中国物理B ›› 2015, Vol. 24 ›› Issue (5): 59501-059501.doi: 10.1088/1674-1056/24/5/059501

• GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS • 上一篇    下一篇

Orbit optimization and time delay interferometry for inclined ASTROD-GW formation with half-year precession-period

王刚a, 倪维斗b   

  1. a Shenzhen National Climate Observatory, Shenzhen 518040, China;
    b Center for Gravitation and Cosmology (CGC), Department of Physics, Tsing Hua University, Hsinchu, Taiwan 30013, China
  • 收稿日期:2014-09-15 修回日期:2014-12-18 出版日期:2015-05-05 发布日期:2015-05-05

Orbit optimization and time delay interferometry for inclined ASTROD-GW formation with half-year precession-period

Wang Gang (王刚)a, Ni Wei-Tou (倪维斗)b   

  1. a Shenzhen National Climate Observatory, Shenzhen 518040, China;
    b Center for Gravitation and Cosmology (CGC), Department of Physics, Tsing Hua University, Hsinchu, Taiwan 30013, China
  • Received:2014-09-15 Revised:2014-12-18 Online:2015-05-05 Published:2015-05-05
  • Contact: Wang Gang, Ni Wei-Tou E-mail:gwanggw@gmail.com;weitou@gmail.com
  • About author:95.10.Eg; 95.55.Ym; 04.80.Nn; 07.60.Ly

摘要:

ASTROD-GW (ASTROD [astrodynamical space test of relativity using optical devices] optimized for gravitational wave detection) is a gravitational-wave mission with the aim of detecting gravitational waves from massive black holes, extreme mass ratio inspirals (EMRIs) and galactic compact binaries together with testing relativistic gravity and probing dark energy and cosmology. Mission orbits of the 3 spacecrafts forming a nearly equilateral triangular array are chosen to be near the Sun–Earth Lagrange points L3, L4, and L5. The 3 spacecrafts range interferometrically with one another with arm length about 260 million kilometers. For 260 times longer arm length, the detection sensitivity of ASTROD-GW is 260 fold better than that of eLISA/NGO in the lower frequency region by assuming the same acceleration noise. Therefore, ASTROD-GW will be a better cosmological probe. In previous papers, we have worked out the time delay interferometry (TDI) for the ecliptic formation. To resolve the reflection ambiguity about the ecliptic plane in source position determination, we have changed the basic formation into slightly inclined formation with half-year precession-period. In this paper, we optimize a set of 10-year inclined ASTROD-GW mission orbits numerically using ephemeris framework starting at June 21, 2035, including cases of inclination angle with 0° (no inclination), 0.5°, 1.0°, 1.5°, 2.0°, 2.5°, and 3.0°. We simulate the time delays of the first and second generation TDI configurations for the different inclinations, and compare/analyse the numerical results to attain the requisite sensitivity of ASTROD-GW by suppressing laser frequency noise below the secondary noises. To explicate our calculation process for different inclination cases, we take the 1.0° as an example to show the orbit optimization and TDI simulation.

关键词: orbit optimization, ASTROD-GW, gravitational wave detector, time delay interferometry

Abstract:

ASTROD-GW (ASTROD [astrodynamical space test of relativity using optical devices] optimized for gravitational wave detection) is a gravitational-wave mission with the aim of detecting gravitational waves from massive black holes, extreme mass ratio inspirals (EMRIs) and galactic compact binaries together with testing relativistic gravity and probing dark energy and cosmology. Mission orbits of the 3 spacecrafts forming a nearly equilateral triangular array are chosen to be near the Sun–Earth Lagrange points L3, L4, and L5. The 3 spacecrafts range interferometrically with one another with arm length about 260 million kilometers. For 260 times longer arm length, the detection sensitivity of ASTROD-GW is 260 fold better than that of eLISA/NGO in the lower frequency region by assuming the same acceleration noise. Therefore, ASTROD-GW will be a better cosmological probe. In previous papers, we have worked out the time delay interferometry (TDI) for the ecliptic formation. To resolve the reflection ambiguity about the ecliptic plane in source position determination, we have changed the basic formation into slightly inclined formation with half-year precession-period. In this paper, we optimize a set of 10-year inclined ASTROD-GW mission orbits numerically using ephemeris framework starting at June 21, 2035, including cases of inclination angle with 0° (no inclination), 0.5°, 1.0°, 1.5°, 2.0°, 2.5°, and 3.0°. We simulate the time delays of the first and second generation TDI configurations for the different inclinations, and compare/analyse the numerical results to attain the requisite sensitivity of ASTROD-GW by suppressing laser frequency noise below the secondary noises. To explicate our calculation process for different inclination cases, we take the 1.0° as an example to show the orbit optimization and TDI simulation.

Key words: orbit optimization, ASTROD-GW, gravitational wave detector, time delay interferometry

中图分类号:  (Orbit determination and improvement)

  • 95.10.Eg
95.55.Ym (Gravitational radiation detectors; mass spectrometers; and other instrumentation and techniques) 04.80.Nn (Gravitational wave detectors and experiments) 07.60.Ly (Interferometers)