TITLE: GCN CIRCULAR NUMBER: 20689 SUBJECT: LIGO/Virgo G274296: Identification of a GW Burst Candidate DATE: 17/02/17 19:43:13 GMT FROM: Peter Shawhan at U of Maryland/LSC The LIGO Scientific Collaboration and Virgo report: The CWB Burst analysis identified candidate G274296 during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2017-02-17 06:05:55.050 UTC (GPS time: 1171346771.050). This circular has been sent around 13 hours after the event due to a processing issue. G274296 is an event of interest because its false alarm rate, as determined by the online analysis, is 1.7e-07 Hz or about one in 2 months, passing our alert threshold of ~0.5/month. The event's properties can be found at this URL: https://gracedb.ligo.org/events/G274296 No other GW event candidates were identified within a 300 s window before or after G274296. One sky maps are available at this time and can be retrieved from the GraceDB event page: skyprobcc_cWB.fits, an initial localization generated by cWB, distributed via GCN notice about 13 hours after the event. The morphology of the event candidate is unclear. We can’t confirm the shape as a chirp, but we can’t discard it. Updates on our analysis of this event will be sent as they become available.