Friday 02 October 2015
to 11:30 at
Benne Holwerda (Leiden Observatory, the Netherlands)
Dust absorption remains the poorest constrained parameter in both Cosmological
distances and multiwavelength studies of galaxy populations. A galaxy's dust
distribution can be measured to great accuracy in the case of an overlapping
pair of galaxies, i.e., when a foreground spiral galaxy accidentally overlaps a
more distant, preferably elliptical galaxy. We have identified bona-fide overlapping
pairs --well separated in redshift but close on the sky-- in the GAMA spectroscopic
survey, taking advantage of its high completeness (98%) on small scales and the GalaxyZoo classification of the SDSS.
The ongoing STARSMOG program aims to map the fine-scale (~50pc) dust
structure in these occulting galaxies, using HST/WFC3 SNAP observations.
The resulting dust maps will (1) serve as an extinction probability for supernova
lightcurve fits in similar type host galaxies, (2) strongly constrain the role of ISM
structure in Spectral Energy Distribution models of spiral galaxies, and (3) map
the level of ISM turbulence (through the spatial power-spectrum).