Swift Spectroscopy of the Accretion Disk Wind in the Black Hole GRO J1655-40

Chandra obtained two High Energy Transmission Grating spectra of the stellar-mass black hole GRO J1655−40 during its 2005 outburst, revealing a rich and complex disk wind. Soon after its launch, the Neil Gehrels Swift Observatory began monitoring the same outburst. Some X-ray Telescope (XRT) observa...

Full description

Saved in:
Bibliographic Details
Published in:The Astrophysical journal 2020-04, Vol.893 (2), p.155
Main Authors: Balakrishnan, M., Miller, J. M., Trueba, N., Reynolds, M., Raymond, J., Proga, D., Fabian, A. C., Kallman, T., Kaastra, J.
Format: Article
Language:English
Subjects:
Absorption
Accretion disks
Astronomy
Astrophysics
Black holes
Calibration
Compact objects
Computational fluid dynamics
Energy transmission
Fluid flow
K alpha line
Line spectra
Magnetohydrodynamics
Manganese
Outflow
Photoionization
Spectroscopy
Spectrum analysis
Stellar accretion disks
Stellar winds
Thermal winds
Wind
Wind models
X ray telescopes
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Chandra obtained two High Energy Transmission Grating spectra of the stellar-mass black hole GRO J1655−40 during its 2005 outburst, revealing a rich and complex disk wind. Soon after its launch, the Neil Gehrels Swift Observatory began monitoring the same outburst. Some X-ray Telescope (XRT) observations were obtained in a mode that makes it impossible to remove strong Mn calibration lines, so the Fe K line region in the spectra was previously neglected. However, these lines enable a precise calibration of the energy scale, facilitating studies of the absorption-dominated disk wind and its velocity shifts. Here we present fits to 15 Swift/XRT spectra, revealing variability and evolution in the outflow. The data strongly point to a magnetically driven disk wind: both the higher-velocity (e.g., ) and lower-velocity (e.g., ) wind components are typically much faster than is possible for thermally driven outflows ( ), and photoionization modeling yields absorption radii that are two orders of magnitude below the Compton radius that defines the typical inner extent of thermal winds. Moreover, correlations between key wind parameters yield an average absorption measure distribution that is consistent with magnetohydrodynamic wind models. We discuss our results in terms of recent observational and theoretical studies of black hole accretion disks and outflows, as well as future prospects.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ab8304