Light attenuation in star-forming regions

This variation in attenuation is even more evident on kiloparsec scales, which is the relevant size for many current spectroscopic integral field unit surveys. To understand the cause of this variation, we present and analyse Swift/UVOT near-UV (NUV) images and SDSS/MaNGA emission-line maps of 29 nearby (z<0.084) star-forming galaxies.

We resolve kiloparsec-sized star-forming regions within the galaxies and compare their optical nebular attenuation (i.e. the Balmer emission line optical depth, {tau}^l^_B_~{tau}_H{beta}_-{tau}_H{alpha}_) and NUV stellar continuum attenuation (via the NUV power-law index, {beta}) to the attenuation law described by Battisti et al. We show the data agree with that model, albeit with significant scatter. We explore the dependence of the scatter of the {beta}-{tau}^l^_B_ measurements from the star-forming regions on different physical parameters, including distance from the nucleus, star formation rate and total dust content.