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, Philip Best, Andra Stroe, Huub Röttgering, Iván Oteo, Ian Smail, Leah Morabito, Ana Paulino-Afonso; The CALYMHA survey: Lyα luminosity function and global escape fraction of Lyα photons at z = 2.23. Mon Not R Astron Soc 2017; 466 (1): 1242-1258. doi: 10.1093/mnras/stw3090 is available online at: https://academic.oup.com/mnras/article/466/1/1242/2617718/
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The CALYMHA survey
T2 - Lyα luminosity function and global escape fraction of Lyα photons at z = 2.23
AU - Sobral, David
AU - Matthee, Jorryt
AU - Best, Philip N.
AU - Stroe, Andra
AU - Röttgering, Huub J A
AU - Oteo, Ivàn
AU - Smail, Ian
AU - Morabito, Leah
AU - Paulino-Afonso, Ana
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, Philip Best, Andra Stroe, Huub Röttgering, Iván Oteo, Ian Smail, Leah Morabito, Ana Paulino-Afonso; The CALYMHA survey: Lyα luminosity function and global escape fraction of Lyα photons at z = 2.23. Mon Not R Astron Soc 2017; 466 (1): 1242-1258. doi: 10.1093/mnras/stw3090 is available online at: https://academic.oup.com/mnras/article/466/1/1242/2617718/
PY - 2017/4
Y1 - 2017/4
N2 - We present the CAlibrating LYMan-α with Hα (CALYMHA) pilot survey and new results on Lyman α (Lyα) selected galaxies at z ∼ 2. We use a custom-built Lyα narrow-band filter at the Isaac Newton Telescope, designed to provide a matched volume coverage to the z = 2.23 Hα HiZELS survey. Here, we present the first results for the COSMOS and UDS fields. Our survey currently reaches a 3σ line flux limit of ∼4 × 10−17 erg s−1 cm−2, and a Lyα luminosity limit of ∼1042.3 erg s−1. We find 188 Lyα emitters over 7.3 × 105 Mpc3, but also find significant numbers of other line-emitting sources corresponding to He ii, C iii] and C iv emission lines. These sources are important contaminants, and we carefully remove them, unlike most previous studies. We find that the Lyα luminosity function at z = 2.23 is very well described by a Schechter function up to LLy α ≈ 1043 erg s−1 with L∗=1042.59+0.16−0.08L∗=1042.59−0.08+0.16 erg s−1, ϕ∗=10−3.09+0.14−0.34ϕ∗=10−3.09−0.34+0.14 Mpc−3 and α = −1.75 ± 0.25. Above LLy α ≈ 1043 erg s−1, the Lyα luminosity function becomes power-law like, driven by X-ray AGN. We find that Lyα-selected emitters have a high escape fraction of 37 ± 7 per cent, anticorrelated with Lyα luminosity and correlated with Lyα equivalent width. Lyα emitters have ubiquitous large (≈40 kpc) Lyα haloes, ∼2 times larger than their Hα extents. By directly comparing our Lyα and Hα luminosity functions, we find that the global/overall escape fraction of Lyα photons (within a 13 kpc radius) from the full population of star-forming galaxies is 5.1 ± 0.2 per cent at the peak of the star formation history. An extra 3.3 ± 0.3 per cent of Lyα photons likely still escape, but at larger radii.
AB - We present the CAlibrating LYMan-α with Hα (CALYMHA) pilot survey and new results on Lyman α (Lyα) selected galaxies at z ∼ 2. We use a custom-built Lyα narrow-band filter at the Isaac Newton Telescope, designed to provide a matched volume coverage to the z = 2.23 Hα HiZELS survey. Here, we present the first results for the COSMOS and UDS fields. Our survey currently reaches a 3σ line flux limit of ∼4 × 10−17 erg s−1 cm−2, and a Lyα luminosity limit of ∼1042.3 erg s−1. We find 188 Lyα emitters over 7.3 × 105 Mpc3, but also find significant numbers of other line-emitting sources corresponding to He ii, C iii] and C iv emission lines. These sources are important contaminants, and we carefully remove them, unlike most previous studies. We find that the Lyα luminosity function at z = 2.23 is very well described by a Schechter function up to LLy α ≈ 1043 erg s−1 with L∗=1042.59+0.16−0.08L∗=1042.59−0.08+0.16 erg s−1, ϕ∗=10−3.09+0.14−0.34ϕ∗=10−3.09−0.34+0.14 Mpc−3 and α = −1.75 ± 0.25. Above LLy α ≈ 1043 erg s−1, the Lyα luminosity function becomes power-law like, driven by X-ray AGN. We find that Lyα-selected emitters have a high escape fraction of 37 ± 7 per cent, anticorrelated with Lyα luminosity and correlated with Lyα equivalent width. Lyα emitters have ubiquitous large (≈40 kpc) Lyα haloes, ∼2 times larger than their Hα extents. By directly comparing our Lyα and Hα luminosity functions, we find that the global/overall escape fraction of Lyα photons (within a 13 kpc radius) from the full population of star-forming galaxies is 5.1 ± 0.2 per cent at the peak of the star formation history. An extra 3.3 ± 0.3 per cent of Lyα photons likely still escape, but at larger radii.
KW - galaxies: evolution
KW - galaxies: haloes
KW - galaxies: high-redshift
KW - galaxies: luminosity function
KW - mass function
KW - galaxies: statistics
KW - cosmology: observations
U2 - 10.1093/mnras/stw3090
DO - 10.1093/mnras/stw3090
M3 - Journal article
VL - 466
SP - 1242
EP - 1258
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -