  We present the results of recent studies on the co-evolution of galaxies and
the supermassive black holes (SMBHs) using Herschel far-infrared and Chandra
X-ray observations in the Bo\"otes survey region. For a sample of star-forming
(SF) galaxies, we find a strong correlation between galactic star formation
rate and the average SMBH accretion rate in SF galaxies. Recent studies have
shown that star formation and AGN accretion are only weakly correlated for
individual AGN, but this may be due to the short variability timescale of AGN
relative to star formation. Averaging over the full AGN population yields a
strong linear correlation between accretion and star formation, consistent with
a simple picture in which the growth of SMBHs and their host galaxies are
closely linked over galaxy evolution time scales.
