Dust in the reionization era: ALMA observations of a $z$=8.38 Galaxy

Understand

We report on the detailed analysis of a gravitationally-lensed Y-band dropout, A2744_YD4, selected from deep Hubble Space Telescope imaging in the Frontier Field cluster Abell 2744.

• Band 7 observations with the Atacama Large Millimeter Array (ALMA) indicate the proximate detection of a significant 1mm continuum flux suggesting the presence of dust for a star-forming galaxy with a photometric redshift of $z\simeq8$.
• Deep X-SHOOTER spectra confirms the high redshift identity of A2744_YD4 via the detection of Lyman $\alpha$ emission at a redshift $z$=8.38.
• The association with the ALMA detection is confirmed by the presence of [OIII] 88$\mu$m emission at the same redshift.