Fast coalescence of post-Newtonian Supermassive Black Hole Binaries in real galaxies

Sobolenko, M.; Berczik, Peter; Spurzem, Rainer; Kupi, Gábor

doi:10.15407/kfnt2017.01.021

Cited by 6 publications

(7 citation statements)

References 64 publications

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“…Numerical models B, B2, and B3 have the same physical parameters, that is, mass of BHs and similar N-body hardening, but they differ in terms of binary eccentricity. According to our restricted number of models, we do not find a dependence of eccentricity on the parameters of our systems, nevertheless it can substantially affect to merging time (Sobolenko et al 2017). As expected from previous results, the binary can form in a system with any initial eccentricity, and a trend was found from a set of models whereby more circular binaries are formed as cusps become steeper (Khan et al 2018).…”

Section: Resultssupporting

confidence: 76%

Merging timescale for the supermassive black hole binary in interacting galaxy NGC 6240

Sobolenko

Berczik

Spurzem

2021

A&A

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Context. One of the mechanisms leading to the creation of a supermassive black hole (SMBH) is the so-called hierarchical merging scenario. Central SMBHs at the final phase of interacting and coalescing host-galaxies are observed as SMBH binary (SMBHB) candidates at different separations from hundreds of parsecs to megaparsecs. Aims. Today one of the strongest SMBHB candidates is the ultraluminous infrared galaxy NGC 6240 which was spatially and spectroscopically resolved in X-rays by Chandra. Dynamical calculation of central SMBHBs merging in a dense stellar environment allows us to retrace their evolution from kiloparsec to megaparsec scales. The main goal of our dynamical modeling was to reach the final, gravitational wave emission regime for the model BHs. Methods. We present direct N-body simulations with up to one million particles and relativistic post-Newtonian corrections for the SMBH particles up to 3.5 post-Newtonian terms. Results. Generally speaking, the set of initial physical conditions can strongly affect our merging time estimations. However, within a certain range of our parameters, we do not find any strong correlation between merging time and BH-to-BH mass or BH-to-bulge mass ratios. Varying the numerical parameters (like particle number – N) does not significantly change the merging time limits. From our 20 models, we find an upper limit on the merging time for central SMBHBs of less than ∼55 Myr. This precise number is only valid for our combination of initial mass ratios. Conclusions. Further detailed research of rare dual and multiple BHs in dense stellar environments (based on observational data) could clarify the dynamical co-evolution of central BHs and their host-galaxies.

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Section: Resultssupporting

confidence: 76%

Merging timescale for the supermassive black hole binary in interacting galaxy NGC 6240

Sobolenko

Berczik

Spurzem

2021

A&A

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“…We also calculate the characteristic strain for all BH merger cases, using estimated parameters at the redshift corresponding to our calculated merger time (Column 8 of Table 2), assuming that t ′ = 0 corresponds to z = 3. The strain signal is calculated using two body Hermite 4 th order Post Newtonian code (Sobolenko et al 2017;Berczik et al 2011Berczik et al , 2013 which calculates the orbital evolution of the SMBH GW merger up to the separation of the last few Schwarzschild radius. LISA sensitivity curve is plotted in accordance with Amaro-Seoane et al (2017); Moore et al (2015) and a very helpful online GW plotting page http://gwplotter.com/.…”

Section: Estimated Merger Time Of Bh Binariesmentioning

confidence: 99%

Dynamical Evolution and Merger Timescales of LISA Massive Black Hole Binaries in Disk Galaxy Mergers

Khan

Capelo

Mayer

et al. 2018

ApJ

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The Laser Interferometer Space Antenna (LISA) will detect gravitational-wave (GW) signals from merging supermassive black holes (BHs) with masses below 10 7 M ⊙ . It is thus of paramount importance to understand the orbital dynamics of these relatively light central BHs, which typically reside in discdominated galaxies, in order to produce reliable forecasts of merger rates. To this aim, realistic simulations probing BH dynamics in unequal-mass disc galaxy mergers, into and beyond the binary hardening stage, are performed by combining smooth particle hydrodynamics and direct N -body codes. The structural properties and orbits of the galaxies are chosen to be consistent with the results of galaxy formation simulations. Stellar and dark matter distributions are triaxial down to the central 100 pc of merger remnant. In all cases, a BH binary forms and hardens on time-scales of at most 100 Myr, coalescing on another few hundred Myr time-scale, depending on the characteristic density and orbital eccentricity. Overall, the sinking of the BH binary takes no more than ∼0.5 Gyr after the merger of the two galaxies is completed, but can be much faster for very plunging orbits. Comparing with previous numerical simulations following the decay of BHs in massive early-type galaxies at z ∼ 3, we confirm that the characteristic density is the most crucial parameter determining the overall BH merging time-scale, despite the structural diversity of the host galaxies. Our results lay down the basis for robust forecasts of LISA event rates in the case of merging BHs.

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“…Their full expressions can be found in Blanchet (2006, equation 168). The detailed references and complete descriptions of the equation of motion in PN formalism up to 3.5PN can be found at Blanchet (2006), Kupi et al (2006), Berentzen et al (2008), Berentzen et al (2009), Brem et al (2013), Sobolenko et al (2017).…”

Section: Numerical Modelling Smbh Particlesmentioning

confidence: 99%

“…For our model with maximum and turning on PN terms ( = 500k, RAND = 3, HMP : LMP = 10:1) we also calculated the expected amplitude-frequency picture for SMBHB merging in NGC 6240. For the simple waveform calculation we used the GW quadrupole term expressions from Kidder (1995) (also see Brem et al 2013;Sobolenko et al 2017):…”

Section: Gravitational Wavesmentioning

confidence: 99%

NGC 6240 supermassive black hole binary dynamical evolution based on Chandra data

Sobolenko

Kompaniiets

Berczik

et al. 2022

Monthly Notices of the Royal Astronomical Society

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The main idea of our research is to estimate the physical coalescence time of the double supermassive black hole (SMBH) system in the centre of NGC 6240 based on the X-ray observations from the Chandra space observatory. The spectra of the Northern and Southern nuclei were fitted by spectral models from Sherpa and both presented the narrow component of the Fe Kα emission line. It enabled us to apply the spectral model to these lines and to find relative offset ≈0.02 keV. The enclosed dynamical mass of the central region of NGC 6240 with radius 1 kpc was estimated $\approx 2.04\times 10^{11} \rm \,\, M_{\odot }$. These data allowed us to carry on the high resolution direct N-body simulations with Newtonian and post-Newtonian (up to $2.5\mathcal {PN}$ correction) dynamics for this particular double SMBH system. As a result, from our numerical models we approximated the central SMBH binary merging time for the different binary eccentricities. In our numerical parameters range the upper limit for the merging time, even for the very small eccentricities, is still below ≈70 Myr. Gravitational waveforms and amplitude-frequency pictures from such events can be detected using Pulsar Timing Array (PTA) projects at the last merging phase.

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Fast coalescence of post-Newtonian Supermassive Black Hole Binaries in real galaxies

Cited by 6 publications

References 64 publications

Merging timescale for the supermassive black hole binary in interacting galaxy NGC 6240

Merging timescale for the supermassive black hole binary in interacting galaxy NGC 6240

Dynamical Evolution and Merger Timescales of LISA Massive Black Hole Binaries in Disk Galaxy Mergers

NGC 6240 supermassive black hole binary dynamical evolution based on Chandra data

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