Issue |
Astron. Astrophys. Suppl. Ser.
Volume 127, Number 2, January II 1998
|
|
---|---|---|
Page(s) | 217 - 232 | |
DOI | https://doi.org/10.1051/aas:1998104 | |
Published online | 15 January 1998 |
The absorption spectrum of the QSO PKS
(
)
at high resolution
*,**
1
International School for Advanced Studies, SISSA, via Beirut 2-4, I-34014 Trieste, Italy
2
Dipartimento di Astronomia dell'Università di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy
3
European Southern Observatory, Karl Schwarzschild Strasse 2, D-85748 Garching, Germany
4
Osservatorio Astronomico di Roma, via dell'Osservatorio, I-00040 Monteporzio, Italy
Send offprint request to: S. Cristiani
Received:
10
February
1997
Accepted:
12
May
1997
Spectra of the quasar PKS 2126-158 have been obtained
in the range
Å with a resolution
and an average signal-to-noise ratio
per
resolution element.
The list of the identified absorption lines is given together with
their fitted column densities and Doppler widths.
The modal value of the Doppler parameter distribution for the Lyα
lines is
km s-1.
The column density distribution can be described by a power-law
with
.
12 metal systems have been identified, two of which were previously
unknown.
In order to make the column densities of the intervening
systems compatible
with realistic assumptions about the cloud sizes and the silicon to carbon
overabundance, it is necessary to assume a jump beyond the He II edge
in the spectrum of the UV ionizing background at
a factor 10 larger than the standard predictions for the
integrated quasar contribution.
An enlarged sample of C IV absorptions
(71 doublets) has been used
to analyze the statistical properties of this class
of absorbers strictly related to galaxies.
The column density distribution is well described by a
single power-law, with
and the Doppler parameter
distribution shows a modal value
km s-1.
The two point correlation function has been computed in the
velocity space for the individual components of C IV features.
A significant signal is obtained for scales smaller than 200-300 km
s-1,
.
A trend of decreasing clustering amplitude with decreasing
column density is apparent, analogously to what has been observed
for Lyα lines.
Key words: quasars: absorption lines / quasars: individual: PKS 2126-158
© European Southern Observatory (ESO), 1998