Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hidden Quasars in Ultraluminous Infrared Galaxies   Many ultraluminous infrared galaxies (ULIRGs) are powered by quasars hidden
in the center, but many are also powered by starbursts. A simply diagnostic
diagram is proposed that can identify obscured quasars in ULIRGs by their
high-ionization emission lines ([O III] 5007/Hbeta >~ 5), and ``warm'' IR color
(f_{25}/f_{60} >~ 0.25).

30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org