TITLE: GCN CIRCULAR NUMBER: 38932 SUBJECT: LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate DATE: 25/01/14 09:06:32 GMT FROM: Enzo Tapia at Nikhef e.tapia@nikhef.nl
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We identified the compact binary merger candidate S250114ax during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2025-01-14 08:22:03.223 UTC (GPS time: 1420878141.223). 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.
S250114ax is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.1e-27 Hz, or about one in 1e19 years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S250114ax
After parameter estimation by RapidPE-RIFT [8], the classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<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%. [8] 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 [10], distributed via GCN notice about 28 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 t his time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 37 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 473 +/- 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] 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/38932. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...