Spectroscopic Confirmation of a Population of Normal Star-forming Galaxies at Redshifts z > 3*

摘要: We report the discovery of a substantial population star-forming galaxies at 3.0 z 3.5. These have been selected using color criteria sensitive to presence Lyman continuum break superposed on an otherwise very blue far-UV continuum, and then confirmed with deep spectroscopy W. M. Keck telescope. The surface density brighter than = 25 3.5 is 0.4 ± 0.07 arcmin-2, approximately 1.3% counts these magnitudes; this value applies both "random" fields centered known QSOs. corresponding comoving space half that luminous (L L*) present-day galaxies. Our sample > 3 large enough we can begin detail spectroscopic characteristics as whole. spectra are remarkably similar those nearby galaxies, dominant features being strong low-ionization interstellar absorption lines high-ionization stellar lines, often P Cygni profiles characteristic Wolf-Rayet O star winds. Lyα emission generally weak (less 20 A rest equivalent width) absent for more 50% assign approximate mass scales strengths heavily saturated find that, if line widths dominated by gravitational motions within implied velocity dispersions 180 km s-1 ≤ σ 320 s-1, in range expected massive formation rates, which be measured directly from continua, lie 4-25 h−250 M☉ yr-1 (for q0 0.5), 8.5 typical. Together morphological properties galaxy population, discuss companion paper, all findings strongly suggest identified high-redshift counterparts spheroid component In any case, it clear was already well underway ~