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Description
We present a comparison of the physical properties of a rest-frame 250um selected sample of massive, dusty galaxies from 0<z<5.3. Our sample comprises 29 high-redshift submillimetre galaxies (SMGs) from the literature, and 843 dusty galaxies at z<0.5 from the Herschel-ATLAS, selected to have a similar stellar mass to the SMGs. The z>1 SMGs have an average SFR of 390^+80^_-70_M_{sun}_/yr which is 110 times that of the low-redshift sample matched in stellar mass to the SMGs (SFR=3.3+/-0.2M_{sun}_/yr). The SMGs harbour a substantial mass of dust (1.2^+0.3^_-0.2_x10^9^M_{sun}_), compared to (1.6+/-0.1)x10^8^M_{sun}_ for low-redshift dusty galaxies. At low redshifts the dust luminosity is dominated by the diffuse ISM, whereas a large fraction of the dust luminosity in SMGs originates from star-forming regions. At the same dust mass SMGs are offset towards a higher SFR compared to the low-redshift H-ATLAS galaxies. This is not only due to the higher gas fraction in SMGs but also because they are undergoing a more efficient mode of star formation, which is consistent with their bursty star-formation histories. The offset in SFR between SMGs and low-redshift galaxies is similar to that found in CO studies, suggesting that dust mass is as good a tracer of molecular gas as CO.
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