Dusting off NGC 4370. A diffuse dust component in this lenticular?
Dust, Gas and Star Formation in Galaxies Throughout Cosmic Time
Sebastien Viaene
Universiteit Gent
A fraction of the early-type galaxy population hosts a prominent dust lane, often decoupled from its stellar body. Methods to quantify the dust content of these systems based on optical imaging data usually yield dust masses that are an order of magnitude lower than dust masses derived from the observed FIR emission. The discrepancy is often explained by invoking a diffuse dust component, which is hard to trace in the UV/optical. High-quality optical data from the Next Generation Virgo cluster Survey (NGVS) and FIR/submm observations from the Herschel Virgo Cluster Survey (HeViCS) allow us to revisit previous methods to determine the dust content in galaxies and explore new ones. We take NGC 4370 as a first test case. This edge-on early-type galaxy has a conspicuous dust lane and a regular morphology, making it suitable for several (semi-) analytical modelling techniques. We use different methods to determine the total dust mass in the dust lane. We create color and attenuation maps, which are converted to approximate dust mass maps based on simple dust geometries. Dust masses are also derived from SED fits to FIR/submm observations. Finally, inverse radiative transfer fitting is performed to investigate more complex dust geometries, such as an exponential dust disc and a dust ring, and to treat the dust-starlight interaction in a self-consistent way. We will present our main results and the effects of geometry on dust mass determination.
09:00 - 10:30