scholarly journals The TianQin project: Current progress on science and technology

2020 ◽  
Author(s):  
Jianwei Mei ◽  
Yan-Zheng Bai ◽  
Jiahui Bao ◽  
Enrico Barausse ◽  
Lin Cai ◽  
...  
Keyword(s):  
Black Hole ◽  
Ecliptic Plane ◽  
Mass Ratio ◽  
Massive Black Hole ◽  
Black Hole Binaries ◽  
Compact Binaries ◽  
Single Body ◽  
Science Operations ◽  
New Generation ◽  
Research Facilities

Abstract TianQin is a planned space-based gravitational wave (GW) observatory consisting of three Earth-orbiting satellites with an orbital radius of about $10^5 \, {\rm km}$. The satellites will form an equilateral triangle constellation the plane of which is nearly perpendicular to the ecliptic plane. TianQin aims to detect GWs between $10^{-4} \, {\rm Hz}$ and $1 \, {\rm Hz}$ that can be generated by a wide variety of important astrophysical and cosmological sources, including the inspiral of Galactic ultra-compact binaries, the inspiral of stellar-mass black hole binaries, extreme mass ratio inspirals, the merger of massive black hole binaries, and possibly the energetic processes in the very early universe and exotic sources such as cosmic strings. In order to start science operations around 2035, a roadmap called the 0123 plan is being used to bring the key technologies of TianQin to maturity, supported by the construction of a series of research facilities on the ground. Two major projects of the 0123 plan are being carried out. In this process, the team has created a new-generation $17 \, {\rm cm}$ single-body hollow corner-cube retro-reflector which was launched with the QueQiao satellite on 21 May 2018; a new laser-ranging station equipped with a $1.2 \, {\rm m}$ telescope has been constructed and the station has successfully ranged to all five retro-reflectors on the Moon; and the TianQin-1 experimental satellite was launched on 20 December 2019—the first-round result shows that the satellite has exceeded all of its mission requirements.

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 Accretion of clumpy cold gas onto massive black hole binaries: a possible fast route to binary coalescence

2018 ◽  
Vol 479 (3) ◽  
pp. 3438-3455 ◽  
Author(s):  
Felipe G Goicovic ◽  
Cristián Maureira-Fredes ◽  
Alberto Sesana ◽  
Pau Amaro-Seoane ◽  
Jorge Cuadra
Keyword(s):  
Black Hole ◽  
Massive Black Hole ◽  
Black Hole Binaries ◽  
Fast Route ◽  
Cold Gas

scholarly journals Thermal and radiation driving can produce observable disc winds in hard-state X-ray binaries

2020 ◽  
Vol 492 (4) ◽  
pp. 5271-5279 ◽  
Author(s):  
Nick Higginbottom ◽  
Christian Knigge ◽  
Stuart A Sim ◽  
Knox S Long ◽  
James H Matthews ◽  
...  
Keyword(s):  
Black Hole ◽  
Binary Systems ◽  
Velocity Structure ◽  
Spectral Energy ◽  
X Ray ◽  
Black Hole Binaries ◽  
Soft State ◽  
Before And After ◽  
Hard State ◽  
New Generation

ABSTRACT X-ray signatures of outflowing gas have been detected in several accreting black hole binaries, always in the soft state. A key question raised by these observations is whether these winds might also exist in the hard state. Here, we carry out the first full-frequency radiation hydrodynamic simulations of luminous (${L = 0.5 \, L_{\mathrm{\mathrm{ Edd}}}}$) black hole X-ray binary systems in both the hard and the soft state, with realistic spectral energy distributions (SEDs). Our simulations are designed to describe X-ray transients near the peak of their outburst, just before and after the hard-to-soft state transition. At these luminosities, it is essential to include radiation driving, and we include not only electron scattering, but also photoelectric and line interactions. We find powerful outflows with ${\dot{M}_{\mathrm{ wind}} \simeq 2 \, \dot{M}_{\mathrm{ acc}}}$ are driven by thermal and radiation pressure in both hard and soft states. The hard-state wind is significantly faster and carries approximately 20 times as much kinetic energy as the soft-state wind. However, in the hard state the wind is more ionized, and so weaker X-ray absorption lines are seen over a narrower range of viewing angles. Nevertheless, for inclinations ≳80°, blueshifted wind-formed Fe xxv and Fe xxvi features should be observable even in the hard state. Given that the data required to detect these lines currently exist for only a single system in a luminous hard state – the peculiar GRS 1915+105 – we urge the acquisition of new observations to test this prediction. The new generation of X-ray spectrometers should be able to resolve the velocity structure.

scholarly journals On the search of electromagnetic cosmological counterparts to coalescences of massive black hole binaries

2006 ◽  
Vol 372 (2) ◽  
pp. 869-875 ◽  
Author(s):  
M. Dotti ◽  
R. Salvaterra ◽  
A. Sesana ◽  
M. Colpi ◽  
F. Haardt
Keyword(s):  
Black Hole ◽  
Massive Black Hole ◽  
Black Hole Binaries

scholarly journals Massive Black Hole Binaries: Dynamical Evolution and Observational Signatures

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
M. Dotti ◽  
A. Sesana ◽  
R. Decarli
Keyword(s):  
Black Hole ◽  
Galaxy Formation ◽  
Dynamical Evolution ◽  
Wave Spectra ◽  
Galaxy Mergers ◽  
Massive Black Hole ◽  
Theoretical Understanding ◽  
Black Hole Binaries ◽  
Recent Developments ◽  
Open Issues

The study of the dynamical evolution of massive black hole pairs in mergers is crucial in the context of a hierarchical galaxy formation scenario. The timescales for the formation and the coalescence of black hole binaries are still poorly constrained, resulting in large uncertainties in the expected rate of massive black hole binaries detectable in the electromagnetic and gravitational wave spectra. Here, we review the current theoretical understanding of the black hole pairing in galaxy mergers, with a particular attention to recent developments and open issues. We conclude with a review of the expected observational signatures of massive binaries and of the candidates discussed in literature to date.

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