Into the Lyα jungle: exploring the circumgalactic medium of galaxies at z ∼ 4 − 5 with MUSE

Bielby, Richard M; Fumagalli, Michele; Fossati, Matteo; Rafelski, Marc; Oppenheimer, Benjamin; Cantalupo, Sebastiano; Christensen, Lise; Fynbo, JPU; Lopez, Sebastian; Morris, Simon L; D’Odorico, Valentina; Peroux, Celine

doi:10.1093/mnras/staa546

Into the Lyα jungle: exploring the circumgalactic medium of galaxies at z ∼ 4 − 5 with MUSE

Bielby, Richard M; Fumagalli, Michele; Fossati, Matteo; Rafelski, Marc; Oppenheimer, Benjamin; Cantalupo, Sebastiano; Christensen, Lise; Fynbo, JPU; Lopez, Sebastian; Morris, Simon L; D’Odorico, Valentina; Peroux, Celine

Authors

Richard M Bielby

Professor Michele Fumagalli michele.fumagalli@durham.ac.uk
Academic Visitor

Matteo Fossati

Marc Rafelski

Benjamin Oppenheimer

Sebastiano Cantalupo

Lise Christensen

JPU Fynbo

Sebastian Lopez

Professor Simon Morris simon.morris@durham.ac.uk
Professor

Valentina D’Odorico

Celine Peroux

Abstract

We present a study of the galaxy environment of 9 strong H I+C IV absorption line systems (16.2 < log(N(HI)) < 21.2) spanning a wide range in metallicity at z ∼ 4 − 5, using MUSE integral field and X-Shooter spectroscopic data collected in a z ≈ 5.26 quasar field. We identify galaxies within a 250 kpc and ±1000 km s−1 window for 6 out of the 9 absorption systems, with 2 of the absorption line systems showing multiple associated galaxies within the MUSE field of view. The space density of Lyα emitting galaxies (LAEs) around the H I and C IV systems is ≈10 − 20 times the average sky density of LAEs given the flux limit of our survey, showing a clear correlation between the absorption and galaxy populations. Further, we find that the strongest C IV systems in our sample are those that are most closely aligned with galaxies in velocity space, i.e. within velocities of ±500 km s−1. The two most metal poor systems lie in the most dense galaxy environments, implying we are potentially tracing gas that is infalling for the first time into star-forming groups at high redshift. Finally, we detect an extended Lyα nebula around the z ≈ 5.26 quasar, which extends up to ≈50 kpc at the surface brightness limit of 3.8 × 10−18 erg s−1 cm−2 arcsec−2. After scaling for surface brightness dimming, we find that this nebula is centrally brighter, having a steeper radial profile than the average for nebulae studied at z ∼ 3 and is consistent with the mild redshift evolution seen from z ≈ 2.

Citation

Bielby, R. M., Fumagalli, M., Fossati, M., Rafelski, M., Oppenheimer, B., Cantalupo, S., …Peroux, C. (2020). Into the Lyα jungle: exploring the circumgalactic medium of galaxies at z ∼ 4 − 5 with MUSE. Monthly Notices of the Royal Astronomical Society, 493(4), 5336-5356. https://doi.org/10.1093/mnras/staa546

Journal Article Type	Article
Acceptance Date	Feb 15, 2020
Online Publication Date	Mar 3, 2020
Publication Date	Apr 30, 2020
Deposit Date	Mar 3, 2020
Publicly Available Date	Mar 3, 2020
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	493
Issue	4
Pages	5336-5356
DOI	https://doi.org/10.1093/mnras/staa546

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Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.