We present the Herschel -SPIRE photometric atlas for a complete flux limited sample of 43 local Ultraluminous Infrared Galaxies ( ULIRGs ) , selected at 60 \mu m by IRAS , as part of the HERschel ULIRG Survey ( HERUS ) .
Photometry observations were obtained using the SPIRE instrument at 250 , 350 and 500 \mu m. We describe these observations , present the results , and combine the new observations with data from IRAS to examine the far-IR spectral energy distributions ( SEDs ) of these sources .
We fit the observed SEDs of HERUS objects with a simple parameterised modified black body model where temperature and emissivity \beta are free parameters .
We compare the fitted values to those of non-ULIRG local galaxies , and find , in agreement with earlier results , that HERUS ULIRGs have warmer dust ( median temperature T = 37.9 \pm 4.7 K compared to 21.3 \pm 3.4 K ) but a similar \beta distribution ( median \beta = 1.7 compared to 1.8 ) to the Herschel reference sample ( HRS , Cortese et al. , 2014 ) galaxies .
Dust masses are found to be in the range of 10 ^ { 7.5 } to 10 ^ { 9 } M _ { \odot } , significantly higher than that of Herschel Reference Sample ( HRS ) sources .
We compare our results for local ULIRGs with higher redshift samples selected at 250 and 850 \mu m. These latter sources generally have cooler dust and/or redder 100-to-250 \mu m colours than our 60 \mu m-selected ULIRGs .
We show that this difference may in part be the result of the sources being selected at different wavelengths rather than being a simple indication of rapid evolution in the properties of the population .