We present 21-cm observations and models of the neutral hydrogen in NGC 4565 , a nearby , edge-on spiral galaxy , as part of the Westerbork Hydrogen Accretion in LOcal GAlaxieS ( HALOGAS ) survey .
These models provide insight concerning both the morphology and kinematics of H i above , as well as within , the disk .
NGC 4565 exhibits a distinctly warped and asymmetric disk with a flaring layer .
Our modeling provides no evidence for a massive , extended H i halo .
We see evidence for a bar and associated radial motions .
Additionally , there are indications of radial motions within the disk , possibly associated with a ring of higher density .
We see a substantial decrease in rotational velocity with height above the plane of the disk ( a lag ) of - 40 ^ { +5 } _ { -20 } km s ^ { -1 } kpc ^ { -1 } and - 30 ^ { +5 } _ { -30 } km s ^ { -1 } kpc ^ { -1 } in the approaching and receding halves , respectively .
This lag is only seen within the inner \scriptstyle \sim 4.75 ’ ( 14.9 kpc ) on the approaching half and \scriptstyle \sim 4.25 ’ ( 13.4 kpc ) on the receding , making this a radially shallowing lag , which is now seen in the H i layers of several galaxies .
When comparing results for NGC 4565 and those for other galaxies , there are tentative indications of high star formation rate per unit area being associated with the presence of a halo .
Finally , H i is found in two companion galaxies , one of which is clearly interacting with NGC 4565 .