Magnetothermal disc winds in X-ray binaries: poloidal magnetic fields suppress thermal winds
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. of Nevada, Las Vegas, NV (United States). Dept. of Physics & Astronomy
Magnetic, radiation pressure, and thermal driving are the three mechanisms capable of launching accretion disc winds. In X-ray binaries, radiation pressure is often not significant, as in many systems the luminosity is too low for driving due to continuum transitions yet too high for driving due to line transitions. This leaves thermal and magnetic driving as the contender launching mechanisms in these systems. Using ATHENA++, here we perform axisymmetric ideal MHD simulations that include radiative heating and cooling processes appropriate for Compton heated winds to show that the inclusion of magnetic fields into a thermally driven wind has the opposite effect of what one might expect: rather than provide a velocity boost, the thermal wind is suppressed in low-plasma beta regions where the field lines are strong enough to reshape the direction of the flow. Our analysis reveals that magneto-centrifugal launching is present but weak, while the reduction in wind velocity is not due to the change in gravitational potential through the magnetically imposed streamline geometry, but rather due to the increased flow tube area just above the surface of the disc, which is less conducive to acceleration. Finally, our results suggest that for magnetothermal wind models to be successful at producing fast dense outflows in low-mass X-ray binaries, the winds must be magnetically launched well within the Compton radius.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE; National Aeronautics and Space Administration (NASA)
- Grant/Contract Number:
- AC52-06NA25396; NNX14AK44G
- OSTI ID:
- 1479999
- Report Number(s):
- LA-UR-18-25178
- Journal Information:
- Monthly Notices of the Royal Astronomical Society, Vol. 481, Issue 2; ISSN 0035-8711
- Publisher:
- Royal Astronomical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
A Comprehensive Chandra Study of the Disk Wind in the Black Hole Candidate 4U 1630-472
|
journal | November 2019 |
| A Comprehensive Chandra Study of the Disk Wind in the Black Hole Candidate 4U 1630-472 | text | January 2019 |
| Science with the X-ray Imaging and Spectroscopy Mission (XRISM) | preprint | January 2020 |
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