This is the third paper of a series describing the Asiago-ESO/RASS QSO survey ( AERQS ) , a project aimed at the construction of an all-sky statistically well-defined sample of relatively bright QSOs ( B \leq 15 ) at z \leq 0.3 .
We present here the clustering analysis of the full spectroscopically identified database ( 392 AGN ) .
The clustering signal at 0.02 < z < 0.22 is detected at a 3 - 4 \sigma level and its amplitude is measured to be r _ { 0 } = 8.6 \pm 2.0 h ^ { -1 } Mpc ( in a \Lambda CDM model ) .
The comparison with other classes of objects shows that low-redshift QSOs are clustered in a similar way to Radio Galaxies , EROs and early-type galaxies in general , although with a marginally smaller amplitude .
The comparison with recent results from the 2QZ shows that the correlation function of QSOs is constant in redshift or marginally increasing toward low redshift .
We discuss this behavior with physically motivated models , deriving interesting constraints on the typical mass of the dark matter halos hosting QSOs , M _ { DMH } \sim 10 ^ { 12.7 } h ^ { -1 } M _ { \odot } ( 10 ^ { 12.0 } -10 ^ { 13.5 } h ^ { -1 } M _ { \odot } at 1 \sigma confidence level ) .
Finally , we use the clustering data to infer the physical properties of local AGN , obtaining M _ { BH } \sim 2 \cdot 10 ^ { 8 } h ^ { -1 } M _ { \odot } 
( 10 ^ { 7 } -3 \cdot 10 ^ { 9 } h ^ { -1 } M _ { \odot } ) for the mass of the active black holes , \tau _ { AGN } \sim 8 \cdot 10 ^ { 6 } yr ( 2 \cdot 10 ^ { 6 } -5 \cdot 10 ^ { 7 } yr ) for their life-time and \eta \sim 0.14 for their efficiency ( always for a \Lambda CDM model ) .