1 99 6 Scaling properties of the Lyman – α forest
نویسنده
چکیده
We present some statistical features of the large number of Lyα absorption lines detected in high redshift quasar spectra, obtained by using the multifractal approach. In the analysed sample of 12 QSO sight–lines, 11 show scaling behaviour with a crossover between two distinct regimes: a non-homogeneous regime at small scales and a homogeneous regime at large scales. The correlation length shows a redshift dependence, suggesting that the Lyα forest can be an intermediate phenomenon between a strongly inhomogeneous galaxy distribution in the local Universe and a homogeneous initial mass distribution.
منابع مشابه
Constraints from the Lyman Α Forest Power Spectrum
We use published measurements of the transmission power spectrum of the Lyman α forest to constrain several parameters that describe cosmology and thermal properties of the intergalactic medium (IGM). A 6 parameter grid is constructed using Particle-Mesh dark matter simulations together with scaling relations to make predictions for the gas properties. We fit for all parameters simultaneously a...
متن کاملA high - resolution study of the evolution of the Lyman α forest in the redshift interval 0 . 9 < z < 1 . 7 ⋆
A high-resolution study of the evolution of the Lyman α forest in the redshift interval 0.9 < z < 1.7 Abstract. Spectroscopy with HST/STIS Echelle and VLT/UVES of the bright QSO HE 0515−4414 (zem = 1.73, B = 15.0) offers for the first time the opportunity to study the Lyman α forest in the redshift range 0.9 < z < 1.7 at a resolution ≤ 10 km s −1. The number density evolution of the Lyman α lin...
متن کاملRadiation Pressure in Lyman-α Forest Clouds
The effective recombination coefficient, αeff , is refined for optically thin cases. Radiation pressure in Lyman-α and HeII Lyman-α is calculated in terms of the number density and the mean free path. Pressure equilibrium between Lyman-α clouds and an adiabatically expanding inter-galactic medium is assumed, niTi = ncTc. Numerical models of isothermal and adiabatic expanding Lyman-α forest clou...
متن کاملar X iv : a st ro - p h / 96 10 22 5 v 1 2 8 O ct 1 99 6 GHRS Observations of the Lyman α Forest
I review the results obtained using the GHRS on low redshift Lyman α absorbers. Until the advent of HST and the GHRS, the existence of such absorbers was doubted. The confirmation of their existence, in one of the first GHRS GTO team results to be published, must rank as one of the HSTs most interesting results. The GHRS resolution allows us to probe equivalent widths well below those detectabl...
متن کاملThe evolution of a pre-heated intergalactic medium
We analyse the evolution of the Intergalactic Medium (IGM) by means of an extended set of large box size hydrodynamical simulations which include pre–heating. We focus on the properties of the z ∼ 2 Lyman-α forest and on the population of clusters and groups of galaxies at z = 0. We investigate the distribution of voids in the Lyman-α flux and the entropy–temperature relation of galaxy groups, ...
متن کامل