Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Star formation in the intragroup medium and other diagnostics of the
  evolutionary stages of compact groups of galaxies   Context: Compact groups of galaxies are entities that have high densities of
galaxies and serve as laboratories to study galaxy interactions, intergalactic
star formation and galaxy evolution.
  Aims: The main goal of this study is to search for young objects in the
intragroup medium of seven compact groups of galaxies: HCG 2, 7, 22, 23, 92,
100 and NGC 92 as well as to evaluate the stage of interaction of each group.
  Methods: We used Fabry-Perot velocity fields and rotation curves together
with GALEX NUV and FUV images and optical R-band and HI maps.
  Results: (i) HCG 7 and HCG 23 are in early stages of interaction, (ii) HCG 2
and HCG 22 are mildly interacting, and (iii) HCG 92, HCG 100 and NGC 92 are in
late stages of evolution. We find that all three evolved groups contain
populations of young blue objects in the intragroup medium, consistent with
ages < 100 Myr, of which several are younger than < 10 Myr. We also report the
discovery of a tidal dwarf galaxy candidate in the tail of NGC 92. These three
groups, besides containing galaxies that have peculiar velocity fields, also
show extended HI tails.
  Conclusions: Our results indicate that the advanced stage of evolution of a
group, together with the presence of intragroup HI clouds, may lead to star
formation in the intragroup medium. A table containing all intergalactic HII
regions and tidal dwarf galaxies confirmed to date is appended.

5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg