Logo image
Back
A feature at z ~ 3.2 in the evolution of the Ly-alpha forest optical depth
Journal article   Open access

A feature at z ~ 3.2 in the evolution of the Ly-alpha forest optical depth

M Bernardi, R. K Sheth, M Subbarao, G. T Richards, S Burles, A. J Connolly, J Frieman, R Nichol, J Schaye, D. P Schneider, …
The Astronomical journal, v 125(1)
17 Jun 2002
DOI: https://doi.org/10.1086/344945
url
https://doi.org/10.1086/344945View
Published, Version of Record (VoR)Maybe Open Access (Publisher Bronze),  Open

Abstract

Physics - Astrophysics of Galaxies Physics - Cosmology and Nongalactic Astrophysics Physics - Earth and Planetary Astrophysics Physics - High Energy Astrophysical Phenomena Physics - Instrumentation and Methods for Astrophysics Physics - Solar and Stellar Astrophysics
Astron.J. 125 (2003) 32 The effective optical depth in the Ly-alpha forest region of 1061 low-resolution QSO spectra drawn from the SDSS database decreases with decreasing redshift over the range 2.5 < z < 4. Although the evolution is relatively smooth, tau_eff ~ (1+z)^{3.8 pm 0.2}, at z ~ 3.2 the effective optical depth decreases suddenly, by about ten percent with respect to this smoother evolution. It climbs back to the original smooth scaling again by z ~ 2.9. We describe two techniques, one of which is new, for quantifying this evolution which give consistent results. A variety of tests show that the feature is not likely to be a consequence of how the QSO sample was selected, nor the result of flux calibration or other systematic effects. Other authors have argued that, at this same epoch, the temperature of the IGM also shows a departure from an otherwise smooth decrease with time. These features in the evolution of the temperature and the optical depth are signatures of the reionization of He II.

Metrics

5 Record Views
86 citations in Web of Science
86 citations in Scopus

Details

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Collaboration types
Domestic collaboration
Web of Science research areas
Astronomy & Astrophysics
Logo image