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 Jorryt Matthee, David Sobral, Iván Oteo, Philip Best, Ian Smail, Huub Röttgering, Ana Paulino-Afonso; The CALYMHA survey: Lyα escape fraction and its dependence on galaxy properties at z = 2.23. Mon Not R Astron Soc 2016; 458 (1): 449-467. doi: 10.1093/mnras/stw322 is available online at: https://academic.oup.com/mnras/article/458/1/449/2622889/
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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 CALYMHA survey
T2 - Lyα escape fraction and its dependence on galaxy properties at z = 2.23
AU - Matthee, Jorryt
AU - Sobral, David
AU - Best, Philip
AU - Stroe, Andra
AU - Röttgering, Huub
AU - Oteo, Iván
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 Jorryt Matthee, David Sobral, Iván Oteo, Philip Best, Ian Smail, Huub Röttgering, Ana Paulino-Afonso; The CALYMHA survey: Lyα escape fraction and its dependence on galaxy properties at z = 2.23. Mon Not R Astron Soc 2016; 458 (1): 449-467. doi: 10.1093/mnras/stw322 is available online at: https://academic.oup.com/mnras/article/458/1/449/2622889/ 19 pages, 11 figures. Accepted for publication in MNRAS.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - We present the CAlibrating LYMan-$\alpha$ with H$\alpha$ (CALYMHA) pilot survey and new results on Lyman-$\alpha$ (Lya) selected galaxies at z~2. We use a custom-built Lya narrow-band filter at the Isaac Newton Telescope, designed to provide a matched volume coverage to the z=2.23 Ha HiZELS survey. Here we present the first results for the COSMOS and UDS fields. Our survey currently reaches a 3$\sigma$ line flux limit of ~4x10$^{-17}$ erg/s/cm$^{2}$, and a Lya luminosity limit of ~10$^{42.3}$ erg/s. We find 188 Lya emitters over 7.3x10$^5$ Mpc$^{3}$, but also find significant numbers of other line emitting sources corresponding to HeII, CIII] and CIV emission lines. These sources are important contaminants, and we carefully remove them, unlike most previous studies. We find that the Lya luminosity function at z=2.23 is very well described by a Schechter function up to L~10$^{43}$ erg/s with L$^*=10^{42.59+-0.05}$ erg/s, $\phi^*=10^{-3.09+-0.08}$ Mpc$^{-3}$ and $\alpha$=-1.75+-0.15. Above L~10$^{43}$ erg/s the Lya luminosity function becomes power-law like, driven by X-ray AGN. We find that Lya-selected emitters have a high escape fraction of 37+-7%, anti-correlated with Lya luminosity and correlated with Lya equivalent width. Lya emitters have ubiquitous large (~40 kpc) Lya haloes, 2x larger than their Ha extents. By directly comparing our Lya and Ha luminosity functions we find that the global/overall escape fraction of Lya photons (within a 13 kpc radius) from the full population of star-forming galaxies is 5.1+-0.2% at the peak of the star formation history. An extra 3.3+-0.3% of Lya photons likely still escape, but at larger radii.
AB - We present the CAlibrating LYMan-$\alpha$ with H$\alpha$ (CALYMHA) pilot survey and new results on Lyman-$\alpha$ (Lya) selected galaxies at z~2. We use a custom-built Lya narrow-band filter at the Isaac Newton Telescope, designed to provide a matched volume coverage to the z=2.23 Ha HiZELS survey. Here we present the first results for the COSMOS and UDS fields. Our survey currently reaches a 3$\sigma$ line flux limit of ~4x10$^{-17}$ erg/s/cm$^{2}$, and a Lya luminosity limit of ~10$^{42.3}$ erg/s. We find 188 Lya emitters over 7.3x10$^5$ Mpc$^{3}$, but also find significant numbers of other line emitting sources corresponding to HeII, CIII] and CIV emission lines. These sources are important contaminants, and we carefully remove them, unlike most previous studies. We find that the Lya luminosity function at z=2.23 is very well described by a Schechter function up to L~10$^{43}$ erg/s with L$^*=10^{42.59+-0.05}$ erg/s, $\phi^*=10^{-3.09+-0.08}$ Mpc$^{-3}$ and $\alpha$=-1.75+-0.15. Above L~10$^{43}$ erg/s the Lya luminosity function becomes power-law like, driven by X-ray AGN. We find that Lya-selected emitters have a high escape fraction of 37+-7%, anti-correlated with Lya luminosity and correlated with Lya equivalent width. Lya emitters have ubiquitous large (~40 kpc) Lya haloes, 2x larger than their Ha extents. By directly comparing our Lya and Ha luminosity functions we find that the global/overall escape fraction of Lya photons (within a 13 kpc radius) from the full population of star-forming galaxies is 5.1+-0.2% at the peak of the star formation history. An extra 3.3+-0.3% of Lya photons likely still escape, but at larger radii.
KW - astro-ph.GA
KW - astro-ph.CO
KW - Galaxies: high-redshift
KW - luminosity function, mass function
KW - evolution
KW - quasars
KW - emission lines
KW - cosmology
KW - observations
M3 - Journal article
VL - 458
SP - 449
EP - 467
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -