%0 Generic %1 sobral2016calymha %A Sobral, David %A Matthee, Jorryt %A Best, Philip %A Stroe, Andra %A Röttgering, Huub %A Oteo, Iván %A Smail, Ian %A Morabito, Leah %A Paulino-Afonso, Ana %D 2016 %K Lya function luminosity %T The CALYMHA survey: Lya luminosity function and global escape fraction of Lya photons at z=2.23 %U http://arxiv.org/abs/1609.05897 %X 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.

@misc{sobral2016calymha, abstract = {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.}, added-at = {2016-09-21T09:30:39.000+0200}, author = {Sobral, David and Matthee, Jorryt and Best, Philip and Stroe, Andra and Röttgering, Huub and Oteo, Iván and Smail, Ian and Morabito, Leah and Paulino-Afonso, Ana}, biburl = {https://www.bibsonomy.org/bibtex/24fdab1e1c480b140d4ccf2b90721697c/miki}, description = {[1609.05897] The CALYMHA survey: Lya luminosity function and global escape fraction of Lya photons at z=2.23}, interhash = {06bee8535078084b388776ef4f650f24}, intrahash = {4fdab1e1c480b140d4ccf2b90721697c}, keywords = {Lya function luminosity}, note = {cite arxiv:1609.05897Comment: 18 pages, 10 figures. Submitted to MNRAS in July. Comments welcome}, timestamp = {2016-09-21T09:30:39.000+0200}, title = {The CALYMHA survey: Lya luminosity function and global escape fraction of Lya photons at z=2.23}, url = {http://arxiv.org/abs/1609.05897}, year = 2016 }