Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Infrared Excess Sources: Compton Thick QSOs, low luminosity Seyferts or
  starbursts?   We explore the nature of Infrared Excess sources (IRX), which are proposed as
candidates for luminous L_X(2-10keV)>1e43erg/s Compton Thick (N_H>2e24cm^{-2}$)
QSOs at z~2. Lower redshift, z~1, analogues of the distant IRX population are
identified by firstly redshifting to z=2 the SEDs of all sources with secure
spectroscopic redshifts in the AEGIS (6488) and the GOODS-North (1784) surveys
and then selecting those that qualify as IRX sources at that redshift. A total
of 19 galaxies are selected. The mean redshift of the sample is $z\approx1$. We
do not find strong evidence for Compton Thick QSOs in the sample. For 9 sources
with X-ray counterparts, the X-ray spectra are consistent with Compton Thin
AGN. Only 3 of them show tentative evidence for Compton Thick obscuration. The
SEDs of the X-ray undetected population are consistent with starburst activity.
There is no evidence for a hot dust component at the mid-infrared associated
with AGN heated dust. If the X-ray undetected sources host AGN, an upper limit
of L_X(2-10keV) =1e43erg/s is estimated for their intrinsic luminosity. We
propose that a large fraction of the $z\approx2$ IRX population are not Compton
Thick QSOs but low luminosity [L_X(2-10keV)<1e43erg/s], possibly Compton Thin,
AGN or dusty starbursts. It is shown that the decomposition of the AGN and
starburst contribution to the mid-IR is essential for interpreting the nature
of this population, as star-formation may dominate this wavelength regime.

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The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
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The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
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The categories of this paper are: adap-org