%0 Generic %1 stroe2017degbf %A Stroe, Andra %A Sobral, David %A Matthee, Jorryt %A Calhau, João %A Oteo, Ivan %D 2017 %K CII CIII CIV agn function galaxies luminosity quasars %T A $1.4$ deg$^2$ blind survey for CII, CIII and CIV at $z\sim0.7-1.5$. II: luminosity functions and cosmic average line ratios %U http://arxiv.org/abs/1704.01124 %X Recently, the CIII and CIV emission lines have been observed in galaxies in the early Universe ($z>5$), providing new ways to measure their redshift and study their stellar populations and AGN. We explore the first blind CII, CIII and CIV survey ($z\sim0.68, 1.05, 1.53$, respectively) presented in Stroe et al. (2017). We derive luminosity functions (LF) and study properties of CII, CIII and CIV line emitters through comparisons to the LFs of H$\alpha$ and Ly$\alpha$ emitters, UV selected star forming (SF) galaxies and quasars at similar redshifts. The CII LF at $z\sim0.68$ is equally well described by a Schechter or a power-law LF, characteristic of a mixture of SF and AGN activity. The CIII LF ($z\sim1.05$) is consistent to a scaled down version of the Schechter H$\alpha$ and Ly$\alpha$ LF at their redshift, indicating a SF origin. In stark contrast, the CIV LF at $z\sim1.53$ is well fit by a power-law, quasar-like LF. We find that the brightest UV sources ($M_UV<-22$) will universally have CIII and CIV emission. However, on average, CIII and CIV are not as abundant as H$\alpha$ or Ly$\alpha$ emitters at the same redshift, with cosmic average ratios of $\sim0.02-0.06$ to H$\alpha$ and $\sim0.01-0.1$ to intrinsic Ly$\alpha$. We predict that the CIII and CIV lines can only be truly competitive in confirming high redshift candidates when the hosts are intrinsically bright and the effective Ly$\alpha$ escape fraction is below 1 per cent. While CIII and CIV were proposed as good tracers of young, relatively low-metallicity galaxies typical of the early Universe, we find that, at least at $z\sim1.5$, CIV is exclusively hosted by AGN/quasars.

@misc{stroe2017degbf, abstract = {Recently, the CIII] and CIV emission lines have been observed in galaxies in the early Universe ($z>5$), providing new ways to measure their redshift and study their stellar populations and AGN. We explore the first blind CII], CIII] and CIV survey ($z\sim0.68, 1.05, 1.53$, respectively) presented in Stroe et al. (2017). We derive luminosity functions (LF) and study properties of CII], CIII] and CIV line emitters through comparisons to the LFs of H$\alpha$ and Ly$\alpha$ emitters, UV selected star forming (SF) galaxies and quasars at similar redshifts. The CII] LF at $z\sim0.68$ is equally well described by a Schechter or a power-law LF, characteristic of a mixture of SF and AGN activity. The CIII] LF ($z\sim1.05$) is consistent to a scaled down version of the Schechter H$\alpha$ and Ly$\alpha$ LF at their redshift, indicating a SF origin. In stark contrast, the CIV LF at $z\sim1.53$ is well fit by a power-law, quasar-like LF. We find that the brightest UV sources ($M_{UV}<-22$) will universally have CIII] and CIV emission. However, on average, CIII] and CIV are not as abundant as H$\alpha$ or Ly$\alpha$ emitters at the same redshift, with cosmic average ratios of $\sim0.02-0.06$ to H$\alpha$ and $\sim0.01-0.1$ to intrinsic Ly$\alpha$. We predict that the CIII] and CIV lines can only be truly competitive in confirming high redshift candidates when the hosts are intrinsically bright and the effective Ly$\alpha$ escape fraction is below 1 per cent. While CIII] and CIV were proposed as good tracers of young, relatively low-metallicity galaxies typical of the early Universe, we find that, at least at $z\sim1.5$, CIV is exclusively hosted by AGN/quasars.}, added-at = {2017-04-06T11:24:18.000+0200}, author = {Stroe, Andra and Sobral, David and Matthee, Jorryt and Calhau, João and Oteo, Ivan}, biburl = {https://www.bibsonomy.org/bibtex/28790cf2261a4cf25195d60b7446dc8e4/miki}, description = {[1704.01124] A ${\bf 1.4}$ deg${\bf ^2}$ blind survey for CII], CIII] and CIV at ${\bf z\sim0.7-1.5}$. II: luminosity functions and cosmic average line ratios}, interhash = {6e7a5bd390813ef0f913220d90e9d6e7}, intrahash = {8790cf2261a4cf25195d60b7446dc8e4}, keywords = {CII CIII CIV agn function galaxies luminosity quasars}, note = {cite arxiv:1704.01124Comment: Submitted to MNRAS. Comments welcome! 11 pages, 7 figures, 5 tables. Paper I can be found here: https://arxiv.org/abs/1703.10169}, timestamp = {2017-04-06T11:24:18.000+0200}, title = {A ${\bf 1.4}$ deg${\bf ^2}$ blind survey for CII], CIII] and CIV at ${\bf z\sim0.7-1.5}$. II: luminosity functions and cosmic average line ratios}, url = {http://arxiv.org/abs/1704.01124}, year = 2017 }