S. Komossa, MPIfR, Bonn

Interacting Galaxies and Binary Quasars: A Cosmic Rendezvous, Trieste, April 2-5, 2012

AGN Pairs And Binary Supermassive AGN Pairs And Binary Supermassive Black Holes:Black Holes:

From Large To Small ScalesFrom Large To Small Scales

0.01 1 100 r (pc)

101 0

106

t (yr)

evolution of SMBBHs

[Begelman, Blandford, Rees 1980]

(1) dynamical friction regime

(2) binary hardening )*

)* [e.g., Saslaw & al. 74, Quinlan & Hernquist 97, Gould & Rix 00, Milosavljevic+ 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, Matsui & al. 06, Zier 07, Alexander 07, Mayer+ 07, Perets & Alexander 08, Sesana & 08, Berentzen & 09, Colpi+ 09, Mayer+ 09, Colpi+ 11, van Wassenhove+ 12 .....]

(3) GW emission

(4) recoil

SMBBHs in astrophysical context

• galaxy mergers are the sites of major BH growth & feedback processes - when does accretion start, for how long, how much gas, when do BHs coalesce, .... ? - initial conditions which determine amplitude of GW recoil

• coalescing BBHs are powerful emitters of grav. waves; & e.m. radiation - GWs: test GR predictions, precisely measure BH mass & spin - e.m.: identify ctrpart, host galaxy, z

• GW recoil: BHs oscillate about gal. cores, or even escape wealth of potential astrophysical applications

• central to our under- standing of assembly history & demography of BHs, & galaxy-BH (co-)evolution

• (0) binary quasars, AGN in clusters of galaxies• (1) pairs of active galaxies, in early phase of interaction and merging - most of them found recently by their double-peaked narrow optical emission lines, if both galaxies have a „Narrow- Line Region“• (2) BH pairs in „single“ galaxies and advanced mergers - two accreting BHs, spatially resolved; often these systems are heavily obscured, and X-ray or radio observations are best suited for finding them • (3) spatially unresolved BBH candidates - semi-periodic lightcurves or spatial structures (radio-jets)• (4) some post-merger candidates - X-shaped radio sources, - galaxies with central light deficits - double-double radio sources - recoiling SMBHs

observational evidence for SMBH pairs and observational evidence for SMBH pairs and binariesbinaries

active cores in interacting galaxies / early active cores in interacting galaxies / early phases of galaxy merging – optical viewphases of galaxy merging – optical view

[e.g., Zhou+ 04, Gerke+ 07, Xu & Komossa 09, Comerford+ 09, Liu+ 10, 11, Smith+ 10, Green+ 10, 11, Fu+ 11a, b,12, Shen+ 11, McGurk+ 11, Comerford+ 11, Barrows+ 12]

• many candidates (>100) recently identified from doubled-peaked optical narrow emission lines; in single sources first, then in large samples based mostly on the SDSS archive of spectra

[Xu

+ K

omos

sa 0

9]

o.k. for candidate selection, but then need follow-ups (esp. imaging) to exclude alternatives:

two-sided outflows, jet-cloud interactions, rotating disks, one AGN illuminating two ISMs....

only small fraction of all „dbl-peakers“ confirmed as good candidates, only a few systems confirmed as „detections“.

active cores in interacting galaxies / early active cores in interacting galaxies / early phases of galaxy merging – optical viewphases of galaxy merging – optical view

[Zhou+ 04, Xu & Komossa 09, Barrows+ 12 , Fu+ 11a]

unusual candidate: with bright, pronounced dbl-peaks, but extra broad components in all forbidden lines

SDSSJ1316+1753

SDSSJ1048+0055

CXOJ1426+35

SDSSJ1502+1115

first (SDSS) candidate: dbl-peaked [OIII] (but single [OII]), + 2 radio sources but nature unknown

most distant candidate: . z=1.175

confirmed case: bright radio cores, compact, almost RL

r = 7.4 kpc

active cores in interacting galaxies / early active cores in interacting galaxies / early phases of galaxy merging – X-ray viewphases of galaxy merging – X-ray view

[Green+ 10, Guainazzi+ 05, Piconcelli+11, Koss+ 11, 12]

SDSS merger: two X-ray/opt quasars, unabsorbedz=0.4

r = 21 kpc

ESO 509/ IG066: two AGN with XMM (only 1 opt)r = 11 kpc

IRAS20210+1121: . likely two AGN with XMM z=0.056

r = 11 kpc

Mrk 739E/W: two X-ray AGN with Chandra (only one opt.) z=0.03

r = 3.4 kpc+ 16 more among Swift-sources

opt.

X-rays

Chandra-X over SDSS-r

(plus several more, + candidates; usually X-fainter so challenge is to distinguish between jets/SB/ULX/AGN)

single galaxies & advanced mergers, still spatially single galaxies & advanced mergers, still spatially resolved – X-ray viewresolved – X-ray view

NGC 6240:nearby (U)LIRG z=0.024 two luminous, hard X-ray AGN incl. strong Fe lines with Chandrar = 1 kpc

[Komossa+ 03, Iwasawa+ 11, Fabbiano+ 11]

NGC 6240Chandra

SDSSJ1254+0846

0402+379

no further one in X-rays, in ~30 LIRGs, observed with Chandra (but could still be there & obscured)

NGC 3933:z=0.012two hard X-ray cores with Chandrar = 150c

radio galaxy, z=0.06

two radio cores C1,C2 compact, variable & flat-spectrum true nuclei,

r = 7 pc

[Rodriguez+ 06,09, Burke-Spolaor+ 10]

no further one in >1000 radio-galaxies

(but BHs could still be there & not be radio-active)

SDSSJ1254+0846

0402+379

single galaxies & advanced mergers, still spatially single galaxies & advanced mergers, still spatially resolved – radio viewresolved – radio view

0.01 1 100 r (pc)

101 0

106

t (yr)

evolution of SMBBHs

[Begelman, Blandford, Rees 1980]

?

SMBBHs: spatially unresolved SMBBHs: spatially unresolved candidatescandidates

• semi-periodic lightcurves, esp. OJ287

• period ~12 yr interpreted as orbital period

• orbital solution: Μ1 = 1.8 101 0 Msun Μ2 =

1.4 108 Msun ε = 0.7, ∆TGW = 0.01 yr/period

• periodic „radio motion“: 3C66B

• syst. shifts in position, with period 1.05 yr

• interpreted as system of massive BBHs

• masses con- strained by PT

• double-peaked broad lines

• BBH interpret. dismissed in the 80s; no orbital motion detected

• new large SDSS samples may contain some

• helical structures in radio jets

• jet-emitting secondary BH orbiting primary; or precession ?

[e.g., Lehto &Valtonen 96, Sundelius+ 97, Pietilä+ 98, Liu & Wu 02, Valtonen+ 97,06,-12; Sudou+ 03, Jenet+ 05, Iguchi+ 10; Lobanov+ 06: Gaskell 83 - 10, Boroson+Lauer 10, Chornock+ 10, Eracleous+ 11, Decarli+ 10, Tsalmantza+11, .....]

SMBBHs: post-merger candidatesSMBBHs: post-merger candidates

• X-shaped radio sources

• change in BH spin direction after BBH coalescence change in jet direction ?

• ejected BHs:• consequence of GW

recoil, • v up to ~5000 km/s

predicted by NR• appear as spatial or

kinematic off-sets • ~4-6 candidates

[e.g.,Merritt & Ekers 02, .... Campanelli+07, Lousto+12, Bonning+ 07, Komossa+ 08, Robinson+ 10, Batcheldor+ 10, Liu+ 12...]

Cid 42: multiple opt. emi-line systems,& two bright cores pre-merger dual AGN, or post-merger recoil ?

[Comerford+ 09, Elvis+ 09, Civano+ 10, 12]

- quasar pairs + interacting galaxies- BH pairs in „single“ galaxies

(NGC 6240; 0402+379, NGC3933, ..)

two accreting BHs, spatially resolved - spatially unresolved BBH candidates

- semi-periodic lightcurves (esp. OJ 287)

2ndary BH hitting disk of primary

2005-2007 monitoring campaign: orbital shrinkage due to GWs

- helically distorted radio jets (e.g. 3C345)

jet-emitting 2ndary BH orbiting primary; or precession ?

- double-peaked broad lines ? no orbital motions detected yet

- post-merger candidates

- (some) X-shaped radio sources spin re-orientation ? - double-double radio sources open gap systems

- recoiling BHs

observational evidence for SMBBHs1000

100

10

1

0.1

0.01

r/pc

• many candidates, but few „safe“ detections

„why so few“ BBHs ?

- large distances, still difficult to resolve, and perhaps obscured (need to distinguish other phenomena, like knots in jets, or lensing) - close pairs: most or all current methods require at least one BH to be active, while many may not be

• wide pairs: - radio, X-ray & optical imaging spectroscopy; ongoing

• close pairs: - Fe-line spectroscopy and variability (IXO)

- periodic shifts in radio position (space-VLBI)

- t-dependent accretn signa- tures (eROSITA, LSST)

future search for SMBBHs prior to, and quasi-future search for SMBBHs prior to, and quasi-simultaneous with, coalescencesimultaneous with, coalescence

• pre/post-coalescence: - e.m. precursors incl. semi- periodicity; or afterglows e.g. when inner disk reforms - other effects (shocks in disk) related to recoil - GWs

[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+ 08,11, Lippai + 08, Schnittman+ 08, Haiman+ 08, 09, Loeb 09, Cuadra+ 09, Palenzuela+ 09, van Meter+ 09, Megevand+ 09, Krolik+ 09, Chen+ 09, Liu+ 09, Wegg & Bode 11, Stone & Loeb 11, Mösta+ 10, Zanotti+ 10, Schnittman 10, Tanaka+ 10, Roedig+ 11....]

• non-active pairs: - tidal disruption rate (dramatically enhanced rate, temporarily, when one BH refills loss-cone of the other) /accretion interrptn)

- identifying active pairs & BBHs in all stages of galaxy merging, and measuring their properties, is central to our understanding of the BH assembly history and demography, and BH-galaxy (co)-evolution

- active search for AGN pairs and SMBBHs is ongoing - many candidates found recently by opt – X – radio obs.

- several active pairs detected at d>10 pc, most of them > 1kpc, -> many more out there;

but safely identified systems are still rare all searches/detections so far required at least one BH to be active

summarysummary

- how best to identify & confirm the compact pairs/binaries (sev. candidates, so far) non-active pairs (none, so far) (pre/post-)coalescences (none, so far) recoiling BHs (sev. candidates, so far)

Meeting-in-a-meeting, at the next AAS assemby Anchorage, June 10-14, 2012

on “Galaxy mergers from the largest to the smallest scales”