@article{bouwens_lyman-continuum_2015,
	title = {The {Lyman}-{Continuum} {Photon} {Production} {Efficiency} xi\_\{ion\} of z{\textasciitilde}4-5 {Galaxies} from {IRAC}-based {Halpha} {Measurements}: {Implications} for the {Escape} {Fraction} and {Cosmic} {Reionization}},
	shorttitle = {The {Lyman}-{Continuum} {Photon} {Production} {Efficiency} xi\_\{ion\} of z{\textasciitilde}4-5 {Galaxies} from {IRAC}-based {Halpha} {Measurements}},
	url = {http://arxiv.org/abs/1511.08504},
	abstract = {Galaxies represent one of the preferred candidate sources to drive the reionization of the universe. Even as gains are made in mapping the galaxy UV luminosity density to z{\textgreater}6, significant uncertainties remain regarding the conversion to the implied ionizing emissivity. The relevant unknowns are the Lyman-continuum (LyC) photon production efficiency xi\_\{ion\} and the escape fraction f\_\{esc\}. As we show here, the first of these unknowns is directly measureable in z=4-5 galaxies, based on the impact the Halpha line has on the observed IRAC fluxes. By computing a LyC photon production rate from the implied Halpha luminosities for a broad selection of z=4-5 galaxies and comparing this against the dust-corrected UV-continuum luminosities, we provide the first-ever direct estimates of the LyC photon production efficiency xi\_\{ion\} for the z{\textgreater}{\textasciitilde}4 galaxy population. We find log\_\{10\} xi\_\{ion\}/[Hz/ergs] to have a mean value of 25.28\_\{-0.09\}{\textasciicircum}\{+0.10\} and 25.34\_\{-0.08\}{\textasciicircum}\{+0.09\} for sub-L* z=4-5 galaxies adopting Calzetti and SMC dust laws, respectively. Reassuringly, both values are consistent with standardly assumed xi\_\{ion\}'s in reionization models, with a slight preference for higher xi\_\{ion\}'s (by {\textasciitilde}0.1 dex) adopting the SMC dust law. A modest {\textasciitilde}0.03-dex increase in these estimates would result if the escape fraction for ionizing photons is non-zero and galaxies dominate the ionizing emissivity at z{\textasciitilde}4.4. High values of xi\_\{ion\} ({\textasciitilde}25.5-25.9 dex) are derived for the bluest galaxies (beta{\textless}-2.3) in our samples, independent of dust law and consistent with results for a z=7.045 galaxy. Such elevated values of xi\_\{ion\} would have important consequences, indicating that f\_\{esc\} cannot be in excess of 13\% unless the galaxy UV luminosity function does not extend down to -13 mag or the clumping factor is greater than 3. A low escape fraction would fit well with the low rate of LyC leakage observed at z{\textasciitilde}3.},
	urldate = {2016-01-27},
	journal = {arXiv:1511.08504 [astro-ph]},
	author = {Bouwens, R. J. and Smit, R. and Labbe, I. and Franx, M. and Caruana, J. and Oesch, P. and Stefanon, M. and Rasappu, N.},
	month = nov,
	year = {2015},
	note = {arXiv: 1511.08504},
	keywords = {Astrophysics - Astrophysics of Galaxies},
}

{"_id":"25GmLCutnodxNx3ve","bibbaseid":"bouwens-smit-labbe-franx-caruana-oesch-stefanon-rasappu-thelymancontinuumphotonproductionefficiencyxiionofztextasciitilde45galaxiesfromiracbasedhalphameasurementsimplicationsfortheescapefractionandcosmicreionization-2015","author_short":["Bouwens, R. J.","Smit, R.","Labbe, I.","Franx, M.","Caruana, J.","Oesch, P.","Stefanon, M.","Rasappu, N."],"bibdata":{"bibtype":"article","type":"article","title":"The Lyman-Continuum Photon Production Efficiency xi_\\ion\\ of z\\textasciitilde4-5 Galaxies from IRAC-based Halpha Measurements: Implications for the Escape Fraction and Cosmic Reionization","shorttitle":"The Lyman-Continuum Photon Production Efficiency xi_\\ion\\ of z\\textasciitilde4-5 Galaxies from IRAC-based Halpha Measurements","url":"http://arxiv.org/abs/1511.08504","abstract":"Galaxies represent one of the preferred candidate sources to drive the reionization of the universe. Even as gains are made in mapping the galaxy UV luminosity density to z\\textgreater6, significant uncertainties remain regarding the conversion to the implied ionizing emissivity. The relevant unknowns are the Lyman-continuum (LyC) photon production efficiency xi_\\ion\\ and the escape fraction f_\\esc\\. As we show here, the first of these unknowns is directly measureable in z=4-5 galaxies, based on the impact the Halpha line has on the observed IRAC fluxes. By computing a LyC photon production rate from the implied Halpha luminosities for a broad selection of z=4-5 galaxies and comparing this against the dust-corrected UV-continuum luminosities, we provide the first-ever direct estimates of the LyC photon production efficiency xi_\\ion\\ for the z\\textgreater\\textasciitilde4 galaxy population. We find log_\\10\\ xi_\\ion\\/[Hz/ergs] to have a mean value of 25.28_\\-0.09\\\\textasciicircum\\+0.10\\ and 25.34_\\-0.08\\\\textasciicircum\\+0.09\\ for sub-L* z=4-5 galaxies adopting Calzetti and SMC dust laws, respectively. Reassuringly, both values are consistent with standardly assumed xi_\\ion\\'s in reionization models, with a slight preference for higher xi_\\ion\\'s (by \\textasciitilde0.1 dex) adopting the SMC dust law. A modest \\textasciitilde0.03-dex increase in these estimates would result if the escape fraction for ionizing photons is non-zero and galaxies dominate the ionizing emissivity at z\\textasciitilde4.4. High values of xi_\\ion\\ (\\textasciitilde25.5-25.9 dex) are derived for the bluest galaxies (beta\\textless-2.3) in our samples, independent of dust law and consistent with results for a z=7.045 galaxy. Such elevated values of xi_\\ion\\ would have important consequences, indicating that f_\\esc\\ cannot be in excess of 13% unless the galaxy UV luminosity function does not extend down to -13 mag or the clumping factor is greater than 3. A low escape fraction would fit well with the low rate of LyC leakage observed at z\\textasciitilde3.","urldate":"2016-01-27","journal":"arXiv:1511.08504 [astro-ph]","author":[{"propositions":[],"lastnames":["Bouwens"],"firstnames":["R.","J."],"suffixes":[]},{"propositions":[],"lastnames":["Smit"],"firstnames":["R."],"suffixes":[]},{"propositions":[],"lastnames":["Labbe"],"firstnames":["I."],"suffixes":[]},{"propositions":[],"lastnames":["Franx"],"firstnames":["M."],"suffixes":[]},{"propositions":[],"lastnames":["Caruana"],"firstnames":["J."],"suffixes":[]},{"propositions":[],"lastnames":["Oesch"],"firstnames":["P."],"suffixes":[]},{"propositions":[],"lastnames":["Stefanon"],"firstnames":["M."],"suffixes":[]},{"propositions":[],"lastnames":["Rasappu"],"firstnames":["N."],"suffixes":[]}],"month":"November","year":"2015","note":"arXiv: 1511.08504","keywords":"Astrophysics - Astrophysics of Galaxies","bibtex":"@article{bouwens_lyman-continuum_2015,\n\ttitle = {The {Lyman}-{Continuum} {Photon} {Production} {Efficiency} xi\\_\\{ion\\} of z{\\textasciitilde}4-5 {Galaxies} from {IRAC}-based {Halpha} {Measurements}: {Implications} for the {Escape} {Fraction} and {Cosmic} {Reionization}},\n\tshorttitle = {The {Lyman}-{Continuum} {Photon} {Production} {Efficiency} xi\\_\\{ion\\} of z{\\textasciitilde}4-5 {Galaxies} from {IRAC}-based {Halpha} {Measurements}},\n\turl = {http://arxiv.org/abs/1511.08504},\n\tabstract = {Galaxies represent one of the preferred candidate sources to drive the reionization of the universe. Even as gains are made in mapping the galaxy UV luminosity density to z{\\textgreater}6, significant uncertainties remain regarding the conversion to the implied ionizing emissivity. The relevant unknowns are the Lyman-continuum (LyC) photon production efficiency xi\\_\\{ion\\} and the escape fraction f\\_\\{esc\\}. As we show here, the first of these unknowns is directly measureable in z=4-5 galaxies, based on the impact the Halpha line has on the observed IRAC fluxes. By computing a LyC photon production rate from the implied Halpha luminosities for a broad selection of z=4-5 galaxies and comparing this against the dust-corrected UV-continuum luminosities, we provide the first-ever direct estimates of the LyC photon production efficiency xi\\_\\{ion\\} for the z{\\textgreater}{\\textasciitilde}4 galaxy population. We find log\\_\\{10\\} xi\\_\\{ion\\}/[Hz/ergs] to have a mean value of 25.28\\_\\{-0.09\\}{\\textasciicircum}\\{+0.10\\} and 25.34\\_\\{-0.08\\}{\\textasciicircum}\\{+0.09\\} for sub-L* z=4-5 galaxies adopting Calzetti and SMC dust laws, respectively. Reassuringly, both values are consistent with standardly assumed xi\\_\\{ion\\}'s in reionization models, with a slight preference for higher xi\\_\\{ion\\}'s (by {\\textasciitilde}0.1 dex) adopting the SMC dust law. A modest {\\textasciitilde}0.03-dex increase in these estimates would result if the escape fraction for ionizing photons is non-zero and galaxies dominate the ionizing emissivity at z{\\textasciitilde}4.4. High values of xi\\_\\{ion\\} ({\\textasciitilde}25.5-25.9 dex) are derived for the bluest galaxies (beta{\\textless}-2.3) in our samples, independent of dust law and consistent with results for a z=7.045 galaxy. Such elevated values of xi\\_\\{ion\\} would have important consequences, indicating that f\\_\\{esc\\} cannot be in excess of 13\\% unless the galaxy UV luminosity function does not extend down to -13 mag or the clumping factor is greater than 3. A low escape fraction would fit well with the low rate of LyC leakage observed at z{\\textasciitilde}3.},\n\turldate = {2016-01-27},\n\tjournal = {arXiv:1511.08504 [astro-ph]},\n\tauthor = {Bouwens, R. J. and Smit, R. and Labbe, I. and Franx, M. and Caruana, J. and Oesch, P. and Stefanon, M. and Rasappu, N.},\n\tmonth = nov,\n\tyear = {2015},\n\tnote = {arXiv: 1511.08504},\n\tkeywords = {Astrophysics - Astrophysics of Galaxies},\n}\n\n","author_short":["Bouwens, R. J.","Smit, R.","Labbe, I.","Franx, M.","Caruana, J.","Oesch, P.","Stefanon, M.","Rasappu, N."],"key":"bouwens_lyman-continuum_2015","id":"bouwens_lyman-continuum_2015","bibbaseid":"bouwens-smit-labbe-franx-caruana-oesch-stefanon-rasappu-thelymancontinuumphotonproductionefficiencyxiionofztextasciitilde45galaxiesfromiracbasedhalphameasurementsimplicationsfortheescapefractionandcosmicreionization-2015","role":"author","urls":{"Paper":"http://arxiv.org/abs/1511.08504"},"keyword":["Astrophysics - Astrophysics of Galaxies"],"metadata":{"authorlinks":{}}},"bibtype":"article","biburl":"https://bibbase.org/zotero/polyphant","dataSources":["7gvjSdWrEu7z5vjjj"],"keywords":["astrophysics - astrophysics of galaxies"],"search_terms":["lyman","continuum","photon","production","efficiency","ion","textasciitilde4","galaxies","irac","based","halpha","measurements","implications","escape","fraction","cosmic","reionization","bouwens","smit","labbe","franx","caruana","oesch","stefanon","rasappu"],"title":"The Lyman-Continuum Photon Production Efficiency xi_\\ion\\ of z\\textasciitilde4-5 Galaxies from IRAC-based Halpha Measurements: Implications for the Escape Fraction and Cosmic Reionization","year":2015}