GOODS-<i>HERSCHEL</i>MEASUREMENTS OF THE DUST ATTENUATION OF TYPICAL STAR-FORMING GALAXIES AT HIGH REDSHIFT: OBSERVATIONS OF ULTRAVIOLET-SELECTED GALAXIES AT<i>z</i>∼ 2

Abstract

We take advantage of the sensitivity and resolution of Herschel at 100 and\n160 micron to directly image the thermal dust emission and investigate the\ninfrared luminosities, L(IR), and dust obscuration of typical star-forming (L*)\ngalaxies at high redshift. Our sample consists of 146 UV-selected galaxies with\nspectroscopic redshifts 1.5&lt;z&lt;2.6 in the GOODS-North field. Supplemented with\ndeep Very Large Array (VLA) and Spitzer imaging, we construct median stacks at\nthe positions of these galaxies at 24, 100, and 160 micron, and 1.4 GHz. The\ncomparison between these stacked fluxes and a variety of dust templates and\ncalibrations implies that typical star-forming galaxies with UV luminosities\nL(UV)&gt;1e10 Lsun at z~2 are luminous infrared galaxies (LIRGs) with a median\nL(IR)=(2.2+/-0.3)e11 Lsun. Typical galaxies at 1.5&lt;z&lt;2.6 have a median dust\nobscuration L(IR)/L(UV) = 7.1+/-1.1, which corresponds to a dust correction\nfactor, required to recover the bolometric star formation rate (SFR) from the\nunobscured UV SFR, of 5.2+/-0.6. This result is similar to that inferred from\nprevious investigations of the UV, H-alpha, 24 micron, radio, and X-ray\nproperties of the same galaxies studied here. Stacking in bins of UV slope\nimplies that L* galaxies with redder spectral slopes are also dustier, and that\nthe correlation between UV slope and dustiness is similar to that found for\nlocal starburst galaxies. Hence, the rest-frame 30 and 50 micron fluxes\nvalidate on average the use of the local UV attenuation curve to recover the\ndust attenuation of typical star-forming galaxies at high redshift. In the\nsimplest interpretation, the agreement between the local and high redshift UV\nattenuation curves suggests a similarity in the dust production and stellar and\ndust geometries of starburst galaxies over the last 10 billion years.\n