The Density of Lyα Emitters at Very High Redshift

摘要: We describe narrowband and spectroscopic searches for emission-line star-forming galaxies in the redshift range 3-6 with 10 m Keck II Telescope. These yield a substantial population of objects only single strong (EW 100 A) emission line, lying 4000-8500 A range. Spectra found narrowband-selected samples at λ~5390 ~6741 show that these very high equivalent width lines are generally redshifted Lyα 1216 z~3.4 4.5. The density emitters above 5 σ detection limit 1.5×10−17 ergs cm-2 s-1 is roughly 15,000 deg-2 per unit z both complementary deeper (1 σ~10−18 s-1) slit search covering wide but more limited spatial area (200 arcsec2) shows such can be over z=3-6, currently highest detected being z=5.64. flux distribution used to estimate minimum star formation rate absence reddening 0.01 M☉ Mpc-3 yr-1 (H0=65 km Mpc-1, q0=0.5). Corrections likely no larger than factor 2, since observed widths close maximum values obtainable from ionization by massive population. Within still significant uncertainties, Lyα-selected sample comparable color-break-selected z~3 may represent an increasing fraction total rates higher redshifts. This readily studied large ground-based telescopes.