Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modelling SCUBA sources in a Lambda-CDM cosmology: hot starbursts or
  cold extended galactic dust?   Previous modelling has demonstrated that it is difficult to reproduce the
SCUBA source counts within the framework of standard hierarchical structure
formation models if the sources are assumed to be the high-redshift
counterparts of local ultra-luminous infrared galaxies with dust temperatures
in the range 40-60 K. Here, we show that the counts are more easily reproduced
in a model in which the bulk of the sub-millimetre emission comes from
extended, cool (20-25 K) dust in objects with star formation rates of 50-100
solar masses per year. The low temperatures imply typical sizes of about 1
(S_{850}/1mJy})^{1/2} arcsec, a factor two to three larger than those predicted
using starburst-like spectral energy distributions. Low dust temperatures also
imply a ratio of optical/UV to 850-micron flux which is 30-100 times smaller,
for the same optical depth, than expected for objects with a hot,
starburst-like SED. This may help explain the small overlap between SCUBA
sources and Lyman-break galaxies.

17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
3
The categories of this paper are: physics