We conduct a detailed case-study of the interstellar shell near the high-mass
X-ray binary, Cygnus X-1. We present new WIYN optical spectroscopic and Chandra
X-ray observations of this region, which we compare with detailed MAPPINGS III
shock models, to investigate the outflow powering the shell. Our analysis
places improved, physically motivated constraints on the nature of the
shockwave and the interstellar medium (ISM) it is plowing through. We find that
the shock is traveling at less than a few hundred km/s through a low-density
ISM (< 5 cm^-3). We calculate a robust, 3 sigma upper limit to the total,
time-averaged power needed to drive the shockwave and inflate the bubble, < 2 x
10^38 erg/s. We then review possible origins of the shockwave. We find that a
supernova origin to the shockwave is unlikely and that the black hole jet
and/or O-star wind can both be central drivers of the shockwave. We conclude
that the source of the Cygnus X-1 shockwave is far from solved.Comment: 16 pages, 8 figures, accepted for publication in MNRA