Boötes-HiZELS: an optical to near-infrared survey of emission-line galaxies at z = 0.4-4.7

Matthee, J.; Sobral, D.; Best, P.; Smail, I.; Bian, F.; Darvish, B.; Röttgering, H.; Fan, X.

Abstract

We present a sample of ∼1000 emission-line galaxies at z = 0.4–4.7 from the ∼0.7deg2 High-z Emission-Line Survey in the Boötes field identified with a suite of six narrow-band filters at ≈0.4–2.1 μm. These galaxies have been selected on their Ly α (73), [O II] (285), H β/[O III] (387) or H α (362) emission line, and have been classified with optical to near-infrared colours. A subsample of 98 sources have reliable redshifts from multiple narrow-band (e.g. [O II]–H α) detections and/or spectroscopy. In this survey paper, we present the observations, selection and catalogues of emitters. We measure number densities of Ly α, [O II], H β/[O III] and H α and confirm strong luminosity evolution in star-forming galaxies from z ∼ 0.4 to ∼5, in agreement with previous results. To demonstrate the usefulness of dual-line emitters, we use the sample of dual [O II]–H α emitters to measure the observed [O II]/H α ratio at z = 1.47. The observed [O II]/H α ratio increases significantly from 0.40 ± 0.01 at z = 0.1 to 0.52 ± 0.05 at z = 1.47, which we attribute to either decreasing dust attenuation with redshift, or due to a bias in the (typically) fibre measurements in the local Universe that only measure the central kpc regions. At the bright end, we find that both the H α and Ly α number densities at z ≈ 2.2 deviate significantly from a Schechter form, following a power law. We show that this is driven entirely by an increasing X-ray/active galactic nucleus fraction with line luminosity, which reaches ≈100 per cent at line luminosities L ≳ 3 × 1044 erg s−1.

Citation

Matthee, J., Sobral, D., Best, P., Smail, I., Bian, F., Darvish, B., …Fan, X. (2017). Boötes-HiZELS: an optical to near-infrared survey of emission-line galaxies at z = 0.4-4.7. Monthly Notices of the Royal Astronomical Society, 471(1), 629-649. https://doi.org/10.1093/mnras/stx1569

• Journal Article Type: Article
• Acceptance Date: Jun 20, 2017
• Online Publication Date: Jun 22, 2017
• Publication Date: Jun 22, 2017
• Deposit Date: Aug 21, 2017
• Publicly Available Date: Aug 22, 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: 471
• Issue: 1
• Pages: 629-649
• DOI: https://doi.org/10.1093/mnras/stx1569
• Public URL: https://durham-repository.worktribe.com/output/1370854
• Publisher URL: http://ukads.nottingham.ac.uk/abs/2017MNRAS.471..629M