We describe techniques for comparing spectra extracted from cosmological
simulations and observational data, using the same methodology to link
Lyman-alpha properties derived from the simulations with properties derived
from observational data. The eventual goal is to measure the coherence or
clustering properties of Lyman-alpha absorbers using observations of quasar
pairs and groups. We quantify the systematic underestimate in opacity that is
inherent in the continuum fitting process of observed spectra over a range of
resolution and signal-to-noise ratio. We present an automated process for
detecting and selecting absorption features over the range of resolution and
signal-to-noise of typical observational data on the Lyman-alpha "forest".
Using these techniques, we detect coherence over transverse scales out to 500
h^{-1}_{50} kpc in spectra extracted from a cosmological simulation at z = 2.Comment: 52 pages, includes 14 figures, to appear in ApJ v566 Feb 200

Cathy E. Petry

Chris D. Impey

David H. Weinberg

Lars E. Hernquist

McGill C.

Neal Katz

English

arXiv

We describe techniques for comparing spectra extracted from cosmological simulations and observational data, using the same methodology to link Lyα properties derived from the simulations with properties derived from observational data. The eventual goal is to measure the coherence or clustering properties of Lyα absorbers using observations of quasar pairs and groups. We quantify the systematic underestimate in opacity that is inherent in the continuum-fitting process of observed spectra over a range of resolution and signal-to-noise ratio (S/N). We present an automated process for detecting and selecting absorption features over the range of resolution and S/N of typical observational data on the Lyα forest. Using these techniques, we detect coherence over transverse scales out to 500 h kpc in spectra extracted from a cosmological simulation at z = 2

Petry, CE

Impey, CD

Katz, N

Weinberg, DH

Hernquist, LE

ScholarWorks@UMass Amherst

Comparing simulations and observations of the Ly alpha forest. I. Methodology

Crossref

Comparing Simulations and Observations of the Lyα Forest. I. Methodology

This is the pre-published version harvested from ArXiv. The published version is located at http://iopscience.iop.org/0004-637X/566/1/30/We describe techniques for comparing spectra extracted from cosmological simulations and observational data, using the same methodology to link Lyα properties derived from the simulations with properties derived from observational data. The eventual goal is to measure the coherence or clustering properties of Lyα absorbers using observations of quasar pairs and groups. We quantify the systematic underestimate in opacity that is inherent in the continuum-fitting process of observed spectra over a range of resolution and signal-to-noise ratio (S/N). We present an automated process for detecting and selecting absorption features over the range of resolution and S/N of typical observational data on the Lyα forest. Using these techniques, we detect coherence over transverse scales out to 500 h kpc in spectra extracted from a cosmological simulation at z = 2.30-5

Comparing Simulations And Observations Of The Ly Alpha Forest. I. Methodology