Rights statement: This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version David Sobral, Jorryt Matthee, Behnam Darvish, Ian Smail, Philip N Best, Lara Alegre, Huub Röttgering, Bahram Mobasher, Ana Paulino-Afonso, Andra Stroe, Iván Oteo; The nature of luminous Ly α emitters at z ∼ 2–3: maximal dust-poor starbursts and highly ionizing AGN, Monthly Notices of the Royal Astronomical Society, Volume 477, Issue 2, 21 June 2018, Pages 2817–2840, https://doi.org/10.1093/mnras/sty782 is available online at: https://academic.oup.com/mnras/article/477/2/2817/4953429
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - The nature of luminous Lyman-alpha emitters at z~2-3
T2 - maximal dust-poor starbursts and highly ionising AGN
AU - Sobral, David
AU - Matthee, Jorryt
AU - Darvish, Behnam
AU - Smail, Ian
AU - Best, Philip N.
AU - Alegre, Lara
AU - Röttgering, Huub
AU - Mobasher, Bahram
AU - Paulino-Afonso, Ana
AU - Stroe, Andra
AU - Oteo, Iván
N1 - This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version David Sobral, Jorryt Matthee, Behnam Darvish, Ian Smail, Philip N Best, Lara Alegre, Huub Röttgering, Bahram Mobasher, Ana Paulino-Afonso, Andra Stroe, Iván Oteo; The nature of luminous Ly α emitters at z ∼ 2–3: maximal dust-poor starbursts and highly ionizing AGN, Monthly Notices of the Royal Astronomical Society, Volume 477, Issue 2, 21 June 2018, Pages 2817–2840, https://doi.org/10.1093/mnras/sty782 is available online at: https://academic.oup.com/mnras/article/477/2/2817/4953429
PY - 2018/6/21
Y1 - 2018/6/21
N2 - Deep narrow-band surveys have revealed a large population of faint Ly α emitters (LAEs) in the distant Universe, but relatively little is known about the most luminous sources (LLyα≳1042.7LLyα≳1042.7 erg s−1; LLyα≳L∗LyαLLyα≳LLyα∗). Here we present the spectroscopic follow-up of 21 luminous LAEs at z ∼ 2–3 found with panoramic narrow-band surveys over five independent extragalactic fields (≈4 × 106 Mpc3 surveyed at z ∼ 2.2 and z ∼ 3.1). We use WHT/ISIS, Keck/DEIMOS, and VLT/X-SHOOTER to study these sources using high ionization UV lines. Luminous LAEs at z ∼ 2–3 have blue UV slopes (β=−2.0+0.3−0.1β=−2.0−0.1+0.3) and high Ly α escape fractions (50+20−1550−15+20 per cent) and span five orders of magnitude in UV luminosity (MUV ≈ −19 to −24). Many (70 per cent) show at least one high ionization rest-frame UV line such as C IV, N V, C III], He II or O III], typically blue-shifted by ≈100–200 km s−1 relative to Ly α. Their Ly α profiles reveal a wide variety of shapes, including significant blue-shifted components and widths from 200 to 4000 km s−1. Overall, 60 ± 11 per cent appear to be active galactic nucleus (AGN) dominated, and at LLyα > 1043.3 erg s−1 and/or MUV < −21.5 virtually all LAEs are AGNs with high ionization parameters (log U = 0.6 ± 0.5) and with metallicities of ≈0.5 − 1 Z⊙. Those lacking signatures of AGNs (40 ± 11 per cent) have lower ionization parameters (logU=−3.0+1.6−0.9logU=−3.0−0.9+1.6and log ξion = 25.4 ± 0.2) and are apparently metal-poor sources likely powered by young, dust-poor ‘maximal’ starbursts. Our results show that luminous LAEs at z ∼ 2–3 are a diverse population and that 2×L∗Lyα2×LLyα∗ and 2×M∗UV2×MUV∗ mark a sharp transition in the nature of LAEs, from star formation dominated to AGN dominated.
AB - Deep narrow-band surveys have revealed a large population of faint Ly α emitters (LAEs) in the distant Universe, but relatively little is known about the most luminous sources (LLyα≳1042.7LLyα≳1042.7 erg s−1; LLyα≳L∗LyαLLyα≳LLyα∗). Here we present the spectroscopic follow-up of 21 luminous LAEs at z ∼ 2–3 found with panoramic narrow-band surveys over five independent extragalactic fields (≈4 × 106 Mpc3 surveyed at z ∼ 2.2 and z ∼ 3.1). We use WHT/ISIS, Keck/DEIMOS, and VLT/X-SHOOTER to study these sources using high ionization UV lines. Luminous LAEs at z ∼ 2–3 have blue UV slopes (β=−2.0+0.3−0.1β=−2.0−0.1+0.3) and high Ly α escape fractions (50+20−1550−15+20 per cent) and span five orders of magnitude in UV luminosity (MUV ≈ −19 to −24). Many (70 per cent) show at least one high ionization rest-frame UV line such as C IV, N V, C III], He II or O III], typically blue-shifted by ≈100–200 km s−1 relative to Ly α. Their Ly α profiles reveal a wide variety of shapes, including significant blue-shifted components and widths from 200 to 4000 km s−1. Overall, 60 ± 11 per cent appear to be active galactic nucleus (AGN) dominated, and at LLyα > 1043.3 erg s−1 and/or MUV < −21.5 virtually all LAEs are AGNs with high ionization parameters (log U = 0.6 ± 0.5) and with metallicities of ≈0.5 − 1 Z⊙. Those lacking signatures of AGNs (40 ± 11 per cent) have lower ionization parameters (logU=−3.0+1.6−0.9logU=−3.0−0.9+1.6and log ξion = 25.4 ± 0.2) and are apparently metal-poor sources likely powered by young, dust-poor ‘maximal’ starbursts. Our results show that luminous LAEs at z ∼ 2–3 are a diverse population and that 2×L∗Lyα2×LLyα∗ and 2×M∗UV2×MUV∗ mark a sharp transition in the nature of LAEs, from star formation dominated to AGN dominated.
KW - astro-ph.GA
KW - astro-ph.CO
KW - galaxies: active
KW - galaxies: evolution
KW - galaxies: high-redshift
KW - galaxies: ISM
KW - galaxies: starburst
KW - cosmology: observations
U2 - 10.1093/mnras/sty782
DO - 10.1093/mnras/sty782
M3 - Journal article
VL - 477
SP - 2817
EP - 2840
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -