6 papers · 1 filter
Cosmological Adventures in the Lyman Forest
S. Cristiani
The properties of the Lyman- absorptions observed in the spectra of QSOs are reviewed: the distribution of column densities and Doppler widths, the redshift evolution, the ``inv…
The Optical Variability of QSO's
S. Cristiani, S. Trentini, F. La Franca +4
The long-term variability of a sample of 486 optically selected QSOs in the fields of the SA94, SA57 and SGP has been studied. The relations of variability with luminosity and reds…
The ESO Key-Programme ``A Homogeneous Bright QSO Survey'' - I The Methods and the ``Deep'' Fields
S. Cristiani, F. La Franca, P. Andreani +13
This is the first paper in a series aimed at defining a statistically significant sample of QSOs in the range and . The selection is carried out u…
THE CLUSTERING OF QUASARS
P. Andreani, S. Cristiani, F. La Franca
We have investigated the spatial distribution of quasars and its relationship with redshift by using the two-point correlation function, the variance of cell counts and the conditi…
CLUSTERING PROPERTIES OF THE LY CLOUDS
S. Cristiani, S. D'Odorico, V. D'Odorico +3
The spectra of the QSOs PKS2126-158 () and Q0055-269 () have been observed at high resolution (). Significant clustering, with $ξ\s…
Clustering of the Lyman Alpha Clouds in the Line of Sight to the Z=3.66 QSO 0055-269
S. Cristiani, S. D'Odorico, A. Fontana +2
The spectrum of the Q0055-269 () has been observed at the resolution of 14 km s in the wavelength interval 4750--6300 Å. The statistical distribution of the Doppler…