Swift J1357.2-0933: the faintest black hole?

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
Number of authors
6
IAC number of authors
1
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.
Related projects
Black hole in outburst
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