2025/11/21 by Mariona Giner Mascarell, Anna–Christina Eilers, Mascarell, Mariona Giner +3
Physics and Astronomy · #Galaxies: Formation, Evolution, Phenomena #Astronomy and Astrophysical Research #Gamma-ray bursts and supernovae
paper · pdf · doi:10.48550/arxiv.2511.17413
We measure the two-point correlation function of a uniformly selected, all-sky sample of ∼1.3 million quasars with magnitudes G≤20.5 from the Gaia--unWISE Quasar Catalog (Quaia) over the redshift range 0 ≤ z ≤ 4 to trace the evolution of the quasar clustering strength across cosmic time. We find a steady increase in the correlation length r0 with redshift, i.e. r0 = 6.8 ± 0.2 h-1Mpc at 0 ≤ z < 1, r0=8.0 ± 0.2 h-1Mpc at 1 ≤ z < 2, r0=10.8 ± 0.2 h-1Mpc at 2 ≤ z < 3, and r0=13.9 ± 1.2 h-1Mpc at 3 ≤ z < 4, and slopes consistent with γ≈ 2. Our measurements suggest a slightly weaker clustering signal at z>3 than previous studies, and thus we find a smooth, monotonic rise in clustering strength. Using a bias-halo mass relation and a step-function for the halo occupation distribution, we infer characteristic minimum halo masses of quasar hosts of log10(Mmin/M_\odot) ≈ 12.8 across all redshifts. Combining these with the observed quasar number densities yields duty cycles that rise from fduty ≈ 2% to ≈ 7% with increasing redshift, corresponding to integrated quasar lifetimes of t\rm QSO∼108~years. These results suggest that both the characteristic halo mass of active quasars and their typical lifetimes have remained remarkably stable over more than 12 ∼ Gyr of cosmic time, implying a self-regulated growth process largely independent of epoch.