Dual constraints with ALMA: new [O III] 88 $\mu$m and dust-continuum observations reveal the ISM conditions of luminous LBGs at $z\sim 7$

Abstract

We present new [O III] 88 $\mu$m observations of five bright $z\sim 7$ Lyman-break galaxies spectroscopically confirmed by ALMA through the [C II] 158 $\mu$m line, unlike recent [O III] detections where Lyman-$\alpha$ 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 $\mu$m non-detection in one source. We find a positive correlation between the equivalent width of the optical [O III] and H$\beta$ 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 $\mu$m, unless we assume an $\alpha$/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, $L_{\mathrm{IR}}/L_{\mathrm{UV}}$, 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.

23 pages, 11 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society

References in corpus (34)

• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• Cosmic Star Formation History
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• UltraVISTA: a new ultra-deep near-infrared survey in COSMOS
• Understanding Galaxy Evolution through Emission Lines
• A dusty, normal galaxy in the epoch of reionization
• Dust in the reionization era: ALMA observations of a $z$=8.38 Galaxy
• Fragmentation of star-forming clouds enriched with the first dust
• The Herschel Dwarf Galaxy Survey: I. Properties of the low-metallicity ISM from PACS spectroscopy
• Dust temperature and mid-to-total infrared color distributions for star-forming galaxies at 0<z<4
• High-precision Photometric Redshifts from Spitzer/IRAC: Extreme [3.6]-[4.5] Colors Identify Galaxies in the Redshift Range z~6.6-6.9
• Deep into the structure of the first galaxies: SERRA views
• Normal, Dust-Obscured Galaxies in the Epoch of Reionization
• Dust attenuation, dust emission, and dust temperature in galaxies at z>=5: a view from the FIRE-2 simulations
• The REBELS ALMA Survey: cosmic dust temperature evolution out to z $\sim$ 7
• Dust production 680-850 million years after the Big Bang
• The Herschel Dwarf Galaxy Survey: II. Physical conditions, origin of [CII] emission, and porosity of the multiphase low-metallicity ISM
• ALMA Characterises the Dust Temperature of z ~ 5.5 Star-Forming Galaxies
• Probing Cosmic Dawn with Emission Lines: Predicting Infrared and Nebular Line Emission for ALMA and JWST
• Dust production scenarios in galaxies at z ~ 6-8.3
• Accurate dust temperature determination in a $z=7.13$ galaxy
• ALMA Reveals Weak [NII] Emission in "Typical" Galaxies and Intense Starbursts at z=5-6
• New Methods for Identifying Lyman Continuum Leakers and Reionization-Epoch Analogues
• Constraining dust formation in high-redshift young galaxies
• Radiative equilibrium estimates of dust temperature and mass in high-redshift galaxies
• High [OIII]/[CII] surface brightness ratios trace early starburst galaxies
• Assessing the sources of reionisation: a spectroscopic case study of a 30$\times$ lensed galaxy at $z\sim 5$ with Lyα, CIV, MgII, and [NeIII]
• No Redshift Evolution of Dust Temperatures from $0<z<2$
• Populating H${}_2$ and CO in galaxy simulation with dust evolution
• The Detection of Ionized Carbon Emission at z~8
• Multi-Phase ISM in the z = 5.7 Hyperluminous Starburst SPT0346-52
• Gas and Star Formation from HD and Dust Emission in a Strongly Lensed Galaxy

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