2mass-allsky

A Controlled Study of Cold Dust Content in Galaxies from z = 0-2

July 2017 • 2017ApJ...843...71K

Authors • Kirkpatrick, Allison • Pope, Alexandra • Sajina, Anna • Dale, Daniel A. • Díaz-Santos, Tanio • Hayward, Christopher C. • Shi, Yong • Somerville, Rachel S. • Stierwalt, Sabrina • Armus, Lee • Kartaltepe, Jeyhan S. • Kocevski, Dale D. • McIntosh, Daniel H. • Sanders, David B. • Yan, Lin

Abstract • 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 ({L}{IR}={10}11{--}{10}12 {L}), (2) galaxies at z∼ 0.1{--}0.5 from 5MUSES ({L}{IR}={10}10{--}{10}12 {L}), and (3) IR luminous galaxies spanning z=0.5{--}3 from GOODS and Spitzer xFLS ({L}{IR}> {10}11 {L}). All samples have Spitzer mid-IR spectra, and Herschel and ground-based 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 {L}160{SF}/{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.

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Lee_armus

Lee Armus

Senior Scientist