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Clustering properties and environment of AGN

Clustering properties and environment of AGN. R. Gilli, T . Miyaji, J. Silverman, G. Zamorani and many others (mainly from the COSMOS collaboration). A few issues and questions. Where do AGN live? ( host galaxies, enviroment , dark matter h alos )

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Clustering properties and environment of AGN

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  1. Clusteringproperties and environmentof AGN R. Gilli, T. Miyaji, J. Silverman, G. Zamorani and many others (mainly from the COSMOS collaboration)

  2. A few issues and questions Where do AGN live? (host galaxies, enviroment, dark matter halos) Does environment play a role in triggering an AGN? Mergers, galaxy interactions or internal secular processes? • From AGN clustering: • Duty cycle and lifetime • Descendants and progenitors • L/LEDDdistribution • Towards an evolutionary sequence

  3. Clustering = spatialdistribution The correlation function – w(θ), ξ(r), wp(rp) - is a statistical description of a spatial distribution: it simply measures how many pairs of objects are found over a random distribution

  4. Random distribution

  5. Highly clustered distribution

  6. Clustering of dark matter and halos z=0.0 z=3.0 z=0.0 ξ(r) z=3.0 Millennium simulation (Springel+05) Moustakas& Somerville04 r [Mpc] Halos form in high density peaks; at eachredshiftmore massive halos are more clustered

  7. Infos from AGN clustering Correlation length r0 ≈ powerlaw normalization On small scales (< 1-2 Mpc): objects in the same dark matter halo (1-halo term). Infos on the mechanisms triggering nuclear activity: mergers, fly by or secular processes? On large scales (>1-2 Mpc): objects in different halos (2-halo term). Infos on location of AGN within the cosmic web; hosting dark matter halos and galaxies; typical environment From 2dF

  8. Host galaxies and dark matter halos at z~1 r0 (z~1) = 5.2+-1.5 Mpc/h Minimum halo mass: logM > 12.4 Msun/h AGN at z~1 seem to be preferentially hosted by massive galaxies (M*>2-3 1010Msun) Consistent with non-clustering studies (eg.Silverman+09)

  9. AGN lifetime from clustering tA nA tHnH = OpticalQSOs (logLbol~46.5 , z~1-2): tA ~ 10-100 Myr X-ray AGN (logLbol~45.5 , z~1):tA~1Gyr

  10. Clustering as a function of redshift Despite earlier claims, X-ray AGN cluster similarly to optically selected QSOs at the same redshifts Radio-galaxies, instead are more clustered. Halo mass, logM/Mo~12-12.5, typical of poor groups, seems the be the same at any epoch: is there any halo threshold mass for nuclear triggering?? CDFS Millennium halos

  11. The Hickoxet al. (2009) cartoon Thresholdhalo mass (group mass)to start the sequencethroughgalaxy mergers

  12. Descendants of z~0.7 X-ray AGN Red, early green, transitional blue, late Loh+10, GALEX X-ray AGN conserving scenario (Nusser & Davis 94,Moscardini+98): objects in halos with a given mass simply evolve without merging along the density field X-ray AGN at z~0.7 will switch off by z=0 and their relic SMBHs will be hosted by local bright (L~L*) early type galaxies

  13. So mergers are thetriggeringmechanism? Hopkins+08 z<0.4 1-halo term QSOs are consistentwithbeingtriggeredbymergers, Seyfertsprobablynot Issuestilltobesolved..

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