{
  "subject": "LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate",
  "bibcode": "2023GCN.34360....1L",
  "circularId": 34360,
  "submittedHow": "web",
  "body": "The LIGO Scientific Collaboration, the Virgo Collaboration, and the\nKAGRA Collaboration report:\n\nWe identified the compact binary merger candidate S230807f during\nreal-time processing of data from LIGO Hanford Observatory (H1) and\nLIGO Livingston Observatory (L1) at 2023-08-07 20:50:45.416 UTC (GPS\ntime: 1375476663.416). The candidate was found by the CWB [1], GstLAL\n[2], MBTA [3], PyCBC Live [4], and SPIIR [5] analysis pipelines.\n\nS230807f is an event of interest because its false alarm rate, as\nestimated by the online analysis, is 7.1e-08 Hz, or about one in 5\nmonths. The event's properties can be found at this URL:\n\nhttps://gracedb.ligo.org/superevents/S230807f\n\nThe classification of the GW signal, in order of descending\nprobability, is BBH (86%), Terrestrial (14%), NSBH (<1%), or BNS\n(<1%). \n\nThere was a high rate of noise transients (glitches) in both the LIGO \nLivingston and Hanford detectors which may affect the parameters or the significance \nof the candidate.\n\nAssuming the candidate is astrophysical in origin, the probability\nthat the lighter compact object is consistent with a neutron star mass\n(HasNS) is <1%. [6] Using the masses and spins inferred from the\nsignal, the probability of matter outside the final compact object\n(HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the\nsupport of several neutron star equations of state. The probability\nthat either of the binary components lies between 3 and 5 solar masses\n(HasMassgap) is 4%.\n\nTwo sky maps are available at this time and can be retrieved from the\nGraceDB event page:\n * bayestar.multiorder.fits,1, an initial localization generated by\nBAYESTAR [7], distributed via GCN notice about 35 seconds after the\ncandidate event time.\n * bayestar.multiorder.fits,2, an initial localization generated by\nBAYESTAR [7], distributed via GCN notice about 5 minutes after the\ncandidate event time.\n\nThe preferred sky map at this time is bayestar.multiorder.fits,2. For\nthe bayestar.multiorder.fits,2 sky map, the 90% credible region is\n6088 deg2. Marginalized over the whole sky, the a posteriori\nluminosity distance estimate is 6818 +/- 2379 Mpc (a posteriori mean\n+/- standard deviation).\n\nFor further information about analysis methodology and the contents of\nthis alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide\nhttps://emfollow.docs.ligo.org/userguide/.\n\n [1] Klimenko et al. PRD 93, 042004 (2016)\n [2] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al.\narXiv:2305.05625 (2023)\n [3] Aubin et al. CQG 38, 095004 (2021)\n [4] Dal Canton et al. ApJ 923, 254 (2021)\n [5] Chu et al. PRD 105, 024023 (2022)\n [6] Chatterjee et al. ApJ 896, 54 (2020)\n [7] Singer & Price PRD 93, 024013 (2016)\n",
  "eventId": "LIGO/Virgo/KAGRA S230807f",
  "createdOn": 1691444800072,
  "submitter": "Dripta Bhattacharjee <dripta.bhattacharjee@ligo.org>"
}