  Persistent gravitational waves from rapidly rotating neutron stars, such as
those found in some young supernova remnants, may fall in the sensitivity band
of the advanced Laser Interferometer Gravitational-wave Observatory (aLIGO).
Searches for these signals are computationally challenging, as the frequency
and frequency derivative are unknown and evolve rapidly due to the youth of the
source. A hidden Markov model (HMM), combined with a maximum-likelihood matched
filter, tracks rapid frequency evolution semi-coherently in a computationally
efficient manner. We present the results of an HMM search targeting 12 young
supernova remnants in data from Advanced LIGO's second observing run. Six
targets produce candidates that are above the search threshold and survive
pre-defined data quality vetoes. However, follow-up analyses of these
candidates show that they are all consistent with instrumental noise artefacts.
