Modelling the cosmological co-evolution
of supermassive black holes and
galaxies
Federico Marulli
Collaborators:
Lauro Moscardini (Università di Bologna)
Enzo Branchini (Università Roma Tre)
Silvia Bonoli, Volker Springel, Simon D. M. White (Max-Planck-Institut fuer Astrophysik, Garching)
Dipartimento di Astronomia
Università di Bologna
Contents


Aim of the study:

Modelling the co-evolution of supermassive black holes and galaxies in the ΛCDM cosmology

Understanding the role of the AGN feedback in the evolution of galaxies and clusters
Working strategy:


Hybrid models: dark halos (N-body) + galaxies + BHs
Observational data:




BH scale relation and fundamental plane
BH mass function
AGN luminosity function
AGN clustering function
Federico Marulli
Torino: May 2008
Hybrid models: DM + galaxies + BH
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
Millennium Simulation
GADGET-2 code (Springel 2005), at the Computing
Centre of the Max-Planck Society in Garching, Germany
Dynamical evolution of 21603 ≃ 1e10 DM particles with
mass 8.6x1e8 Msun/h in a periodic box of 500 Mpc/h on
a side, in a LCDM “concordance” cosmological framework
(2-degree Field Galaxy Redshift Survey (2dFGRS)
(Colless et al. 2001) and first-year WMAP data (Spergel
et al. 2003), as shown by Sanchez et al. (2006))
Mass resolution: DM halo of 0.1L⋆ galaxies with ~ 100
particles
Spatial resolution: co-moving scale of 5 kpc/h
Hierarchical merging trees extracted from this simulation
DM haloes and subhalos identified with, respectively, a
friends-of-friends (FOF) group-finder and an extended
version of the SUBFIND algorithm (Springel et al. 2001)
http://www.mpa-garching.mpg.de/millennium
Federico Marulli
Torino: May 2008
Hybrid models: DM + galaxies + BH
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
Croton, Springel, White, De Lucia, Frenk, Gao, Jenkins,
Kauffmann, Navarro, Yoshida 2006
De Lucia–Blaizot 2007
Gas cooling (White-Frenk 1991,
Springel et al. 2001):
Photon-ionization heating (Kravtzov
et al. 2004):
Star formation (Kauffmann 1996):
Gas reated by supernovae:
tcool 
 m p kT
3
2  g ( r )  (T , Z )
 g (r ) 
mhot
4Rvir r 2
 cool  4g ( rcool ) r 2 cool rcool
m
f
halo
b
f bcos mic
( z , M vir ) 
(1  0.26 M F ( z ) / M vir ) 3
 *  0.03
m
mcold  mcrit
t dyn,disc
mreheated  3.5m*
 burst
Energy released by supernovae:
 m 
eburst  burst  sat 
 mcentral 
Disk instability (Mo et al. 1998):
Vc
1/ 2  1
Gmdisk / rdisk 
Fraction of gas turned into stars after a merger
(Cox 2004):
2
ESN  0.5 halom*VSN
Federico Marulli
Torino: May 2008
Hybrid models: DM + galaxies + BH
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
M BH ,Q 
quasar mode:
'
 f BH
f BH
'
mcold
f BH
 280 km / s 

1  
V

vir

msat
mcentral
2
f Edd (t ) : Lbol (t ) / LEdd (t )
dt

t Edd
d ln M BH (t ) 
, tef (t ) 
tef (t )
1   f Edd (t )
radio mode:
Vvir
 M
 f 

M BH , R  k AGN  8 BH  hot 
1 
10
M
0
.
1
200
km
/
s
 



L
'
 cool
 cool  BH 2
m
m
0.5Vvir
Croton et al. 2006, De Lucia-Blaizot 2007
3
Federico Marulli
Torino: May 2008
BH scale relations at z=0
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
Black dots : observations
Black dashed lines : best fit to the
observational datasets
Red dots : model output
Blue solid lines : fit to the model prediction
* K- and B-band bulge magnitude :Marconi
et al. (2004)
* sigma: Ferrarese & Ford (2005)
* Mbulge: Haring & Rix (2004)
* Vc: Baes et al. (2003)
* Mbh: Ferrarese (2002) equations 4 (cyan),
6 (green) and 7 (magenta) and Baes et al.
(2003) (red)
Federico Marulli
Torino: May 2008
BH fundamental plane
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
Black dashed lines: Hopkins et al. (2007)
Red dots: model outputs
Blue solid lines: best-fits to the model
outputs
The galaxy stellar mass is given in units of
1e11 Msun, the bulge velocity dispersion is in
units of 200 km/s
Federico Marulli
Torino: May 2008
BH mass function
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
Federico Marulli
Torino: May 2008
AGN luminosity function
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
Optical: Kennefick et al. 1995; Schmidt et al.
1995; Koehler et al. 1997; Grazian et al. 2000;
Fan et al. 2001; Wolff et al.
 12003; Hunt et al.
Edd
2004; Cristiani et al. 2004; Croom et al. 2005;
Richards et al. 2005, 2006; Siana et al. 2006;
Fontanot et al. 2007; Shankar & Mathur 2007;
f Edd , 0
z3

Bongiorno
f ( et
z ) al. 2007

1.4
f
[(
1

z
)
/
4
]
z3
Edd , 0

Infra-red: Brown et al. 2006; Matute et al.
f Edd , 0  0.3 et al. 2006
2006; Babbedge
Edd
Soft X-ray: Miyaji et al. 2000, 2001; Silverman

et al. 2005b;
Hasinger
et
al.
2005
 L (t ) 
dt

|  | t  bol9
Hard
et al. 2003; 10
Ueda et
dX-ray:
ln LBarger
Lal. 
bol

2003; Barger et al. 2003; Nandra et al. 2005;
f BH
Sazonov & Revnivtsev 2004; Silverman et al.
2005a; La Franca et al. 2005; Shinozaki et al.
 M

2006;
 0.01Beckmann
 log BHet al.
 12006
 z z  1.5, M  106 M
 103 M




Emission lines: Hao et al. 2005
M BH ,Q  0.01  mcold
BH

z6
Federico Marulli
Torino: May 2008
AGN clustering function
Marulli, Branchini, Gilli, Moscardini, Bonoli in preparation
CDFs AGN clustering: Gilli et al. 2005
Federico Marulli
Torino: May 2008
Summary
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
BH scaling relations
BH fundamental plane
AGN luminosity function
BH mass function
AGN clustering
Federico Marulli
Torino: May 2008
Summary
Marulli, Bonoli, Branchini, Moscardini, Springel 2008, MNRAS.368.1269M
Galaxy luminosity function at z=0
Galaxy evolution - downsizig
Cooling flows in clusters
“Radio mode” BH feedback
- Not triggered by mergers
- Low z
- High mass DM halos
BH scaling relations
BH mass functions
AGN evolution – downsizing
AGN clustering
Federico Marulli
Torino: May 2008
Conclusions
• The cosmological co-evolution of BHs, AGN and galaxies can be well described within the ΛCDM model
• At redshifts z>1, the evolution history of DM halo fully determines the overall properties of the BH and
AGN populations. The AGN emission is triggered mainly by DM halo major mergers and, on average, AGN
shine at their Eddington luminosity
• The cold gas fraction accreted by BHs at high redshifts seems to be larger than at low redshifts
• At redshifts z<1, BH growth decouples from halo growth. Galaxy major mergers cannot constitute the
only trigger to accretion episodes in this phase
• When a static hot halo has formed around a galaxy, a fraction of the hot gas continuously accretes onto
the central BH, causing a low-energy “radio'' activity at the galactic centre, which prevents significant
gas cooling and thus limiting the mass of the central galaxies and quenching the star formation at late time
The end!
…thanks!
Federico Marulli
Torino: May 2008