Appearance of Dusty Filaments at Different Viewing Angles
  Context: In the last years, there have been many studies on the omnipresence
and structures of filaments in star-forming regions, as well as their role in
the process of star formation. Those filaments are normally identified as
elongated fibres across the plane of the sky. But how would we detect filaments
that are inclined? Aims: We aim to learn more about whether, and how, total
column density or dust temperature change with respect to the line of sight.
Such variations would enable observers to use dust observations to identify and
study filaments at any inclination and gain more insight on the distribution
and orientations of filaments within the Galactic plane. Methods: As a first
step, we perform numerical calculations on simple cylindrical models to
evaluate the influence of filament geometry on the average flux density. After
that, we apply our three-dimensional Monte Carlo dust radiative transfer code
on two models of star-forming regions and derive maps of effective total column
density and dust temperature at different viewing angles. Results: We see only
slight changes of average flux density for all cylinders we study. For our more
complex models, we find that the effective dust temperature is not sensitive to
viewing angle, while the total column density is strongly influenced, with
differences exceeding an order of magnitude. The variations are not injective
with the viewing angle and depend on the structure of the object. Conclusions:
We conclude that there is no single quantity in our analysis that can uniquely
trace the inclination and three-dimensional structure of a filament based on
dust observations alone. However, observing wide variations in total column
density at a given effective dust temperature is indicative of inclined
filaments.
