  We have measured the spectral energy distribution (SED) of the host galaxy of
the z_s=1.7 gravitationally lensed quasar SDSS J1004+4112 from 0.44-8.0 micron
(0.16-3.0 micron in the rest frame). The large angular extent of the lensed
images and their separation from the centralgalaxy of this cluster lens allows
the images to be resolved even with the Spitzer Space Telescope. Based on the
SED, the host galaxy is a mixture of relatively old and intermediate age stars
with an inferred stellar mass of log(M_stars/M_sun)=11.09+/-0.28 and a star
formation rate of log(Mdot/1 M_sun per yr)=1.21+/-0.26. Given the estimated
black hole mass of M_BH ~10^8.6 M_sun from locally-calibrated correlations of
black hole masses with line widths and luminosities, the black hole represents
a fraction log(M_BH/M_stars) = -2.49+/-0.28 of the stellar mass and it is
radiating at 0.24+/-0.05 of the Eddington limit. The ratio of the host stellar
mass to the black hole mass is only marginally consistent with the locally
observed ratio.

Cosmology and Nongalactic Astrophysics