TY - JOUR

T1 - A 10 deg2 Lyman α survey at z=8.8 with spectroscopic follow-up

T2 - strong constraints on the luminosity function and implications for other surveys

AU - Matthee, Jorryt J. A.

AU - Sobral, David

AU - Swinbank, A. M.

AU - Smail, Ian

AU - Best, P. N.

AU - Kim, Jae Woo

AU - Franx, Marijn

AU - Milvang-Jensen, Bo

AU - Fynbo, Johan

PY - 2014/5/21

Y1 - 2014/5/21

N2 - 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.

AB - 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.

KW - Cosmology: observations

KW - Dark ages, reionization, first stars

KW - Galaxies: evolution

KW - Galaxies: high-redshift

U2 - 10.1093/mnras/stu392

DO - 10.1093/mnras/stu392

M3 - Journal article

AN - SCOPUS:84898787236

VL - 440

SP - 2375

EP - 2387

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -