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A clean sightline to quiescence: multiwavelength observations of the high Galactic latitude black hole X-ray binary Swift J1357.2-0933.
- Source :
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Monthly Notices of the Royal Astronomical Society . 3/1/2016, Vol. 456 Issue 3, p2707-2716. 10p. - Publication Year :
- 2016
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Abstract
- We present coordinated multiwavelength observations of the high Galactic latitude (b = +50°) black hole X-ray binary (BHXB) Swift J1357.2−0933 in quiescence. Our broad-band spectrum includes strictly simultaneous radio and X-ray observations, and near-infrared, optical, and ultraviolet data taken 1-2 d later. We detect Swift J1357.2-0933 at all wavebands except for the radio (f5GHz < 3.9 μJy beam-1; 3σrms). Given current constraints on the distance (2.3-6.3 kpc), its 0.5-10 keV X-ray flux corresponds to an Eddington ratio LX/LEdd = 4 × 10-9-3 × 10-8 (assuming a black hole mass of 10 M⊙). The broad-band spectrum is dominated by synchrotron radiation from a relativistic population of outflowing thermal electrons, which we argue to be a common signature of short-period quiescent BHXBs. Furthermore, we identify the frequency where the synchrotron radiation transitions from optically thick-to-thin (νb ≈ 2-5 × 1014 Hz), which is the most robust determination of a 'jet break' for a quiescent BHXB to date. Our interpretation relies on the presence of steep curvature in the ultraviolet spectrum, a frequency window made observable by the low amount of interstellar absorption along the line of sight. High Galactic latitude systems like Swift J1357.2-0933 with clean ultraviolet sightlines are crucial for understanding black hole accretion at low luminosities. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 456
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 112752910
- Full Text :
- https://doi.org/10.1093/mnras/stv2861