New results are presented, as part of the Hi-z Emission Line Survey (HiZELS), from the largest area survey to date (1.4 sq.deg) for Lyman-alpha emitters (LAEs) at z~9. The survey, which is primarily targeting H-alpha emitters at z<3, uses the Wide Field CAMera on the United Kingdom Infrared Telescope and a custom narrow-band filter in the J band and reaches a Lyman-alpha luminosity limit of ~10^43.8 erg/s over a co-moving volume of 1.12x10^6 Mpc^3 at z=8.96+-0.06. Only 2 candidates were found out of 1517 line emitters and those were rejected as LAEs after follow-up observations. The limit on the space density of bright LAEs is improved by 3 orders of magnitude, consistent with suppression of the bright end of the Lyman-alpha luminosity function beyond z~6. Combined with upper limits from smaller but deeper surveys, this rules out some of the most extreme models for high-redshift LAEs. The potential contamination of future narrow-band Lyman-alpha surveys at z>7 by Galactic brown dwarf stars is also examined, leading to the conclusion that such contamination may well be significant for searches at 7.7<z<8.0, 9.1<z<9.5 and 11.7 < z < 12.2.
@article{arxiv.0907.0003,
title = {Bright Lyman-alpha Emitters at z~9: constraints on the luminosity function from HiZELS},
author = {D. Sobral and P. N. Best and J. E. Geach and Ian Smail and J. Kurk and M. Cirasuolo and M. Casali and R. J. Ivison and K. Coppin and G. B. Dalton},
journal= {arXiv preprint arXiv:0907.0003},
year = {2015}
}
Comments
5 pages, 3 figures. Accepted for publication in MNRAS Letters