Zusammenfassung
Recent deep Chandra surveys of the Galactic center region have revealed the
existence of a faint, hard X-ray source population. While the nature of this
population is unknown, it is likely that several types of stellar objects
contribute. For sources involving binary systems, accreting white dwarfs and
accreting neutron stars with main sequence companions have been proposed. Among
the accreting neutron star systems, previous studies have focused on stellar
wind-fed sources. In this paper, we point out that binary systems in which mass
transfer occurs via Roche lobe overflow (RLOF) can also contribute to this
X-ray source population.
A binary population synthesis study of the Galactic center region has been
carried out, and it is found that evolutionary channels for neutron star
formation involving the accretion induced collapse of a massive ONeMg white
dwarf, in addition to the core collapse of massive stars, can contribute to
this population. The RLOF systems would appear as transients with quiescent
luminosities, above 2 keV, in the range from 10^31-10^32 ergs/s. The results
reveal that RLOF systems primarily contribute to the faint X-ray source
population in the Muno et al. (2003) survey and wind-fed systems can contribute
to the less sensitive Wang et al. (2002) survey. However, our results suggest
that accreting neutron star systems are not likely to be the major contributor
to the faint X-ray source population in the Galactic center.
Nutzer