A 1.4 deg^2 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 / Letter to editorSterrewach

A 1.4 deg^2 blind survey for C II], C III] and C IV at z ~ 0.7-1.5 - II. Luminosity functions and cosmic average line ratios

Galaxie

A 10 deg^2 Lyman α survey at z=8.8 with spectroscopic follow-up: strong constraints on the luminosity function and implications for other surveys

Candidate galaxies at redshifts of z ∼ 10 are now being found in extremely deep surveys, probing very small areas. As a consequence, candidates are very faint, making spectroscopic confirmation practically impossible. In order to overcome such limitations, we have undertaken the CF-HiZELS survey, which is a large-area, medium-depth near-infrared narrow-band survey targeted at z = 8.8 Lyman α (Lyα) emitters (LAEs) and covering 10 deg2 in part of the SSA22 field with the Canada–France–Hawaii Telescope (CFHT). We surveyed a comoving volume of 4.7 × 106 Mpc3 to a Lyα luminosity limit of 6.3 × 1043 erg s−1. We look for Lyα candidates by applying the following criteria: (i) clear emission-line source, (ii) no optical detections (ugriz from CFHTLS), (iii) no visible detection in the optical stack (ugriz > 27), (iv) visually checked reliable NBJ and J detections and (v) J − K ≤ 0. We compute photometric redshifts and remove a significant amount of dusty lower redshift line-emitters at z ∼ 1.4 or 2.2. A total of 13 Lyα candidates were found, of which two are marked as strong candidates, but the majority have very weak constraints on their spectral energy distributions. Using follow-up observations with SINFONI/VLT, we are able to exclude the most robust candidates as LAEs. We put a strong constraint on the Lyα luminosity function at z ∼ 9 and make realistic predictions for ongoing and future surveys. Our results show that surveys for the highest redshift LAEs are susceptible of multiple contaminations and that spectroscopic follow-up is absolutely necessary

Revealing the impact of quasar luminosity on giant Ly α nebulae

Galaxie

Evidence for PopIII-like Stellar Populations in the Most Luminous Lyman-α Emitters at the Epoch of Reionization: Spectroscopic Confirmation

Galaxie

Identifying the origins of galaxy formation

This thesis investigates how galaxies form and what diversifies the evolutionary histories of galaxies. The first part of this thesis describes the identification of luminous galaxies in the early Universe and the follow-up study of their properties with the Very Large Telescope, ALMA and the Hubble Space Telescope. Luminous galaxies are assembling through merging of multiple components and heavy elements as carbon are already in place relatively shortly after galaxies have formed. The second part describes the study of the Lyman-alpha escape fraction of galaxies at the peak of star formation history. The Lyman-alpha escape fraction is generally low, except for rare massive galaxies with AGN activity or for low mass galaxies. This implies that Lyman-alpha radiation escapes more efficiently in the early Universe, when galaxies tend to be less massive with a lower dust content. The final part of this thesis is a theoretical investigation of the co-evolution of dark matter halos and galaxies in the cosmological hydrodynamical EAGLE simulation. Galaxy stellar mass growth is driven by both the mass and formation time of dark matter halos. As a result, present-day growth rates of galaxies are coherent with the long time-scale histories.Galaxie