The dust attenuation law in z ∼ 6 quasars. Issue 3 (8th July 2021)

• Record Type: Journal Article
• Authors: Di Mascia, F; Gallerani, S; Ferrara, A; Pallottini, A; Maiolino, R; Carniani, S; D'Odorico, V
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 506:Issue 3(2021)
• Page Start: 3946
• Page End: 3961
• Publication Date: 2021-07-08
• Subjects: radiative transfer -- methods: numerical -- dust, extinction -- galaxies: ISM -- quasars: general; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab1876
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We investigate the attenuation law in z ∼ 6 quasars by combining cosmological zoom-in hydrodynamical simulations of quasar host galaxies, with multifrequency radiative transfer calculations. We consider several dust models differing in terms of grain-size distributions, dust mass, and chemical composition, and compare the resulting synthetic spectral energy distributions with data from bright, early quasars. We show that only dust models with grain-size distributions in which small grains ($a\lesssim 0.1~\mu {\rm m}$, corresponding to $\approx 60{{\ \rm per\ cent}}$ of the total dust mass) are selectively removed from the dusty medium provide a good fit to the data. Removal can occur if small grains are efficiently destroyed in quasar environments and/or early dust production preferentially results in large grains. Attenuation curves for these models are close to flat, and consistent with recent data; they correspond to an effective dust-to-metal ratio fd ≃ 0.38, i.e. close to the Milky Way value.