Bibcode
in't Zand, Jean; Verbunt, Frank; Heise, John; Bazzano, Angela; Cocchi, Massimo; Cornelisse, Remon; Kuulkers, Erik; Natalucci, Lorenzo; Ubertini, Pietro
Referencia bibliográfica
Nuclear Physics B Proceedings Supplements, Volume 132, p. 486-495.
Fecha de publicación:
6
2004
Número de citas
47
Número de citas referidas
36
Descripción
We review the results obtained with the Galactic center campaigns of the
BeppoSAX Wide Field X-ray Cameras (WFCs). This pertains to the study of
luminous low-mass X-ray binaries (LMXBs). When pointed at the Galactic
center, the WFC field of view contains more than half of the Galactic
LMXB population. The results exemplify the excellent WFC capability to
detect brief X-ray transients. Firstly, the WFCs expanded the known
population of Galactic thermonuclear X-ray bursters by 50%. At least
half of all LMXBs are now established to burst and, thus, to contain a
neutron star as compact accretor rather than a black hole candidate. We
provide a complete list of all 76 currently known bursters, including
the new case 1RXS J170854.4-321857. Secondly, the WFCs have uncovered a
population of weak transients with peak luminosities up to ~
1037 erg s-1 and durations from days to weeks. One
is the first accretion-powered millisecond pulsar SAX J1808.4-3658.
Thirdly, the WFCs contributed considerably towards establishing that
nearly all (12 out of 13) luminous low-mass X-ray binaries in Galactic
globular clusters contain neutron stars rather than black holes. Thus,
the neutron star to black hole ratio in clusters differs from that in
the Galactic disk at a marginal confidence level of 97%.