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摘要
At z = 1-3, the formation of new stars is dominated by dusty galaxies whose far-IR emission indicates they contain colder dust than local galaxies of a similar luminosity. We explore the reasons for the evolving IR emission of similar galaxies over cosmic time using (1) local galaxies from GOALS (LIR = 10(11)-10(12) L-circle dot), (2) galaxies at z similar to 0.1-0.5 from 5MUSES (L-IR = 10(10) -10(12) L-circle dot), and (3) IR luminous galaxies spanning z = 0.5-3 from GOODS and Spitzer xFLS (L-IR > 10(11) L-circle dot). All samples have Spitzer mid-IR spectra, and Herschel and groundbased submillimeter imaging covering the full IR spectral energy distribution, allowing us to robustly measure L-IR(SF), T-dust, and M-dust for every galaxy. Despite similar infrared luminosities, z > 0.5 dusty star-forming galaxies (DSFG) have a factor of 5 higher dust masses and 5 K colder temperatures. The increase in dust mass is linked to an increase in the gas fractions with redshift, and we do not observe a similar increase in stellar mass or star formation efficiency. L-160(SF)/L-70 (SF), a proxy for T-dust, is strongly correlated with L-IR (SF)/M-dust independently of redshift. We measure merger classification and galaxy size for a subsample, and there is no obvious correlation between these parameters and L-IR (SF)/M-dust or (SF)(160)/L-70 (SF). In DSFG, the change in L-IR (SF)/M-dust can fully account for the observed colder dust temperatures, suggesting that any change in the spatial extent of the interstellar medium is a second-order effect.
- 出版日期2017-7-1
- 单位南京大学; rutgers
