2017/02/28 by Jorryt Matthee, David Sobral, P. N. Best +7 · 2 citations
Environmental Science · Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Doubly ionized oxygen #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Line (geometry) #Luminosity #Luminous infrared galaxy #Physics #Plant Water Relations and Carbon Dynamics #Redshift #Spectral line #Spectroscopy #Star formation #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stx1569
Accepted for publication in MNRAS. Main text 16 pages, 7 Figures. Catalogues of line-emitters available
openalex created_date 2017/03/03 · openalex publication_date 2017/06/21 · arxiv created 2017/06/22 · arxiv updated 2017/08/09 · openalex updated_date 2026/08/05
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.