Compact supermassive black hole binaries & recoiling black holesBBHsmulti-wavelength evidencenew e.m. signals/ future searchesrecoiling BHsStefanie Komossa, MPE GarchingProbing Strong Gravity Near Black Holes, Prague, Feb. 15-18, 2010

dynamical friction regime binary hardening e.g., by stellar slingshot effects (loss-cone refilling), interact. with gas, stalling at ~1-0.1 pc ?... )* emission of GWs )*[e.g., Saslaw & al. 74, Quinlan & Hernquist 97, Gould & Rix 00, Merritt 01,03, Milosavljevic & Merritt 01,03, Zier & Biermann 01, Ivanov+ 99,04, Yu 02, Blaes et al. 02, Poon & Merritt 02, Haehnelt & Kauffmann 02, Hemsendorf+ 02, Armitage & Natarajan 02,05, Escala+ 03,05, Makino & Funato 04, Berczik+ 05,06, Haardt+. 06, Dotti+ 06, Merritt 06, 07, Matsui & al. 06, Zier 07, Alexander 07, Mayer+ 07, Perets & Alexander 08, Sesana & 08, Berentzen & 08, Mayer+ 09, ....................][Begelman, Blandford, Rees 1980]1232evolution of SMBBHs

BH pairs in single galaxies (NGC 6240, 0402+379, ...) two accreting BHs, spatially resolved spatially unresolved BBH candidates - semi-periodic lightcurves (esp. OJ 287) 2ndary BH hitting disk of primary ? 2005-2007 monitoring: orbital shrinkage due to GWs ? - helically distorted radio jets (e.g. 3C345) jet-emitting 2ndary BH orbiting primary; or precession ? ( - double-peaked broad lines ? )- post-merger candidates - X-shaped radio sources spin flips ? - double-double radio sources open gap systems ? decreasing nuclear separationobservational evidence for SMBBHs[e.g., Lehto & Valtonen 96, Silanp 00, Merritt & Ekers 02, Komossa+ 03, Liu+ 03, Zhou+ 04, Lobanov+ 06, Rodriguez+ 07, Comerford+ 08, Valtonen+ 07-10, ... ]

spatially resolved systems in single galaxies: NGC 6240, 0402+379, COSMJ1000+0206, SDSSJ1254+0846 nearby (U)LIRG z=0.024 luminous, hard X-ray emission from two coresaccreting BHs at separation of ~ 1 kpc [Komossa+ 03] [Rodriguez+ 07] [Comerford+ 09, Elvis+ 09] [Green+ 10] radio galaxy, z=0.06 two radio cores C1,C2compact, variable & flat-spectrum true nuclei, at 7 pc sep.COSMOS gal, z=0.36 2 cores with HST1.8 kpc sep.SDSS merger, z=0.4two opt. quasars, unabsorberd21 kpc sep. (lensing unlikely) opt. X-rays

spatially unresolved can-didates: semi-periodic variability of OJ287semi-periodic optical variability with period ~12 yr BBH model: burst interval = orbital perioddouble-peak structure: 2ndary in pre-cessing orbit impacts warped, thick disk twice essential for finding orbital solutions: timing of all prev. peaks orbital parameters: M1 = 1.8 1010 Msun )* M2 = 1.4 108 Msun e = 0.7, Df = 40 /orbit

shift in Sept. 2007 maximum: interpreted as orbital shrinkage due to emission of gravitational waves ( DTGW = 0.01 yr/period)[e.g. Silanp et al. 88, 96, Lehto &Valtonen 96, Sundelius+ 97, Pietil+ 98, Liu & Wu 02, Valtonen+ 97,06, 07,10.....][Valtonen+ 07][LV96; Nilsson et al. 06])* note that the host galaxy appears to imply lower mass Liu&Wu 02

interlude:no BBHs in broad double peakers, so fara few % of all quasars show broad double-peaked emission linesone early idea: BBH systems; gas clouds bound to each BHstrong prediction: should see orbital motion on timescale of years not detectedinstead, processes in outer warped accretion disk around a single BH[e.g., Gaskell 83, 88, 96, Halpern & Filippenko 88, Eracleous et al. 97, Halpern & Eracleous 00, Gaskell 10]flux

interlude:no BBHs in broad double peakers, so fara few % of all quasars show broad double-peaked emission linesone early idea: BBH systems; gas clouds bound to each BHstrong prediction: should see orbital motion on timescale of years not detectedinstead, processes in outer warped accretion disk around a single BH[e.g., Gaskell 83, 88, 96, Halpern & Filippenko 88, Eracleous et al. 97, Halpern & Eracleous 00, Gaskell 10]SDSS1536+04 [Boroson & Lauer 09] turned out to be another double-peaker; no orbital motion detected so far, v < 70 km /s /yr; [Chornock+ 09, 10]fluxArp 102B[Gaskell 10]

solar-type stars: GWs only detectable from GCWDs: (partially) tidally disrupted for MBH < 105-6 Msun em & GW signal LISA rates: 0.1 100 /yr[e.g., Amaro-Seoane 07, Sesana+ 08; Menou+ 08]X-ray lightcurve of giant-amplitude stellar tidal dis-ruption flares from inactive galaxies [e.g., Komossa & Bade 99, Halpern+ 04, Komossa+ 04, 08]extreme mass-ratio pairs: tidal disruption of white dwarfs in WD MBH mergersEMRIs: Lx huge: sev. 1044 erg/s very soft X-ray spectra from optically inactive galaxies factor 6000 variability t-5/3 decline law the few known events are consist. with disruption of solar-type star

wide pairs: - radio, X-ray & optical imaging spectroscopy close pairs: - Fe-line spectroscopy and variability (IXO) - periodic shifts in radio position (space-VLBI) - acceleration of precession rate - t-dependent accretn signatures non-active pairs: - tidal disruption rate (dramatically enhanced rate, temporarily, when one BH refills loss-cone of the other) /accretion interrptn)future e.m. search for SMBBHs prior to, and quasi-simultaneous with, coalescence pre/post-coalescence: - e.m. precursors or afterglows; e.g. when inner disk reforms - other effects (shocks in disk) related to recoil - GW heating of disk

GW recoil - off-nuclear quasars/ emission-line shifts - disk flares - tidal recoil flares - HCSS [e.g. Milosavljevic & Phinney 05, Armitage & Natarajan 02, Liu+ 03, Yu & Lu 02, Torres+ 04, Dotti+ 06, Koc sis+ 08, Shields+ 08, Liu & Chen 07, Tao+ 07, Hayasaki+ 08, Lippai + 08, Schnittman+ 08, Haiman+ 08, 09, Loeb 09, Palenzuela+ 09, van Meter+ 09, Megevand+ 09, Rossi+ 09, Krolik+ 09, Chen+ 09, Liu+ 09, ..........]talk by Fukun Liu

anisotropic emission of GWs from coalescing BBHs leads to recoil of the newly formed single BHrecent NR simulations of BBH mergers predict BH kicks with velocities up to 3800 km/s (10000 km/s); highest for m1=m2, a1=-a2=max & in orb. plane recoiling BHs will oscillate about galaxy core, or could even leave massive ellipticals various astrophysical implicationsrecoiling supermassive black holes: kicks & superkicks[e.g., Peres 1962, Bekenstein 73, Redmount & Rees 89, ... / Baker+ 06,07,08, Brgmann+ 08, Campanelli+ 06, 07a,b, 08, Dain+08, Gonzales+ 06, 07a,b, Healy+ 08, Herrman+ 07a,b, Koppitz+ 07, Lousto & Zlochower 08, Pretorius 05, 07, Pollney+07, Schnittman+ 07, 08, Tichy & Maronetti 07, ...]

predicted spectroscopic signatures

- kinematically off-set Broad Line Regions, ideally at v>> few 100 km/s, to distinguish from BLR physics

- lack of ionization stratification

- symmetric broad lines, (and MgII at same v as Balmer lines)

Sloan Digital Sky Survey (SDSS) ideally suited; in DR7: >100.000 quasar (= major merger) spectra recoiling SMBHs spectroscopic signatures[Bonning+ 07][Komossa & Merritt 08]

SDSSJ0927+2943, @ 2650 km/s shows all predicted spectral features of a recoiling BH, plus an extra peculiar syst. of NELs [Komossa et al. 08]2 other candidates, again based on kinematic broad line shifts, + polarimetry, recently reported, @ ~1000 km/s [Axon et al., in prep 2009 Ringberg workshop on GN]

recoiling SMBHs search for candidates via spectroscopic signaturesKomossa+ 08ongoing spectroscopic searches, & ongoing predictions of other signatures of recoiling BHs in gas-rich and gas-poor systems: disk flares after recoil, off-nuclear tidal-disruption flares, hypercompact stellar systems, .......

several lines of observational evidence for presence of supermassive binary black holes; good candidates still rare (one reason: detection requires one, or both, BHs to be active).

predictions of quasi-simultaneous e.m. and GW signals from SMBBH mergers, and WD-MBH mergers promising for future searches

recoiling BHs: wealth of potential astrophysical implications -- depending on vkick -- still being explored, first observed candidates

summary