Ultraviolet Extinction at High Galactic Latitudes
  In order to study the properties and effects of high Galactic latitude dust
we present an analysis of 373,303 galaxies selected from the Galaxy Evolution
Explorer (GALEX) All-Sky Survey and Wide-Field Infrared Explorer (WISE) All-Sky
Data Release. By examining the variation in aggregate ultraviolet colors and
number density of these galaxies we measure the extinction curve at high
latitude. We additionally consider a population of spectroscopically selected
galaxies from the Sloan Digital Sky Survey (SDSS) to measure extinction in the
optical. We find that dust at high latitude is neither quantitatively nor
qualitatively consistent with standard reddening laws. Extinction in the FUV
and NUV is ~10% and ~35% higher than expected, with significant variation
across the sky. We find that no single R_V parameter fits both the optical and
ultraviolet extinction at high latitude, and that while both show detectable
variation across the sky, these variations are not related. We propose that the
overall trends we detect likely stem from an increase in very small silicate
grains in the ISM.
