[Fe II] $1.64{\mu}m$ Outflow Features around Ultracompact H II Regions in the First Galactic Quadrant

We present [Fe II] $1.644{\mu}m$ features around ultracompact H II regions (UCHIIs) found on a quest for the "footprint" outflow features of UCHIIs -the features produced by outflowing materials ejected during an earlier, active accretion phase of massive young stellar objects (MYSOs). We surveyed 237 UCHIIs in the first Galactic quadrant, employing the CORNISH UCHII catalog and UWIFE data, which is an imaging survey in [Fe II] $1.644{\mu}m$ performed with UKIRT-WFCAM under ~0.''8 seeing conditions. The [Fe II] features were found around five UCHIIs. We interpret the [Fe II] features to be shock-excited by outflows from YSOs and estimate the outflow mass-loss rates from the [Fe II] flux which are ${\sim}1{\times}10^{-6}-4{\times}10^{-5}M{\odot}yr^{-1}$. We propose that the [Fe II] features might be the "footprint" outflow features, but more studies are required to clarify whether or not this is the case. This is based on the morphological relation between the [Fe II] and 5 GHz radio features, the outflow mass-loss rate, the travel time of the [Fe II] features, and the existence of several YSO candidates near the UCHIIs.