Di Mascia, F.F.Di MasciaGallerani, S.S.GalleraniFerrara, A.A.FerraraPallottini, A.A.PallottiniMaiolino, R.R.MaiolinoCarniani, S.S.CarnianiD'ODORICO, ValentinaValentinaD'ODORICO2024-11-142024-11-1420210035-8711http://hdl.handle.net/20.500.12386/35377We 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 f<SUB>d</SUB> ≃ 0.38, i.e. close to the Milky Way value.STAMPAenArticle10.1093/mnras/stab1876https://academic.oup.com/mnras/article/506/3/3946/63176242021MNRAS.506.3946DFIS/05 - ASTRONOMIA E ASTROFISICA