{
"subject": "LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate",
"eventId": "LIGO/Virgo/KAGRA S240413p",
"submittedHow": "web",
"bibcode": "2024GCN.36075....1L",
"createdOn": 1712977984672,
"circularId": 36075,
"submitter": "rein.yongxiang.yang@gmail.com",
"body": "The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:\n\nWe identified the compact binary merger candidate S240413p during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2024-04-13 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.\n\nS240413p 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:\n\nhttps://gracedb.ligo.org/superevents/S240413p\n\nAfter parameter estimation by RapidPE-RIFT [5], the classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), NSBH (<1%), or BNS (<1%).\n\nAssuming 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%.\n\nTwo sky maps are available at this time and can be retrieved from the GraceDB event page:\n * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 31 seconds after the candidate event time.\n * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN notice about 5 minutes after the candidate event time.\n\nThe 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, semi-major axis, semi-minor axis, position angle of the semi-minor axis):\n icrs; ellipse(10h53m, +09d27m, 8.32d, 1.75d, 130.27d)\nMarginalized over the whole sky, the a posteriori luminosity distance estimate is 510 +/- 115 Mpc (a posteriori mean +/- standard deviation).\n\nFor 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/.\n\n [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004\n [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625\n [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913\n [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.1088/1361-6382/abe913\n [5] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002\n [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe\n [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013"
}