Directed searches for continuous gravitational waves from twelve supernova remnants in data from Advanced LIGO’s second observing run

We describe directed searches for continuous gravitational waves from twelve well-localized nonpulsing candidate neutron stars in young supernova remnants using data from Advanced LIGO's second observing run. We assumed that each neutron star is isolated and searched a band of frequencies from 15 to 150 Hz, consistent with frequencies expected from known young pulsars. After coherently integrating spans of data ranging from 12.0 to 55.9 days using the F-statistic and applying data-based vetoes, we found no evidence of astrophysical signals. We set upper limits on intrinsic gravitational wave amplitude in some cases stronger than 10−25, generally about a factor of two better than upper limits on the same objects from Advanced LIGO's first observing run.