Dual constraints with ALMA: new [O III] 88 ${\rm \mu}$m and dust-continuum observations reveal the ISM conditions of luminous LBGs at $z \sim 7$
| Autor: | Joris Witstok, Renske Smit, Roberto Maiolino, Nimisha Kumari, Manuel Aravena, Leindert Boogaard, Rychard Bouwens, Stefano Carniani, Jacqueline A Hodge, Gareth C Jones, Mauro Stefanon, Paul van der Werf, Sander Schouws |
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| Přispěvatelé: | Witstok, Joris [0000-0002-7595-121X], Maiolino, Roberto [0000-0002-4985-3819], Apollo - University of Cambridge Repository, Witstok, Jori, Smit, Renske, Maiolino, Roberto, Kumari, Nimisha, Aravena, Manuel, Boogaard, Leindert, Bouwens, Rychard, Carniani, Stefano, Hodge, Jacqueline A., Jones, Gareth C., Stefanon, Mauro, van der Werf, Paul, Schouws, Sander |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
dark age
interstellar-medium astro-ph.GA FOS: Physical sciences C II emission star-forming galaxie line emission Astrophysics::Cosmology and Extragalactic Astrophysics photometric redshift Submillimetre - ISM Settore FIS/05 - Astronomia e Astrofisica Reionization Astrophysics::Solar and Stellar Astrophysics observational [Methods] ISM [submillimetre] QC Astrophysics::Galaxy Astrophysics Galaxies - high-redshift QB First stars Methods - observational first star Astronomy and Astrophysics imaging spectroscopy [techniques] Astrophysics - Astrophysics of Galaxies Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Dark ages Techniques - imaging spectroscopy reionization Astrophysics::Earth and Planetary Astrophysics high-redshift [galaxies] |
| Zdroj: | Monthly Notices of the Royal Astronomical Society, 515(2), 1751-1773 |
| ISSN: | 0035-8711 |
| Popis: | We present new [O III] 88 ${\rm \mu}$m observations of five bright $z \sim 7$ Lyman-break galaxies spectroscopically confirmed by ALMA through the [C II] 158 ${\rm \mu}$m line, unlike recent [O III] detections where Lyman-${\rm \alpha}$ was used. This nearly doubles the sample of Epoch of Reionisation galaxies with robust ($5 \sigma$) detections of [C II] and [O III]. We perform a multi-wavelength comparison with new deep HST images of the rest-frame UV, whose compact morphology aligns well with [O III] tracing ionised gas. By contrast, we find more spatially extended [C II] emission likely produced in neutral gas, as indicated by a [N II] 205 ${\rm \mu}$m non-detection in one source. We find a positive correlation between the equivalent width of the optical [O III] and H${\rm \beta}$ lines and the [O III]/[C II] ratio, as seen in local metal-poor dwarf galaxies. Cloudy models of a nebula of typical density harbouring a young stellar population with a high ionisation parameter appear to adequately reproduce the far-infrared lines. Surprisingly, however, our models fail to reproduce the strength of [O III] 88 ${\rm \mu}$m, unless we assume an ${\rm \alpha}$/Fe enhancement and a near-solar nebular oxygen abundance. On spatially resolved scales, we find [O III]/[C II] shows a tentative anti-correlation with infrared excess, $L_{\rm IR}/L_{\rm UV}$, also seen on global scales in the local Universe. Finally, we introduce the far-infrared spectral energy distribution fitting code MERCURIUS to show that dust-continuum measurements of one source appear to favour a low dust temperature coupled with a high dust mass. This implies a high stellar metallicity yield and may point towards the need of dust production or grain-growth mechanisms beyond supernovae. Comment: 23 pages, 11 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society |
| Databáze: | OpenAIRE |
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