Abstract
We present the clustering measurement of hard X-ray selected active galactic nuclei (AGNs) in the local universe. We used a sample of 199 sources spectroscopically confirmed, detected by Swift-BAT in its 15-55 keV all-sky survey. We measured the real space projected autocorrelation function (ACF) and detected a signal significant on projected scales lower than 200 Mpc h-1. We measured a correlation length of r0 = 5.56-0.43+0.49 Mpc h-1 and a slope γ = 1.64-0.07-0.08. We also measured the ACF of Type I and Type II AGNs and found higher correlation length for Type I AGNs. We have a marginal evidence of luminosity dependent clustering of AGNs, as we detected a larger correlation length of luminous AGNs than that of low-luminosity sources. The corresponding typical host dark matter halo masses of Swift-BAT are ∼ log(MDMH)∼ 12-14 h-1M/M⊙, depending on the subsample. For the whole sample, we measured log(MDMH)∼ 13.15 h-1M/M⊙ which is the typical mass of a galaxy group.We estimated that the local AGN population has a typical lifetime τAGN ∼0.7 Gyr, it is powered by supermassive black hole with mass MBH∼ (1-10) × 108 M⊙ and accreting with very low efficiency, log(∈)∼ -2.0. We also conclude that local AGN host galaxies are typically red-massive galaxies with stellar mass of the order (2-80) × 1010 h-1M⊙.We compared our results with clustering predictions of merger-driven AGN triggering models and found a good agreement.
Original language | English (US) |
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Pages (from-to) | L209-L213 |
Journal | Astrophysical Journal Letters |
Volume | 716 |
Issue number | 2 |
DOIs | |
State | Published - Jun 20 2010 |
Externally published | Yes |
Keywords
- Dark matter
- Diffuse radiation
- Galaxies: Active
- Large-scale structure of universe
- X-rays: Galaxies
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science