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

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., Christensen, L., Fynbo, J., Lopez, S., Morris, S. L., D’Odorico, V., & 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
• Public URL: https://durham-repository.worktribe.com/output/1275923