The Proximity Effect, the UV Background and the Statistics of the Lyman-Alpha Lines at High Resolution

Details The Proximity Effect, the UV Background and the Statistics of the Lyman-Alpha Lines at High Resolution The Proximity Effect, the UV Background and the Statistics of the Lyman-Alpha Lines at High Resolution

1996-02-06

arxiv.org/abs/astro-ph/9602026v2

Astronomy and Astrophysics

Astrophysics

24 pages (2 macros included) + 9 figures. Accepted for publication on ApJ. Revised version: minor changes to text and fig 8 an

Scientific paper

10.1086/177492

We present results from high resolution (R\simeq 28000) spectra of six high- redshift QSOs taken at the ESO NTT telescope that allow the detailed study of the Ly-alpha population in the redshift interval z=2.8-4.1. The typical Doppler parameters found for the Ly-alpha lines lie in the interval b=20\div30 km/s, corresponding to temperatures T>24000K, with a fraction of the order 15% in the range 10=13.3) in the redshift interval z=1.7-4.1. A Maximum Likelihood analysis has been applied to estimate SIMULTANEOUSLY the best fit parameters of the Ly-alpha$ statistics AND of the UV background. After correcting for the blanketing of weak lines, we confirm that the column density distribution is best represented by a double power-law with a break at logN_{HI}\simeq14, with a slope beta_s=1.8 for higher column densities and a flatter slope beta_f=1.4 below the break. A value J_{LL}= 5 \pm1 \times10^{-22} erg/cm^2/s/Hz/sr is derived for the UV background in the redshift interval z=1.7-4.1, consistent with the predicted QSO contribution. No evidence is found for redshift evolution of the UVB in the same redshift interval. The comoving volume density distributions of protogalactic Damped and Lyman Lymit systems and Ly-alpha clouds with log N_{HI}>= 14 and radii R\simeq 200 kpc are found to be similar, suggesting a possible common association with galaxies.

Affiliated with

Also associated with

No associations

Rating

The Proximity Effect, the UV Background and the Statistics of the Lyman-Alpha Lines at High Resolution 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 The Proximity Effect, the UV Background and the Statistics of the Lyman-Alpha Lines at High Resolution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Proximity Effect, the UV Background and the Statistics of the Lyman-Alpha Lines at High Resolution will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-700286