Towards a unified description of the intergalactic medium at redshift z ≈ 2.5
Prochaska, J.X.; Madau, P.; O'Meara, J.M.; Fumagalli, M.
Professor Michele Fumagalli firstname.lastname@example.org
We examine recent measurements of the z ≈ 2.5 intergalactic medium (IGM) which constrain the H I frequency distribution f(NHI) and the mean free path λ912mfp to ionizing radiation. We argue that line-blending and the clustering of strong absorption-line systems have led previous authors to systematically overestimate the effective Lyman limit opacity, yielding too small of a λ912mfp for the IGM. We further show that recently published measurements of f(NHI) at NHI≈1016cm−2 lie in strong disagreement, implying underestimated uncertainty from sample variance and/or systematics like line-saturation. Allowing for a larger uncertainty in the f(NHI) measurements, we provide a new cubic Hermite spline model for f(NHI) which reasonably satisfies all of the observational constraints under the assumption of randomly distributed absorption systems. We caution, however, that this formalism is invalid in the light of absorber clustering and use a toy model to estimate the effects. Future work must properly account for the non-Poissonian nature of the IGM.
Prochaska, J., Madau, P., O'Meara, J., & Fumagalli, M. (2014). Towards a unified description of the intergalactic medium at redshift z ≈ 2.5. Monthly Notices of the Royal Astronomical Society, 438(1), 476-486. https://doi.org/10.1093/mnras/stt2218
|Journal Article Type||Article|
|Publication Date||Feb 11, 2014|
|Deposit Date||Apr 6, 2014|
|Publicly Available Date||Jun 20, 2014|
|Journal||Monthly Notices of the Royal Astronomical Society|
|Publisher||Royal Astronomical Society|
|Peer Reviewed||Peer Reviewed|
Published Journal Article
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society © 2013 The Authors Published by Oxford University Press on behalf of Royal Astronomical Society. All rights reserved.
You might also like
The relationship between gas and galaxies at z < 1 using the Q0107 quasar triplet
Discovery of a Damped Lyα Galaxy at z ∼ 3 toward the Quasar SDSS J011852+040644
Sub-damped Lyman α systems in the XQ-100 survey – II. Chemical evolution at 2.4 ≤ z ≤ 4.3
The stochastic enrichment of Population II stars