An Obscured, Seyfert-2-like State of the Stellar-mass Black Hole GRS
  1915+105 Caused by Failed Disk Winds
  We report on Chandra gratings spectra of the stellar-mass black hole GRS
1915+105 obtained during a novel, highly obscured state. As the source entered
this state, a dense, massive accretion disk wind was detected through strong
absorption lines. Photionization modeling indicates that it must originate
close to the central engine, orders of magnitude from the outer accretion disk.
Strong, nearly sinusoidal flux variability in this phase yielded a key insight:
the wind is blue-shifted when its column density is relatively low, but
red-shifted as it approaches the Compton-thick threshold. At no point does the
wind appear to achieve the local escape velocity; in this sense, it is a
"failed wind." Later observations suggest that the disk ultimately fails to
keep even the central engine clear of gas, leading to heavily obscured and
Compton-thick states characterized by very strong Fe K emission lines. Indeed,
these later spectra are successfully described using models developed for
obscured AGN. We discuss our results in terms the remarkable similarity of GRS
1915+105 deep in its "obscured state" to Seyfert-2 and Compton-thick AGN, and
explore how our understanding of accretion and obscuration in massive black
holes is impacted by our observations.
