Searching for Non-axisymmetries in NGC 6503: A Weak End-on Bar
  The isolation, simple apparent structure, and low luminosity of the nearby
spiral galaxy NGC 6503 make it an ideal candidate for an in-depth kinematic and
photometric study. We introduce a new publicly available code, DiskFit, that
implements procedures for fitting non-axisymmetries in either kinematic or
photometric data. We use DiskFit to analyze new Halpha and CO velocity field
data as well as HI kinematics from Greisen et al. to search for non-circular
motions in the disc of NGC 6503. We find NGC 6503 to have remarkably regular
gas kinematics that are well-described by rotation only. We also use DiskFit
and a new Ks-band image of NGC 6503 to constrain photometric models of the
disc, bar and bulge. We find the galaxy to be photometrically dominated by the
disc. We find NGC 6503 to contain a faint bar and an exponential bulge which
together contribute only ~5% of the total galaxy light. The combination of our
kinematic and photometric DiskFit models suggest that NGC 6503 contains a weak,
end-on bar that may have produced its Type II surface brightness profile but is
unlikely to be responsible for its strong sigma-drop.
