TianQin is a geocentric space-based gravitational-wave observatory mission consisting of three drag-free controlled satellites in an equilateral triangle with an orbital radius of $ 10^{5}$ km. The constellation faces the white-dwarf binary RX J0806.3+1527 located slightly below the ecliptic plane, and is subject to gravitational perturbations that can distort the formation. In this study, we present combined methods to optimize the TianQin orbits so that a set of 5-year stability requirements can be met. Moreover, we discuss slow long-term drift of the detector pointing due to orbital precession, and put forward stable orbits with six other pointings along the lunar orbital plane. Some implications of the findings are pointed out.
In future geocentric space-based gravitational-wave observatory missions, eclipses due to passing through the Moon's and Earth's shadows can negatively impact the sciencecraft's thermal stability and steady power supply. The occurrence should be reduced as much as possible in orbit design. In regard to TianQin's circular high orbits, we tackle the combined challenges of avoiding eclipses and stabilizing the nearly equilateral-triangle constellation. Two strategies are proposed, including initial phase selection and orbit resizing to 1:8 synodic resonance with the Moon, where the latter involve…
The paper is a sequel to our previous work (Zhang et al. Phys. Rev. D 103, 062001 (2021)). For proposed geocentric space-based gravitational wave detectors such as TianQin, gLISA, and GADFLI, the gravity-field disturbances, i.e., the so called ``orbital noise'', from the Earth-Moon system on the sensitive intersatellite laser interferometric measurements should be carefully evaluated and taken into account in the concept studies. Based on TianQin, we investigate how the effect, in terms of frequency spectra, varies with different choices of orbital orientations and radii through single-variabl…
TianQin is a proposed space-based gravitational-wave observatory mission to be deployed in high circular Earth orbits. The equilateral-triangle constellation, with a nearly fixed orientation, can be distorted primarily under the lunisolar perturbations. To accommodate science payload requirements, one must optimize the orbits to stabilize the configuration in terms of arm-length, relative velocity, and breathing angle variations. In this work, we present an efficient optimization method and investigate how changing the two main design factors, i.e., the orbital orientation and radius, impacts …
TianQin is a space-based laser interferometric gravitational wave detector aimed at detecting gravitational waves at low frequencies (0.1 mHz -- 1 Hz). It is formed by three identical drag-free spacecrafts in an equilateral triangular constellation orbiting around the Earth. The distance between each pair of spacecrafts is approximately $1.7 \times 10^{5} ~\rm{km}$. The spacecrafts are interconnected by infrared laser beams forming up to three Michelson-type interferometers. The detailed mission design and the study of science objectives for the TianQin project depend crucially on the orbit an…
TianQin is a proposed space gravitational-wave detection mission using circular high Earth orbits. The geocentric concept has raised questions about the disturbing effect of the nearby gravity field of the Earth-Moon system on the highly-sensitive intersatellite ranging measurements. Here we examine the issue through high precision numerical orbit simulation with detailed gravity-field models. By evaluating range accelerations between distant free-falling test masses, the study shows that the majority of the Earth-Moon's gravity disturbances are not in TianQin's detection frequency band above …
The proposed space-borne laser interferometric gravitational wave (GW) observatory TianQin adopts a geocentric orbit for its nearly equilateral triangular constellation formed by three identical drag-free satellites. The geocentric distance of each satellite is $\approx 1.0 \times 10^{5} ~\mathrm{km}$, which makes the armlengths of the interferometer be $\approx 1.73 \times 10^{5} ~\mathrm{km}$. It is aimed to detect the GWs in $0.1 ~\mathrm{mHz}-1 ~\mathrm{Hz}$. For space-borne detectors, the armlengths are unequal and change continuously which results in that the laser frequency noise is nea…
TianQin is a proposal for a space-borne detector of gravitational waves in the millihertz frequencies. The experiment relies on a constellation of three drag-free spacecraft orbiting the Earth. Inter-spacecraft laser interferometry is used to monitor the distances between the test masses. The experiment is designed to be capable of detecting a signal with high confidence from a single source of gravitational waves within a few months of observing time. We describe the preliminary mission concept for TianQin, including the candidate source and experimental designs. We present estimates for the …
The TianQin space Gravitational Waves (GW) observatory will contain 3 geocentric and circularly orbiting spacecraft with an orbital radius of 10^5 km, to detect the GW in the milli-hertz frequency band. Each spacecraft pair will establish a 1.7*10^5 km-long laser interferometer immersed in the solar wind and the magnetospheric plasmas to measure the phase deviations induced by the GW. GW detection requires a high-precision measurement of the laser phase. The cumulative effects of the long distance and the periodic oscillations of the plasma density may induce an additional phase noise. This pa…
TianQin is a proposed space-based gravitational wave observatory. It is designed to detect the gravitational wave signals in the frequency range of 0.1 mHz -- 1 Hz. At a geocentric distance of $10^5$ km, the plasma in the earth magnetosphere will contribute as the main source of environmental noises. Here, we analyze the acceleration noises that are caused by the magnetic field of space plasma for the test mass of TianQin. The real solar wind data observed by the Advanced Composition Explorer are taken as the input of the magnetohydrodynamic simulation. The Space Weather Modeling Framework is …
Gravitational wave (GW) detection in space probes GW spectrum that is inaccessible from the Earth. In addition to LISA project led by European Space Agency, and the DECIGO detector proposed by the Japan Aerospace Exploration Agency, two Chinese space-based GW observatories -- TianQin and Taiji -- are planned to be launched in the 2030s. TianQin has a unique concept in its design with a geocentric orbit. Taiji's design is similar to LISA, but is more ambitious with longer arm distance. Both facilities are complementary to LISA, considering that TianQin is sensitive to higher frequencies and Tai…
While general relativity predicts only two tensor modes for gravitational wave polarization, general metric theories of gravity allows up to four additional modes, including two vector and two scalar modes. Observing the polarization modes of gravitational waves could provide a direct test of the modified gravity. The stochastic gravitational wave background (SGWB), which may be detected by space-based laser-interferometric detectors at design sensitivity, will provide an opportunity to directly measure alternative polarization. In this paper, we investigate the performance of the LISA-TianQin…
TianQin is a proposed space-borne gravitational wave (GW) observatory composed of three identical satellites orbiting around the geocenter with a radius of $10^5$ km. It aims at detecting GWs in the frequency range of 0.1 mHz -- 1 Hz. The detection of GW relies on the high precision measurement of optical path length at $10^{-12}$~m level. The dispersion of space plasma can lead to the optical path difference (OPD, $Δl$) along the propagation of laser beams between any pair of satellites. Here, we study the OPD noises for TianQin. The Space Weather Modeling Framework is used to simulate the in…
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 a 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 m…
We explore the prospects of detecting of Galactic double white dwarf (DWD) binaries with the space-based gravitational wave (GW) observatory TianQin. In this work, we analyze both a sample of currently known DWDs and a realistic synthetic population of DWDs to assess the number of guaranteed detections and the full capacity of the mission. We find that TianQin can detect 12 out of $\sim100$ known DWDs; GW signals of these binaries can be modeled in detail ahead of the mission launch, and therefore they can be used as verification sources. Besides we estimate that TianQin has potential to detec…
Subtraction of the confusion foreground and parameter uncertainty of resolvable galactic binaries on the networks of space-based gravitational-wave detectors
TianQin is a proposed geocentric space-based gravitational wave observatory mission, which requires time-delay interferometry (TDI) to cancel laser frequency noise. With high demands for precision, solar-wind plasma environment at $\sim 10^5$ km above the Earth may constitute a non-negligible noise source to laser interferometric measurements between satellites, as charged particles perturb the refractivity along light paths. In this paper, we first assess the plasma noises along single links from space-weather models and numerical orbits, and analyze the time and frequency domain characterist…
Constraints and detection capabilities of GW polarizations with space-based detectors in different TDI combinations
College of Physics, Chongqing University（重庆大学物理学院）；Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics, Chongqing University（重庆大学物理系及强耦合物理重庆市重点实验室）
Gravitational wave signatures from periodic orbits around a Schwarzschild-Bertotti-Robinson black hole
National Research University TIIAME（国立TIIAME大学）；Institute for Theoretical Physics and Cosmology, Zhejiang University of Technology（浙江工业大学理论物理与宇宙学研究所）；University of Tashkent for Applied Sciences（塔什干应用科学大学）；United Center for Gravitational Wave Physics (UCGWP), Zhejiang University of Technology（浙江工业大学引力波物理联合中心）
Gravitational wave (GW) detection in space is aimed at low frequency band (100 nHz - 100 mHz) and middle frequency band (100 mHz - 10 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 and payload concept of the current proposed GW detectors in spa…
Periodic Orbits and Gravitational Wave Signatures around the Bonanno--Reuter Regular Black Hole
School of Physics, Damghan University（达姆甘大学物理学院）；Center for Theoretical Physics, Khazar University（哈扎尔大学理论物理中心）；Department of Physics, Faculty of Basic Sciences, University of Mazandaran（马赞德兰大学基础科学学院物理学系）
A general method is presented for estimating the uncertainty in hybrid models of gravitational waveforms from binary black-hole systems with arbitrary physical parameters, and thence the highest allowable initial orbital frequency for a numerical-relativity simulation such that the combined analytical and numerical waveform meets some minimum desired accuracy. The key strength of this estimate is that no prior numerical simulation in the relevant region of parameter space is needed, which means that these techniques can be used to direct future work. The method is demonstrated for a selection …
Detectability of Gravitational Waves from Extreme-Mass-Ratio Inspirals on Periodic Orbits around Bardeen Black Holes
School of Physics and Electronic Information, Yunnan Normal University（云南师范大学物理与电子信息学院）；School of Mathematics and Physics, Shangrao Normal University（上饶师范学院数学与物理学院）
Chaotic Imprints in Gravitational Waves from Conformal-Anomaly-Corrected Extreme-Mass-Ratio Inspirals
Nanjing University of Aeronautics and Astronautics（南京航空航天大学）；MIIT Key Laboratory of Aerospace Information Materials and Physics, Nanjing University of Aeronautics and Astronautics（南京航空航天大学工业和信息化部航空航天信息材料与物理重点实验室）
We present a general survey of heliocentric LISA orbits, hoping it might help in the exercise of rescoping the mission. We try to semi-analytically optimize the orbital parameters in order to minimize the disturbances coming from the Earth-LISA interaction. In a set of numerical simulations we include nonautonomous perturbations and provide an estimate of Doppler shift and breathing as a function of the trailing angle.
Gravitational Wave Signatures of Schwarzschild Black Hole in a Generalized Dehnen-Type $(1,4,γ)$ Dark Matter Halo
National University of Uzbekistan（乌兹别克斯坦国立大学）；Institute for Theoretical Physics and Cosmology, Zhejiang University of Technology（浙江工业大学理论物理与宇宙学研究所）；Institute of Fundamental and Applied Research, National Research University TIIAME（塔什干信息技术与应用科学国立研究院基础与应用研究所）；University of Tashkent for Applied Sciences（塔什干应用科学大学）
Periodic orbits and gravitational wave signatures from magnetic dipoles around magnetized Kerr black holes
New Uzbekistan University（新乌兹别克斯坦大学）；Tashkent State Technical University（塔什干国立技术大学）；Kimyo International University in Tashkent（塔什干化学国际大学）；University of Tashkent for Applied Sciences（塔什干应用科学大学）；Harbin Institute of Technology（哈尔滨工业大学）；National University of Uzbekistan（乌兹别克斯坦国立大学）；Samarkand State Pedagogical Institute（撒马尔罕国立师范学院）；Zaozhuang University（枣庄学院）；Khazar University（哈扎尔大学）；University of Management and Technology（管理与科技大学）
Gravitational waveforms from periodic orbits around Gauss-Bonnet black holes
Chongqing Normal University（重庆师范大学）；Fuyang University of Technology（阜阳职业技术学院）；Universidade Federal de Campina Grande（坎皮纳格兰德联邦大学）；Universidade de São Paulo（圣保罗大学）
Faster likelihood evaluation enhances the efficiency of gravitational wave signal analysis. We present Mode-by-mode Relative Binning (MRB), a new method designed for obtaining fast and accurate likelihoods for advanced waveform models that include spin-orbit precession effects and multiple radiation harmonics from compact binary coalescence. Leveraging the "twisting-up" procedure of constructing precessing waveform modes from non-precessing ones, the new method mitigates degrade of relative binning accuracy due to interference from superimposed modes. Additionally, we supplement algorithms for…
Periodic orbits as probes of charged loop quantum gravity black holes through gravitational waves
School of Science, Hunan Institute of Technology（湖南理工学院理学院）；Centre for Theoretical Physics, Jamia Millia Islamia（贾米亚米利亚伊斯兰大学理论物理中心）；Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal（夸祖鲁-纳塔尔大学数学、统计与计算机科学学院天体物理学与宇宙学研究中心）
Probing Gravitational Wave Signatures from Periodic Orbits of Regular Black Holes in Asymptotically Safe Gravity
Institute for Theoretical Physics and Cosmology, Zhejiang University of Technology（浙江工业大学理论物理与宇宙学研究所）；School of Science, Hunan Institute of Technology（湖南工学院理学院）；Centre for Theoretical Physics, Jamia Millia Islamia（贾米娅米利亚伊斯兰大学理论物理中心）；Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal（夸祖鲁-纳塔尔大学数学、统计与计算机科学学院天体物理与宇宙学研究单元）
Detecting gravitational wave background with equivalent configurations in the network of space based optical lattice clocks
Hangzhou Institute for Advanced Study, UCAS（杭州高等研究院，UCAS）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Wuhan University（武汉大学）；CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；Taiji Laboratory for Gravitational Wave Universe (Beijing/Hangzhou), University of Chinese Academy of Sciences（中国科学院大学太极引力波宇宙实验室（北京/杭州））
We revisit the problem of searching for gravitational waves from inspiralling compact binaries in Gaussian coloured noise. For binaries with quasicircular orbits and non-precessing component spins, considering dominant mode emission only, if the intrinsic parameters of the binary are known then the optimal statistic for a single detector is the well-known two-phase matched filter. However, the matched filter signal-to-noise ratio is /not/ in general an optimal statistic for an astrophysical population of signals, since their distribution over the intrinsic parameters will almost certainly not …
