TITLE: GCN CIRCULAR NUMBER: 21281 SUBJECT: LIGO/Virgo G270580: Candidate retracted due to H1 data quality DATE: 17/06/28 23:01:02 GMT FROM: Brennan Hughey at Embry-Riddle Aeronautical U The LIGO Scientific Collaboration and Virgo Collaboration report: In off-line reanalysis, the stretch of H1 data containing burst candidate G270580 has been removed due to an issue with data quality. Typically, a few percent of LIGO observational data are removed from analysis due to data quality concerns prior to producing final published search results (see https://dcc.ligo.org/LIGO-P1500238/public for details). In this specific case, noise transients in H1 strain data and elevated noise in external seismic monitors were observed to correlate with periods of active snow plowing in the area. Several hours of data over the course of the winter, including the data containing candidate event G270580, were flagged as contaminated by nearby snow clearing.