The Experts below are selected from a list of 199902 Experts worldwide ranked by ideXlab platform
A Buonanno - One of the best experts on this subject based on the ideXlab platform.
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improved effective one body model of spinning nonprecessing binary black holes for the era of gravitational wave astrophysics with advanced detectors
Physical Review D, 2017Co-Authors: Alejandro Bohe, M Purrer, A Taracchini, A Buonanno, L Shao, S Babak, I W Harry, Ian Hinder, S Ossokine, V RaymondAbstract:We improve the accuracy of the effective-one-body (EOB) waveforms that were employed during the first observing run of Advanced LIGO for binaries of spinning, nonprecessing black holes by calibrating them to a set of 141 numerical-relativity (NR) waveforms. The NR simulations expand the domain of calibration toward larger Mass Ratios and spins, as compared to the previous EOBNR model. Merger-ringdown waveforms computed in black-hole perturbation theory for Kerr spins close to extremal provide additional inputs to the calibration. For the inspiral-plunge phase, we use a Markov-chain Monte Carlo algorithm to efficiently explore the calibration space. For the merger-ringdown phase, we fit the NR signals with phenomenological formulae. After extrapolation of the calibrated model to arbitrary Mass Ratios and spins, the (dominant-mode) EOBNR waveforms have faithfulness—at design Advanced-LIGO sensitivity—above 99% against all the NR waveforms, including 16 additional waveforms used for validation, when maximizing only on initial phase and time. This implies a negligible loss in event rate due to modeling for these binary configurations. We find that future NR simulations at Mass Ratios ≳4 and double spin ≳0.8 will be crucial to resolving discrepancies between different ways of extrapolating waveform models. We also find that some of the NR simulations that already exist in such region of parameter space are too short to constrain the low-frequency portion of the models. Finally, we build a reduced-order version of the EOBNR model to speed up waveform generation by orders of magnitude, thus enabling intensive data-analysis applications during the upcoming observation runs of Advanced LIGO.
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effective one body model for black hole binaries with generic Mass Ratios and spins
Physical Review D, 2014Co-Authors: A Taracchini, A Buonanno, T Hinderer, Michael Boyle, Daniel A Hemberger, Lawrence E Kidder, Geoffrey Lovelace, Abdul H Mroue, Harald P PfeifferAbstract:Gravitational waves emitted by black-hole binary systems have the highest signal-to-noise ratio in LIGO and Virgo detectors when black-hole spins are aligned with the orbital angular momentum and extremal. For such systems, we extend the effective-one-body inspiral-merger-ringdown waveforms to generic Mass Ratios and spins calibrating them to 38 numerical-relativity nonprecessing waveforms produced by the SXS Collaboration. The numerical-relativity simulations span Mass Ratios from 1 to 8, spin magnitudes up to 98% of extremality, and last for 40 to 60 gravitational-wave cycles. When the total Mass of the binary is between 20 and 200M_⊙, the effective-one-body nonprecessing (dominant mode) waveforms have overlap above 99% (using the advanced-LIGO design noise spectral density) with all of the 38 nonprecessing numerical waveforms, when maximizing only on initial phase and time. This implies a negligible loss in event rate due to modeling. We also show that—without further calibration— the precessing effective-one-body (dominant mode) waveforms have overlap above 97% with two very long, strongly precessing numerical-relativity waveforms, when maximizing only on the initial phase and time.
Peter Berczik - One of the best experts on this subject based on the ideXlab platform.
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mergers of unequal Mass galaxies superMassive black hole binary evolution and structure of merger remnants
The Astrophysical Journal, 2012Co-Authors: Fazeel Mahmood Khan, Miguel Preto, Peter Berczik, I Berentzen, A Just, Rainer SpurzemAbstract:Galaxy centers are residing places for superMassive black holes (SMBHs). Galaxy mergers bring SMBHs close together to form gravitationally bound binary systems, which, if able to coalesce in less than a Hubble time, would be one of the most promising sources of gravitational waves (GWs) for the Laser Interferometer Space Antenna. In spherical galaxy models, SMBH binaries stall at a separation of approximately 1 pc, leading to the 'final parsec problem' (FPP). On the other hand, it has been shown that merger-induced triaxiality of the remnant in equal-Mass mergers is capable of supporting a constant supply of stars on the so-called centrophilic orbits that interact with the binary and thus avoid the FPP. In this paper, using a set of direct N-body simulations of mergers of initially spherically symmetric galaxies with different Mass Ratios, we show that the merger-induced triaxiality is also able to drive unequal-Mass SMBH binaries to coalescence. The binary hardening rates are high and depend only weakly on the Mass Ratios of SMBHs for a wide range of Mass Ratios q. There is, however, an abrupt transition in the hardening rates for mergers with Mass Ratios somewhere between q {approx} 0.05 and 0.1, resulting from the monotonicmore » decrease of merger-induced triaxiality with Mass ratio q, as the secondary galaxy becomes too small and light to significantly perturb the primary, i.e., the more Massive one. The hardening rates are significantly higher for galaxies having steep cusps in comparison with those having shallow cups at centers. The evolution of the binary SMBH leads to relatively shallower inner slopes at the centers of the merger remnants. The stellar Mass displaced by the SMBH binary on its way to coalescence is {approx}1-5 times the combined Mass of binary SMBHs. The coalescence timescales for SMBH binary with Mass {approx}10{sup 6} M{sub Sun} are less than 1 Gyr and for those at the upper end of SMBH Masses 10{sup 9} M{sub Sun} are 1-2 Gyr for less eccentric binaries whereas they are less than 1 Gyr for highly eccentric binaries. SMBH binaries are thus expected to be promising sources of GWs at low and high redshifts.« less
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mergers of unequal Mass galaxies superMassive black hole binary evolution and structure of merger remnants
arXiv: Cosmology and Nongalactic Astrophysics, 2012Co-Authors: Fazeel Mahmood Khan, Miguel Preto, Peter Berczik, I Berentzen, A Just, Rainer SpurzemAbstract:Galaxy centers are residing places for Super Massive Black Holes (SMBHs). Galaxy mergers bring SMBHs close together to form gravitationally bound binary systems which, if able to coalesce in less than a Hubble time, would be one of the most promising sources of gravitational waves for the Laser Interferometer Space Antenna (LISA). In spherical galaxy models, SMBH binaries stall at a separation of approximately one parsec, leading to the "final parsec problem" (FPP). On the other hand, it has been shown that merger-induced triaxiality of the remnant in equal-Mass mergers is capable of supporting a constant supply of stars on so-called centrophilic orbits that interact with the binary and thus avoid the FPP. In this paper, using a set of direct N-body simulations of mergers of initially spherically symmetric galaxies with different Mass Ratios, we show that the merger-induced triaxiality is able to drive unequal-Mass SMBH binaries to coalescence. The binary hardening rates are high and depend only weakly on the Mass Ratios of SMBHs for a wide range of Mass Ratios q. The hardening rates are significantly higher for galaxies having steep cusps in comparison with those having shallow cups at centers. The evolution of the binary SMBH leads to relatively shallower inner slopes at the centers of the merger remnants. The stellar Mass displaced by the SMBH binary on its way to coalescence is ~ 1-5 times the combined Mass of binary SMBHs. The coalescence times for SMBH binary with Mass ~ million solar Masses are less than 1 Gyr and for those at the upper end of SMBH Masses (~ billion solar Masses) are 1-2 Gyr for less eccentric binaries whereas less than 1 Gyr for highly eccentric binaries. SMBH binaries are thus expected to be promising sources of gravitational waves at low and high redshifts.
Fazeel Mahmood Khan - One of the best experts on this subject based on the ideXlab platform.
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mergers of unequal Mass galaxies superMassive black hole binary evolution and structure of merger remnants
The Astrophysical Journal, 2012Co-Authors: Fazeel Mahmood Khan, Miguel Preto, Peter Berczik, I Berentzen, A Just, Rainer SpurzemAbstract:Galaxy centers are residing places for superMassive black holes (SMBHs). Galaxy mergers bring SMBHs close together to form gravitationally bound binary systems, which, if able to coalesce in less than a Hubble time, would be one of the most promising sources of gravitational waves (GWs) for the Laser Interferometer Space Antenna. In spherical galaxy models, SMBH binaries stall at a separation of approximately 1 pc, leading to the 'final parsec problem' (FPP). On the other hand, it has been shown that merger-induced triaxiality of the remnant in equal-Mass mergers is capable of supporting a constant supply of stars on the so-called centrophilic orbits that interact with the binary and thus avoid the FPP. In this paper, using a set of direct N-body simulations of mergers of initially spherically symmetric galaxies with different Mass Ratios, we show that the merger-induced triaxiality is also able to drive unequal-Mass SMBH binaries to coalescence. The binary hardening rates are high and depend only weakly on the Mass Ratios of SMBHs for a wide range of Mass Ratios q. There is, however, an abrupt transition in the hardening rates for mergers with Mass Ratios somewhere between q {approx} 0.05 and 0.1, resulting from the monotonicmore » decrease of merger-induced triaxiality with Mass ratio q, as the secondary galaxy becomes too small and light to significantly perturb the primary, i.e., the more Massive one. The hardening rates are significantly higher for galaxies having steep cusps in comparison with those having shallow cups at centers. The evolution of the binary SMBH leads to relatively shallower inner slopes at the centers of the merger remnants. The stellar Mass displaced by the SMBH binary on its way to coalescence is {approx}1-5 times the combined Mass of binary SMBHs. The coalescence timescales for SMBH binary with Mass {approx}10{sup 6} M{sub Sun} are less than 1 Gyr and for those at the upper end of SMBH Masses 10{sup 9} M{sub Sun} are 1-2 Gyr for less eccentric binaries whereas they are less than 1 Gyr for highly eccentric binaries. SMBH binaries are thus expected to be promising sources of GWs at low and high redshifts.« less
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mergers of unequal Mass galaxies superMassive black hole binary evolution and structure of merger remnants
arXiv: Cosmology and Nongalactic Astrophysics, 2012Co-Authors: Fazeel Mahmood Khan, Miguel Preto, Peter Berczik, I Berentzen, A Just, Rainer SpurzemAbstract:Galaxy centers are residing places for Super Massive Black Holes (SMBHs). Galaxy mergers bring SMBHs close together to form gravitationally bound binary systems which, if able to coalesce in less than a Hubble time, would be one of the most promising sources of gravitational waves for the Laser Interferometer Space Antenna (LISA). In spherical galaxy models, SMBH binaries stall at a separation of approximately one parsec, leading to the "final parsec problem" (FPP). On the other hand, it has been shown that merger-induced triaxiality of the remnant in equal-Mass mergers is capable of supporting a constant supply of stars on so-called centrophilic orbits that interact with the binary and thus avoid the FPP. In this paper, using a set of direct N-body simulations of mergers of initially spherically symmetric galaxies with different Mass Ratios, we show that the merger-induced triaxiality is able to drive unequal-Mass SMBH binaries to coalescence. The binary hardening rates are high and depend only weakly on the Mass Ratios of SMBHs for a wide range of Mass Ratios q. The hardening rates are significantly higher for galaxies having steep cusps in comparison with those having shallow cups at centers. The evolution of the binary SMBH leads to relatively shallower inner slopes at the centers of the merger remnants. The stellar Mass displaced by the SMBH binary on its way to coalescence is ~ 1-5 times the combined Mass of binary SMBHs. The coalescence times for SMBH binary with Mass ~ million solar Masses are less than 1 Gyr and for those at the upper end of SMBH Masses (~ billion solar Masses) are 1-2 Gyr for less eccentric binaries whereas less than 1 Gyr for highly eccentric binaries. SMBH binaries are thus expected to be promising sources of gravitational waves at low and high redshifts.
Brian D Farris - One of the best experts on this subject based on the ideXlab platform.
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binary black hole accretion from a circumbinary disk gas dynamics inside the central cavity
The Astrophysical Journal, 2014Co-Authors: Paul C Duffell, Andrew Macfadyen, Brian D Farris, Zoltan HaimanAbstract:We present the results of two-dimensional (2D) hydrodynamical simulations of circumbinary disk accretion using the finite-volume code DISCO. This code solves the 2D viscous Navier-Stokes equations on a high-resolution moving mesh which shears with the fluid flow, greatly reducing advection errors in comparison with a fixed grid. We perform a series of simulations for binary Mass Ratios in the range 0.026 ≤ q ≤ 1.0, each lasting longer than a viscous time so that we reach a quasi-steady accretion state. In each case, we find that gas is efficiently stripped from the inner edge of the circumbinary disk and enters the cavity along accretion streams, which feed persistent "mini disks" surrounding each black hole. We find that for q 0.1, the binary excites eccentricity in the inner region of the circumbinary disk, creating an overdense lump which gives rise to enhanced periodicity in the accretion rate. The dependence of the periodicity on Mass ratio may provide a method for observationally inferring Mass Ratios from measurements of the accretion rate. We also find that for all Mass Ratios studied, the magnitude of the accretion onto the secondary is sufficient to drive the binary toward larger Mass ratio. This suggests a mechanism for biasing Mass-ratio distributions toward equal Mass.
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binary black hole accretion from a circumbinary disk gas dynamics inside the central cavity
arXiv: High Energy Astrophysical Phenomena, 2013Co-Authors: Paul C Duffell, Andrew Macfadyen, Brian D Farris, Zoltan HaimanAbstract:We present the results of 2D hydrodynamical simulations of circumbinary disk accretion using the finite-volume code DISCO. This code solves the 2D viscous Navier-Stokes equations on a high-resolution moving mesh which shears with the fluid flow, greatly reducing advection errors in comparison with a fixed grid. We perform a series of simulations for binary Mass Ratios in the range 0.026 0.1, the binary excites eccentricity in the inner region of the circumbinary disk, creating an overdense lump which gives rise to enhanced periodicity in the accretion rate. The dependence of the periodicity on Mass ratio may provide a method for observationally inferring Mass Ratios from measurements of the accretion rate. We also find that for all Mass Ratios studied, the magnitude of the accretion onto the secondary is sufficient to drive the binary toward larger Mass ratio. This suggests a mechanism for biasing Mass ratio distributions toward equal Mass.
A Taracchini - One of the best experts on this subject based on the ideXlab platform.
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improved effective one body model of spinning nonprecessing binary black holes for the era of gravitational wave astrophysics with advanced detectors
Physical Review D, 2017Co-Authors: Alejandro Bohe, M Purrer, A Taracchini, A Buonanno, L Shao, S Babak, I W Harry, Ian Hinder, S Ossokine, V RaymondAbstract:We improve the accuracy of the effective-one-body (EOB) waveforms that were employed during the first observing run of Advanced LIGO for binaries of spinning, nonprecessing black holes by calibrating them to a set of 141 numerical-relativity (NR) waveforms. The NR simulations expand the domain of calibration toward larger Mass Ratios and spins, as compared to the previous EOBNR model. Merger-ringdown waveforms computed in black-hole perturbation theory for Kerr spins close to extremal provide additional inputs to the calibration. For the inspiral-plunge phase, we use a Markov-chain Monte Carlo algorithm to efficiently explore the calibration space. For the merger-ringdown phase, we fit the NR signals with phenomenological formulae. After extrapolation of the calibrated model to arbitrary Mass Ratios and spins, the (dominant-mode) EOBNR waveforms have faithfulness—at design Advanced-LIGO sensitivity—above 99% against all the NR waveforms, including 16 additional waveforms used for validation, when maximizing only on initial phase and time. This implies a negligible loss in event rate due to modeling for these binary configurations. We find that future NR simulations at Mass Ratios ≳4 and double spin ≳0.8 will be crucial to resolving discrepancies between different ways of extrapolating waveform models. We also find that some of the NR simulations that already exist in such region of parameter space are too short to constrain the low-frequency portion of the models. Finally, we build a reduced-order version of the EOBNR model to speed up waveform generation by orders of magnitude, thus enabling intensive data-analysis applications during the upcoming observation runs of Advanced LIGO.
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effective one body model for black hole binaries with generic Mass Ratios and spins
Physical Review D, 2014Co-Authors: A Taracchini, A Buonanno, T Hinderer, Michael Boyle, Daniel A Hemberger, Lawrence E Kidder, Geoffrey Lovelace, Abdul H Mroue, Harald P PfeifferAbstract:Gravitational waves emitted by black-hole binary systems have the highest signal-to-noise ratio in LIGO and Virgo detectors when black-hole spins are aligned with the orbital angular momentum and extremal. For such systems, we extend the effective-one-body inspiral-merger-ringdown waveforms to generic Mass Ratios and spins calibrating them to 38 numerical-relativity nonprecessing waveforms produced by the SXS Collaboration. The numerical-relativity simulations span Mass Ratios from 1 to 8, spin magnitudes up to 98% of extremality, and last for 40 to 60 gravitational-wave cycles. When the total Mass of the binary is between 20 and 200M_⊙, the effective-one-body nonprecessing (dominant mode) waveforms have overlap above 99% (using the advanced-LIGO design noise spectral density) with all of the 38 nonprecessing numerical waveforms, when maximizing only on initial phase and time. This implies a negligible loss in event rate due to modeling. We also show that—without further calibration— the precessing effective-one-body (dominant mode) waveforms have overlap above 97% with two very long, strongly precessing numerical-relativity waveforms, when maximizing only on the initial phase and time.
