SDSS-IV MaNGA: spatially resolved dust attenuation in spiral galaxies
  Dust attenuation in star-forming spiral galaxies affects stars and gas in
different ways due to local variations in dust geometry. We present spatially
resolved measurements of dust attenuation for a sample of 232 such star-forming
spiral galaxies, derived from spectra acquired by the SDSS-IV MaNGA survey. The
dust attenuation affecting the stellar populations of these galaxies (obtained
using full spectrum stellar population fitting methods) is compared with the
dust attenuation in the gas (derived from the Balmer decrement). Both of these
attenuation measures increase for local regions of galaxies with higher star
formation rates; the dust attenuation affecting the stellar populations
increases more so than the dust attenuation in the gas, causing the ratio of
the dust attenuation affecting the stellar populations to the dust attenuation
in the gas to decrease for local regions of galaxies with higher star formation
rate densities. No systematic difference is discernible in any of these dust
attenuation quantities between the spiral arm and inter-arm regions of the
galaxies. While both the dust attenuation in the gas and the dust attenuation
affecting the stellar populations decrease with galactocentric radius, the
ratio of the two quantities does not vary with radius. This ratio does,
however, decrease systematically as the stellar mass of the galaxy increases.
Analysis of the radial profiles of the two dust attenuation measures suggests
that there is a disproportionately high concentration of birth clouds
(incorporating gas, young stars and clumpy dust) nearer to the centres of
star-forming spiral galaxies.
