The variance of quasar counts in cells
P. Andreani, S. Cristiani, F. Lucchin, S. Matarrese, Lauro Moscardini · The Astrophysical Journal · 1994
From three quasar samples with a total of 1038 objects in the redshift range 1.0-2.2 we measure the variance σ^2^ of counts in cells of volume V_u_. By a maximum-likelihood analysis applied separately on these samples we obtain estimates of σ^2^(l), with l = V_u_^1/3^. The analysis from a single catalog for l = 40 h^-1^ Mpc and from a suitable average over the three catalogs for l = 60, 80, and 100 h^-1^ Mpc, gives σ^2^(l) = 0.46_-0.27_^+0.27^, 0.18_-0.15_^+0.14^, 0.05_- 0.05_^+0.14^ and 0.12_-0.12_^+0.13^, respectively, where the 70% confidence ranges account for both sampling errors and statistical fluctuations in the counts. This allows a comparison of QSO clustering on large scales with analogous data recently obtained both for optical and IRAS galaxies: QSOs seem to be more clustered than these galaxies by a biasing factor b_QSO_/b_gal_ ~ 1.4-2.3.