Bibcode
Armas Padilla, M.; Wijnands, R.; Degenaar, N.; Muñoz-Darias, T.; Casares, J.; Fender, R. P.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 444, Issue 1, p.902-905
Advertised on:
10
2014
Citations
36
Refereed citations
35
Description
Swift J1357.2-0933 is a confirmed very faint black hole X-ray transient
and has a short estimated orbital period of 2.8 h. We observed Swift
J1357.2-0933 for ˜50 ks with XMM-Newton in 2013 July during its
quiescent state. The source is clearly detected at a 0.5-10 keV
unabsorbed flux of ˜3 × 10-15 erg cm-2
s-1. If the source is located at a distance of 1.5 kpc (as
suggested in the literature), this would imply a luminosity of ˜8
× 1029 erg s-1, making it the faintest
detected quiescent black hole low-mass X-ray binary. This would also
imply that there is no indication of a reversal in the quiescence X-ray
luminosity versus orbital period diagram down to 2.8 h, as has been
predicted theoretically and recently supported by the detection of the
2.4 h orbital period black hole MAXI J1659-152 at a 0.5-10 keV X-ray
luminosity of ˜1.2 × 1031 erg s-1.
However, there is considerable uncertainty in the distance of Swift
J1357.2-0933 and it may be as distant as 6.3 kpc. In this case, its
quiescent luminosity would be LX ˜ 1.3 ×
1031 erg s-1, i.e. similar to MAXI J1659-152 and
hence, it would support the existence of such a bifurcation period. We
also detected the source in optical at r' ˜ 22.3 mag
with the Liverpool telescope, simultaneously to our X-ray observation.
The X-ray/optical luminosity ratio of Swift J1357.2-0933 agrees with the
expected value for a black hole at this range of quiescent X-ray
luminosities.
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Black holes, neutron stars, white dwarfs and their local environment
Accreting black-holes and neutron stars in X-ray binaries provide an ideal laboratory for exploring the physics of compact objects, yielding not only confirmation of the existence of stellar mass black holes via dynamical mass measurements, but also the best opportunity for probing high-gravity environments and the physics of accretion; the most
Montserrat
Armas Padilla