{
  "submitter": "Jessica Irwin at University of Glasgow <jessica.irwin@ligo.org>",
  "bibcode": "2023GCN.33938....1L",
  "circularId": 33938,
  "subject": "LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate",
  "createdOn": 1686260360922,
  "eventId": "LIGO/Virgo/KAGRA S230608as",
  "body": "The LIGO Scientific Collaboration, the Virgo Collaboration, and the\nKAGRA Collaboration report:\n\nWe identified the compact binary merger candidate S230608as during\nreal-time processing of data from LIGO Hanford Observatory (H1) and\nLIGO Livingston Observatory (L1) at 2023-06-08 20:50:47.161 UTC (GPS\ntime: 1370292665.161). The candidate was found by the CWB [1], MBTA\n[2], GstLAL [3], and SPIIR [4] analysis pipelines.\n\nS230608as is an event of interest because its false alarm rate, as\nestimated by the online analysis, is 1.4e-10 Hz, or about one in 1e2\nyears. The event's properties can be found at this URL:\n\nhttps://gracedb.ligo.org/superevents/S230608as\n\nThe classification of the GW signal, in order of descending\nprobability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS\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%. [5] Using the masses and spins inferred from the\nsignal, the probability of matter outside the final compact object\n(HasRemnant) is <1%. [5] 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,1, an initial localization generated by\nBAYESTAR [6], distributed via GCN notice about 24 seconds after the\ncandidate event time.\n * bayestar.multiorder.fits,2, an initial localization generated by\nBAYESTAR [6], distributed via GCN notice about 41 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\n2217 deg2. Marginalized over the whole sky, the a posteriori\nluminosity distance estimate is 3193 +/- 956 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.\narXiv:2305.05625 (2023)\n [4] Chu et al. PRD 105, 024023 (2022)\n [5] Chatterjee et al. ApJ 896, 54 (2020)\n [6] Singer & Price PRD 93, 024013 (2016)\n"
}