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J.E. Rhoads (STScI), S. Malhotra (JHU), A. Dey (NOAO), D. Stern, H. Spinrad (UC Berkeley), B.T. Jannuzi (NOAO)
Young galaxies undergoing their first burst of star formation are expected to have strong Lyman-\alpha emission, due to low metallicity and dust content. However, studies to date have found comparatively small samples of such objects.
We have embarked on a major project to obtain a statistically useful sample of several hundred Lyman-\alpha emitters at z \approx 4.5 (the Large Area Lyman Alpha, or LALA, survey). We are using the 8k \times 8k CCD Mosaic camera at the Kitt Peak National Observatory 4m Mayall telescope. To date, we have surveyed a total volume of 1.3 \times 106 comoving Mpc3 (H0=70, \Omegam=0.2, \Lambda=0) to 5 \sigma flux limits of (1.8~to~2.6) \times 10-17erg cm2 sec. We are finding an emission line object density of 9 \, deg-2 Å-1 with narrowband flux between 2.6 and 5.2 \times 10-17 erg cm2 sec at wavelength \lambda ~q 6640 Å. Our first spectroscopic followup with the Keck 10m telescope implies that ~1/3 to 1/2 of these are z\approx 4.5 Lyman-\alpha emitters, and that the density of Lyman-\alpha emitters in this restricted flux range is ~4000 \, deg-2 (unit z)-1, or ~9\times 10-4 Mpc-3 for our assumed cosmology.
The author(s) of this abstract have provided an email address for comments about the abstract: jrhoads@noao.edu