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Demography of supermassive black holes: mergers & gravitational waves. Françoise Combes Observatoire de Paris. Monday 9 November. Overview. 1- Co-evolution of galaxies and Black holes 2-Feedback effects? 3- Quasars at z~6 4- MBH growth 5-Steps in the BH merging
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Demography of supermassive black holes: mergers & gravitational waves Françoise Combes Observatoire de Paris Monday 9 November
Overview 1- Co-evolution of galaxies and Black holes 2-Feedback effects? 3- Quasars at z~6 4- MBH growth 5-Steps in the BH merging 6- Observing binary black holes 7- LISA
Ubiquity of Massive holes in galaxies Giant Ellipticals/S0s Spirals Dwarfs Globular Clusters The most massive BH Black hole mass scales with bulge mass not total mass Some BH at least Maybe
Scaling SMBH, M-s relation Mbh = 0.2% Mbulge Blue: stellar velocitiesGreen: gas velocities Red: disks with masers H2O, OH.. (Magorrian et al 98, Gebhardt et al 02, Ferrarese &Merritt 01, Tremaine et al 02, Shields et al 02)
Invoked mechanisms Co-evolution: each time gas is driven to the center to form stars, a fraction fuels the BH Possible, but through secular evolution/pseudo-bulges & interactions Delayed co-evolution: Different time-scales Better, since it is difficult to find good correlations of AGN and bars, or with interactions Self-regulated growth Feedback mechanisms: related to the potential well (bulge mass)
Co-evolution BH and galaxies Ratio 1000 since mass loss 50% PLE: Pure Luminosity Evolution LDDE Luminosity-dependent Density Evolution
--SFR BHAR and SFR versus z __BHAR Dotted lines are BHAR shifted by 100 in Number and 20 in Rate
BHAR and SFR split for intensity z=1 Total is dominated by low-intensities Zheng et al 2009
BHA and SF not in the same objects z=1 Zheng et al 2009 fbulge-bh = 650, frecycle=2 1300
Hierarchical formation of BCG dry mergers since z=1 50% of stars formed at z=5; mass assembling after z=0.5 De Lucia & Blaizot 2007
Overview 1- Co-evolution of galaxies and Black holes 2-Feedback effects? 3- Quasars at z~6 4- MBH growth 5-Steps in the BH merging 6- Observing binary black holes 7- LISA
Feedback due to Starburst or AGN Di Matteo et al 2005
Perseus Clusterexample of AGN feedback Salomé et al 2006 Fabian et al 2003
Overview 1- Co-evolution of galaxies and Black holes 2-Feedback effects? 3- Quasars at z~6 4- MBH growth 5-Steps in the BH merging 6- Observing binary black holes 7- LISA
CII The most distant QSO at z=6.4 Beam 0.3" PdB Age ~ 1 Gyr Keck z-band Djorgovski et al Fan et al 2003, White et al 2003 Mdust ~108Mo (Bertoldi et al 2003) MBH = 1.5 109Mo (Willot et al 2003) No HCN detected CII, Walter et al 2009 1kpc scale starburst, 1000Mo/yr/kpc2
A very early assembly epoch for QSOs The highest redshift quasar currently known SDSS 1148+3251 at z=6.4 has estimates of the SMBH mass MBH=2-6 x109 Msun(Willott et al 2003, Barth et al 2003) As massive as the largest SMBHs today, but when the Universe was <1 Gyr old!
THE HIGHEST-REDSHIFT QUASARS How do they get a mass Mbh ~4 109 Mo ? Seed mass ~4 Mo 20 e-folding times At Eddington luminosity e-folding time 40 (e/0.1) Myr Age of the universe at z=6 Is 800 Myrs Becker et al. (2000)
Brief History of the Universe Fluctuation generator Fluctuation amplifier Hot Dense Smooth Cool Rarefied Clumpy (Graphics from Gary Hinshaw/WMAP team)
First ‘seed’ black holes? Hierarchical Galaxy Formation: small scales collapse first and merge later to form more massive systems BARYONS: need to COOL First ‘action’ happens in the smallest halos with deep enough potential wells to allow this (at z~20-30) courtesy of M. Kuhlen
Overview 1- Co-evolution of galaxies and Black holes 2-Feedback effects? 3- Quasars at z~6 4- MBH growth 5-Steps in the BH merging 6- Observing binary black holes 7- LISA
Descendant Mh= 2 x 1015M Quasars end up in cD galaxies at centres of rich galaxy clusters today Mh= 21015M Dark matter Galaxies Quasar host Mh= 5 x 1012M Mh= 51012M M*= 1011M SFR = 235 M/yr MBH= 108M
MBH Growth Enoki et al 2005 • Coalescence dominates dM/dt for z<1 • From Halos to MBHs • Gas physics • Heating, cooling, star formation • Accretion
BH growth For simple dimensional relations, we can infer Racc = 0.3 M6/v22 pc and dM/dt is the Bondi accretion rate: dM/dt = 4 p R2 v r = (10-4 Mo/yr) M62/v23r since dM/dt ~ M2, then the accretion time is ~ 1/M. for very low BH this takes much larger than the Hubble time. Therefore it requires a large seed, mergers of BH, or very large densities, like in MW, 107 Mo/pc3 Accretion-dominated growth, tg = tacc. Nice for Seyfert 1 For QSO, they reach the Eddington limit, Ledd ~ M, the L ~ dM/dt ~ M2 L/Ledd ~ M, the BH growth slows down when approching Ledd. tedd = M/(dM/dt)edd = 4.5 107 yr (0.1/e) equating tacc = tedd, this occurs for Mt = 2 108 Mo v23/r (e/0.1)
IMBH: do they exist? Some theories predict them Observational constraints: lensing, X-ray sources, galaxy centers, if the BBR extrapolate? Globular clusters (M15?, G1 in M31) AGN in dwarf galaxies: NGC 4395(Filippenko & Ho 2003) MBH = likely 104-105 Mo (Seyf 1, no bulge) Low-ionisation, Lbol/LE = 210-2- 2 10-3 problem of dwarfs: host nuclear star clusters of ~106 Mo solution: only in the Local Group, possible to separate In M33 < 103Mo, factor 10 below the BBR
Overview 1- Co-evolution of galaxies and Black holes 2-Feedback effects? 3- Quasars at z~6 4- MBH growth 5-Steps in the BH merging 6- Observing binary black holes 7- LISA
Merging steps for binary holes 1. Dynamical friction t a 2. Binary hardening due to stars or accretion of gas 3. Gravitational radiation t a4 Do they merge?
Gravitational rocket binary center of mass recoil during coalescence due to asymmetric emission of GW (e.g. Fitchett 1983, Favata et al 2004, Blanchet et al 2005, Baker et al 2006) vrec ≤ 250 km/s GR SIMULATIONS ELLIPTICAL GALAXIES 1000 «vesc from today galaxies 100 Vrecoil (km/s) Vesc (km/s) ≈vesc from high-z ones 10 DWARF GALAXIES/ MINIHALOS mass 1013 109
at z >10 more than 80% of merging MBHs can be kicked out of their halo (Volonteri & Rees 2006) the gravitational rocket effect is a threat at the highest redshifts, when host halos are small and have shallow potential wells Can the merger process start early enough to Allow build-up of supermassive holes?
Evidence of recoil? Broad-line region dragged with the MBH 2650 km/s difference with the Narrow-line region Komossa et al 2008 The ringdown radiation produces anti-kick Le Tiec et al 2009
L L L Recoiling MBHs a2 a1 a2 a1 Low kick velocities (~100 km s-1) High kick velocities (~1000 km s-1) a1 a2 Volonteri 2009
Recoiling MBH Random distribution of spin moduli Aligned or anti-aligned spins spin-orbit isotropy
Overview 1- Co-evolution of galaxies and Black holes 2-Feedback effects? 3- Quasars at z~6 4- MBH growth 5-Steps in the BH merging 6- Observing binary black holes 7- LISA
Predicted Nb binary quasars Today 2 out of 17500 detected Not detected in the SDSS high z, low M, and low L Volonteri et al 2009
BH Spin and host morphology Are massive black holes rapidly spinning? Radio jets are observed preferentially in E-galaxies Due to spin? Spin is modified by BH mergers and the coupling with the accretion disc mergers can spin BHs either up or down; alignment with the disc spins up • In spiral galaxies, more random accretion, tidal disruption of stars, molecular cloud accretion
spin evolution by BH mergers only X-ray Fe Ka line spin evolution by BH mergers AND accretion
Mergers of SMBH Merging should take place rapidly enough, to avoid 3 BH and slingshot effect Milosavljevic & Merritt 2001 Wandering simulations
OJ287, light curve 100yrs Pietila 98 3C75,Owen et al 1985 Roos et al 1993 VLBI maps of 1928+738 jet oscillations due to the orbital motions of the BH, period 3.2 yr
Overview 1- Co-evolution of galaxies and Black holes 2-Feedback effects? 3- Quasars at z~6 4- MBH growth 5-Steps in the BH merging 6- Observing binary black holes 7- LISA
LISA Will see mergers of 105 –107 Msol black holes
Binary BH merger Centrella Kip Thorne