Monte-Carlo simulations of the detailed iron absorption line profiles from thermal winds in X-ray binaries

Abstract

Blue shifted absorption lines from highly ionised iron are seen in some high inclination X-ray binary systems, indicating the presence of an equatorial disc wind. This launch mechanism is under debate, but thermal driving should be ubiquitous. X-ray irradiation from the central source heats disc surface, forming a wind from the outer disc where the local escape velocity is lower than the sound speed. The mass loss rate from each part of the disc is determined by the luminosity and spectral shape of the central source. We use these together with an assumed density and velocity structure of the wind to predict the column density and ionisation state, then combine this with a Monte Carlo radiation transfer to predict the detailed shape of the absorption (and emission) line profiles. We test this on the persistent wind seen in the bright neutron star binary GX 13+1, with luminosity L/LEdd ~ 0.5. We approximately include the effect of radiation pressure because of high luminosity, and compute line features. We compare these to the highest resolution data, the Chandra third order grating spectra, which we show here for the first time. This is the first physical model for the wind in this system, and it succeeds in reproducing many of the features seen in the data, showing that the wind in GX13+1 is most likely a thermal-radiation driven wind. This approach, combined with better streamline structures derived from full radiation hydrodynamic simulations, will allow future calorimeter data to explore the detail wind structure.

10 pages, 13 figures , Accepted by MNRAS

References in corpus (9)

• The magnetic nature of disk accretion onto black holes
• X-ray Spectral Study of the Photoionized Stellar Wind in Vela~X-1
• The origin of ultra-fast outflows in AGN: Monte-Carlo simulations of the wind in PDS 456
• Thermal Winds in Stellar Mass Black Hole and Neutron Star Binary Systems
• XMM-Newton observations reveal the disappearance of the wind in 4U 1630-47
• Coronae and Winds from Irradiated Disks in X-ray binaries
• Chandra X-ray spectroscopy of a clear dip in GX 13+1
• Radiation hydrodynamics simulations of wide-angle outflows from super-critical accretion disks around black holes
• Sensitivity of the Fe K-alpha Compton shoulder to the geometry and variability of the X-ray illumination of cosmic objects

Cited by in corpus (10)

• Monte Carlo Radiative Transfer
• Multiphase AGN winds from X-ray irradiated disk atmospheres
• The Disk Wind in the Neutron Star Low-mass X-Ray Binary GX 13+1
• The thermal-radiative wind in low mass X-ray binary H 1743-322; Radiation hydrodynamic simulations
• The thermal-radiative wind in low mass X-ray binary H 1743-322: II. iron line predictions from Monte Carlo radiation transfer
• Chandra high-resolution spectra of 4U~1630-47: the disappearance of the wind
• The thermal-radiative wind in the neutron star low mass X-ray binary GX 13+1
• Geometry of the X-ray source 1H 0707-495
• Swift Spectroscopy of the Accretion Disk Wind in the Black Hole GRO J1655-40
• Accretion disc winds in X-ray binaries