Milky Way Star Forming Complexes and the Turbulent Motion of the
  Galaxy's Molecular Gas
  We analyze Spitzer GLIMPSE, MSX, and WMAP images of the Milky Way to identify
8 micron and free-free sources in the Galaxy. Seventy-two of the eighty-eight
WMAP sources have coverage in the GLIMPSE and MSX surveys suitable for
identifying massive star forming complexes (SFC). We measure the ionizing
luminosity functions of the SFCs and study their role in the turbulent motion
of the Galaxy's molecular gas. We find a total Galactic free-free flux f_{\nu}
= 46177.6 Jy; the 72 WMAP sources with full 8 micron coverage account for
34263.5 Jy (~75%), with both measurements made at \nu=94GHz (W band). We find a
total of 280 SFCs, of which 168 have unique kinematic distances and free-free
luminosities. We use a simple model for the radial distribution of star
formation to estimate the free-free and ionizing luminosity for the sources
lacking distance determinations. The total dust-corrected ionizing luminosity
is Q = 2.9 \pm 0.5 x 10^53 photons s^-1, which implies a galactic star
formation rate of 1.2 \pm 0.2 M_{\sun} yr^-1. We present the (ionizing)
luminosity function of the SFCs, and show that 24 sources emit half the
ionizing luminosity of the Galaxy. The SFCs appear as bubbles in GLIMPSE or MSX
images; the radial velocities associated with the bubble walls allow us to
infer the expansion velocity of the bubbles. We calculate the kinetic
luminosity of the bubble expansion and compare it to the turbulent luminosity
of the inner molecular disk. SFCs emitting 80% of the total galactic free-free
luminosity produce a kinetic luminosity equal to 65% of the turbulent
luminosity in the inner molecular disk. This suggests that the expansion of the
bubbles is a major driver of the turbulent motion of the inner Milky Way
molecular gas.
