{
  "bibcode": "2024GCN.36587....1L",
  "submittedHow": "web",
  "circularId": 36587,
  "createdOn": 1717228813443,
  "body": "The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:\n\nWe identified the compact binary merger candidate S240601aj during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2024-06-01 06:12:00.359 UTC (GPS time: 1401257538.359). The candidate was found by the CWB [1] and GstLAL [2] analysis pipelines.\n\nS240601aj is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.1e-08 Hz, or about one in 1 year. The event's properties can be found at this URL:\n\nhttps://gracedb.ligo.org/superevents/S240601aj\n\nThe classification of the GW signal, in order of descending probability, is BBH (51%), Terrestrial (49%), BNS (<1%), or NSBH (<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%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] 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 <1%.\n\nThree 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 [4], distributed via GCN notice about 36 seconds after the candidate event time.\n * cwb.multiorder.fits,0, an initial localization generated by cWB [1], distributed via GCN notice about a minute after the candidate event time.\n * cwb.multiorder.fits,1, an initial localization generated by cWB [1], distributed via GCN notice about 6 minutes after the candidate event time.\n\nThe preferred sky map at this time is cwb.multiorder.fits,1. For the cwb.multiorder.fits,1 sky map, the 90% credible region is 2468 deg2.\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] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe\n [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013\n\n",
  "format": "text/plain",
  "subject": "LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate",
  "submitter": "Jacopo Tissino at GSSI <jacopok@gmail.com>",
  "eventId": "LIGO/Virgo/KAGRA S240601aj"
}