scholarly journals Extreme mass-ratio gravitational-wave sources: Mass segregation and post binary tidal-disruption captures

2020 ◽  
Author(s):  
Yael Raveh ◽  
Hagai B Perets
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Mass Function ◽  
Compact Objects ◽  
Relaxation Processes ◽  
Mass Ratio ◽  
Eccentric Orbits ◽  
Close Proximity ◽  
Nuclear Clusters ◽  
Mass Segregation

Abstract The gravitational-wave (GW) inspirals of stellar-mass compact objects onto a supermassive black hole (MBH), are some of the most promising GW sources detectable by next-generation space-born GW-detectors. The rates and characteristics of such extreme mass ratio inspirals (EMRIs) sources are highly uncertain. They are determined by the dynamics of stars near MBHs, and the rate at which compacts objects are driven to the close proximity of the MBH. Here we consider weakly and strongly mass-segregated nuclear clusters, and the evolution of stars captured into highly eccentric orbits following binary disruptions by the MBH. We make use of a Monte-Carlo approach to model the diffusion of both captured objects, and compact-objects brought through two-body relaxation processes. We calculate the rates of GW-inspirals resulting from relaxation-driven objects, and characterize EMRIs properties. We correct previous studies and show that relaxation-driven sources produce GW-sources with lower-eccentricity than previously found, and provide the detailed EMRI eccentricity distribution in the weak and strong mass-segregation regimes. We also show that binary-disruption captured-stars could introduce low-eccentricity GW-sources of stellar black-hole EMRIs in mass-segregated clusters. The eccentricities of the GW-sources from the capture channel, however, are strongly affected by relaxation processes, and are significantly higher than previously suggested. We find that both the rate and eccentricity distribution of EMRIs could probe the dynamics near MBHs, and the contribution of captured stars, characterize the mass-function of stellar compact objects, and verify whether weak or strong mass-segregation processes take place near MBHs.

scholarly journals Constraint on Hybrid Stars with Gravitational Wave Events

Universe ◽  
2020 ◽  
Vol 6 (12) ◽  
pp. 231
Author(s):  
Kilar Zhang ◽  
Feng-Li Lin
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Compact Object ◽  
Compact Objects ◽  
Compact Stars ◽  
Hybrid Star ◽  
Hybrid Stars

Motivated by the recent discoveries of compact objects from LIGO/Virgo observations, we study the possibility of identifying some of these objects as compact stars made of dark matter called dark stars, or the mix of dark and nuclear matters called hybrid stars. In particular, in GW190814, a new compact object with 2.6 M⊙ is reported. This could be the lightest black hole, the heaviest neutron star, and a dark or hybrid star. In this work, we extend the discussion on the interpretations of the recent LIGO/Virgo events as hybrid stars made of various self-interacting dark matter (SIDM) in the isotropic limit. We pay particular attention to the saddle instability of the hybrid stars which will constrain the possible SIDM models.

Black (W)hole: An Artscience and Education Collaboration

Leonardo ◽  
2016 ◽  
Vol 49 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Sara Mast ◽  
Jessica Jellison ◽  
Christopher O’Leary ◽  
Jason Bolte ◽  
Cindy Stillwell ◽  
...  
Keyword(s):  
Black Hole ◽  
Science Education ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Data Visualization ◽  
21St Century ◽  
Mass Ratio ◽  
Art Installation ◽  
Mind And Body ◽  
Astronomical Object

Black (W)hole is an immersive art installation created collaboratively by artists and scientists utilizing data visualization of an extreme mass ratio inspiral (EMRI) and the sonification of its emitted gravitational waves in an experiential work of “artscience” and science education. The sensory-rich environment of the installation engages mind and body, expanding and enriching the participant’s capacity to imagine and wonder about the beauty and meaning of this highly abstract astronomical object, the black hole. The work investigates both historical and current gravitational wave astronomy, illustrating our 21st-century understanding of the cosmos.

scholarly journals LISA extreme-mass-ratio inspiral events as probes of the black hole mass function

2010 ◽  
Vol 81 (10) ◽  
Author(s):  
Jonathan R. Gair ◽  
Christopher Tang ◽  
Marta Volonteri
Keyword(s):  
Black Hole ◽  
Mass Function ◽  
Black Hole Mass ◽  
Mass Ratio

scholarly journals Gravitational wave astronomy, relativity tests, and massive black holes

2009 ◽  
Vol 5 (S261) ◽  
pp. 240-248 ◽  
Author(s):  
Peter L. Bender
Keyword(s):  
General Relativity ◽  
Gravitational Wave ◽  
Galactic Center ◽  
Galactic Nuclei ◽  
Compact Objects ◽  
Mass Ratio ◽  
Intermediate Mass ◽  
Massive Black Holes ◽  
New Information ◽  
Laser Interferometer Space Antenna

AbstractThe gravitational wave detectors that are operating now are looking for several kinds of gravitational wave signals at frequencies of tens of Hertz to kilohertz. One of these is mergers of roughly 10 M⊙ BH binaries. Sometime between now and about 8 years from now, it is likely that signals of this kind will be observed. The result will be strong tests of the dynamical predictions of general relativity in the high field regime. However, observations at frequencies below 1 Hz will have to wait until the launch of the Laser Interferometer Space Antenna (LISA), hopefully only a few years later. LISA will have 3 main objectives, all involving massive BHs. The first is observations of mergers of pairs of intermediate mass (100 to 105M⊙) and higher mass BHs at redshifts out to roughly z=10. This will provide new information on the initial formation and growth of BHs such as those found in most galaxies, and the relation between BH growth and the evolution of galactic structure. The second objective is observations of roughly 10 M⊙ BHs, neutron stars, and white dwarfs spiraling into much more massive BHs in galactic nuclei. Such events will provide detailed information on the populations of such compact objects in the regions around galactic centers. And the third objective is the use of the first two types of observations for testing general relativity even more strongly than ground based detectors will. As an example, an extreme mass ratio event such as a 10 M⊙ BH spiraling into a galactic center BH can give roughly 105 observable cycles during about the last year before merger, with a mean relative velocity of 1/3 to 1/2 the speed of light, and the frequencies of periapsis precession and Lense-Thirring precession will be high. The LISA Pathfinder mission to prepare for LISA is scheduled for launch in 2011.

scholarly journals Spin-orbit precession along eccentric orbits for extreme mass ratio black hole binaries and its effective-one-body transcription

2017 ◽  
Vol 96 (6) ◽  
Author(s):  
Chris Kavanagh ◽  
Donato Bini ◽  
Thibault Damour ◽  
Seth Hopper ◽  
Adrian C. Ottewill ◽  
...  
Keyword(s):  
Black Hole ◽  
Spin Orbit ◽  
Mass Ratio ◽  
Black Hole Binaries ◽  
Eccentric Orbits

scholarly journals Testing Gravity Theory With Extreme Mass-Ratio Inspirals: Recent Progress

Proceedings ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 11
Author(s):  
Shucheng Yang ◽  
Shuo Xin ◽  
Chen Zhang ◽  
Wenbiao Han
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Recent Progress ◽  
Central Body ◽  
Low Frequency ◽  
Kerr Black Hole ◽  
Compact Object ◽  
Wave Dispersion ◽  
Gravity Theory ◽  
Mass Ratio

A compact object captured by a supermassive black hole, named as extreme-mass-ratio inspiral (EMRI), is one of the most important gravitational wave sources for low-frequency interferometers such as LISA, Taiji, and TianQin. EMRIs can be used to accurately map the space-time of the central massive body. In the present paper, we introduce our recent progress on testing gravity theory with EMRIs. We demonstrate how to constrain gravitational wave dispersion and measure the deviation of the central body from the Kerr black hole. By using binary-EMRIs, the gravitational recoil and mass loss due to merger will be measured in a higher accuracy compared with the current LIGO observations. All these potential constrains and measurements will be useful for test of the gravity theory.

scholarly journals New insights on binary black hole formation channels after GWTC-2: young star clusters versus isolated binaries

2021 ◽  
Author(s):  
Yann Bouffanais ◽  
Michela Mapelli ◽  
Filippo Santoliquido ◽  
Nicola Giacobbo ◽  
Ugo N Di Carlo ◽  
...  
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Star Clusters ◽  
Credible Interval ◽  
Young Star ◽  
Compact Objects ◽  
Bayesian Hierarchical ◽  
Binary Black Hole ◽  
Higher Spin ◽  
Young Star Clusters

Abstract With the recent release of the second gravitational-wave transient catalogue (GWTC-2), which introduced dozens of new detections, we are at a turning point of gravitational wave astronomy, as we are now able to directly infer constraints on the astrophysical population of compact objects. Here, we tackle the burning issue of understanding the origin of binary black hole (BBH) mergers. To this effect, we make use of state-of-the-art population synthesis and N-body simulations, to represent two distinct formation channels: BBHs formed in the field (isolated channel) and in young star clusters (dynamical channel). We then use a Bayesian hierarchical approach to infer the distribution of the mixing fraction f, with f = 0 (f = 1) in the pure dynamical (isolated) channel. We explore the effects of additional hyper-parameters of the model, such as the spread in metallicity σZ and the parameter σsp, describing the distribution of spin magnitudes. We find that the dynamical model is slightly favoured with a median value of f = 0.26, when σsp = 0.1 and σZ = 0.4. Models with higher spin magnitudes tend to strongly favour dynamically formed BBHs (f ≤ 0.1 if σsp = 0.3). Furthermore, we show that hyper-parameters controlling the rates of the model, such as σZ, have a large impact on the inference of the mixing fraction, which rises from 0.18 to 0.43 when we increase σZ from 0.2 to 0.6, for a fixed value of σsp = 0.1. Finally, our current set of observations is better described by a combination of both formation channels, as a pure dynamical scenario is excluded at the $99{{\ \rm per\ cent}}$ credible interval, except when the spin magnitude is high.

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