 13.315| 0.157| 11.553| 0.007|3.01e-08| 4.72e-10|
|WISEA J132455.49-693406.5| 201.23112| -69.56850| G| 437.92| null| null| null| 13.260| 0.104| 10.339| 0.009|3.34e-08| 4.65e-10|
|WISEA J123740.62-313649.6| 189.41925| -31.61381| G| 722.19| null| null| null| 13.336| 0.152| 12.811| 0.016|1.16e-07| 4.33e-10|
|WISEA J124714.84-370926.8| 191.81200| -37.15761| G| 893.44| null| null| null| 13.387| 0.175| 11.189| 0.007|1.69e-08| 4.29e-10|
|WISEA J123430.15-321012.3| 188.62558| -32.17014| G| 775.60| null| null| null| 13.235| 0.162| 12.175| 0.007|5.55e-08| 4.29e-10|
|WISEA J124147.63-342211.4| 190.44854| -34.36983| G| 793.48| null| null| null| 12.976| 0.155| 12.310| 0.015|5.67e-08| 4.04e-10|
|WISEA J123049.72-274538.3| 187.70717| -27.76067| G| 623.50| 0.65| null| null| 12.240| 0.131| 12.326| 0.011|8.32e-08| 3.60e-10|
|WISEA J124249.24-333427.7| 190.70513| -33.57442| G| 671.43| null| null| null| 13.549| 0.170| 12.653| 0.011|8.67e-08| 3.23e-10|
|WISEA J123504.87-303414.8| 188.77025| -30.57083| G| 649.87| null| null| null| 13.244| 0.154| 12.952| 0.012|1.15e-07| 3.05e-10|
|WISEA J123610.19-321649.9| 189.04258| -32.28058| G| 716.32| 0.65| 20.323| 0.327| 13.274| 0.176| 12.858| 0.015|8.44e-08| 2.97e-10|
|WISEA J124741.34-362923.6| 191.92217| -36.48997| G| 656.72| null| null| null| 13.403| 0.158| 11.898| 0.007|4.15e-08| 2.96e-10|
|WISEA J131211.01-690910.9| 198.04579| -69.15317| G| 437.81| null| null| null| 12.829| 0.149| 12.276| 0.038|1.21e-07| 2.87e-10|
|WISEA J124059.32-332226.3| 190.24717| -33.37400| G| 744.09| null| null| null| 13.550| 0.195| 13.093| 0.022|8.89e-08| 2.72e-10|
Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S241127aj 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 38361
Subject
LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
Date
2024-11-28T05:18:19Z (6 months ago)
From
ethan.payne@ligo.org
Via
Web form
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We have conducted further offline 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 S241127aj (GCN Circular 38336). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page:
https://gracedb.ligo.org/superevents/S241127aj
For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 105 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1100 +/- 99 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. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040
GCN Circular 38394
Subject
LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
Date
2024-11-30T14:56:01Z (6 months ago)
From
ethan.payne@ligo.org
Via
Web form
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We have conducted additional 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 S241127aj (GCN Circular 38361). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline1.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page:
https://gracedb.ligo.org/superevents/S241127aj
For the Bilby.offline1.multiorder.fits,0 sky map, the 90% credible region is 53 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1050 +/- 67 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. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040