Non-Voigt Lyman-alpha absorption line profiles

Abstract

Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium, and the loss of a physical justification for Voigt profile fitting of the Lyman-alpha forest. Many individual lines seen in simulated spectra have significant departures from the Voigt profile, yet could be well fitted by a blend of two or more such lines. We discuss the expected effect on the line profiles due to ongoing gravitational structure formation and Hubble expansion. We develop a method to detect departures from Voigt profiles of the absorption lines in a statistical way and apply this method to simulated Lyman-alpha forest spectra, confirming that the profiles seen do statistically differ from Voigt profiles.

Accepted for publication in ApJL. 10 pages, 3 figures

References in corpus (2)

• P3M-SPH simulations of the Lyman-alpha Forest
• The Lyman-alpha Forest and Heavy Element Systems of GB1759+7539

Cited by in corpus (3)

• Further evidence for a variable fine-structure constant from Keck/HIRES QSO absorption spectra
• The Lyman-Alpha Forest at 1.5 < z < 4
• The Statistical and Physical Properties of the Low Redshift Lyman Alpha Forest Observed with HST/STIS