Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The hot stars in orbit around the M31 central supermassive black hole:
  are they young or old?   AIMS: The cluster of hot stars observed in orbit around the central black
hole of M31 has been interpreted as a 200 Myr starburst. The formation of a
population of young stars in close proximity to a massive black hole presents a
difficult challenge to star formation theory. We point out that in a high
stellar density environment, the course of stellar evolution is modified by
frequent collisions and mergers. METHODS: Blue stragglers, which are the
results of mergers in globular clusters, occupy the same position in the
color-magnitude diagram as the observed hot stars in M31. For confirmation, the
integrated spectrum of P3 is shown to be compatible with the spectral energy
distribution of a blue horizontal branch field star. RESULTS: We suggest an old
stellar population of evolved blue horizontal-branch stars and of merger
products cannot be ruled out on the basis of the available data. Observations
are suggested that would help distinguish between a ``young'' and ``old''
stellar population interpretation of the observations.

24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas