We present 350 \mu m observations of 36 ultraluminous infrared galaxies ( ULIRGs ) at intermediate redshifts ( 0.089 \leq z \leq 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 \geq 3 , providing the first flux measurements longward of 100 \mu m for a statistically significant sample of ULIRGs in the redshift range of 0.1 \mathrel { \raise 1.505 pt \hbox { $ \scriptstyle < $ } \kern - 6.0 pt \lower 1.72 pt \hbox { % { $ \scriptstyle \sim$ } } } z \mathrel { \raise 1.505 pt \hbox { $ \scriptstyle < $ } \kern - 6.0 % pt \lower 1.72 pt \hbox { { $ \scriptstyle \sim$ } } } 1.0 .
Combining our 350 \mu m flux measurements with the existing IRAS 60 and 100 \mu m 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 T _ { d } ~ { } = 42.8 \pm 7.1 K~ { } and log ( L _ { \mbox { \tiny { FIR } } } / L _ { \odot } ) = 12.2 \pm 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 \mathrel { \raise 1.505 pt \hbox { $ \scriptstyle < $ } \kern - 6.0 pt \lower 1.72 pt \hbox { % { $ \scriptstyle \sim$ } } } z \mathrel { \raise 1.505 pt \hbox { $ \scriptstyle < $ } \kern - 6.0 % pt \lower 1.72 pt \hbox { { $ \scriptstyle \sim$ } } } 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 L _ { \mbox { \tiny { FIR } } } - T _ { d } ~ { } 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 .