Presentation on theme: "The joint formation of spheroids and Super Massive Black Holes Gian Luigi Granato (INAF-Padova & SISSA) with: Michele Cirasuolo Luigi Danese Gianfranco."— Presentation transcript:
The joint formation of spheroids and Super Massive Black Holes Gian Luigi Granato (INAF-Padova & SISSA) with: Michele Cirasuolo Luigi Danese Gianfranco De Zotti Andrea Lapi Francesco Shankar Laura Silva
To compare scenarios of galaxy formation with observations two very critical and uncertain steps: 1. Model the non linear evolution of ordinary matter: most driving processes occur well below the resolution of any simulation (sub-grid physics) and are poorly understood ) a lot of uncertainty; 2. Model the interaction of photons produced by stars and accretion processes with the dusty ISM. Since long (Silva et al 1998, Granato et al 2001, 2004) we have devoted efforts to these aspects
Di Matteo et al 05 Simulation of merging of spirals without treatment of induced QSO activity…..and WITH (crude and uncertain sub-grid treatment of) induced QSO activity and ensuing feedback on ISM
Fate of initial gasWithout AGNWith AGN In stars89%52% Cold SF gas1.2%0% Hot halo gas9.8%11.1% Expelled from halo0.05%38% In SMBH-1.6% The predicted star formation histories and final morphologies are completely different Di Matteo et al 05
Ab-initio or first principles models do not really exist Most extensive comparison between possible scenarios and data are done by means of the semi-analytic models (SAM), which by definition have many a-priori assumptions, and you get what you put in
Almost all SAMs assume a galaxy merger driven sequence of processes leading to present day galaxy populations (Rees & Ostriker 1977, Silk 1977, White & Rees 1978…) 1.The first result of gas cooling is gaseous, disk formation, supported by rotation and with mild SF; 2. Disk mergers are the only driver of bursty SF and of the formation of spheroids. 1-2 are not necessarily true and for sure do not break “naturally” the hierarchy: baryons tend to follow the bottom-up hierarchy of CDM (i.e. gravity leads);
Problems of standard simulations: room for quasar? Calculations based on this general scheme shows mismatches indicating holes in our understanding of galaxy formation. In particular the evidence is growing that the co- evolution of SMBHs and galaxies could play a role in at least some of the following problems: Overcooling Cooling flow conundrum Scaling relations of clusters (L-T) Sub-mm and near IR selected high z-populations, and properties of Ellipticals
Observations suggest an assembly of baryons in Es mimicking to some extent the monolithic scenario with more massive objects forming faster. To get this within hierarchical assembly of DMH we proposed a revision of SAM (Granato et al. 2001, 2004; Anti-hierarchical Baryonic Collapse ABC): 1. Reduced role of gas disk formation at high z: cool collapsing gas in big halos at high-z start vigorous SF without setting in a quiescent disk, and promoting the development of SMBH. 2. Keep into account the mutual feed-back between formation of high-z QSO and their host galaxies largely ignored by simulation (before us).
Recent N-body results (Wechsler et al 2003; Zhao et al. 2003) indicate a two phase build up of large DMH: 1. Fast accretion (» 1 Gyr) by sudden merge of many similar clumps, during which the final potential well is set; 2. Slow accretion of matter in the outskirt (» 10 Gyr), hardly affecting the central region (galaxy?) Potential well development Mass development z=4 z=0
HOT GAS COLD GAS RESERVOIR (low J) STARS IGM SMBH-QSO SNae feedback & QSO feedback Radiative cooling Radiation drag ( SFR) Viscous accretion Collapse baryonic components and mass transfer processes Stellar evolution Arrows give a set of simple differential equations for the masses in the various components, solved numerically
Halos form, gas is heated to virial T Scheme of our semi analytical model at high z Gas cools, collapse and forms stars directly, in small halos SNae quench SF, in big ones nothing prevents a huge burst of SF ( ' 1000 M ¯ /yr over 0.5 Gyr), SMGs phase… (almost) passive evolution of stellar population. ERO phase with dormant SMBH..with SMBH growth promoted by SF eventually powering high z QSO after » 0.5 Gyr, which cleans ISM and quenchs further SF and then itself. QSO phase
Galaxy SMBH Accretion rate SFR VERY Dusty and huge SF ) Sub-mm – dusty ERO SMBH cleans the ISM ) high z QSO Little ISM, almost passive evolution ) passive ERO Local Ell and SMBH Plugging this into statistic of dark matter halos as a function of M vir and z vir we get predictions for many populations, connected by evolutionary sequence
Galaxy SMBH SFR Accretion rate Phase 1: VERY Dusty and huge SF and baby SMBH growth lasting » 0.5-1 Gyr ) SMG with mild obscured AGN activity – dusty ERO
ABC naturally reproduces SMGs (e.g. no ad-hoc IMF) 5.7 mJy z distMEDIANQUARTILE Chapman et al 2005 (73 sources) 2.21.7-2.8 Model2.21.6-3.3 SCUBA 850 m MAMBO 1200 m model data
THE PRE-QSO PHASE IN SMGs The build up by accretion of the SMBH, promoted by SF and before the bright optical QSO phase, gives rise to a mild AGN activity in sub-mm galaxies, detectable only in hard-X Indeed » 50% of 5 mJy SCUBA sources host an X-ray AGN with intrinsic L X [0.5-8] ' 10 43 -10 44 erg s -1 (Alexander et al 03,04,05) dM/dt(BH)>0.013 M ¯ /yr ) L(0.5-8)>1E43 erg/s dM/dt(BH)>0.13 M ¯ /yr ) L(0.5-8)>1E44 erg/s (Granato et al 2006)
By converse, the normal disk merging scenario for SMGs predicts too high M and dM/dt for the SMBH in SMG, because of the ' 1 Gyr phase of disturbance and SMBG growth preceding the final merge and huge SF.
Phase 2: SMBH cleans the ISM ) high z QSO ( » 5 £ 10 7 -10 8 yrs) Galaxy SMBH Accretion rate SFR T delay ' 0.3-1 Gyr, a key built-in point
Several semi-analytical or toy models for the growth of BHs and QSO activity in CDM cosmology. The baryonic physics is usually extremely crude. With ad hoc prescriptions models reproduces aspects of the observed evolution of QSO (LFs) and/or the M BH - relations. Very few efforts compare simultaneously with galaxy properties, i.e. try to explain consistently the (co-)evolution of galaxies and QSOs, a much more demanding task. Introduction to cosmological models of evolution of QSOs I
General methodology of “QSO only models” (e.g. Whythe & Loeb 2003; Mahmood et al 2004): Ingredients and assumptions: Haloes formation rate (e.g. derivative of HMF (PS) ) SMBH-DMH mass relationship (e.g. from self-regulation) SMBH mass-luminosity relation (e.g. Eddington) QSO appears immediately and shines for time t Q But the required shine time t Q is too short ( ' galaxy dynamical time-scale ' 10 7 ys at z=3 and a few 10 6 at z=6) to satisfy the Soltan argument and the local SMBH mass function with plausible accretion efficiency 10-15%.
In our view the problem is mainly due to neglecting the time delay between virialization and detectable QSO activity Lapi et al in prep. HMF or formation rate has to be considered at z(t vir -t delay ) rather than at z(t vir ) ) less objects ) higher t Q Our ABC model for QSO-spheroids co-evolution has this delay and the intrinsic light curve built-in (but not the visibility time t Q ). The (high-z) QSO LFs are another fundamental test!
Optical QSO LF (t Q '4x10 7 yr) z=1.5 data Croom et al 2004 z=3 data Pei et al 1995 z=4.5z=6 data Fan et al 2004 Lapi et al submitted
X-ray QSO LF (t Q '10 8 yr) z=1.5z=2 Barger et al. (2005) Ueda et al. (2003) La Franca et al. (2005) Lapi et al submitted
The ABC model well reproduces the evolution of high-z optical and X-ray LF of QSO with the only addition of a plausible visibility time ' (a few) 10 7 yr in optical and '10 8 yr in X, as suggested by demography studies of local SMBH (Shankar et al 2005, Marconi et al 2005). The delay between halo formation and peak of SMBH accretion is a crucial ingredient.
Galaxy SMBH Accretion rate SFR Phase 3: Little ISM ' passive evolution ) red and (almost) dead massive high-z galaxies (many Gyrs)
Z ' 0.5 Z ' 0.9 Z ' 1.3 Z ' 1.8 Fontana et al 2004: galaxy stellar mass function in K20 sample Standard SAMs Granato et al 2004 Standard SAMs underproduce massive galaxy, by a fraction increasing with z
Adapted from Drory et al 2005 Massive galaxies at high redshift Baugh et al 2005 (Durham SAM) Granato et al 2004 ABC
While standard semi-analytical models severely under-predict EROs (Somerville et al. 2004), our ABC model can even over- produce the number of EROs (of both classes). There are observational and model issues, to be clarified by more observations. Extremely Red Objects (R-K)>5 Silva et al 2005
Galaxy SMBH Accretion rate SFR Phase 4: Local Ellipticals and dormant SMBHs
Local K band Luminosity function of spheroids Data: Huang et al 2003 Kochanek et al 2001 Granato et al 2004
The central BH = 0.57 ± 0.05 V vir dispersion interpreted as different virialization epochs Tighter M BH -M * ?
Work in progress: comparison of Lick spectral indices computed from models with available data (Silva et al. in preparation). Sigma [km/s] Mg1
CONCLUSION The mutual link between the formation of spheroids and the AGN activity is a key ingredient that must be included into models of galaxy formation. The prescriptions of the ABC scenario (Granato et al. 2001, 2004) lead (in one shot) to predictions in general agreement with many observations which are disturbing for traditional SAMs: statistic of sub-mm galaxies and their mild AGN activity cosmic evolution of QSO activity statistic of massive galaxies at high-z local mass function of SMBH local K band LF of spheroids abundances in ellipticals Main papers to look: Granato et al. 2001, 2004; Silva et al 2005; Granato et al 2006; Lapi et al submitted, Silva et al in prep Evolution