scholarly journals Mass–redshift degeneracy for the gravitational-wave sources in the vicinity of supermassive black holes

2019 ◽  
Vol 485 (1) ◽  
pp. L141-L145 ◽  
Author(s):  
Xian Chen ◽  
Shuo Li ◽  
Zhoujian Cao
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Supermassive Black Holes

The stellar graveyard

2019 ◽  
pp. 177-206
Author(s):  
Nils Andersson
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Stellar Evolution ◽  
White Dwarfs ◽  
Supermassive Black Holes ◽  
Compact Objects ◽  
Fermi Gases ◽  
The 1950S

This chapter introduces the different classes of compact objects—white dwarfs, neutron stars, and black holes—that are relevant for gravitational-wave astronomy. The ideas are placed in the context of developing an understanding of the likely endpoint(s) of stellar evolution. Key ideas like Fermi gases and the Chandrasekhar mass are discussed, as is the emergence of general relativity as a cornerstone of astrophysics in the 1950s. Issues associated with different formation channels for, in particular, black holes are considered. The chapter ends with a discussion of the supermassive black holes that are found at the centre of galaxies.

scholarly journals The Gravitational Wave Symphony of Structure Formation: Overview

2015 ◽  
Vol 11 (A29B) ◽  
pp. 283-284
Author(s):  
T. Joseph W. Lazio ◽  
Sarah Burke-Spolaor
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Structure Formation ◽  
Cosmic Strings ◽  
Supermassive Black Holes ◽  
The Universe

This Focus Meeting was designed to lie at the scientific intersection of structure formation and gravitational wave studies. In broad-strokes terms, binary supermassive black holes (BSMBHs) and cosmic strings may both play a central role in shaping the Universe as we know it.

scholarly journals COALESCENCE RATE OF SUPERMASSIVE BLACK HOLE BINARIES DERIVED FROM COSMOLOGICAL SIMULATIONS: DETECTION RATES FOR LISA AND ET

2011 ◽  
Vol 20 (12) ◽  
pp. 2399-2417 ◽  
Author(s):  
CH. FILLOUX ◽  
J. A. DE FREITAS PACHECO ◽  
F. DURIER ◽  
J. C. N. DE ARAUJO
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Detection Rate ◽  
Signal To Noise Ratio ◽  
Supermassive Black Holes ◽  
Frequency Interval ◽  
Signal To Noise ◽  
Cosmological Simulations ◽  
Coalescence Rate ◽  
Noise Ratio

The coalescence history of massive black holes has been derived from cosmological simulations, in which the evolution of those objects and that of the host galaxies are followed in a consistent way. The present study indicates that supermassive black holes having masses greater than ~ 109 M⊙ underwent up to 500 merger events along their history. The derived coalescence rate per comoving volume and per mass interval permitted to obtain an estimate of the expected detection rate distribution of gravitational wave signals ("ring-down") along frequencies accessible by the planned interferometers either in space (LISA) or in the ground (Einstein). For LISA, in its original configuration, a total detection rate of about 15 yr-1 is predicted for events having a signal-to-noise ratio equal to 10, expected to occur mainly in the frequency range 4–9 mHz. For the Einstein gravitational wave telescope, one event each 14 months down to one event each four years is expected with a signal-to-noise ratio of 5, occurring mainly in the frequency interval 10–20 Hz. The detection of these gravitational signals and their distribution in frequency would be in the future an important tool able to discriminate among different scenarios explaining the origin of supermassive black holes.

scholarly journals Gravitational wave driven mergers and coalescence time of supermassive black holes

2018 ◽  
Vol 615 ◽  
pp. A71 ◽  
Author(s):  
Fazeel Mahmood Khan ◽  
Peter Berczik ◽  
Andreas Just
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Supermassive Black Holes ◽  
Orbital Energy ◽  
Large Set ◽  
Galaxy Mergers ◽  
Graphic Processing Units ◽  
Semi Major Axis ◽  
Coalescence Time ◽  
The Impact

Aims. The evolution of supermassive black holes (SMBHs) initially embedded in the centres of merging galaxies realised with a stellar mass function (SMF) is studied from the onset of galaxy mergers until coalescence. Coalescence times of SMBH binaries are of great importance for black hole evolution and gravitational wave detection studies. Methods. We performed direct N-body simulations using the highly efficient and massively parallel phi-GRAPE+GPU code capable of running on high-performance computer clusters supported by graphic processing units (GPUs). Post-Newtonian terms up to order 3.5 are used to drive the SMBH binary evolution in the relativistic regime. We performed a large set of simulations with three different slopes of the central stellar cusp and different random seeds. The impact of a SMF on the hardening rate and the coalescence time is investigated. Results. We find that SMBH binaries coalesce well within one billion years when our models are scaled to galaxies with a steep cusp at low redshift. Here higher central densities provide a larger supply of stars to efficiently extract energy from the SMBH binary orbit and shrink it to the phase where gravitational wave (GW) emission becomes dominant, leading to the coalescence of the SMBHs. Mergers of models with shallow cusps that are representative of giant elliptical galaxies having central cores result in less efficient extraction of the binary’s orbital energy, due to the lower stellar densities in the centre. However, high values of eccentricity witnessed for SMBH binaries in such galaxy mergers ensure that the GW emission dominated phase sets in earlier at larger values of the semi-major axis. This helps to compensate for the less efficient energy extraction during the phase dominated by stellar encounters resulting in mergers of SMBHs in about 1 Gyr after the formation of the binary. Additionally, we witness mass segregation in the merger remnant resulting in enhanced SMBH binary hardening rates. We show that at least the final phase of the merger in cuspy low-mass galaxies would be observable with the GW detector eLISA.

scholarly journals GRAVITATIONAL WAVE SIGNAL FROM ASSEMBLING THE LIGHTEST SUPERMASSIVE BLACK HOLES

2010 ◽  
Vol 713 (2) ◽  
pp. 1016-1025 ◽  
Author(s):  
Kelly Holley-Bockelmann ◽  
Miroslav Micic ◽  
Steinn Sigurdsson ◽  
Louis J. Rubbo
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Supermassive Black Holes ◽  
Wave Signal

scholarly journals Future merger of the Milky Way with the Andromeda galaxy and the fate of their supermassive black holes

2020 ◽  
Vol 642 ◽  
pp. A30
Author(s):  
Riccardo Schiavi ◽  
Roberto Capuzzo-Dolcetta ◽  
Manuel Arca-Sedda ◽  
Mario Spera
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Relative Motion ◽  
Milky Way ◽  
Close Approach ◽  
Supermassive Black Holes ◽  
Andromeda Galaxy ◽  
The Galaxy ◽  
Inner Region ◽  
First Time

Our Galaxy and the nearby Andromeda galaxy (M 31) are the most massive members of the Local Group, and they seem to be a bound pair, despite the uncertainties on the relative motion of the two galaxies. A number of studies have shown that the two galaxies will likely undergo a close approach in the next 4−5 Gyr. We used direct N-body simulations to model this interaction to shed light on the future of the Milky Way – Andromeda system and for the first time explore the fate of the two supermassive black holes (SMBHs) that are located at their centers. We investigated how the uncertainties on the relative motion of the two galaxies, linked with the initial velocities and the density of the diffuse environment in which they move, affect the estimate of the time they need to merge and form “Milkomeda”. After the galaxy merger, we follow the evolution of their two SMBHs up to their close pairing and fusion. Upon the fiducial set of parameters, we find that Milky Way and Andromeda will have their closest approach in the next 4.3 Gyr and merge over a span of 10 Gyr. Although the time of the first encounter is consistent with other predictions, we find that the merger occurs later than previously estimated. We also show that the two SMBHs will spiral in the inner region of Milkomeda and coalesce in less than 16.6 Myr after the merger of the two galaxies. Finally, we evaluate the gravitational-wave emission caused by the inspiral of the SMBHs, and we discuss the detectability of similar SMBH mergers in the nearby Universe (z ≤ 2) through next-generation gravitational-wave detectors.

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