%0 Generic %1 dressler2014confirmation %A Dressler, Alan %A Henry, Alaina %A Martin, Crystal L. %A Sawicki, Marcin %A McCarthy, Patrick %A Villaneuva, Edward %D 2014 %K function luminosity lya reionization %T Confirmation of a Steep Luminosity Function for Lyman-alpha Emitters at z = 5.7: A Major Component of Reionization %U http://arxiv.org/abs/1412.0655 %X We report the first direct and robust measurement of the faint-end slope of the Lyman-alpha emitter (LAE) luminosity function at z = 5.7. Candidate LAEs from a low-spectral-resolution blind search with IMACS on Magellan-Baade were targeted at higher resolution to distinguish high redshift LAEs from foreground galaxies. All but 2 of our 42 single-emission-line systems are fainter than F = 2.0 $10^-17$ ergs/s/cm$^2$, making these the faintest emission-lines observed for a z = 5.7 sample with known completeness, an essential property for determining the faint end slope of the LAE luminosity function. We find 13 LAEs as compared to 29 foreground galaxies, in very good agreement with the modeled foreground counts predicted in Dressler et al. (2011a) that had been used to estimate a faint-end slope of $\alpha$ = -2.0 for the LAE luminosity function. A 32% LAE fraction, LAE/(LAE+foreground) within the flux interval F = 2-20 $10^-18$ ergs/s/cm$^2$ constrains the faint end slope of the luminosity function to 1.95 < $\alpha$ < -2.35 (1-$\sigma$). We show how this steep LF should provide, to the limit of our observations, more than 20% of the flux necessary to maintain ionization at z=5.7, with a factor-of-ten extrapolation in flux reaching more than 55%. We suggest that this bodes well for a comparable contribution by similar, low-mass star forming galaxies at higher-redshift -- within the reionization epoch at z > 7, only 250 Myr earlier -- and that such systems provide a substantial, if not dominant, contribution to the late-stage reionization of the IGM.

@misc{dressler2014confirmation, abstract = {We report the first direct and robust measurement of the faint-end slope of the Lyman-alpha emitter (LAE) luminosity function at z = 5.7. Candidate LAEs from a low-spectral-resolution blind search with IMACS on Magellan-Baade were targeted at higher resolution to distinguish high redshift LAEs from foreground galaxies. All but 2 of our 42 single-emission-line systems are fainter than F = 2.0 $\times 10^{-17}$ ergs/s/cm$^2$, making these the faintest emission-lines observed for a z = 5.7 sample with known completeness, an essential property for determining the faint end slope of the LAE luminosity function. We find 13 LAEs as compared to 29 foreground galaxies, in very good agreement with the modeled foreground counts predicted in Dressler et al. (2011a) that had been used to estimate a faint-end slope of $\alpha$ = -2.0 for the LAE luminosity function. A 32% LAE fraction, LAE/(LAE+foreground) within the flux interval F = 2-20 $\times 10^{-18}$ ergs/s/cm$^2$ constrains the faint end slope of the luminosity function to 1.95 < $\alpha$ < -2.35 (1-$\sigma$). We show how this steep LF should provide, to the limit of our observations, more than 20% of the flux necessary to maintain ionization at z=5.7, with a factor-of-ten extrapolation in flux reaching more than 55%. We suggest that this bodes well for a comparable contribution by similar, low-mass star forming galaxies at higher-redshift -- within the reionization epoch at z > 7, only 250 Myr earlier -- and that such systems provide a substantial, if not dominant, contribution to the late-stage reionization of the IGM.}, added-at = {2014-12-03T10:11:31.000+0100}, author = {Dressler, Alan and Henry, Alaina and Martin, Crystal L. and Sawicki, Marcin and McCarthy, Patrick and Villaneuva, Edward}, biburl = {https://www.bibsonomy.org/bibtex/26bb29eecc251ca877b4f3ba66fa588d2/miki}, description = {[1412.0655] Confirmation of a Steep Luminosity Function for Lyman-alpha Emitters at z = 5.7: A Major Component of Reionization}, interhash = {61742b3856a6b34658c27a2e553bd801}, intrahash = {6bb29eecc251ca877b4f3ba66fa588d2}, keywords = {function luminosity lya reionization}, note = {cite arxiv:1412.0655Comment: 9 pages, 4 figures}, timestamp = {2014-12-03T10:11:31.000+0100}, title = {Confirmation of a Steep Luminosity Function for Lyman-alpha Emitters at z = 5.7: A Major Component of Reionization}, url = {http://arxiv.org/abs/1412.0655}, year = 2014 }