  We present 350micron observations of 36 ultraluminous infrared galaxies
(ULIRGs) at intermediate redshifts (0.089 <= z <= 0.926) using the
Submillimeter High Angular Resolution Camera II (SHARC-II) on the Caltech
Submillimeter Observatory (CSO). In total, 28 sources are detected at S/N >= 3,
providing the first flux measurements longward of 100micron for a statistically
significant sample of ULIRGs in the redshift range of 0.1 < z < 1.0. Combining
our 350micron flux measurements with the existing IRAS 60 and 100micron data,
we fit a single-temperature model to the spectral energy distribution (SED),
and thereby estimate dust temperatures and far-IR luminosities. Assuming an
emissivity index of beta = 1.5, we find a median dust temperature and far-IR
luminosity of Td = 42.8+-7.1K and log(Lfir/Lsolar) = 12.2+-0.5, respectively.
The far-IR/radio correlation observed in local star-forming galaxies is found
to hold for ULIRGs in the redshift range 0.1 < z < 0.5, suggesting that the
dust in these sources is predominantly heated by starbursts. We compare the
far-IR luminosities and dust temperatures derived for dusty galaxy samples at
low and high redshifts with our sample of ULIRGs at intermediate redshift. A
general Lfir-Td relation is observed, albeit with significant scatter, due to
differing selection effects and variations in dust mass and grain properties.
The relatively high dust temperatures observed for our sample compared to that
of high-z submillimeter-selected starbursts with similar far-IR luminosities
suggest that the dominant star formation in ULIRGs at moderate redshifts takes
place on smaller spatial scales than at higher redshifts.
