A Search for the Barkana-Loeb Effect in the Spectra of High-Redshift Quasars: Probing the Quasar Formation Era?

摘要: Massive host galaxies of the first luminous quasars should be still undergoing a considerable cosmological infall of the neutral IGM. This process may be observable as a distinct spectroscopic signature in the blue wing of their Lyα line, as predicted by Barkana & Loeb (2002). We report on a search for such and effect and its possible redshift evolution in a sample of high-S/N, moderate-resolution spectra of~ 80 QSOs in the redshift range z~ 3.8-6.28, obtained using the ESI instrument at the WMKO Keck-II telescope. While associated Lyα absorption features are common, their physical interpretation is not yet clear. A key observational uncertainty is the determination of the systemic redshift for the QSOs. We will present a detailed analysis of this sample, and the possible interpretations in the context of Barkana-Loeb model and a general picture of early QSO and massive galaxy formation.