Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Self-Absorption Census of Cold HI Clouds in the Canadian Galactic
  Plane Survey   We present a 21cm line HI self-absorption (HISA) survey of cold atomic gas
within Galactic longitudes 75 to 146 degrees and latitudes -3 to +5 degrees. We
identify HISA as spatially and spectrally confined dark HI features and extract
it from the surrounding HI emission in the arcminute-resolution Canadian
Galactic Plane Survey (CGPS). We compile a catalog of the most significant
features in our survey and compare our detections against those in the
literature. Within the parameters of our search, we find nearly all previously
detected features and identify many new ones. The CGPS shows HISA in much
greater detail than any prior survey and allows both new and
previously-discovered features to be placed into the larger context of Galactic
structure. In space and radial velocity, faint HISA is detected virtually
everywhere that the HI emission background is sufficiently bright. This ambient
HISA population may arise from small turbulent fluctuations of temperature and
velocity in the neutral interstellar medium. By contrast, stronger HISA is
organized into discrete complexes, many of which follow a longitude-velocity
distribution that suggests they have been made visible by the velocity reversal
of the Perseus arm's spiral density wave. The cold HI revealed in this way may
have recently passed through the spiral shock and be on its way to forming
molecules and, eventually, new stars. This paper is the second in a series
examining HISA at high angular resolution. A companion paper (Paper III)
describes our HISA search and extraction algorithms in detail.

22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an