GCN Circular 21600

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.