Astronomy and Astrophysics – Astrophysics
Scientific paper
1998-04-08
Astronomy and Astrophysics
Astrophysics
14 pages, 5 figures, requires mn.sty, accepted for publication in MNRAS
Scientific paper
10.1046/j.1365-8711.1998.01695.x
We estimate the evolution of the contribution of galaxies to the cosmic background flux at $912 \AA$ by means of a semi-analytic model of galaxy formation and evolution. Such a modelling has been quite successful in reproducing the optical properties of galaxies. We assume hereafter the high-redshift damped Lyman-$\alpha$ (DLA) systems to be the progenitors of present day galaxies, and we design a series of models which are consistent with the evolution of cosmic comoving emissivities in the available near infrared (NIR), optical, ultraviolet (UV), and far infrared (FIR) bands along with the evolution of the neutral hydrogen content and average metallicity of damped Lyman-$\alpha$ systems (DLA). We use these models to compute the galactic contribution to the Lyman-limit emissivity and background flux for $0 \simeq z \le 4$. We take into account the absorption of Lyman-limit photons by HI and dust in the interstellar medium (ISM) of the galaxies. We find that the background Lyman-limit flux due to galaxies might dominate (or be comparable to) the contribution from quasars at almost all redshifts if the absorption by HI in the ISM is neglected. The ISM HI absorption results in a severe diminishing of this flux--by almost three orders of magnitude at high redshifts to between one and two orders at $z \simeq 0$. Though the resulting galaxy flux is completely negligible at high redshifts, it is comparable to the quasar flux at $z \simeq 0$.
Devriendt Julien E. G.
Guiderdoni Bruno
Nath Biman B.
Sethi Shiv K.
No associations
LandOfFree
Contribution of Galaxies to the Background Hydrogen-Ionizing Flux does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Contribution of Galaxies to the Background Hydrogen-Ionizing Flux, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Contribution of Galaxies to the Background Hydrogen-Ionizing Flux will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-216914