Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A comprehensive study of NGC 2023 with XMM-Newton and Spitzer   Nearby star-forming regions are ideal laboratories to study high-energy
emission of different stellar populations, from very massive stars to brown
dwarfs. NGC 2023 is a reflection nebula situated on the south of the Flame
Nebula (NGC 2024) and at the edge of the H ii region IC 434, which also
contains the Horsehead Nebula (Barnard 33). NGC 2023, NGC 2024, Barnard 33 and
the surroundings of the O-type supergiant star {\zeta} Ori constitute the south
part of the Orion B molecular complex. In this work, we present a comprehensive
study of X-ray emitters in the region of NGC 2023 and its ?surroundings. We
combine optical and infrared data to determine physical properties (mass,
temperature, luminosity, presence of accretion disks) of the stars detected in
an XMM-Newton observation. This study has allowed us to analyze spectral energy
distribution of these stars for the first time and determine their evolutionary
stage. Properties of the X-ray emitting plasma of these stars are compared to
those found in other nearby star-forming regions. The results indicate that the
stars that are being formed in this region have characteristics, in terms of
physical properties and luminosity function, similar to those found in the
Taurus-Auriga molecular complex.

21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th