This is the second in a series of papers presenting results from the SCUBA Local Universe Galaxy Survey .
In our first paper we provided 850 \mu m flux densities for 104 galaxies selected from the IRAS Bright Galaxy Sample and we found that the 60 , 100 \mu m ( IRAS ) and 850 \mu m ( SCUBA ) fluxes could be adequately fitted by emission from dust at a single temperature .
In this paper we present 450 \mu m data for the galaxies .
With the new data , the spectral energy distributions of the galaxies can no longer be fitted with an isothermal dust model – two temperature components are now required .
Using our 450 \mu m data and fluxes from the literature , we find that the 450 \mu m/850 \mu m flux ratio for the galaxies is remarkably constant and this holds from objects in which the star formation rate is similar to our own Galaxy , to ultraluminous infrared galaxies ( ULIRGS ) such as Arp 220 .
The only possible explanation for this is if the dust emissivity index for all of the galaxies is \sim 2 and the cold dust component has a similar temperature in all galaxies ( T _ { c } \sim 20 - 21 K ) .
The 60 \mu m luminosities of the galaxies were found to depend on both the dust mass and the relative amount of energy in the warm component , with a tendency for the temperature effects to dominate at the highest L _ { 60 } .
The dust masses estimated using the new temperatures are higher by a factor \sim 2 than those determined previously using a single temperature .
This brings the gas-to-dust ratios of the IRAS galaxies into agreement with those of the Milky Way and other spiral galaxies which have been intensively studied in the submm .