Roeland van der Marel Black Hole Demographics: Observations, Theory and Extrapolation to Intermediate-Mass

Roeland van der Marel - Space Telescope Science Institute 2 Active Galaxies P Some galaxies show active phenomena in their centers: P radio emission P X-rays / gamma-rays P Jets of material P Superluminal motion P Broad emission lines P …  Supermassive black holes (BHs) (  M  ) [M87]

Roeland van der Marel - Space Telescope Science Institute 3 Quiescent Galaxies P Quasar and Active Galaxy Population Statistics as function of redshift  many normal galaxies were active in the past  BHs common in quiescent galaxies [Fan et al. 2001]

Roeland van der Marel - Space Telescope Science Institute 4 BH Detections and Mass Measurements P A BH reveals itself through the gravitational pull it exerts on surrounding material. P Close to a black hole material will move rapidly P Kepler: V 2 ~ GM/r P Detection: Massive Dark Object (MDO) P If an MDO can be demonstrated to be very small  density must be enormous  assumed to be a BH

Roeland van der Marel - Space Telescope Science Institute 5 Dynamical Tracers and Complications P Stars: P Pro: Available in all galaxies; motions completely gravitational. Hubble SpaceTelescope

Roeland van der Marel - Space Telescope Science Institute 6 The Milky Way Galaxy Center P Near-infrared images show proper motions of stars that move rapidly around a central black hole (Sgr A*) with M BH = 3 x 10 6 M  [Ghez et al.]

Roeland van der Marel - Space Telescope Science Institute 7 Dynamical Interpretation of Stellar Motions P Stars: P Con: Interpretation often complicated, because generally only projected motions are observed, and the 3D orbital structure is unknown P Various codes exist to do the necessary modeling, but discussion continue about interpretation and error analysis

Roeland van der Marel - Space Telescope Science Institute 8 Dynamical Tracers and Complications P Gas: P Pro: Rapid gas motions observed in many AGN (narrow-line regions and broad- line regions). P Con: Interpretation often complicated, because hydrodynamical forces, outflow, inflow, etc. may be as important as gravity. [Bower, Green, et al.] [M84]

Roeland van der Marel - Space Telescope Science Institute 9 BH Masses From Gas Kinematics P Rotating nuclear gas disks in (active) galaxy centers: Water maser disks (VLBI)Optical emission-line gas disks [NGC 7052][NGC 4258]

Roeland van der Marel - Space Telescope Science Institute 10 BH Masses From Gas Kinematics BLR reverberation mappingX-ray iron K emission lines [Welsh et al.][Reynolds]

Roeland van der Marel - Space Telescope Science Institute 11 Black Hole Demographics P BH mass relation to P galaxy properties? (do all galaxies have BHs?) P galaxy activity and quasar statistics? P galaxy formation and galaxy interactions?

Roeland van der Marel - Space Telescope Science Institute 12 Back-of-the-Envelope Demographics P Insights from some well-studied galaxies: GalaxyTypeM gal (log10) M BH (log10) M bulge (log10) M BH / M gal (log10) M BH / M bulge (log10) M87E M32E NGC 4258 Sbc

Roeland van der Marel - Space Telescope Science Institute 13 Back-of-the-Envelope Demographics P Faber-Jackson : L bul   3.5 P Fundamental Plane : M bul /L bul  L bul 0.2  M bul   4.2 P BH Demographics : M BH  M bul  M BH   4.2

Roeland van der Marel - Space Telescope Science Institute 14 M BH -  relation P ~30 trustworthy MBH determinations P Good correlation with  P Scatter ~0.3 dex P Slope = 4.0 ± 0.3 (but lots of discussion about the exact value; Gebhardt et al., Ferrarese & Merritt, etc.) [Tremaine et al., 2002]

Roeland van der Marel - Space Telescope Science Institute 15 M BH – M bul relation P Long history, e.g., P Kormendy & Richstone (1995) P Magorrian et al. (1998) P Recent work P Marconi & Hunt (2003) P Haring & Rix (2004) P Scatter ~0.3 dex P similar as M BH -  relation! P Slope = 1.0 ± 0.1 P Correlation with L bul not much worse … [Marconi & Hunt 2003]

Roeland van der Marel - Space Telescope Science Institute 16 M BH – M DM relation P Demographics : M BH   4.0 P Bulges :   V circ 1.2 P Assume : V circ ~ V vir P Cosmology : M DM  V circ 3  M BH  M DM 1.6 [Ferrarese 2002]

Roeland van der Marel - Space Telescope Science Institute 17 M BH – concentration relation P M BH also correlates with a measure of galaxy light concentration (Graham et al. 2001) P Scatter ~0.3 dex P also similar as M BH -  relation … [Graham et al. 2001] Concentration

Roeland van der Marel - Space Telescope Science Institute 18 Comparison of BH Demographics Relations P What fundamentally drives M BH ? P At present there is little reason to consider any of the relations more “fundamental” than the others P Important for extrapolations, e.g, P M BH driven by  : globular clusters could have IMBHs P M BH driven by M DM : globular clusters may not have IMBHs P M BH -  is popular because P  is a directly observed quantity (and emission line width can be used as a proxy) P  can be theoretically related to dark halo properties (Mgal, Lgal, and light concentration relate to baryons)

Roeland van der Marel - Space Telescope Science Institute 19 Evolution of the M BH -  relation for AGNs P BLR: M BH ~ V 2 R / G P V : line-width(BLR) P R : reverberation mapping photoionization modeling R  L cont 0.5 P NLR:   FWHM[OIII] P Shields et al. (2003): no sign of evolution with redshift (z < 3)

Roeland van der Marel - Space Telescope Science Institute 20 The Link between Nearby Galaxies and Distant AGN P Integral over M BH -  relation  Local BHs:  ~ 3  10 5 M  Mpc -3 P Energy density in QSO radiation + assumed accretion efficiency ~0.1  Integrated luminous QSO accretion:  ~ 2  10 5 M  Mpc -3 P X-ray background + corrections  Integrated obscured accretion:  ~ 2  10 5 M  Mpc -3 P All BHs (more-or-less) accounted for ….

Roeland van der Marel - Space Telescope Science Institute 21 The Questions of BH Formation P How is a BH formed initially? P A small seed BH is formed originally P From Population III evolution [Madau & Rees; Volonteri et al.; Schneider et al; Islam et al.] P From Evolution of a dense star cluster [Quinlan & Shapiro; Lee; Portegies Zwart & McMillan; Baumgarth et al; Gurkan et al] P A massive BH is formed by direct collapse of a gas cloud P H2 cooling must be suppressed [Bromm & Loeb] Rees (1984)

Roeland van der Marel - Space Telescope Science Institute 22 The Questions of BH Formation P When is a BH formed initially? P Before galaxy/bulge formation P During galaxy/bulge formation [Adams et al.] P After galaxy/bulge formation P When do BHs gain their mass? P Early on P Intermittent over time (e.g., during mergers) P Slowly over time (e.g., adiabatic growth)

Roeland van der Marel - Space Telescope Science Institute 23 The Questions of BH Formation P What do BHs accrete to grow in mass? P Gas [Kauffmann & Haehnelt; Di Matteo et al; Bromley et al] P Stars [Zhao et al.] P BHs [Volonteri et al.; Schneider et al; Islam et al.; Hughes & Blandford] P Dark Matter [Ostriker]

Roeland van der Marel - Space Telescope Science Institute 24 The Questions of BH Formation P How does galaxy merging affect the BHs? P Trigger accretion/activity [Kauffmann & Haehnelt; Di Matteo et al; Bromley et al] P Changes both galaxy and BH properties P Merging timescale P Slingshot ejection P Gravitational Wave Recoil [Madau & Quataert ] [NGC 6240]

Roeland van der Marel - Space Telescope Science Institute 25 The Questions of BH Formation P What mechanism regulates BH mass/growth? P Availability of material to accrete P Feedback/Self-Regulation P Competition between star formation and BH growth [Burkert & Silk] P Accretion limited by mechanical feedback [Silk & Rees; King] P Accretion limited by heating due to the BH [Ciotti & Ostriker]

Roeland van der Marel - Space Telescope Science Institute 26 Comparison of Models to BH Demographics P Scaling arguments in many models give M BH   k (k~4) P Cosmologically motivated (semi-analytical) models fit M BH   4 and many other observations, but require fine- tuning of ad-hoc assumptions P Our improved understanding of BH demographics hasn’t really reduced the number of plausible scenarios … [Haehnelt & Kauffmann 2000]

Roeland van der Marel - Space Telescope Science Institute 27 Are there IMBHs in Galaxy Centers? P BHs detected so far in P Hot stellar systems P With  >70 km/s P Do all galaxies have BHs? P Do intermediate-mass BHs (IMBHs) exist in galaxy centers with  < 50 km/s?

Roeland van der Marel - Space Telescope Science Institute 28 Does Theory suggest a Minimum M BH ? P Most models make no definitive statement about this P Models that address this face difficulties for low-mass galaxies P Star formation and feedback critically important P High-redshift physics critical P Cosmological simulations lack resolution P If supermassive BH formation involves growth from seeds < 10 6 M , it is easy to imagine that some BHs may not have had the opportunity to grow supermassive P  Observational study of late-type galaxies needed

Roeland van der Marel - Space Telescope Science Institute 29 Central Structure of Late Type Spiral Galaxies P Late-type galaxies (Sc-Sd) generally host a nuclear star cluster P HST imaging (Boeker et al) P in 75% of a large sample P Barely resolved (<0.1”) P VLT spectroscopy (Walcher et al) P Age ~ years P M ~ 10 6 M  [Boeker et al. 2002]

Roeland van der Marel - Space Telescope Science Institute 30 Central Structure of Dwarf Elliptical (dE) Galaxies P dEs brighter than M V = -16 generally host a nuclear star cluster (“nucleated”) P Keck spectroscopy (Geha et al) P Age ~ 5 Gyrs P M ~ 10 6 M  P dEs may have formed from harassment of late-type spirals  Evolutionary Connection ? [Cuillandre et al.] [NGC 205]

Roeland van der Marel - Space Telescope Science Institute 31 Relation of Nuclear Clusters to Other Hot Stellar Systems P In Fundamental-Plane space, nuclear star clusters are most similar to Globular Clusters; they have similar size, but are more massive and denser MM M/L ~I 3

Roeland van der Marel - Space Telescope Science Institute 32 Black Hole constraints in Low Dispersion Systems P Some very late-type galaxies are active, e.g., NGC 4395 (Sm), POX52 (dE) P BH mass estimated at M BH ~ 10 5 M  P Both galaxies have a nuclear star cluster P Questions: P How typical are these galaxies? P Did the BH form because of the galaxy potential well? or P Did the BH form because there is a cluster? and if so P Do such BHs also form/exist in isolated star clusters?

Roeland van der Marel - Space Telescope Science Institute 33 Stellar Kinematical BH studies in Late-Type Galaxies P Stellar kinematics: only M BH upper limits P Irregulars ?? Dwarf Spheroidals ?? P Dwarf Ellipticals (Geha, Guhathakurta & vdM) P  = km/s; M BH < 10 7 M  P Late-Type spirals (IC 342 Boeker, vdM & Vacca) P  = 33 km/s; M BH < M  P Interesting BH limits/detections: P Requires spatial resolution of cluster P restricted to HST data for Local Group galaxies

Roeland van der Marel - Space Telescope Science Institute 34 Case Study: IC 342 P  = 33 km/s  M BH < M  (upper limit).

Roeland van der Marel - Space Telescope Science Institute 35 M33 P Nucleus/star cluster dominates central few arcsec P HST/STIS: P Gebhardt et al., Merritt et al. P  = 24 km/s P M BH < M  (upper limit)

Roeland van der Marel - Space Telescope Science Institute 36 IMBHs in Globular Clusters? P Studies of Globular Cluster kinematics are probing an interesting mass range P Controversial results/upper limits P G1 P M15 P Interestingly, consistent with M BH -  relation …

Roeland van der Marel - Space Telescope Science Institute 37 Conclusions: P BH demographics well mapped for supermassive BHs P M BH  M bul   4 can be explained by many scenarios P BH studies in late-type galaxies are emerging; IMBHs exist there but may not be ubiquitous P There may be a continuum in central structure from early-type galaxies to late-type galaxies to Globular Clusters