The Lyalpha forest of the quasar HS 1946+7658: properties of the Lyalpha absorbing systems at high Z

Details The Lyalpha forest of the quasar HS 1946+7658: properties of the Lyalpha absorbing systems at high Z The Lyalpha forest of the quasar HS 1946+7658: properties of the Lyalpha absorbing systems at high Z

Jul 1996

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996mnras.281..463d&link_type=abstract

Monthly Notices of the Royal Astronomical Society, Volume 281, Issue 2, pp. 463-474.

Astronomy and Astrophysics

Astronomy

1

Techniques: Spectroscopic, Quasars: Absorption Lines, Quasars: Individual: Hs 1946+7658

Scientific paper

The optical spectrum of the QSO HS 1946+7658 (z_em=3.05) has been observed at high resolution (b~14 km s^-1) in the wavelength interval 4120-4970 A. The high signal-to-noise ratio (>=10) in the Lyalpha forest allows the determination of the neutral hydrogen column density as well as the velocity dispersion of the intervening clouds by fitting Voigt profiles. These results have been included in a global sample of Lyalpha lines from six QSOs ranging from redshift 2.14 to 4.51, at a similar signal-to-noise ratio and resolution selected from the literature (654 lines satisfying our criteria). The study of this sample confirms a plateau and a strong fall-off (cut-off point at log N_HI~=14) in the N_HI distribution. The b distributions above and below such a cut-off show similar asymmetric bell-shaped forms but significantly different mean and median values (b>=28, 36 km s^-1 and b_med=32, 37 km s^-1, for weak and strong lines respectively), arguing against the independence of b and N_HI. Supporting such a relation, the b-N_HI diagram suffers a deficit of strong lines with low b values (K-S probability of the data coming from uncorrelated distributions p_K-S=0.047). We have found that the number density of systems per unit interval of redshift can be fitted to a power law with index gamma=2.35+/-0.22 when all the QSOs are included, but a higher slope gamma=3.22+/-0.41 is obtained for the redshift range 2.1<z<3.7. The characteristic Doppler parameters do not show evolution with z for weak (log N_HI<14) absorbing systems, while, for strong (log N_HI<~14) ones, typical b values decrease with z.

Affiliated with

Also associated with

No associations

Rating

The Lyalpha forest of the quasar HS 1946+7658: properties of the Lyalpha absorbing systems at high Z 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 Lyalpha forest of the quasar HS 1946+7658: properties of the Lyalpha absorbing systems at high Z, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Lyalpha forest of the quasar HS 1946+7658: properties of the Lyalpha absorbing systems at high Z will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1383307