Galaxy Formation Through Filamentary Accretion at z=6.1

Abstract

We present ALMA observations of the dust continuum and [C II] 158um line emission from the z=6.0695 Lyman Break Galaxy WMH5. These observations at 0.3" spatial resolution show a compact (~3kpc) main galaxy in dust and [C II] emission, with a 'tail' of emission extending to the east by about 5kpc (in projection). The [C II] tail is comprised predominantly of two distinct sub-components in velocity, separated from the core by ~100 and 250km/s, with narrow intrinsic widths of about 80km/s, which we call 'sub-galaxies'. The sub-galaxies themselves are extended east-west by about 3kpc in individual channel images. The [C II] tail joins smoothly into the main galaxy velocity field. The [C II] line to continuum ratios are comparable for the main and sub-galaxy positions, within a factor 2. In addition, these ratios are comparable to z~5.5 LBGs. We conjecture that the WMH5 system represents the early formation of a galaxy through the accretion of smaller satellite galaxies, embedded in a smoother gas distribution, along a possibly filamentary structure. The results are consistent with current cosmological simulations of early galaxy formation, and support the idea of very early enrichment with dust and heavy elements of the accreting material.

arXiv comment10 pages, 9 figures, Accepted for publication in ApJ

References in corpus (22)

• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Cool Gas in High Redshift Galaxies
• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• Observational constraints on Cosmic Reionization
• The Interstellar Medium In Galaxies Seen A Billion Years After The Big Bang
• The applicability of FIR fine-structure lines as Star Formation Rate tracers over wide ranges of metallicities and galaxy types
• A Herschel [CII] Galactic plane survey I: the global distribution of ISM gas components
• The VISTA Deep Extragalactic Observations (VIDEO) Survey
• Dust in the reionization era: ALMA observations of a $z$=8.38 Galaxy
• [CII] 158 $\mu$m Emission as a Star Formation Tracer
• On the [CII]-SFR relation in high redshift galaxies
• Star formation and the interstellar medium in z>6 UV-luminous Lyman-break galaxies
• Zooming on the internal structure of $z\simeq 6$ galaxies
• A Herschel [CII] Galactic plane survey III: [CII] as a tracer of star formation
• Interpreting ALMA Observations of the ISM During the Epoch of Reionisation
• Vindicating single-T modified blackbody fits to Herschel SEDs (Research Note)
• The Global History of Reionisation
• Far-infrared and Molecular CO Emission From the Host Galaxies of Faint Quasars at z~6
• ALMA suggests outflows in z~5.5 galaxies
• FIR line emission from high redshift galaxies
• [CII] 158 micron Emission from the Host Galaxies of Damped Lyman Alpha Systems
• An exponential decline at the bright end of the z=6 galaxy luminosity function

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