Limits on the luminosity function of Lyα emitters at z = 7.7^*

¹ Laboratoire d'Astrophysique de Marseille, OAMP, Université Aix-Marseille & CNRS, 38 rue Frédéric Joliot Curie, 13388 Marseille Cedex 13, France
² Korean Institute for Advanced Study, Dongdaemun-gu, Seoul 130-722, Korea
³ Department of Physics and Astronomy, University of Victoria, Elliot Building, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada
⁴ European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19, Chile
⁵ Canada France Hawaii Telescope Corporation, Kamuela, HI 96743, USA
⁶ Herzberg Institute of Astrophysics, National Research Council, 5071 West Saanich Rd, Victoria, BC V9E 2E7, Canada
⁷ Institut d'Astrophysique de Paris, Université Pierre et Marie Curie, 98bis boulevard d'Arago, 75014 Paris, France

Received: 19 March 2009
Accepted: 13 January 2010

Abstract

Aims. The Lyα luminosity function (LF) of high-redshift Lyα emitters (LAEs) is one of the few observables of the re-ionization epoch accessible with 8–10 m class telescopes. The evolution of the LAE LF with redshift is dependent upon the physical evolution of LAEs and the ionisation state of the Universe towards the end of the Dark Ages.

Methods. We performed a narrow-band imaging program at 1.06 μm using CFHT/WIRCam. The observations target Lyα emitters at redshift z ~ 7.7 in the CFHT-LS D1 field. From these observations we derived a photometric sample of 7 LAE candidates at z ~ 7.7.

Results. We derive luminosity functions for the full sample of seven objects and for subsamples of four objects. Assuming the brightest objects in our sample are real, we find that the resulting luminosity function is not consistent with previous work at lower redshifts. More definitive conclusions will require spectroscopic confirmation.