Zusammenfassung
The Ly$\alpha$ forest flux 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 flux PDF from
3393 Baryon Oscillations Spectroscopic Survey (BOSS) quasars from SDSS Data
Release 9, and compare with mock spectra that include careful modeling of the
noise, continuum, and astrophysical uncertainties. The BOSS flux 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, $\gamma$, and temperature at
mean-density, $T_0$, where $T(\Delta) = T_0 \Delta^\gamma-1$. We find that a
significant population of partial Lyman-limit systems with a column-density
distribution slope of $\beta_pLLS -2$ are required to explain the
data at the low-flux end of flux PDF, while uncertainties in the mean łya\
forest transmission affect the high-flux end. After modelling the LLSs and
marginalizing over mean-transmission uncertainties, we find that $\gamma=1.6$
best describes the data over our entire redshift range, although constraints on
$T_0$ are affected by systematic uncertainties. Isothermal or inverted
temperature-density relationships ($1$) are disfavored at a
significance of over 4$\sigma$.
Beschreibung
[1405.1072] IGM Constraints from the SDSS-III/BOSS DR9 Ly-alpha Forest Flux Probability Distribution Function
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