NGC4370: a case study for testing our ability to infer dust distribution
  and mass in nearby galaxies
  A fraction of the early-type galaxy population hosts a prominent dust lane.
Methods to quantify the dust content of these systems based on optical imaging
data usually yield dust masses which are an order of magnitude lower than dust
masses derived from the observed FIR emission. 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 aim to
derive the dust mass in NGC 4370 from both optical and FIR data, and
investigate the need to invoke a putative diffuse dust component. 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. The empirical methods
applied to the optical data yield lower limits of 3.4e5 solar masses, an order
of magnitude below the total dust masses derived from SED fitting. In contrast,
radiative transfer models yield dust masses which are slightly lower, but fully
consistent with the FIR-derived mass. Dust is more likely to be distributed in
a ring around the centre of NGC 4370 as opposed to an exponential disc or a
simple foreground screen. Moreover, using inverse radiative transfer fitting,
we are able to constrain most of the parameters describing these geometries.
The resulting dust masses are high enough to account for the dust observed at
FIR/submm wavelengths, so that no diffuse dust component needs to be invoked.
We furthermore caution for the interpretation of dust masses and optical depths
based on optical data alone, using overly simplistic star-dust geometries and
the neglect of scattering effects. [ABRIDGED]
