The Evolution of the Effective Equation of State of the IGM

Preprint

10 September 1999

preprint
Published by arXiv in arXiv

Abstract

We develop a method to extract the "effective equation of state" of the intergalactic medium from the doppler b parameter distribution of the low-density Lyman-alpha forest. We test the method on numerical simulations and then apply it to published observations of the Lyman-alpha forest at redshifts z from 0 to 4. We find that the effective equation of state is close to isothermal at redshift z=3, indicating that a second reheating of the IGM took place at z=3. This reheating can plausibly be identified with the reionization of HeII observed to occur at z about 3.

Keywords

NUMERICAL SIMULATIONS
INTERGALACTIC MEDIUM
EFFECTIVE EQUATION
REIONIZATION
REDSHIFTS Z
LYMAN ALPHA
REHEATING
EVOLUTION
FOREST

All Related Versions

Version 1, 1999-06-25, ArXiv
Version 2, 1999-09-10, ArXiv
Version 3, 1999-12-11, ArXiv
Published version: The Astrophysical Journal, 534 (1), 41.

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