TITLE: GCN CIRCULAR NUMBER: 21600 SUBJECT: LIGO/Virgo G298389: Identification of a GW Burst Candidate DATE: 17/08/19 19:06:15 GMT FROM: Alan Weinstein at Caltech/LIGO The LIGO Scientific Collaboration and Virgo report: The LIB (Lynch et al., PRD 95, 104046) Burst analysis identified candidate G298389 during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2017-08-19 15:50:46.990 UTC (GPS time: 1187193064.990). Virgo was also taking data at this time in nominal condition. G284239 is a low-significance short-duration burst candidate. It is an event of interest because its false alarm rate, as determined by the online analysis, is 1.56e-07 Hz or about one in 2 months, passing our stated alert threshold of ~1/month. The event's properties can be found at this URL: https://gracedb.ligo.org/events/G298389 No other GW event candidates were identified within a 300 s window before or after G298389. A sky map, LIB.fits.gz, is available to be retrieved from the GraceDB event page. This is the preferred sky map at this time. The 50% confidence region covers 252 squares degrees and the 90% confidence region covers 799 square degrees. Updates on our analysis of this event will be sent as they become available.