scholarly journals Gravitational wave detection in space

2016 ◽  
Vol 25 (14) ◽  
pp. 1630001 ◽  
Author(s):  
Wei-Tou Ni
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Frequency Band ◽  
Low Frequency ◽  
Big Bang ◽  
Mass Ratio ◽  
Intermediate Mass ◽  
Compact Binaries ◽  
Laser Interferometer Space Antenna ◽  
Deployment Time

Gravitational Wave (GW) detection in space is aimed at low frequency band (100[Formula: see text]nHz–100[Formula: see text]mHz) and middle frequency band (100[Formula: see text]mHz–10[Formula: see text]Hz). The science goals are the detection of GWs from (i) Supermassive Black Holes; (ii) Extreme-Mass-Ratio Black Hole Inspirals; (iii) Intermediate-Mass Black Holes; (iv) Galactic Compact Binaries and (v) Relic GW Background. In this paper, we present an overview on the sensitivity, orbit design, basic orbit configuration, angular resolution, orbit optimization, deployment, time-delay interferometry (TDI) and payload concept of the current proposed GW detectors in space under study. The detector proposals under study have arm length ranging from 1000[Formula: see text]km to [Formula: see text][Formula: see text]km (8.6[Formula: see text]AU) including (a) Solar orbiting detectors — (ASTROD Astrodynamical Space Test of Relativity using Optical Devices (ASTROD-GW) optimized for GW detection), Big Bang Observer (BBO), DECi-hertz Interferometer GW Observatory (DECIGO), evolved LISA (e-LISA), Laser Interferometer Space Antenna (LISA), other LISA-type detectors such as ALIA, TAIJI etc. (in Earthlike solar orbits), and Super-ASTROD (in Jupiterlike solar orbits); and (b) Earth orbiting detectors — ASTROD-EM/LAGRANGE, GADFLI/GEOGRAWI/g-LISA, OMEGA and TIANQIN.

scholarly journals Gravitational Wave (GW) Classification, Space GW Detection Sensitivities and AMIGO (Astrodynamical Middle-frequency Interferometric GW Observatory)

2018 ◽  
Vol 168 ◽  
pp. 01004 ◽  
Author(s):  
Wei-Tou Ni
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Wave ◽  
Frequency Band ◽  
Low Frequency ◽  
Spectral Classification ◽  
Mass Ratio ◽  
Intermediate Mass ◽  
Black Hole Binaries ◽  
Compact Binaries

After first reviewing the gravitational wave (GW) spectral classification. we discuss the sensitivities of GW detection in space aimed at low frequency band (100 nHz–100 mHz) and middle frequency band (100 mHz–10 Hz). The science goals are to detect GWs from (i) Supermassive Black Holes; (ii) Extreme-Mass-Ratio Black Hole Inspirals; (iii) Intermediate-Mass Black Holes; (iv) Galactic Compact Binaries; (v) Stellar-Size Black Hole Binaries; and (vi) Relic GW Background. The detector proposals have arm length ranging from 100 km to 1.35×109 km (9 AU) including (a) Solar orbiting detectors and (b) Earth orbiting detectors. We discuss especially the sensitivities in the frequency band 0.1-10 μHz and the middle frequency band (0.1 Hz–10 Hz). We propose and discuss AMIGO as an Astrodynamical Middlefrequency Interferometric GW Observatory.

scholarly journals ASTROD-GW: OVERVIEW AND PROGRESS

2013 ◽  
Vol 22 (01) ◽  
pp. 1341004 ◽  
Author(s):  
WEI-TOU NI
Keyword(s):  
Black Holes ◽  
Low Frequency ◽  
Detection Sensitivity ◽  
Mass Ratio ◽  
Lagrange Points ◽  
Compact Binaries ◽  
Simulation And Optimization ◽  
Spacecraft Formation ◽  
Length Changes ◽  
Spacecraft Orbits

In this paper, we present an overview of Astrodynamical Space Test of Relativity using Optical Devices (ASTROD-GW) optimized for Gravitational Wave (GW) detection mission concept and its studies. ASTROD-GW is an optimization of ASTROD which focuses on low frequency GW detection. The detection sensitivity is shifted by a factor of 260 (52) towards longer wavelengths compared with that of NGO/eLISA (LISA). The mission consists of three spacecraft, each of which orbits near one of the Sun–Earth Lagrange points (L3, L4 and L5), such that the array forms an almost equilateral triangle. The three spacecraft range interferometrically with one another with an arm length of about 260 million kilometers. The orbits have been optimized resulting in arm length changes of less than ± 0.00015 AU or, fractionally, less than ±10-4 in 20 years, and relative Doppler velocities of the three spacecraft of less than ±3 m/s. In this paper, we present an overview of the mission covering: the scientific aims, the sensitivity spectrum, the basic orbit configuration, the simulation and optimization of the spacecraft orbits, the deployment of ASTROD-GW formation, Time Delay Interferometry (TDI) and the payload. The science goals are the detection of GWs from (i) Supermassive Black Holes; (ii) Extreme-Mass-Ratio Black Hole Inspirals; (iii) Intermediate-Mass Black Holes; (iv) Galactic Compact Binaries and (v) Relic GW Background. For the purposes of primordial GW detection, a six spacecraft formation would be needed to enable the correlated detection of stochastic GWs. A brief discussion of the six spacecraft orbit optimization is also presented.

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 GRAVITATIONAL WAVES, DARK ENERGY AND INFLATION

2010 ◽  
Vol 25 (11n12) ◽  
pp. 922-935 ◽  
Author(s):  
WEI-TOU NI
Keyword(s):  
Dark Energy ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Frequency Band ◽  
High Frequency ◽  
Low Frequency ◽  
Big Bang ◽  
Complete Classification ◽  
High Frequency Band ◽  
Very High Frequency

In this paper we first present a complete classification of gravitational waves according to their frequencies: (i) Ultra high frequency band (above 1 THz); (ii) Very high frequency band (100 kHz–1 THz); (iii) High frequency band (10 Hz–100 kHz); (iv) Middle frequency band (0.1 Hz–10 Hz); (v) Low frequency band (100 nHz–0.1 Hz); (vi) Very low frequency band (300 pHz–100 nHz); (vii) Ultra low frequency band (10 fHz–300 pHz); (viii) Hubble (extremely low) frequency band (1 aHz–10 fHz); (ix) Infra-Hubble frequency band (below 1 aHz). After briefly discussing the method of detection for different frequency bands, we review the concept and status of space gravitational-wave missions — LISA, ASTROD, ASTROD-GW, Super-ASTROD, DECIGO and Big Bang Observer. We then address to the determination of dark energy equation, and probing the inflationary physics using space gravitational wave detectors.

scholarly journals The current status of contribution activities in Japan for LISA

2020 ◽  
Author(s):  
Kiwamu Izumi ◽  
Norichika Sago ◽  
Tomotada Akutsu ◽  
Masaki Ando ◽  
Ryuichi Fujita ◽  
...  
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
International Collaboration ◽  
Supermassive Black Holes ◽  
Wave Frequency ◽  
Current Status ◽  
Theoretical Studies ◽  
Mass Ratio ◽  
Compact Binaries ◽  
Frequency Window

Abstract LISA is a space gravitational-wave mission that will open the unexplored gravitational-wave frequency window at around millihertz, shedding light on the study of supermassive black holes and the nature of gravity. The LISA project has been propelled by international collaboration in order to maximize the scientific outcome. With the aim of making scientifically important contributions to LISA, instrument and science groups were newly formed in Japan. This article summarizes the current status of the contribution activities conducted by each group to date, highlighting a few selected topics including the development of photoreceivers and theoretical studies on compact binaries and extreme mass ratio inspirals.

scholarly journals Scope Out Multiband Gravitational-Wave Observations of GW190521-Like Binary Black Holes with Space Gravitational Wave Antenna B-DECIGO

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 53
Author(s):  
Hiroyuki Nakano ◽  
Ryuichi Fujita ◽  
Soichiro Isoyama ◽  
Norichika Sago
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Frequency Band ◽  
Strong Field ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Next Generation ◽  
Estimation Errors ◽  
Tests Of General Relativity ◽  
Wave Signal

The gravitational wave event, GW190521, is the most massive binary black hole merger observed by ground-based gravitational wave observatories LIGO/Virgo to date. While the observed gravitational wave signal is mainly in the merger and ringdown phases, the inspiral gravitational wave signal of the GW190521-like binary will be more visible to space-based detectors in the low-frequency band. In addition, the ringdown gravitational wave signal will be louder in the next generation (3G) of ground-based detectors in the high-frequency band, displaying the great potential of multiband gravitational wave observations. In this paper, we explore the scientific potential of multiband observations of GW190521-like binaries with a milli-Hz gravitational wave observatory: LISA; a deci-Hz observatory: B-DECIGO; and (next generation of) hecto-Hz observatories: aLIGO and ET. In the case of quasicircular evolution, the triple-band observations of LISA, B-DECIGO, and ET will provide parameter estimation errors of the masses and spin amplitudes of component black holes at the level of order of 1–10%. This would allow consistency tests of general relativity in the strong field at an unparalleled precision, particularly with the “B-DECIGO + ET” observation. In the case of eccentric evolution, the multiband signal-to-noise ratio found in “B-DECIGO + ET” observation would be larger than 100 for a five-year observation prior to coalescence, even with high final eccentricities.

scholarly journals Probing gas disc physics with LISA: simulations of an intermediate mass ratio inspiral in an accretion disc

2019 ◽  
Vol 486 (2) ◽  
pp. 2754-2765 ◽  
Author(s):  
A M Derdzinski ◽  
D D’Orazio ◽  
P Duffell ◽  
Z Haiman ◽  
A MacFadyen
Keyword(s):  
Small Deviation ◽  
Compact Object ◽  
Accretion Disc ◽  
Mass Ratio ◽  
Intermediate Mass ◽  
Laser Interferometer Space Antenna ◽  
Total Phase ◽  
Accretion Rates ◽  
Hydrodynamical Simulations ◽  
And Migration

Abstract The coalescence of a compact object with a $10^{4}\hbox{--}10^{7}\, {\rm M_\odot }$ supermassive black hole (SMBH) produces mHz gravitational waves (GWs) detectable by the future Laser Interferometer Space Antenna (LISA). If such an inspiral occurs in the accretion disc of an active galactic nucleus (AGN), the gas torques imprint a small deviation in the GW waveform. Here, we present two-dimensional hydrodynamical simulations with the moving-mesh code disco of a BH inspiraling at the GW rate in a binary system with a mass ratio q = M2/M1 = 10−3, embedded in an accretion disc. We assume a locally isothermal equation of state for the gas (with Mach number $\mathcal {M}=20$) and implement a standard α-prescription for its viscosity (with α = 0.03). We find disc torques on the binary that are weaker than in previous semi-analytic toy models, and are in the opposite direction: the gas disc slows down, rather than speeds up the inspiral. We compute the resulting deviations in the GW waveform, which scale linearly with the mass of the disc. The SNR of these deviations accumulates mostly at high frequencies, and becomes detectable in a 5 yr LISA observation if the total phase shift exceeds a few radians. We find that this occurs if the disc surface density exceeds $\Sigma _0 \gtrsim 10^{2-3}\rm g\, cm^{-2}$, as may be the case in thin discs with near-Eddington accretion rates. Since the characteristic imprint on the GW signal is strongly dependent on disc parameters, a LISA detection of an intermediate mass ratio inspiral would probe the physics of AGN discs and migration.

scholarly journals Dark matter gravity waves at LIGO and LISA

2019 ◽  
Vol 34 (16) ◽  
pp. 1950124
Author(s):  
Paul H. Frampton
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Gravitational Wave ◽  
Gravity Waves ◽  
Gravitational Radiation ◽  
Massive Stars ◽  
Strain Sensitivity ◽  
Intermediate Mass ◽  
To Come ◽  
Merger Rate

We study the merger rate of dark matter PIMBHs (Primordial Intermediate Mass Black Holes). We conclude that the black holes observed by LIGO in GW150914 and later events were probably not dark matter PIMBHs but rather the result of gravitational collapse of very massive stars. To study the PIMBHs by gravitational radiation will require a detector sensitive to frequencies below 10 Hz and otherwise more sensitive than LIGO. The LISA detector, expected to come online in 2034, will be useful at frequencies below 1 Hz but further gravitational wave detectors beyond LISA, sensitive up to 10 Hz, and higher strain sensitivity will be necessary to fully study dark matter.

scholarly journals The Taiji program: A concise overview

2020 ◽  
Author(s):  
Ziren Luo ◽  
Yan Wang ◽  
Yueliang Wu ◽  
Wenrui Hu ◽  
Gang Jin
Keyword(s):  
Black Hole ◽  
Gravitational Waves ◽  
Frequency Band ◽  
Space Mission ◽  
Mass Ratio ◽  
Intermediate Mass ◽  
Concise Overview

Abstract Taiji is a Chinese space mission to detect gravitational waves in the frequency band 0.1 mHz to 1.0 Hz, which aims at detecting super (intermediate) mass black hole mergers and extreme (intermediate) mass ratio in-spirals. A brief introduction of its mission overview, scientific objectives, and payload design is presented. A roadmap is also given in which the launching time is set to the 2030s.

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