Available formats: HTML | PDF | (gzipped) PostScript
Evolution of the Lyman forest from high to low redshift
Rüdiger Riediger 1,
Patrick Petitjean 2, 3 and
Jan P. Mücket 1
Received 30 January 1997 / Accepted 12 September 1997
We study the evolution with redshift, from to , of the Lyman forest in a CDM model using numerical simulations including collisionless particles only. The baryonic component is assumed to follow the dark matter distribution.
We distinguish between two populations of particles: Population traces the filamentary structures of the dark matter, evolves slowly with redshift and, for , dominates the number density of lines at ; most of population is located in underdense regions and for the same column densities, disappears rapidly at high redshift.
We generate synthetic spectra from the simulation and show that the redshift evolution of the Lyman forest (decrement, distribution) is well reproduced over the whole redshift range for and at where is the UV background flux intensity in units of erg cm-2 s-1 Hz-1 sr-1.
The total number of lines with remains approximately constant from to . At , the number density of lines per unit redshift with is of the order of 400, 100, and 20 respectively. Therefore, at low redshift, if most of the strong ( ) lines are expected to be associated with galaxies, the bulk of the Lyman forest however should have lower equivalent width and should not be tightly correlated with galaxies.
Key words: large-scale structure intergalactic medium quasars: absorption lines
Send offprint requests to: R. Riediger
© European Southern Observatory (ESO) 1998
Online publication: November 24, 1997