{
  "body": "The LIGO Scientific Collaboration, the Virgo Collaboration, and the\nKAGRA Collaboration report:\n\nWe identified the compact binary merger candidate S230601bf during\nreal-time processing of data from LIGO Hanford Observatory (H1) and\nLIGO Livingston Observatory (L1) at 2023-06-01 22:41:34.101 UTC (GPS\ntime: 1369694512.101). The candidate was found by the CWB [1], MBTA\n[2], GstLAL [3], oLIB [4], PyCBC Live [5], and SPIIR [6] analysis\npipelines.\n\nS230601bf is an event of interest because its false alarm rate, as\nestimated by the online analysis, is 1.7e-15 Hz, or about one in 1e7\nyears. The event's properties can be found at this URL:\n\nhttps://gracedb.ligo.org/superevents/S230601bf\n\nThe classification of the GW signal, in order of descending\nprobability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), or NSBH\n(<1%).\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%. [7] Using the masses and spins inferred from the\nsignal, the probability of matter outside the final compact object\n(HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the\nsupport of several neutron star equations of state. The probability\nthat any one of the binary components lie between 3 to 5 solar mass\n(HasMassgap) is <1%.\n\nTwo sky maps are available at this time and can be retrieved from the\nGraceDB event page:\n * bayestar.multiorder.fits,0, an initial localization generated by\nBAYESTAR [8], distributed via GCN notice about 31 seconds after the\ncandidate event time.\n * bayestar.multiorder.fits,1, an initial localization generated by\nBAYESTAR [8], distributed via GCN notice about 5 minutes after the\ncandidate event time.\n\nThe preferred sky map at this time is bayestar.multiorder.fits,1. For\nthe bayestar.multiorder.fits,1 sky map, the 90% credible region is\n2109 deg2. Marginalized over the whole sky, the a posteriori\nluminosity distance estimate is 3578 +/- 998 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\n<https://emfollow.docs.ligo.org/userguide/>.\n\n [1] Klimenko et al. PRD 93, 042004 (2016)\n [2] Aubin et al. CQG 38, 095004 (2021)\n [3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al. arXiv:2305.05625 (2023)\n [4] Lynch et al. PRD 95, 104046 (2017)\n [5] Dal Canton et al. ApJ 923, 254 (2021)\n [6] Chu et al. PRD 105, 024023 (2022)\n [7] Chatterjee et al. The Astrophysical Journal 896, 54 (2020)\n [8] Singer & Price PRD 93, 024013 (2016)\n",
  "bibcode": "2023GCN.33903....1L",
  "circularId": 33903,
  "submitter": "S. P. Stevenson at Swinburne University of Technology <simon.stevenson@ligo.org>",
  "createdOn": 1685662080887,
  "eventId": "LIGO/Virgo/KAGRA S230601bf",
  "subject": "LIGO/Virgo/KAGRA S230601bf: Identification of a GW compact binary merger candidate"
}