Abstract
Disk and wind signatures are seen in the soft state of Galactic black holes,
while the jet is seen in the hard state. Here we study the disk-wind connection
in the \$\rho\$ class of variability in GRS 1915+105 using a joint NuSTAR-Chandra
observation. The source shows 50 sec limit cycle oscillations. By including new
information provided by the reflection spectrum, and using phase-resolved
spectroscopy, we find that the change in the inner disk inferred from the
blackbody emission is not matched by reflection measurements. The latter is
almost constant, independent of the continuum model. The two radii are
comparable only if the disk temperature color correction factor changes, an
effect that could be due to the changing opacity of the disk caused by changes
in metal abundances. The disk inclination is similar to that inferred from the
jet axis, and oscillates by \~10 deg. The simultaneous Chandra data show the
presence of two wind components with velocities between 500-5000 km/s, and
possibly two more with velocities reaching 20,000 km/s (\~0.06 c). The column
densities are \~5e22 cm\$^-2\$. An upper limit to the wind response time of 2
sec is measured, implying a launch radius of <6e10 cm. The changes in wind
velocity and absorbed flux require the geometry of the wind to change during
the oscillations, constraining the wind to be launched from a distance of 290 -
1300 rg from the black hole. Both datasets support fundamental model
predictions in which a bulge originates in the inner disk and moves outward as
the instability progresses.
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