We study the effect of galactic outflows on the statistical properties of the Lyα forest and its correlation with galaxies. The winds are modelled as fully ionised spherical bubbles centered around the haloes in an N-body simulation of a ΛCDM model. The observed flux probability distribution and flux power spectrum limit the volume filling factor of bubbles to be less than 10%. We have compared...

We present new measurements of the temperature of the intergalactic medium (IGM) derived from the Lyα forest over 2.0 ≤ z ≤ 4.8. The small-scale structure in the forest of 61 highresolution quasi-stellar object spectra is quantified using a new statistic, the curvature, and the conversion to temperature calibrated using a suite of hydrodynamic simulations. At each redshift, we focus on obtainin...

Lyα forests are usually associated with intergalactic gas clouds intercepting the quasar sight–line. Using as an example the Lyα forest of QSO 0055–26 (zem = 3.66), we show that the probability of observing a line at the velocity difference ∆v has an intermittent structure in the redshift space. On small scales (70 km s ≤ ∆v ≤ 1580 km s) the signature of intermittency appears as a self–similar ...

We present preliminary results on the low-redshift Lyα forest as based on STIS spectra of 3C 273. A total of 121 intergalactic Lyα-absorbing systems were detected, of which 60 are above the 3.5σ com-pletness limit, logN HI ≈12.3. The median line-width parameter, b = 27 km/s, is similar to that seen at high redshift. However the distribution of HI column densities has a steeper slope, β = 2.02 ±...

ABSTRACT We evaluate the performance of Lyman α forest weak gravitational lensing estimator Metcalf et al. on data from hydrodynamic simulations and ray-trace simulated potentials. compare results to those obtained Gaussian random field Lyα potentials used in previous work. find that is able reconstruct more realistic investigate dependence spectrum signal noise. The non-linearity non-Gaussiani...

I discuss recent HST observations and interpretation of low-z Lyα clouds toward nearby Seyferts and QSOs, including their frequency, space density, estimated mass, association with galaxies, and contribution to Ωb. Our HST/GHRS detections of 73 Lyα absorbers with NHI ≥ 10 12.6 cm along 11 sightlines covering pathlength ∆(cz) = 86, 000 km s show f(> NHI) ∝ N −0.6±0.2 HI . A group of strong absor...