LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
Abstract
We identified the compact binary merger candidate S240413p during realtime processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 20240413 02:20:19.852 UTC (GPS time: 1397010037.852). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines. S240413p is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S240413p After parameter estimation by RapidPERIFT [5], the classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), 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%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] 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 40%. 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 [7], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], 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 well fit by an ellipse with an area of 46 deg2 described by the following DS9 region (right ascension, declination, semimajor axis, semiminor axis, position angle of the semiminor axis): icrs; ellipse(10h53m, +09d27m, 8.32d, 1.75d, 130.27d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 510 +/ 115 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] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/13616382/abe913 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/13616382/abe913 [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/15384357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013
 Publication:

GRB Coordinates Network
 Pub Date:
 April 2024
 Bibcode:
 2024GCN.36075....1L