A gravitationally boosted MUSE survey for emission-line galaxies at z ≳ 5 behind the massive cluster RCS 0224

Smit, Renske; Swinbank, A.M.; Massey, Richard; Richard, Johan; Smail, Ian; Kneib, J.-P.

Abstract

We present a Very Large Telescope/Multi Unit Spectroscopic Explorer (MUSE) survey of lensed high-redshift galaxies behind the z = 0.77 cluster RCS 0224−0002. We study the detailed internal properties of a highly magnified (μ ∼ 29) z = 4.88 galaxy seen through the cluster. We detect widespread nebular C iv λλ1548,1551 Å emission from this galaxy as well as a bright Lyα halo with a spatially uniform wind and absorption profile across 12 kpc in the image plane. Blueshifted high- and low-ionization interstellar absorption indicate the presence of a high-velocity outflow (Δv ∼ 300 km s− 1) from the galaxy. Unlike similar observations of galaxies at z ∼ 2 − 3, the Lyα emission from the halo emerges close to the systemic velocity – an order of magnitude lower in velocity offset than predicted in ‘shell’-like outflow models. To explain these observations, we favour a model of an outflow with a strong velocity gradient, which changes the effective column density seen by the Lyα photons. We also search for high-redshift Lyα emitters and identify 14 candidates between z = 4.8 − 6.6, including an overdensity at z = 4.88, of which only one has a detected counterpart in Hubble Space Telescope/Advanced Camera for Surveys+Wide Field Camera 3 imaging.

Citation

Smit, R., Swinbank, A., Massey, R., Richard, J., Smail, I., & Kneib, J. (2017). A gravitationally boosted MUSE survey for emission-line galaxies at z ≳ 5 behind the massive cluster RCS 0224. Monthly Notices of the Royal Astronomical Society, 476(3), 3306-3323. https://doi.org/10.1093/mnras/stx245

• Journal Article Type: Article
• Acceptance Date: Jan 26, 2017
• Online Publication Date: Mar 7, 2017
• Publication Date: Jun 1, 2017
• Deposit Date: Mar 9, 2017
• Publicly Available Date: Mar 9, 2017
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 476
• Issue: 3
• Pages: 3306-3323
• DOI: https://doi.org/10.1093/mnras/stx245
• Public URL: https://durham-repository.worktribe.com/output/1361901