Detections of far-infrared [O III] and dust emission in a galaxy at z = 8.312: Early metal enrichment in the heart of the reionization era
Abstract
We present ALMA detection of the [O III] 88 μm line and 850 μm dust continuum emission in a Y-dropout Lyman break galaxy, MACS0416_Y1. The [O III] detection confirms the object with a spectroscopic redshift to be z = 8.3118±0.0003. The 850 μm continuum intensity (0.14 mJy) implies a large dust mass on the order of 4×106M⊙. The ultraviolet-to-far infrared spectral energy distribution modeling, where the [O III] emissivity model is incorporated, suggests the presence of a young (τage ≈ 4 Myr), star-forming (SFR ≈ 60M⊙yr-1), and moderately metal-polluted (Z ≈ 0.2Z⊙) stellar component with a stellar mass of 3 × 108M⊙. An analytic dust mass evolution model with a single episode of star formation does not reproduce the metallicity and dust mass in ≈ 4 Myr, suggesting an underlying evolved stellar component as the origin of the dust mass.
- Publication:
-
Panchromatic Modelling with Next Generation Facilities
- Pub Date:
- 2020
- DOI:
- 10.1017/S1743921319002436
- Bibcode:
- 2020IAUS..341..211T
- Keywords:
-
- galaxies: formation;
- galaxies: high-redshift;
- galaxies: ISM