The accreting black hole Swift J1753.5–0127 from radio to hard X-ray
- Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States)
- European Southern Observatory, Karl Schwarzschild-Strasse 2, D-85748 Garching bei Munchen (Germany)
- Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)
- International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia)
- California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
- Solar-Terrestrial Environment Laboratory, Nagoya University, Furocho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan)
- Hiroshima Astrophysical Science Center, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)
- Laboratoire AIM (CEA/IRFU—CNRS/INSU—Université Paris Diderot), CEA DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France)
- Institut de Recherche en Astrophysique et Planétologie (IRAP), 9 Avenue du Colonel Roche, F-31028 Toulouse Cedex 4 (France)
- Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom)
- School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)
- Department of Mathematics and Science National Taiwan Normal University, Lin-kou District, New Taipei City 24449, Taiwan (China)
- Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States)
- Sabanci University, Orhanli-Tuzla, Istanbul, 34956 (Turkey)
We report on multiwavelength measurements of the accreting black hole Swift J1753.5–0127 in the hard state at low luminosity (L ∼ 2.7 × 10{sup 36} erg s{sup −1} assuming a distance of d = 3 kpc) in 2014 April. The radio emission is optically thick synchrotron, presumably from a compact jet. We take advantage of the low extinction (E(B−V)=0.45 from earlier work) and model the near-IR to UV emission with a multitemperature disk model. Assuming a black hole mass of M{sub BH} = 5 M{sub ⊙} and a system inclination of i = 40°, the fits imply an inner radius for the disk of R{sub in}/R{sub g} > 212d{sub 3}(M{sub BH}/5 M{sub ⊙}){sup −1}, where R{sub g} is the gravitational radius of the black hole and d{sub 3} is the distance to the source in units of 3 kpc. The outer radius is R{sub out}/R{sub g}=90,000 d{sub 3}(M{sub BH}/5 M{sub ⊙}){sup −1}, which corresponds to 6.6 × 10{sup 10} d{sub 3} cm, consistent with the expected size of the disk given previous measurements of the size of the companion's Roche lobe. The 0.5–240 keV energy spectrum measured by Swift/X-ray Telescope (XRT), Suzaku (XIS, PIN, and GSO), and Nuclear Spectroscopic Telescope Array is relatively well characterized by an absorbed power law with a photon index of Γ = 1.722 ± 0.003 (90% confidence error), but a significant improvement is seen when a second continuum component is added. Reflection is a possibility, but no iron line is detected, implying a low iron abundance. We are able to fit the entire (radio to 240 keV) spectral energy distribution (SED) with a multitemperature disk component, a Comptonization component, and a broken power law, representing the emission from the compact jet. The broken power law cannot significantly contribute to the soft X-ray emission, and this may be related to why Swift J1753.5–0127 is an outlier in the radio/X-ray correlation. The broken power law (i.e., the jet) might dominate above 20 keV, which would constrain the break frequency to be between 2.4 × 10{sup 10} and 3.6 × 10{sup 12} Hz. Although the fits to the full SED do not include significant thermal emission in the X-ray band, previous observations have consistently seen such a component, and we find that there is evidence at the 3.1σ level for a disk-blackbody component with a temperature of kT{sub in}=150{sub −20}{sup +30} eV and an inner radius of 5R{sub g}–14R{sub g}. If this component is real, it might imply the presence of an inner optically thick accretion disk in addition to the strongly truncated (R{sub in}> 212R{sub g}) disk. We also perform X-ray timing analysis, and the power spectrum is dominated by a Lorentzian component with ν{sub max} = 0.110 ± 0.003 Hz and ν{sub max} = 0.16 ± 0.04 Hz as measured by XIS and XRT, respectively.
- OSTI ID:
- 22882807
- Journal Information:
- Astrophysical Journal, Vol. 808, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
- Country of Publication:
- United Kingdom
- Language:
- English
Similar Records
Optical and near-infrared spectroscopy of the black hole Swift J1753.5–0127
SUZAKU BROADBAND SPECTROSCOPY OF SWIFT J1753.5-0127 IN THE LOW-HARD STATE