Presentation on theme: "SIGRAV Graduate School in Contemporary Relativity and Gravitational Physics Laura Ferrarese Rutgers University Lecture 5: SBH Demographics."— Presentation transcript:
SIGRAV Graduate School in Contemporary Relativity and Gravitational Physics Laura Ferrarese Rutgers University Lecture 5: SBH Demographics
Lecture Outline 1. The First Clue: Supermassive Black Hole Masses and the Total Luminosity of the Host Bulge 2. The M BH - Relation 3. Black Holes and Dark Matter Haloes (?) 4. Applications
Kormendy & Richstone 1995, ARA&A, 33, 581 SBHs and Bulges Kormendy & Richstone (1995) first pointed out that given the eight SBH detections available at the time, SBH masses correlate with the total blue magnitude of their host bulge (meaning the entire galaxy in the case of ellipticals). This suggests a connection between SBH and bulge masses.
SBHs and Bulges This correlation was further elaborated by Magorrian (1998), who published a correlation between SBH and bulge masses based on axysimmetric, 2-I dynamical models. The ratio between SBH and bulge mass was measures to be M BH /M bulge ~0.6%.
R (arcsec) ( km s -1 ) R (arcsec) ( km s -1 ) R (arcsec) Data from Magorrian et al. (1998)
SBHs and Bulges We have discussed several problems affecting the Magorrian analysis: the use of 2-I models might bias the mass estimates perhaps more importantly, the models were applied to data which did not resolve the SBH sphere of influence, and therefore contained no information about the central SBH. What if we only include masses which are: based on data that resolves the SBH sphere of influence. are derived from 3-I models Note that these two conditions do not assure that the mass estimate is reliable, but at least it’s a starting point! Two things happen (Merritt & Ferrarese 2000): the average M BH /M bulge ration decreases (from ~0.6% to ~0.1%). This is because most of the Magorrian SBH masses are overestimates. The scatter in the relation, however, does not really seem to change.
SBHs and Bulges Is the scatter in the M BH -M bulge relation really as large as it seems? McLure & Dunlop (2002) suggest that the scatter depends (perhaps through systematic errors in the bulge magnitudes) on the Hubble type of the host galaxy. They include (almost) only (but not all) elliptical galaxies, and use R-band instead of B-band magnitudes. Ferrarese 2002/astro-ph/ McLure & Dunlop 2002
SBHs and Bulges Marconi & Hunt (2003, astro-ph/ ) found that a tighter correlation is obtained if K- band magnitudes, instead of B-band magnitudes, are used. This is not surprising: if it is the mass of bulge to drive the correlation, the mass is better traced in the K rather than in the B-band. Also, the B-band magnitudes commonly used are likely very inaccurate, especially for spiral bulges. The bulge mass is simply the virial mass given by: where r e and e are the bulge effective radius and velocity dispersion respectively. k depends on the dynamical state of the system, and is therefore not likely (but was assumed to be) constant for all galaxies.
SBHs and Bulges A tighter relation is obtained if the bulge velocity dispersion is substituted to the bulge blue magnitude (Ferrarese & Merritt 2000 and Gebhardt et al. 2000): Gebhardt et al Ferrarese 2002
The Discovery of the M Relation What is relevant about the M BH relation? After all, bulge luminosity and velocity dispersion are known to correlate through the “Faber-Jackson” relation: Therefore, the existence of the M BH -M bulge relation, combined with the Faber-Jackson relation, implies that M BH must correlate with . The significance of the M BH relation lies in its small scatter, which is smaller than the scatter in either the M BH -M bulge or Faber Jackson relations. This indicates that the M BH relation is more fundamental. From Faber & Jackson 1976, ApJ, 204, 668
The “Discovery” of the M Relation SBH Mass vs. Bulge Velocity Dispersion SBH Mass vs. Bulge Magnitude What if only BH detections obtained from the highest resolution data are used? (MW, H 2 0, HST data)
SBHs and the Concentration of Bulge Light Graham et al. (2001) found evidence of a strong correlation between the concentration of bulges and the mass of their central SBH. whatever mechanisms are responsible for the formation of the SBH, they not only control the bulge luminosity, but also the distribution of bulge light. CONS: Use of the concentration index might not be applicable to studies of morphologically disturbed galaxies or dominant cD galaxies with extended envelopes. PROS: Measuring central mass concentration is relatively easy, even for galaxies at large distance.
SBHs and the Concentration of Bulge Light Could we have “expected” a correlation between SBH masses and concentration of bulge light to exist? Probably yes: However, just as is the case for the M BH relation, the M BH C relation seems to be tighter, and therefore more fundamental, than the relations from which it can be “built” The fundamental plane for 226 galaxies in 10 clusters (from Jorgensen et al. 1996, MNRAS, 280, 167
The tightness of the M BH relation must be telling us something fundamental about the connection between BHs and bulges. Simple interpretation: A constant fraction of the bulge mass is channeled into the BH (Ferrarese & Merritt 2000) M BH M bulge L bulge (M/L) bulge L bulge L bulge 1/4 (e.g. Jorgensen et al. 1996) L bulge 5/4 ( 4 ) 5/4 5 (Faber Jackson relation) But: a) the M BH relation is tighter than the relation between M BH and mass (or luminosity). b) Even if a M BH - M bulge relation were setup in the early universe it is difficult to imagine how it could have survived in the face of mergers. An additional feedback mechanism must act to directly connect black hole mass to stellar velocity dispersion. The M- Relation - Why is it Interesting?
Black Hole Galaxies Sellwood & Moore (1999) BH growth driven by bar instabilities which develop during the early stages of galaxy formation. When the BH mass reaches ~1.5% the mass of the disk the bar weakens and the accretion halts. No BHs should be found in DM dominated galaxies; Predicts a much larger M BH /M bulge than observed Merritt (1998) The BH shapes the distribution of stellar orbits destroying triaxiliaty in less than a Hubble time for fainter (M < -19 mag) ellipticals if M BH /M gal ~ 3%. Once the non-axisymmetric component is weakened, further growth of the BH is halted. Requires a much larger M BH /M bulge than observed Silk & Rees (1998), Haehnelt, Natarajan & Rees (1998) The formation and accretion history of SMBHs is determined by accretion at the center of a gravitationally unstable self-gravitating disk in the core of a newly-formed dark matter halo. An upper limit to BH growth will be reached when the emitted energy exceeds the energy deposition rate necessary to unbind the disk. The back reaction of the radiation wind will produce a dramatic decrease in the accretion rate. (Eddington luminosity) (dynamical time) = binding energy of the galaxy 4 GM BH m p / T R bulge / ≈ GM 2 bulge /R bulge ≈ R bulge /G M BH ≈ ( T / m p 4 cG 2 ) ≈ Neglects star formation, deviations from spherical symmetry, mergers. Burkert & Silk (2001) Self regulated BH growth within a major-merger scenario for the formation of spheroids. BH growth following merging is halted when the onset of star formation in the outer regions of the disk limits the amount of gas available for accretion. M BH ~ 4-5 The tightness of the M relation is not explained Galaxy Mergers Kauffman & Haehnelt 2000 Semi-analytical models of merger driven starbursts in CDM hierarchical models. The cooling of gas that falls in during mergers is assumed to be balanced by energy input from SNe. M BH ~ >2 Arbitrarily steep slopes can be produced; the model does not reproduce the small scatter in the M relation Feedback Mechanisms
SBH Formation from the The M BH - Relation Haehnelt & Kauffmann 2000 Constrain models of SBH/galaxy formation Silk & Rees 1998; Haehnelt, Natarajan & Rees 1998; Kauffmann & Haehnelt 2000; Haehnelt & Kauffmann 2000; Burkert & Silk 2001; Ciotti & van Albada 2001; Fabian et al. 2001; Cavaliere & Vittorini 2001; Portegies-Zwart & McMillan 2002; MacMillan & Henriksen 2002; Zhao et al. 2002;Volonteri, Haardt & Madau 2002; Islam,Taylor & Silk 2002; Wyithe & Loeb 2002, 2003.
Magorrian et al Merritt & Ferrarese 2001 Merritt & Ferrarese (2001): M BH derived from the M BH relation M bulge from Magorrian et al. (1998) Mass density in local Black Holes: x = M BH /M bulge ~ 0.13% bulge ~ 3.7 10 8 M Mpc -3 (Fukugita et al. 1998) ~ 4.9 10 5 M Mpc -3 SBH Demographics from the M BH - Relation: I Compare the SBH mass function in high redshift quasars and local quiescent galaxies: Learn about the existence/evolution of obscured quasars Constrain the accretion
1) Schechter Luminosity Function (e.g. Marzke et al. 1998) 2) Faber-Jackson relation (e.g. Kormendy & Illingworth 1993) 3)M BH relation Where M * must incorporate a term accounting for the ratio between bulge and total luminosity for galaxies of different Hubble types (see also Merritt & Ferrarese 2001; Aller & Richstone 2002) Ferrarese 2002a (astro-ph/ ) SBH Demographics from the M BH - Relation - II
Comparison of SBH Mass Functions Once the contribution of obscured AGN is accounted for, the cumulative SBH mass density in quasars is larger, by a factor 2, than the one measured in local quiescent galaxies. The SBH mass densities are different for the quasar and quiescent galaxy population. This seems to be significant at least at the high mass end. Ferrarese 2002a astroph/ (See also Yu & Tremaine 2002)
Comparison of SBH Mass Functions Yu & Tremaine (2002): Cumulative mass density for Early Type galaxies from SDSS sample. (> M, total) = 1.44 (> M, Early)=(3.3 0.5) 10 5 M Mpc 3 (for H 0 = 75 km s 1 Mpc 1 ) (Although using the M BH L relation gives 5.8 10 5 M Mpc 3 ) Yu & Tremaine 2002 (H 0 = 65 km s 1 Mpc 1 ) Quasars Early Type Galaxies
InterpretationInterpretation For M BH > 10 8 M The SBH mass function in local quiescent galaxies is not consistent (in particular, it is lower) with the high-z quasar luminosity function derived from optical surveys if the accretion efficiency is =0.1 Higher ( =0.2) accretion efficiencies might apply to the more massive SBHs, i.e. massive SBHs are rapidly rotating (Yu & Tremaine 2002; Elvis, Risaliti & Zamorani 2002). Quasars might have super-Eddington luminosities (cfr. Begelman 2001, 2002) SBHs might be ejected from galactic nuclei as a consequence of merging (Yu & Tremaine 2002; cfr. Milosavljevic & Merritt 2001) Optically faint accretion (Type II QSOs, advection dominated accretion flow) is negligible for massive SBHs (Yu & Tremaine 2002; but see Elvis, Risaliti & Zamorani 2002) What happens in the lower mass regime (M BH < 10 8 M ) is still to be investigated. Details depend on the contribution of obscured QSOs, and the exact characterization of the QSO luminosity function at low redshifts.
The M BH - Relation - Why is it Interesting? Measure SBH masses (30% accuracy!) Individual galaxies (e.g. Barth et al. 2002) Test accretion processes and unification schemes BL Lacs (Falomo, Kotilainen & Treves 2002; Barth, Ho & Sargent 2002) Radio Loud AGN (O’Dowd, Urry & Scarpa 2002, also Woo & Urry 2002) Investigate FRI/FRII dichotomy (Marchesini, Celotti & Ferrarese 2002, in prep) Falomo, Kotilainen & Treves 2001
0.03% 0.25% M /M bulge 0.6% SBH Demographics in Local AGNs: the M BH M B Relation Laor (1998)Wandel (1999)McLure & Dunlop (2000) BLR Size R L 0.5 Rev.Map. R L 0.7 Virial velocityv = 0.87 FWHM(H ) v = 0.87 FWHM(H )v = 1.55 FWHM(H ) Bulge MagnitudeV-bandB-bandI-band Bulge/Disk decomp. (Simien & de Vaucouleurs) Bulge/disk decomp. DistancesH 0 =80H 0 =75 H 0 =50
BH Demographics in Local AGNs (cont’d) M BH /M bulge ~ 0.2% in agreement with the value determined for local quiescent galaxies (Merritt & Ferrarese 2001a, Merritt & Ferrarese (2001b, astro-ph/ )
Malkan, Gorjiam & Tam (1998) NGC 5548 KPNO/4m - Gemini : On-going program to measure for all reverberation mapped galaxies (Ferrarese et al. 2001, 2003) Testing Reverberation Mapping With the M BH - Relation
Ferrarese et al Ferrarese et al Testing Reverberation Mapping with the M BH Relation Comparison between mass estimates from resolved kinematics in quiescent galaxies, and reverberation mapping in Type 1 AGNs shows that reverberation mapping works! Future studies targeting the low and high mass end of the M BH relation, as well as its redshift evolution, will rely on reverberation mapping or secondary mass estimators calibrated using reverberation mapping.
Part III: Beyond the Bulge: the Dark Side of Galaxies Recently, it has become commonplace to assume that SBH formation/evolution is driven exclusively by the dynamically hot stellar component Kormendy & Gebhardt 2001 However, most self-regulating models of SBH formation link M to the total gravitational mass of the host galaxy or to the mass of the dark matter halo, rather than to the mass of the bulge (e.g. Umemura, Loeb & Turner 1993; Loeb & Rasio 1994; Haehenlt, Natarajan & Rees 1998; Silk & Rees 1998; Cattaneo et al. 1999; Haehnelt & Kauffmann 2000; Adams, Graff & Richstone 2000; Whyithe & Loeb 2002; Volonteri, Haardt & Madau 2002; Islam,Taylor & Silk 2002). Is the M relation the fundamental reflection of the processes that lead to the formation of SBHs? Could M be controlled by the total gravitation mass of the host galaxy instead?
Mass Tracers Begeman 1987 R 25 r/r e v(circ)/v(max,circ) Elliptical Galaxies: circular velocity derived from non-parametric dynamical modeling: 20 objects (Kronawitter et al. 2000) Spiral Galaxies: circular velocity of the cold disk component: 15 objects with HI or optical rotation curves extending beyond R 25 (e.g. Broeils 1992; Begeman 1987; Olling & Merrifield 1998; Newton 1980; Kent 1989;Corbelli & Salucci 2000; van Albada 1980, Krumm & Salpeter 1979; Bosma 1981) Gerhard et al. 2001
Beyond the Bulge: the v c - Relation
The v c - Relation M33 N6503 N3198 Ferrarese 2002c, ApJ
The v c - Relation The relation has been recently confirmed, with unchanged slope and scatter using a new sample of 12 spirals (Baes et al. 2003)
Is the v c - Relation a Tautology? 1.Are v c and sensitive to the same mass distribution? NO: v c is measured at distances > 15 Kpc, is measured within 0.5 kpc 2.Is the v c relation a consequence of dynamical homology? NO: spirals do not form an homologous family 3.Is the v c relation just a reflection of the “disk-halo” conspiracy? NO: the conspiracy does not extend to the bulge 4.Is the v c relation simply the Tully-Fisher relation in disguise? NO: the Tully-Fisher relation probes different scales and extends to smaller circular velocities
Is the v c - Relation a Tautology? 1. Are v c and sensitive to the same mass distribution? vcvc cc
Is the v c - Relation a Tautology? 2. Is the v c - relation a consequence of dynamical homology? Casertano & van Gorkom 1991
Is the v c - Relation a Tautology? 3. Is the v c - relation just a reflection of the “disk-halo” conspiracy? NGC2841NGC2403 Begeman 1987
Is the v c - Relation a Tautology? 4. Is the v c - relation simply the Tully-Fisher relation in disguise? Verheijen 2001
Implications of the v c Relation Numerical simulations for the formation of disk galaxies (Steinmetz & Muller 1995) : Disk rotational velocity Bulge velocity dispersion
Estimating M DM from v c vcvc v vir Bullock et al. 2001
The M - M DM Relation M /M DM ~ 6 10 5 M /M DM ~ 10 6 ???
The M BH - M DM Relation Wyithe & Loeb 2002 Theoretical models for the quasar luminosity function (Wyithe & Loeb 2002; Hatziminaoglou et al. 2002) QSO emission triggered by galaxy mergers in a Press-Schechter formalism SBH mass proportional to a power of the halo circular velocity
Suggested Readings Ferrarese, L. & Merritt, D Gebhardt, K. et al Ferrarese, L. 2001