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

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 1.35x109 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 microHz and the middle frequency band (0.1 Hz-10 Hz). We propose and discuss AMIGO as an Astrodynamical Middle-frequency Interferometric GW Observatory.Comment: 10 pages, 2 figures, 1 table, Plenary talk given in Joint Meeting of 13th International Conference on Gravitation, Astrophysics, and Cosmology and 15th Italian-Korean Symposium on Relativistic Astrophysics, Ewha Womans University, Seoul, Korea, July 3-7, 201

From Equivalence Principles to Cosmology: Cosmic Polarization Rotation, CMB Observation, Neutrino Number Asymmetry, Lorentz Invariance and CPT

In this paper, we review the approach leading to cosmic polarization rotation observation and present the current status with an outlook. In the study of the relations among equivalence principles, we found that long-range pseudoscalar-photon interaction is allowed. Pseudoscalar-photon interaction would induce a rotation of linear polarization of electromagnetic wave propagating with cosmological/astrophysical distance. In 2002, DASI successfully observed the polarization of the cosmological microwave background radiation. In 2003, WMAP observed the correlation of polarization with temperature anisotropy at more than 10 sigma in the cosmological microwave background. From this high polarization-temperature correlation in WMAP observation, we put a limit of 0.1 rad on the rotation of linear polarization of cosmological microwave background (CMB) propagation. Pseudoscalar-photon interaction is proportional to the gradient of the pseudoscalar field. From phenomenological point of view, this gradient could be neutrino number asymmetry current, other density current, or a constant vector. In these situations, Lorentz invariance or CPT may or may not effectively be violated. In this paper, we review and compile various results. Better accuracy in CMB polarization observation is expected from PLANCK mission to be launched next year. A dedicated CMB polarization observer in the future would probe this fundamental issue more deeply.Comment: 9 pages, 2 figures, a few references with corresponding text change added in this version, invited talk given in VIII Asia-Pacific International Conference on Gravitation and Astophysics (ICGA8), August 29 - September 1, 2007, Nara Women's University, Japan, submitted to Progress of Theoretical Physics Supplemen

Deployment and simulation of the ASTROD-GW formation

Constellation or formation flying is a common concept in space Gravitational Wave (GW) mission proposals for the required interferometry implementation. The spacecraft of most of these mission proposals go to deep space and many have Earthlike orbits around the Sun. ASTROD-GW, Big Bang Observer and DECIGO have spacecraft distributed in Earthlike orbits in formation. The deployment of orbit formation is an important issue for these missions. ASTROD-GW (Astrodynamical Space Test of Relativity using Optical Devices optimized for Gravitation Wave detection) is to focus on the goal of detection of GWs. The mission orbits of the 3 spacecraft forming a nearly equilateral triangular array are chosen to be near the Sun-Earth Lagrange points L3, L4 and L5. The 3 spacecraft range interferometrically with one another with arm length about 260 million kilometers with the scientific goals including detection of GWs from Massive Black Holes (MBH), and Extreme-Mass-Ratio Black Hole Inspirals (EMRI), and using these observations to find the evolution of the equation of state of dark energy and to explore the co-evolution of massive black holes with galaxies. In this paper, we review the formation flying for fundamental physics missions, design the preliminary transfer orbits of the ASTROD-GW spacecraft from the separations of the launch vehicles to the mission orbits, and simulate the arm lengths of the triangular formation. From our study, the optimal delta-Vs and propellant ratios of the transfer orbits could be within about 2.5 km/s and 0.55, respectively. From the simulation of the formation for 10 years, the arm lengths of the formation vary in the range 1.73210 +- 0.00015 AU with the arm length differences varying in the range +- 0.00025 AU for formation with 1 degree inclination to the ecliptic plane. This meets the measurement requirements.Comment: 15 pages, 5 figures, 3 tables, to be published in IJMPD vol. 22,1341005 (2013); this version to match the printed versio