AN ULTRA-FAST X-RAY DISK WIND IN THE NEUTRON STAR BINARY GX 340+0
Author(s)Miller, J. M.; Raymond, J.; Cackett, E.; Grinberg, Victoria; Nowak, Michael A.
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We present a spectral analysis of a brief Chandra/HETG observation of the neutron star low-mass X-ray binary GX 340+0. The high-resolution spectrum reveals evidence of ionized absorption in the Fe K band. The strongest feature, an absorption line at approximately 6.9 keV, is required at the 5σ level of confidence via an F-test. Photoionization modeling with XSTAR grids suggests that the line is the most prominent part of a disk wind with an apparent outflow speed of v = 0.04c. This interpretation is preferred at the 4σ level over a scenario in which the line is H-like Fe xxvi at a modest redshift. The wind may achieve this speed owing to its relatively low ionization, enabling driving by radiation pressure on lines; in this sense, the wind in GX 340+0 may be the stellar-mass equivalent of the flows in broad absorption line quasars. If the gas has a unity volume filling factor, the mass ouflow rate in the wind is over 10⁻⁵ M ⊙ yr⁻¹, and the kinetic power is nearly 10³⁹ erg s⁻¹ (or, 5–6 times the radiative Eddington limit for a neutron star). However, geometrical considerations—including a small volume filling factor and low covering factor—likely greatly reduce these values.
DepartmentMIT Kavli Institute for Astrophysics and Space Research
Astrophysical Journal. Letters
Miller, J. M., J. Raymond, E. Cackett, V. Grinberg, and M. Nowak. “AN ULTRA-FAST X-RAY DISK WIND IN THE NEUTRON STAR BINARY GX 340+0.” The Astrophysical Journal 822, 1 (April 2016): L18 © 2016 The American Astronomical Society
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