A new Measurement of the Intergalactic Temperature at $z\sim 2.55-2.95$

Abstract

We present two measurements of the temperature-density relationship (TDR) of the intergalactic medium (IGM) in the redshift range $2.55<z<2.95$ using a sample of 13 high-quality quasar spectra and high resolution numerical simulations of the IGM. Our approach is based on fitting the neutral hydrogen column density $N_{HI}$ and the Doppler parameter $b$ of the absorption lines in the \mlya\ forest. The first measurement is obtained using a novel Bayesian scheme which takes into account the statistical correlations between the parameters characterising the lower cut-off of the $b-N_{HI}$ distribution and the power-law parameters $T_0$ and $\gamma$ describing the TDR. This approach yields $T_0/10^3\mathrm{K}=15.6\pm 4.4$ and $\gamma =1.45\pm 0.17$ independent of the assumed pressure smoothing of the small scale density field. In order to explore the information contained in the overall $b-N_{HI}$ distribution rather than only the lower cut-off, we obtain a second measurement based on a similar Bayesian analysis of the median Doppler parameter for separate column-density ranges of the absorbers. In this case we obtain $T_0/10^3\mathrm{K}=14.6\pm 3.7$ and $\gamma =1.37\pm 0.17$ in good agreement with the first measurement. Our Bayesian analysis reveals strong anti-correlations between the inferred $T_0$ and $\gamma$ for both methods as well as an anti-correlation of the inferred $T_0$ and the pressure smoothing length for the second method, suggesting that the measurement accuracy can in the latter case be substantially increased if independent constraints on the smoothing are obtained. Our results are in good agreement with other recent measurements of the thermal state of the IGM probing similar (over-)density ranges.

Accepted for publication in MNRAS

References in corpus (8)

• High resolution CMB power spectrum from the complete ACBAR data set
• HeII Reionization and its Effect on the IGM
• Possible evidence for an inverted temperature-density relation in the intergalactic medium from the flux distribution of the Lyman-alpha forest
• The thermal history of the intergalactic medium down to redshift z=1.5: a new curvature measurement
• IGM Constraints from the SDSS-III/BOSS DR9 Ly-alpha Forest Flux Probability Distribution Function
• Exploring the Thermal State of the Low-Density Intergalactic Medium at z=3 with an Ultra-High Signal-to-Noise QSO Spectrum
• The broadening of Lyman-alpha forest absorption lines
• Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II Reionization

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