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The accreting black hole swift J1753.5-0127 from radio to hard x-ray

Tomsick, John A. and Rahoui, Farid and Kolehmainen, Mari and Miller-Jones, James and Fürst, Felix and Yamaoka, Kazutaka and Akitaya, Hiroshi and Corbel, Stephane and Coriat, Mickael and Done, Chris and Gandhi, Poshak and Harrison, Fiona, A. and Huang, Kuiyun and Kaaret, Philip and Kalemci, Emrah and Kanda, Yuka and Migliari, Simone and Miller, Jon M. and Moritani, Yuki and Stern, Daniel and Uemura, Makato and Urata, Yuji (2015) The accreting black hole swift J1753.5-0127 from radio to hard x-ray. Astrophysical Journal, 808 (1). ISSN 0004-637X (Print) 1538-4357 (Online)

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Official URL: http://dx.doi.org/10.1088/0004-637X/808/1/85

Abstract

We report on multiwavelength measurements of the accreting black hole Swift J1753.5-0127 in the hard state at low luminosity (L ˜ 2.7 × 10^36 erg s-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 MBH = 5 M⊙ and a system inclination of i = 40°, the fits imply an inner radius for the disk of Rin/Rg > 212d3(MBH/5 M⊙)^-1, where Rg is the gravitational radius of the black hole and d3 is the distance to the source in units of 3 kpc. The outer radius is Rout/Rg=90,000 d3(MBH/5 M⊙)-1, which corresponds to 6.6 × 10^10 d3 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 × 10^10 and 3.6 × 10^12 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}}{in}={150}-20+30 eV and an inner radius of 5Rg-14Rg. If this component is real, it might imply the presence of an inner optically thick accretion disk in addition to the strongly truncated (Rin> 212Rg) disk. We also perform X-ray timing analysis, and the power spectrum is dominated by a Lorentzian component with νmax = 0.110 ± 0.003 Hz and νmax = 0.16 ± 0.04 Hz as measured by XIS and XRT, respectively.

Item Type:Article
Additional Information:Article Number: 85
Uncontrolled Keywords:accretion, accretion disks; black hole physics; stars: individual (Swift J1753.5-0127); X-rays: general; X-rays: stars
Subjects:Q Science > QB Astronomy > QB460-466 Astrophysics
ID Code:27620
Deposited By:Emrah Kalemci
Deposited On:09 Dec 2015 11:54
Last Modified:09 Dec 2015 11:54

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