The relative growth of Optical and Radio Quasars in SDSS (2009)
Shankar, Francesco, Sivakoff, Gregory R., Vestergaard, Marianne, Dai, Xinyu
We cross-correlate the SDSS DR3 quasar sample with FIRST and the Vestergaard et al. black hole (BH) mass sample to compare the mean accretion histories of optical and radio quasars. We find...
On merger bias and the clustering of quasars (2009)
Bonoli, Silvia, Shankar, Francesco, White, Simon, Springel, Volker, Wyithe, Stuart
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...
Binary Quasars at High Redshift I: 24 New Quasar Pairs at z ~ 3-4 (2009)
Hennawi, Joseph F., Myers, Adam D., Shen, Yue, Strauss, Michael A., Djorgovski, S. G., Fan, Xiaohui, ...
The clustering of quasars on small scales yields fundamental constraints on models of quasar evolution and the buildup of supermassive black holes. This paper describes the first systematic survey to...
Binary Quasars at High Redshift II: Sub-Mpc Clustering at z ~ 3-4 (2009)
Shen, Yue, Hennawi, Joseph F., Shankar, Francesco, Myers, Adam D., Strauss, Michael A., Djorgovski, S. G., ...
We present measurements of the small-scale (0.1
The Demography of Super-Massive Black Holes: Growing Monsters at the Heart of Galaxies (2009)
Supermassive black holes (BHs) appear to be ubiquitous at the center of all galaxies which have been observed at high enough sensitivities and resolution with the Hubble Space Telescope. Their masses...
The age dependence of the size-stellar mass relation and some implications (2009)
Shankar, Francesco, Bernardi, Mariangela
We use a sample of about 48,000 SDSS early-type galaxies to show that older galaxies have smaller half-light radii re and larger velocity dispersions sigma than younger ones of the same stellar mass...
Shankar, Francesco, Crocce, Martin, Miralda-Escude', Jordi, Fosalba, Pablo, Weinberg, David H.
We investigate the characteristic radiative efficiency \epsilon, Eddington ratio \lambda, and duty cycle P_0 of high-redshift active galactic nuclei (AGN), drawing on measurements of the AGN...
Quasar Clustering from SDSS DR5: Dependences on Physical Properties (2008)
Shen, Yue, Strauss, Michael A., Ross, Nicholas P., Hall, Patrick B., Lin, Yen-Ting, Richards, Gordon T., ...
Using a homogenous sample of 38,208 quasars with a sky coverage of $4000 {\rm deg^2}$ drawn from the SDSS Data Release Five quasar catalog, we study the dependence of quasar clustering on luminosity,...
Shankar, Francesco, Bernardi, Mariangela, Haiman, Zoltan
We utilize the local velocity dispersion function (VDF) of spheroids, together with their inferred age--distributions, to predict the VDF at higher redshifts (0
Dependence of the BALQSO fraction on Radio Luminosity (2008)
Shankar, Francesco, Dai, Xinyu, Sivakoff, Gregory R.
We find that the fraction of classical Broad Absorption Line quasars (BALQSOs) among the FIRST radio sources in the Sloan Data Release 3, is 20.5^{+7.3}_{-5.9}% at the faintest radio powers detected...
The Optical-Radio Mapping: the kinetic efficiency of Radio-Loud AGNs (2007)
Shankar, Francesco, Cavaliere, Alfonso, Cirasuolo, Michele, Maraschi, Laura
We constrain the mean kinetic efficiency of radio-loud active galactic nuclei by using an optically selected sample for which both the optical and the radio luminosity functions (LFs) have been...
The growth of the nuclear black holes in submillimetre galaxies (2007)
Granato, Gian Luigi, Silva, Laura, Lapi, Andrea, Shankar, Francesco, De Zotti, Gianfranco, Danese, Luigi
We show that the ABC scenario we proposed for the co-evolution of spheroids and QSOs predicts accretion rates and masses of supermassive black holes in sub-mm galaxies in keeping with recent X-ray...
Measuring the Spin of Spiral Galaxies (2007)
Tonini, Chiara, Lapi, Andrea, Shankar, Francesco, Salucci, Paolo
We compute the angular momentum, the spin parameter and the related distribution function for Dark Matter halos hosting a spiral galaxy. We base on scaling laws, inferred from observations, that link...
Shankar, Francesco, Lapi, Andrea, Salucci, Paolo, De Zotti, Gianfranco, Danese, Luigi
We present new relationships between halo masses M_h and several galaxy properties, including r*-band luminosities L_r, stellar (M_star) and baryonic masses, stellar velocity dispersions (sigma), and...
Quasar Luminosity Functions from Joint Evolution of Black Holes and Host Galaxies (2007)
Lapi, Andrea, Shankar, Francesco, Mao, Jirong, Granato, Gian Luigi, Silva, Laura, De Zotti, Gianfranco, ...
We show that our previously proposed anti-hierarchical baryon collapse scenario for the joint evolution of black holes and host galaxies predicts quasar luminosity functions at redshifts 1.5
Shankar, Francesco, Weinberg, David H., Miralda-Escude', Jordi
We construct evolutionary models of the populations of AGN and supermassive black holes, in which the black hole mass function grows at the rate implied by the observed luminosity function, given...
2MASS Reveals a Large Intrinsic Fraction of BALQSOs (2007)
Dai, Xinyu, Shankar, Francesco, Sivakoff, Gregory R.
The intrinsic fraction of broad absorption line quasars (BALQSOs) is important in constraining geometric and evolutionary models of quasars. We present the fraction of BALQSOs in 2MASS detected...
On the faint end of the high redshift AGN luminosity function (2007)
Shankar, Francesco, Mathur, Smita
Using the results of recent optical surveys we conclude that the {\it non}-detection of quasars down to faint magnitudes implies a significant flattening of the high redshift (z~6) optical active...
A physical model for co-evolution of QSOs and of their spheroidal hosts (2006)
De Zotti, Gianfranco, Shankar, Francesco, Lapi, Andrea, Granato, Gian Luigi, Silva, Laura, Cirasuolo, Michele, ...
At variance with most semi-analytic models, in the Anti-hierarchical Baryon Collapse scenario (Granato et al. 2001, 2004) the main driver of the galaxy formation and evolution is not the merging...
Measuring the Spin of Spiral Galaxies (2005)
Tonini, Chiara, Lapi, Andrea, Shankar, Francesco, Salucci, Paolo
We compute the angular momentum, the spin parameter and the related distribution function for Dark Matter halos hosting a spiral galaxy. We base on scaling laws, inferred from observations, that link...
Super-massive Black Holes: the missing link in galaxy evolution (2005)
Danese, Luigi, Salucci, Paolo, Shankar, Francesco
The aim of this thesis is to investigate the key points concerning the evolution of the local Super-massive Black Hole (SMBH) population and to understand the origin of the links the SMBH have with...
local supermassive black hole mass function and mass density Elektronische Daten (2003)
Shankar, Francesco, Astrophysics Conference
Poster von Kongress: Star and Structure Formation: From First Light to the Milky Way, Astrophysics Conference, August 18-22, 2003, ETH Zurich, Switzerland