The Intergalactic Medium

Intergalactic Medium

Simulations of the Intergalactic Medium

I present a review by epoch of baryons in the intergalac-tic medium (IGM), from the first star until today. Recent observations indicate a protracted period of reionization, suggesting multiple populations of reionizers; detection of these z ∼ > 6 sources is a key goal that is now coming within reach. The optical Lyman alpha forest (2 ∼ < z ∼ < 4) is well-described by the Fluctuating Gunn-Peter...

The thermal history of the intergalactic medium

At redshifts z2, most of the baryons reside in the smooth intergalactic medium which is responsible for the low column density Lyα forest. This photoheated gas follows a tight temperature-density relation which introduces a cut-off in the distribution of widths of the Lyα absorption lines (b-parameters) as a function of column density. We have measured this cut-off in a sample of nine high reso...

Measuring the Temperature of the Intergalactic Medium

Numerical simulations indicate that the smooth, photoionized intergalactic medium (IGM) responsible for the low column density Lyα forest follows a well defined temperaturedensity relation. We show that such an equation of state results in a cutoff in the distribution of line widths (b-parameters) as a function of column density (N) for the low column density absorption lines. This explains the...

Galactic Winds in the Intergalactic Medium

We have performed hydrodynamical simulations to investigate the effects of galactic winds on the high-redshift (z = 3) universe. Strong winds suppress the formation of low-mass galaxies significantly, and the metals carried by them produce C IV absorption lines with properties in reasonable agreement with observations. The winds have little effect on the statistics of the H I-absorption lines, ...