Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dust in the early Universe: Evidence for non-stellar dust production or
  observational errors?   Observations have revealed unexpectedly large amounts of dust in
high-redshift galaxies and its origin is still much debated. Valiante et al.
(2009, MNRAS, 397, 1661) suggested the net stellar dust production of the
quasar host galaxy SDSS J1148+5251 may be sufficient to explain the large dust
mass detected in this galaxy, albeit under some very special assumptions (e.g.,
'closed box' evolution and a rather high gas mass). Here it is shown that since
accretion of essentially pristine material may lower the efficiency of dust
formation significantly, and the observationally derived dust-to-gas ratios for
these high-redshift galaxies are remarkably high, stellar dust production is
likely insufficient. A model including metallicity-dependent, non-stellar dust
formation ('secondary dust') is presented. The required contribution from this
non-stellar dust component appears too large, however. If all observational
constraints are to be met, the resultant dust-to-metals ratio is close to
unity, which means that almost all interstellar metals exist in the form dust.
This is a very unlikely situation and suggests the large dust-to-gas ratios at
high-redshifts may be due to observational uncertainties and/or or incorrect
calibration of conversion factors for gas and dust tracers.

26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph