A 1.4 deg2 blind survey for C II], C III] and C IV at z ∼ 0.7–1.5 – II. Luminosity functions and cosmic average line ratios

article A 1.4 deg2 blind survey for C II], C III] and C IV at z ∼ 0.7–1.5 – II. Luminosity functions and cosmic average line ratios published yes Andra Stroe author David Sobral author Jorryt J Matthee author 7439a258-f3c0-11ec-9501-9df22fe067200000-0003-2871-127X João Calhau author Ivan Oteo author Recently, the C III] and C IV 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 active galactic nuclei (AGN). We explore the first blind C II], C III] and C IV survey (z ∼ 0.68, 1.05, 1.53, respectively) presented in Stroe et al. (2017). We derive luminosity functions (LF) and study properties of C II], C III] and C IV line emitters through comparisons to the LFs of H α and Ly α emitters, UV selected star-forming (SF) galaxies and quasars at similar redshifts. The C II] LF at z ∼ 0.68 is equally well described by a Schechter or a power-law LF, characteristic of a mixture of SF and AGN activity. The C III] LF (z ∼ 1.05) is consistent to a scaled down version of the Schechter H α and Ly α LF at their redshift, indicating a SF origin. In stark contrast, the C IV LF at z ∼ 1.53 is well fit by a power-law, quasar-like LF. We find that the brightest UV sources (MUV < −22) will universally have C III] and C IV emission. However, on average, C III] and C IV are not as abundant as H α or Ly α emitters at the same redshift, with cosmic average ratios of ∼0.02–0.06 to H α and ∼0.01–0.1 to intrinsic Ly α. We predict that the C III] and C IV lines can only be truly competitive in confirming high-redshift candidates when the hosts are intrinsically bright and the effective Ly α escape fraction is below 1 per cent. While C III] and C IV were proposed as good tracers of young, relatively low-metallicity galaxies typical of the early Universe, we find that, at least at z ∼ 1.5, C IV is exclusively hosted by AGN/quasars, especially at large line equivalent widths. Oxford University Press2017 eng Space and Planetary ScienceAstronomy and Astrophysicsgalaxies: activegalaxies: high redshiftgalaxies: luminosity functionmass functionquasars: emission linesstar formationcosmology: observations Monthly Notices of the Royal Astronomical Society 0035-8711 1365-2966 1703.1016910.1093/mnras/stx1713 47132575-2586 yes A. Stroe, D. Sobral, J. J. Matthee, J. Calhau, and I. Oteo, “A 1.4 deg2 blind survey for C II], C III] and C IV at z ∼ 0.7–1.5 – II. Luminosity functions and cosmic average line ratios,” Monthly Notices of the Royal Astronomical Society, vol. 471, no. 3. Oxford University Press, pp. 2575–2586, 2017. Stroe A, Sobral D, Matthee JJ, Calhau J, Oteo I. A 1.4 deg2 blind survey for C II], C III] and C IV at z ∼ 0.7–1.5 – II. Luminosity functions and cosmic average line ratios. Monthly Notices of the Royal Astronomical Society. 2017;471(3):2575-2586. doi:<a href="https://doi.org/10.1093/mnras/stx1713">10.1093/mnras/stx1713</a> Stroe, Andra, et al. “A 1.4 Deg2 Blind Survey for C II], C III] and C IV at z ∼ 0.7–1.5 – II. Luminosity Functions and Cosmic Average Line Ratios.” Monthly Notices of the Royal Astronomical Society, vol. 471, no. 3, Oxford University Press, 2017, pp. 2575–86, doi:<a href="https://doi.org/10.1093/mnras/stx1713">10.1093/mnras/stx1713</a>. Stroe, Andra, David Sobral, Jorryt J Matthee, João Calhau, and Ivan Oteo. “A 1.4 Deg2 Blind Survey for C II], C III] and C IV at z ∼ 0.7–1.5 – II. Luminosity Functions and Cosmic Average Line Ratios.” Monthly Notices of the Royal Astronomical Society. Oxford University Press, 2017. <a href="https://doi.org/10.1093/mnras/stx1713">https://doi.org/10.1093/mnras/stx1713</a>. Stroe A, Sobral D, Matthee JJ, Calhau J, Oteo I. 2017. A 1.4 deg2 blind survey for C II], C III] and C IV at z ∼ 0.7–1.5 – II. Luminosity functions and cosmic average line ratios. Monthly Notices of the Royal Astronomical Society. 471(3), 2575–2586. A. Stroe, D. Sobral, J.J. Matthee, J. Calhau, I. Oteo, Monthly Notices of the Royal Astronomical Society 471 (2017) 2575–2586. Stroe, A., Sobral, D., Matthee, J. J., Calhau, J., & Oteo, I. (2017). A 1.4 deg2 blind survey for C II], C III] and C IV at z ∼ 0.7–1.5 – II. Luminosity functions and cosmic average line ratios. Monthly Notices of the Royal Astronomical Society. Oxford University Press. <a href="https://doi.org/10.1093/mnras/stx1713">https://doi.org/10.1093/mnras/stx1713</a> 115672022-07-12T12:54:57Z2022-08-19T08:02:04Z