We have used several complete samples of quasars (450 objects in total) to gain information on the large-scale structure of the Universe at redshifts 0.4 < z < 2.2. We have evaluated the conditional density and the average density functions to establish that on scales larger than 12.5 h-1 Mpc the quasar distribution becomes homogeneous. The use of a more conventional and time-honoured technique such as the correlation function is therefore appropriate in the case of the present samples and equivalent to the conditional and average density functions. These latter functions allow us, however, to put slightly stronger constraints on the amplitude of clustering at large scales. Possible observational biases which could lead to incorrect conclusions on quasar clustering are discussed.
Andreani, P., Cristiani, S., LA FRANCA, F. (1991). IS THE UNIVERSE A FRACTAL - TESTS ON QUASAR SAMPLES. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 253(3), 527-532.
IS THE UNIVERSE A FRACTAL - TESTS ON QUASAR SAMPLES
LA FRANCA, Fabio
1991-01-01
Abstract
We have used several complete samples of quasars (450 objects in total) to gain information on the large-scale structure of the Universe at redshifts 0.4 < z < 2.2. We have evaluated the conditional density and the average density functions to establish that on scales larger than 12.5 h-1 Mpc the quasar distribution becomes homogeneous. The use of a more conventional and time-honoured technique such as the correlation function is therefore appropriate in the case of the present samples and equivalent to the conditional and average density functions. These latter functions allow us, however, to put slightly stronger constraints on the amplitude of clustering at large scales. Possible observational biases which could lead to incorrect conclusions on quasar clustering are discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
