Compact supermassive black hole Compact supermassive black hole binaries binaries & recoiling black holes& recoiling black holes

• BBHsBBHs• multi-wavelength multi-wavelength

evidenceevidence• new e.m. signals/ new e.m. signals/

future searches future searches• recoiling BHsrecoiling BHs

Stefanie Komossa,

MPE Garching

Probing 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]

1

2

3

1

2

3

evolution of SMBBHsevolution 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 separation

observational evidence for SMBBHsobservational evidence for SMBBHs

[e.g., Lehto & Valtonen 96, Silanpää 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: spatially resolved systems in single galaxies: NGC 6240, 0402+379, NGC 6240, 0402+379,

COSMJ1000+0206, SDSSJ1254+0846COSMJ1000+0206, SDSSJ1254+0846

• nearby (U)LIRG z=0.024

• luminous, hard X-ray emission from two cores

• accreting 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,C2

• compact, variable & flat-spectrum true nuclei, at 7 pc sep.

• COSMOS gal,

z=0.36 • 2 cores

with HST• 1.8 kpc

sep.

• SDSS merger, z=0.4

• two opt. quasars, unabsorberd

• 21 kpc sep. (lensing

unlikely)

opt.

X-rays

spatially unresolved spatially unresolved can-didates:can-didates: semi- semi-

periodic variability of periodic variability of OJ287OJ287

• semi-periodic optical variability with period ~12 yr • BBH model: burst interval = orbital period• double-peak structure: 2ndary in pre-

cessing orbit impacts warped, thick disk twice • essential for finding orbital solutions:

timing of all prev. peaks • orbital parameters:

1 = 1.8 10 Msun )* 2 = 1.4 10 Msun = 0.7, = 40° /orbit

• „ shift“ in Sept. 2007 maximum: interpreted as orbital shrinkage due to emission of gravitational waves ( TGW = 0.01 yr/period)

[e.g. Silanpää et al. 88, 96, Lehto &Valtonen 96, Sundelius+ 97, Pietilä+ 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:interlude:no BBHs in „broad double peakers“, so farno BBHs in „broad double peakers“, so far

• a few % of all quasars show broad double-peaked emission lines

• one early idea: BBH systems; gas clouds bound to each BH

• strong prediction: should see orbital motion on timescale of years

• not detected• instead, 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]

flu

x

interlude:interlude:no BBHs in „broad double peakers“, so farno BBHs in „broad double peakers“, so far

• a few % of all quasars show broad double-peaked emission lines

• one early idea: BBH systems; gas clouds bound to each BH

• strong prediction: should see orbital motion on timescale of years

• not detected• instead, 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]

flu

x

Arp 102B

[Gask

ell

10]

solar-type stars: GWs only detectable from GC

WDs: (partially) tidally disrupted for MBH < 10

Msun em & GW signal LISA rates: 0.1 – 100 /yr

[e.g

., A

maro

-Seoane 0

7,

Sesa

na+

08

; M

enou+

08]

X-ray lightcurve of giant-amplitude stellar tidal dis-ruption flares from inactive galaxies

[e.g

., K

om

oss

a &

Bade 9

9,

Halp

ern

+ 0

4, K

om

oss

a+

04,

08

]

extreme mass-ratio pairs: tidal extreme mass-ratio pairs: tidal disruption of white dwarfs in WD – MBH disruption of white dwarfs in WD – MBH

mergersmergers

EMRIs:• Lx huge: sev. 10 erg/s • very soft X-ray spectra• from optically inactive galaxies • factor 6000 variability• t 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, future e.m. search for SMBBHs prior to, and quasi-simultaneous with, coalescenceand 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

recoiling supermassive black holes: recoiling supermassive black holes: kicks & superkickskicks & superkicks• anisotropic emission of GWs from coalescing BBHs leads to

recoil of the newly formed single BH• recent 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 implications

[e.g., Peres 1962, Bekenstein 73, Redmount &

Rees 89, ... / Baker+ 06,07,08, Brügmann+ 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, ...]

z

• 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 recoiling SMBHs – spectroscopic signaturessignatures

[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 recoiling SMBHs – search for candidates via spectroscopic signaturesvia spectroscopic signatures

Komossa+ 08

• ongoing 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

summarysummary