Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovery of multiple ultraluminous X-ray sources in the galaxy KUG
  0214-057   We report the serendipitous discovery of several unresolved X-ray sources
lying in the prominent spiral arms of the galaxy KUG 0214-057 in XMM-Newton
observations. The location of these X-ray sources strongly suggests that at
least three, and possibly four, of these may be physically related to the
galaxy. The luminosity of each of these sources at the distance of KUG 0214-057
is > 5 x 10^39 erg/s (0.3-10 keV), making each a strong candidate ultraluminous
X-ray source (ULX). Using the ULXs as a metric implies that this relatively
low-mass galaxy may be experiencing rather intense starburst activity. The
serendipitous discovery of these ULXs suggests that such objects are not a
negligible component of the overall extragalactic X-ray source population.

22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc