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

作者：Matthee Jorryt J A^*; Sobral David; Swinbank A M; Smail Ian; Best P N; Kim Jae Woo; Franx Marijn; Milvang Jensen Bo; Fynbo Johan

来源：Monthly Notices of the Royal Astronomical Society, 2014, 440(3): 2375-2387.

DOI：10.1093/mnras/stu392

• galaxies: evolution
• galaxies: high-redshift
• cosmology: observations
• dark ages, reionization, first stars

Candidate galaxies at redshifts of z similar to 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 alpha (Ly alpha) emitters (LAEs) and covering 10 deg(2) in part of the SSA22 field with the Canada-France-Hawaii Telescope (CFHT). We surveyed a comoving volume of 4.7 x 10(6) Mpc(3) to a Ly alpha luminosity limit of 6.3 x 10(43) erg s(-1). We look for Ly alpha 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 similar to 1.4 or 2.2. A total of 13 Ly alpha 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 Ly alpha luminosity function at z similar to 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.

• 出版日期2014-5