Dust attenuation in Ultra Dusty Star-Forming galaxies up to z ∼ 4

Despite its low contribution to the total mass of the interstellar medium (ISM), dust plays a crucial role in the evolution of galaxies. Moreover, the dust properties have crucial impact on the shape of the galaxy spectral energy distribution. The affluence of infrared and radio detections of millions of galaxies in the COSMOS field, provided by powerful instruments such as Herschel and ALMA, has allowed to study the cold dust in galaxies over a wide range of redshift. A key element in reproducing the total spectral energy distribution of galaxies, is assuming a dust attenuation law which accounts for the behavior and the imprints of dust in the ISM. However, different studies have shown that widely used in the literature single law cannot fully model dust in a large sample of galaxies. This non-universality of attenuation laws should be considered in order to accurately account for dust, and therefore in deriving the physical properties of galaxies. In this work, we study different attenuation laws in a statistical sample of ALMA-detected galaxies in the COSMOS field. We probe the resulting variation of key physical properties of these galaxies such as the stellar mass and spatial extent of the dust continuum and the implication that it might have on the attenuation curve. We find that a bouquet of attenuation curves must be used in order to reproduce the UV spectrum. Although these curves are not redshift dependent, they are correlated to the relative spatial distribution to the stellar population of heavily dust-obscured galaxies.