On merger bias and the clustering of quasars

Understand

We use the large catalogues of haloes available for the Millennium Simulation to test whether recently merged haloes exhibit stronger large-scale clustering than other haloes of the same mass.

• This effect could help to understand the very strong clustering of quasars at high redshift.
• However, we find no statistically significant excess bias for recently merged haloes over the redshift range 2 < z < 5, with the most massive haloes showing an excess of at most ~5%.
• We also consider galaxies extracted from a semianalytic model built on the Millennium Simulation.