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IGM constraints from the SDSS-III/BOSS DR9 Ly? forest transmission probability distribution function

Lee, Khee Gan; Lee, K.-G.; Hennawi, J.P.; Spergel, David N.; Weinberg, David H.; Hogg, David W.; Viel, Matteo; Bolton, James S.; Bailey, Stephen; Pieri, Matthew M.; Carithers, William; Schlegel, David J.; Lundgren, Britt; Palanque-Delabrouille, Nathalie; Suzuki, Nao; Schneider, Donald P.; Yeche, C.


Khee Gan Lee

K.-G. Lee

J.P. Hennawi

David N. Spergel

David H. Weinberg

David W. Hogg

Matteo Viel

Stephen Bailey

Matthew M. Pieri

William Carithers

David J. Schlegel

Britt Lundgren

Nathalie Palanque-Delabrouille

Nao Suzuki

Donald P. Schneider

C. Yeche


© 2015. The American Astronomical Society. All rights reserved. The Lyα forest transmission probability distribution function (PDF) is an established probe of the intergalactic medium (IGM) astrophysics, especially the temperature-density relationship of the IGM. We measure the transmission PDF from 3393 Baryon Oscillations Spectroscopic Survey (BOSS) quasars from Sloan Digital Sky Survey Data Release 9, and compare with mock spectra that include careful modeling of the noise, continuum, and astrophysical uncertainties. The BOSS transmission PDFs, measured at 〈z〉 = [2.3, 2.6, 3.0], are compared with PDFs created from mock spectra drawn from a suite of hydrodynamical simulations that sample the IGM temperature-density relationship, γ, and temperature at mean density, T0, where T (Δ) = T0Δγ-1. We find that a significant population of partial Lyman-limit systems (LLSs) with a column-density distribution slope of βpLLS ∼ -2 are required to explain the data at the low-transmission end of transmission PDF, while uncertainties in the mean Lyα forest transmission affect the high-transmission end. After modeling the LLSs and marginalizing over mean transmission uncertainties, we find that γ = 1.6 best describes the data over our entire redshift range, although constraints on T0 are affected by systematic uncertainties. Within our model framework, isothermal or inverted temperature-density relationships (γ & le; 1) are disfavored at a significance of over 4σ, although this could be somewhat weakened by cosmological and astrophysical uncertainties that we did not model.


Lee, K. G., Lee, K., Hennawi, J., Spergel, D. N., Weinberg, D. H., Hogg, D. W., …Yeche, C. (2015). IGM constraints from the SDSS-III/BOSS DR9 Lyα forest transmission probability distribution function. Astrophysical Journal, 799(2), 196.

Journal Article Type Article
Acceptance Date Dec 4, 2014
Online Publication Date Jan 29, 2015
Publication Date Jan 29, 2015
Deposit Date May 4, 2017
Publicly Available Date May 4, 2017
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 799
Issue 2
Article Number 196
Pages 196
Keywords intergalactic medium; large-scale structure of universe; methods: data analysis; quasars: absorption lines; quasars: emission lines; techniques: spectroscopic
Public URL
Publisher URL
Additional Information C 2015. The American Astronomical Society. All rights reserved.


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