Coalescences of IMBH binaries as sources for the future IMBH - PowerPoint PPT Presentation

Coalescences of IMBH binaries as sources for the future ET detector Coalescences of IMBH binaries as sources for the future IMBH binaries as seen by the GW ET detector detectors The (disputed) existence of IMBHs Modeling BBH Lucía Santamaría, Pau Amaro-Seoane coalescence Event rates of IMBH (Albert-Einstein-Institut Potsdam, Germany) binaries Summary and Conclusions February 23, 2010 f2f WG4 ET meeting, Nikhef, Amsterdam 1 / 16

Coalescences of Plan of the talk IMBH binaries as sources for the future ET detector IMBH binaries as IMBH binaries as seen by the GW detectors seen by the GW detectors The (disputed) existence of IMBHs The (disputed) existence of IMBHs Modeling BBH coalescence Event rates of IMBH Modeling BBH coalescence binaries Summary and Conclusions Event rates of IMBH binaries Summary and Conclusions 2 / 16

Coalescences of Different detectors for different sources IMBH binaries as sources for the future ET detector 10 − 16 coalescence of massive black holes 10 − 17 IMBH binaries as seen by the GW 10 − 18 detectors SN core collapse Hz ) 10 − 19 BNS and BBH The (disputed) coalescence √ existence of IMBHs S n ( f ) ( 1 / 10 − 20 resolved unresolved galactic Modeling BBH galactic binaries 10 − 21 extreme coalescence binaries mass-ratio � inspirals Event rates of IMBH 10 − 22 binaries Advanced LIGO Advanced Virgo 10 − 23 Summary and Einstein Telescope Conclusions ET (Xylophone config.) 10 − 24 LISA 10 − 25 10 − 4 10 − 3 10 − 2 10 − 1 10 0 10 1 10 2 10 3 10 4 Frequency (Hz) ◮ Current ground-based GW astronomy: neutron-star binaries and solar-mass BBHs. Scarce sources (for now) - around-threshold events ◮ Space-based projects: SMBHs, EMRIs, galactic binaries. Abundance of sources - huge SNRs ◮ ET: IMBHs? Expected event rates? Foreground noise? 3 / 16

Coalescences of ET opens a window in the intermediate-mass region IMBH binaries as sources for the future ET detector 1000 Η� 0.25 initial LIGO IMBH binaries as Η� 0.08 ... 100 seen by the GW detectors advanced LIGO 10 The (disputed) f � Hz � f Light Ring f LRD f ISCO ET existence of IMBHs 1 Modeling BBH coalescence 0.1 Event rates of IMBH binaries 0.01 LISA Summary and Conclusions 10 100 1000 10 4 10 5 10 6 Total mass � M sun � ◮ As total mass of the system increases, BBHs merge at lower frequencies ◮ Shown are the ISCO ( r = 6 M ), Light ring ( r = 3 M ) and Lorentzian ringdown (after merger) frequencies of equal-mass ( η = 0 . 25 ) and 1:10 ( η = 0 . 08 ) � � m 1 m 2 binary systems η ≡ ( m 1 + m 2 ) 2 ◮ While LIGO’s efforts are targeted towards stellar-mass binaries, LISA will see mergers of supermassive BBHs (and also IMBHs’ inspirals ) ◮ ET will open a window in the intermediate-mass region 10 2 − 10 4 M ⊙ ◮ IMRIs and IMBH-IMBH binaries. In this talk: IMBHBs! 4 / 16

Coalescences of What advanced LIGO/Virgo will see vs what ET could see IMBH binaries as sources for the future At 100 Mpc - Sources for LIGO/Virgo ET detector IMBH binaries as Initial LIGO seen by the GW Initial Virgo detectors 100 M � � Adv LIGO Hz � The (disputed) � 50 M � Adv Virgo existence of IMBHs 10 � 21 � f � 1 � Modeling BBH 20 M � � coalescence 10 M � Event rates of IMBH � � � f �� binaries � S n � f � and 2 � h � 10 � 22 Summary and � Conclusions � � 10 � 23 � � 10 100 1000 f � Hz � • : f ISCO , � : f LightRing , � : f LRD , 5 / 16

Coalescences of What advanced LIGO/Virgo will see vs what ET could see IMBH binaries as sources for the future At 100 Mpc - Sources for ET ET detector IMBH binaries as Initial LIGO 10 � 19 seen by the GW Initial Virgo � detectors � Adv LIGO base � � Adv LIGO BHBH Hz � The (disputed) 10 � 20 � Adv Virgo � existence of IMBHs � ET base � � ET Xylophone f � 1 � Modeling BBH � 10 � 21 coalescence � Event rates of IMBH � � � f �� binaries S n � f � and 2 � h 10 � 22 Summary and Conclusions 10 � 23 1 0 0 600 M � 0 300 M � 2 M 0 10 � 24 0 � M � 10 � 25 1 10 100 1000 f � Hz � • : f ISCO , � : f LightRing , � : f LRD , 6 / 16

Coalescences of The ET and LISA IMBH binaries as sources for the future ET detector 10 � 17 Hz � 10 � 18 IMBH binaries as � seen by the GW f � 1 � 10 � 19 detectors 0 . 2 y The (disputed) r s 10 � 20 existence of IMBHs � � � f �� 10 � 21 S n � f � and 2 � h Modeling BBH coalescence 10 � 22 LISA Event rates of IMBH 10 � 23 ET base binaries Adv LIGO base 10 � 24 � 439.2 � 439.2 � M � � 1Gpc Summary and Conclusions 10 � 25 10 � 4 10 � 3 10 � 2 10 � 1 1 10 100 1000 f � Hz � IMBHBs with masses of hundreds of M ⊙ could be seen by both LISA and the ET The long inspiral seen in the LISA band will allow for precise estimation of the parameters of the binary The merger of the IMBHB within the ET band would produce high-SNR events 7 / 16

Coalescences of But do IMBHs exist? IMBH binaries as sources for the future ET detector There is indirect evidence but also uncertainties... IMBH binaries as • If yes, formed after . seen by the GW collapse of a Very detectors Massive Star The (disputed) • Double-cluster channel: existence of IMBHs in systems of two Modeling BBH grav.-bound clusters, coalescence IMBHs sink down to the Event rates of IMBH centers binaries • Single-cluster channel: Summary and in clusters with a fraction Conclusions of primordial binaries > 10 % two IMBH might form • Observed ultraluminous X-ray sources could be explained by accretion onto IMBHs BUT there are also works suggesting that VMSs will not form in this way GW astronomy might as well beat traditional astronomy in this case! 8 / 16

Coalescences of Theoretical models of BBHs coalescence IMBH binaries as sources for the future GW searches of known signals require templates ET detector BBH coalescence: 2-body problem in GR in vacuum: R µ ν = 0 Evolution of 2 distant BHs inspiralling around each other in a quasi-circular orbit IMBH binaries as → for the moment we will ignore the role of eccentricity! seen by the GW detectors The (disputed) existence of IMBHs Modeling BBH coalescence Event rates of IMBH binaries Summary and Conclusions [ Sketch credit: K. Thorne ] 9 / 16

Coalescences of Theoretical models of BBHs coalescence IMBH binaries as sources for the GW searches of known signals require templates future BBH coalescence: 2-body problem in GR in vacuum: R µ ν = 0 ET detector Evolution of 2 distant BHs inspiralling around each other in a quasi-circular orbit → for the moment we will ignore the role of eccentricity! IMBH binaries as seen by the GW detectors Dh GW The (disputed) ringdown existence of IMBHs waveform Modeling BBH merger coalescence waveform Event rates of IMBH inspiral binaries waveform Summary and Conclusions time Given a model for the full BBH coalescence and a sensitivity curve we can compute expected SNR values, horizon distance, reach of the detector 10 / 16

Coalescences of Phenomenological PN-NR model in the frequency domain IMBH binaries as sources for the future ET detector 100 IMBH binaries as 10 seen by the GW 2,2 � Mf �� detectors 1 SPA 3PN The (disputed) 0.1 � h � NR CCE existence of IMBHs PN � NR hybrid 0.01 Matching point Modeling BBH coalescence 0.001 0.002 0.005 0.010 0.020 0.050 0.100 0.200 Event rates of IMBH Mf binaries ◮ ˜ h ( f ) = A ( f ) e i φ ( f ) Summary and Conclusions For comparable-mass systems: radiation mainly in the ℓ = 2 , m = 2 mode ◮ Amplitude: PN with corrections up to 3PN + NR waveforms at null infinity new AEI Llama code + Cauchy characteristic extraction (Reisswig et al. 2009) ◮ Phase: PN up to 3.5PN + NR (but not needed for SNR calculations) ◮ Convenience of using a frequency domain model (SNR, horizon distance: integrals of FD quantities) ◮ Parametrized as function of ( M , η, χ ) for spin-aligned systems → Santamaria et al. to be submitted (2010) 11 / 16

Coalescences of Yes, but how many of those IMBHBs are out there? IMBH binaries as sources for the future ◮ Assuming that formation of IMBHs in stellar cluster is possible ET detector ◮ Following Fregeau et al. (2006) and Miller (2002) ◮ The integral to compute is IMBH binaries as seen by the GW � z max � M cl , max detectors d 2 M SF d 2 N cl R = dN event g cl g dt e dV c = dM cl dz The (disputed) dt 0 dV c dt e dt 0 dz dM SF , cl dM cl M cl , min existence of IMBHs 0 Modeling BBH coalescence ◮ R is the event rate observed at z = 0 Event rates of IMBH ◮ dt e / dt 0 = ( 1 + z ) − 1 and dV c / dz rate of change of comoving volume binaries (depends on cosmological model) Summary and ◮ d 2 M SF / dV c dt e star formation rate in mass per unit of comoving Conclusions volume per unit of local time (peaks at 1 < z < 2 then decreases and stays ∼ constant) ◮ d 2 N cl / dM SF , cl dM cl distribution function of clusters over individual cluster mass M cl and total star-forming mass in clusters M SF , cl ( ∝ 1 / M 2 cl ) ◮ g fraction of clusters where IMBH are formed (??? g ∼ 0 . 1 ) ◮ g cl fraction of star-forming mass that goes into star clusters more massive than 10 3 . 5 M ⊙ (??? g cl ∼ 0 . 1 ) ◮ z max Maximum redshift to which ET is capable of seeing an IMBHB coalescence (can be calculated given expected GW signal and PSD) 12 / 16