Publication Date:
2021-09-09
Description:
We report ALMA Band 9 continuum observations of the normal, dusty star-forming galaxy A1689-zD1 at z = 7.13, resulting in a ∼4.6 σ detection at 702 GHz. For the first time, these observations probe the far-infrared spectrum shortward of the emission peak of a galaxy in the Epoch of Reionization (EoR). Together with ancillary data from earlier works, we derive the dust temperature, Td, and mass, Md, of A1689-zD1 using both traditional modified blackbody spectral energy density fitting, and a new method that relies only on the [C ii] 158 μm line and underlying continuum data. The two methods give $T_{
m d} = (42^{+13}_{-7}, 40^{+13}_{-7}$) K, and $M_{
m d} = (1.7^{+1.3}_{-0.7}, 2.0^{+1.8}_{-1.0}), imes {}, 10^{7} , mathrm{ M}_{odot }$. Band 9 observations improve the accuracy of the dust temperature (mass) estimate by ∼50 per cent (6 times). The derived temperatures confirm the reported increasing Td-redshift trend between z = 0 and 8; the dust mass is consistent with a supernova origin. Although A1689-zD1 is a normal UV-selected galaxy, our results, implying that ∼85 per cent of its star-formation rate is obscured, underline the non-negligible effects of dust in EoR galaxies.
Print ISSN:
1745-3925
Electronic ISSN:
1745-3933
Topics:
Physics
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