The dependence on redshift of quasar black hole masses from the SLOAN survey R. Decarli Università dell’Insubria, Como, Italy A. Treves Università dell’Insubria, Como, Italy R. Falomo INAF, Osservatorio Astronomico di Padova, Italy Marzia Labita

Torino, 20/05/2008 AGN8 2 SMBHs and host galaxies Most (if not all) nearby (early type) galaxies host a supermassive black hole (SMBH) at their centers - proper motion of stars (Milky Way) - rotation curves of gas clouds – MASER (22 objects) The host galaxies of low redshift quasars contain a massive spheroidal component (observative results) (Ferrarese 2006 for a review) Elliptical galaxies ↔ SMBHs

Torino, 20/05/2008 AGN8 3 Joint formation of SMBHs and massive spheroids According to the hierarchical merging scenario, massive spheroids should be the products of successive merging events At low redshift, the central BH mass is strongly correlated to the properties of the host galaxy bulge (of both active and inactive galaxies) …OUTSIDE THE SPHERE OF INFLUENCE! Formation ofFormation and fuelling Elliptical galaxies of their active nuclei

Torino, 20/05/2008 AGN8 4 Quasar – Host Galaxy connection:  Host galaxy luminosity (mass) dependence on redshift  Study the BH – host mass correlation at low z and trace its cosmological evolution close and beyond the peak of the quasar activity  BH mass dependence on redshift SLOAN McLure & Dunlop SDSS Shen et al. SDSS Fine et al. 2dF

Torino, 20/05/2008 AGN8 5 SDSS Sloan Digital Sky Survey (Fifht data release) 8000 square degrees imaged spectra quasars (0.1 < z < 4.5) …of which: quasars for which MgII line width and 3000Å monochromatic flux are available (0.35 < z < 2.3)  Uniform BH mass determinations: (McLure & Dunlop 2004)

Torino, 20/05/2008 AGN8 6 Absolute magnitude and BH mass vs. redshift ? Malmquist Bias

Torino, 20/05/2008 AGN8 7 The luminosity-FWHM plane GROWING REDSHIFT

Torino, 20/05/2008 AGN8 8 The luminosity-FWHM plane Constant luminosity

Torino, 20/05/2008 AGN8 9 The luminosity-FWHM plane Constant luminosity Constant BH mass

Torino, 20/05/2008 AGN8 10 The luminosity-FWHM plane Constant luminosity Constant BH mass Constant Eddington ratio

Torino, 20/05/2008 AGN8 11 M MAX E MAX L MIN The luminosity-FWHM plane

Torino, 20/05/2008 AGN8 12 M MAX E MAX L MIN The luminosity-FWHM plane PROBABILITY DENSITY:

Torino, 20/05/2008 AGN8 13 Focus on the lowest redshift sample: Description of the assumed probability density 6 FREE PARAMETERS: L MIN M MAX E MAX σLσL σEσE σMσM

Torino, 20/05/2008 AGN8 14 Best fit to the luminosity-FWHM distribution  Construction of the discrete observed distribution:  Division in boxes with ΔlogλL λ =0.15; ΔlogFWHM=0.04  Number of objects in each box  Construction of the discrete expected distribution from the assumed probability density:  Discretization in boxes  Normalization to the observed number of objects  Evaluation of the best fit parameters:  For each choice of the 6 free parameters, evaluation of the rms between the observed and the expected distributions  Minimization of the rms  BEST FIT PARAMETERS Contour plot = Levels of constant probability Errors on the best fit parameters: MONTE CARLO SIMULATIONS

Torino, 20/05/2008 AGN8 15 Comparison between the observed and the expected distribution Contour plot of a sample of quasars simulated adopting the best fit probability density (Monte Carlo simulation) Contour plot of the observed quasar sample Contour plot of the residuals between the observed and the simulated distributions

Torino, 20/05/2008 AGN8 16 Best fit parameters in function of redshift The rms of the best fit is almost the same in all the redshift bins. (If we assumed that M MAX is constant redshift, the fit would be awful!) The best fit parameters M MAX (z) and E MAX (z) give the (unbiassed!) dependence on redshift of the maximum mass and Eddington ratio L MIN is a free parameter L MIN is a NOT a free parameter: its dependence on redshift is fixed by COSMOLOGY GROWING REDSHIFT

Torino, 20/05/2008 AGN8 17 Evolution of the quasar populations with the Cosmic Time: EDDINGTON RATIO

Torino, 20/05/2008 AGN8 18 Evolution of the quasar populations with the Cosmic Time: EDDINGTON RATIO This work Simple mean

Torino, 20/05/2008 AGN8 19 Evolution of the quasar populations with the Cosmic Time: MASS Log (M BH MAX /M SUN ) = 1/3 z + 9

Torino, 20/05/2008 AGN8 20 This work Simple mean Fine et al. Evolution of the quasar populations with the Cosmic Time: MASS Log (M BH MAX /M SUN ) = 1/3 z + 9

Torino, 20/05/2008 AGN8 21 Conclusions The maximum mass of quasar populations seems to decrease with Cosmic Time i.e. the more a BH is massive, the earliest it starts its quasar activity Future Use C IV line to study this trend till z=4.5 Compare and contrast this trend in RQQs and RLQs Compare this results with the bulge mass evolution with redshift …WORK IN PROGRESS!