Galaxy Structure in the Ultraviolet: The Dependence of Morphological
  Parameters on Rest-Frame Wavelength
  Evolutionary studies that compare galaxy structure as a function of redshift
are complicated by the fact that any particular galaxy's appearance depends in
part on the rest-frame wavelength of the observation. This leads to the
necessity for a "morphological k-correction" between different pass-bands,
especially when comparing the rest-frame optical or infrared (IR) to the
ultraviolet (UV). This is of particular concern for high redshift studies that
are conducted in the rest-frame UV. We investigate the effects of this
"band-pass shifting" out of the UV by quantifying nearby galaxy structure via
"CAS parameters" (concentration, asymmetry, and clumpiness). For this study we
combine pan-chromatic data from the UV through the near-IR with GALEX (Galaxy
Evolution Explorer) data of 2073 nearby galaxies in the "NUV" (~230 nm) and
1127 in the "FUV" (~150 nm), providing the largest study of this kind in the
mid- to far-UV. We find a relationship between the CAS parameters and observed
rest-frame wavelength that make galaxies appear more late-type at shorter
wavelengths, particularly in the UV. The effect is strongest for E/S0 galaxies
in the far-UV, which have concentrations and asymmetries that more resemble
those of spiral and peculiar/merging galaxies in the optical. This may be
explained by extended disks containing recent star formation. Here we also
release the CAS values of the galaxies imaged in GALEX NUV and FUV for use in
comparisons with deep HST imaging and JWST in the future.
