Seeing the Light Through the Dark:
Infrared Dust Extinction and the Structure of
Molecular Clouds

Abstract:

To understand the structure of molecular clouds is to
understand the initial conditions of present day star and
planet formation. We developed a new approach to study the
structure of these poorly understood objects that uses
infrared dust extinction of starlight and that is free from
the problems that plague molecular line data. With this new
method we are able to construct high resolution maps of the
distribution of dust inside molecular clouds over unprecedented
ranges of cloud depth: 1 < Av < 40 magnitudes.

In this talk we review the technique and present maps of dust
column density derived from large scale near-infrared observations
of two molecular clouds in Cygnus. Through comparison with
molecular-line data and dust emission data we introduce a new and
wealthier view on the physical and chemical structure of these
clouds. We will also present a pilot study application of this new
technique to the All-Sky NIR data base 2MASS and the first results of
an ongoing VLT deep near-infrared imaging survey of dense molecular
clouds and its implications on current star formation theories.