Numerical simulation of time delay interferometry for eLISA/NGO

Abstract

eLISA/NGO is a new gravitational wave detection proposal with arm length of 10 6 km and one interferometer down-scaled from LISA. Just like LISA and ASTROD-GW, in order to attain the requisite sensitivity for eLISA/NGO, laser frequency noise must be suppressed to below the secondary noises such as the optical path noise, acceleration noise etc. In previous papers, we have performed the numerical simulation of the time delay interferometry (TDI) for LISA and ASTROD-GW with one arm dysfunctional by using the CGC 2.7 ephemeris. The results are well below their respective limits which the laser frequency noise is required to be suppressed. In this paper, we follow the same procedure to simulate the time delay interferometry numerically. To do this, we work out a set of 1000-day optimized mission orbits of the eLISA/NGO spacecraft starting at January 1st, 2021 using the CGC 2.7 ephemeris framework. We then use the numerical method to calculate the residual optical path differences in the second-generation TDI solutions as in our previous papers. The maximum path length difference, for all configurations calculated, is below 13 mm (43 ps). It is well below the limit which the laser frequency noise is required to be suppressed for eLISA/NGO. We compare and discuss the resulting differences due to the different arm lengths for various mission proposals --eLISA/NGO, an NGO-LISA-type mission with a nominal arm length of 2 × 10 6 km, LISA and ASTROD-GW.

Astrodynamical middle-frequency interferometric gravitational wave observatory AMIGO: Mission concept and orbit design

“…where a Newton and a 1PN are the Newtonian and first-order post-Newtonian acceleration from the major celestial bodies in the solar system considered as point mass, a fig is the acceleration due to the figure effects from the Sun, Earth and Moon, and a asteroid is the acceleration from Newtonian perturbation of the 340 asteroids. The explicit interactions in our CGC ephemeris framework are fully described in references [24,36,37]. The thruster needs to provide acceleration a thruster a thruster = a traj  a traj (10) to maintain the constant arm length trajectories.…”

Gravitational wave detection in space

“…Since then we have worked out the same things numerically for LISA, 84 eLISA/NGO, 85 LISA-type with 2 × 10 6 km arm length, 85 ASTROD-GW with no inclination, 86,87 and ASTROD-GW with inclination. 41 Time delay interferometry has been worked out for LISA much more thoroughly on various aspects since 1999.…”

“…7.1] in making our initial choice of the initial conditions in Ref. [85]; these initial conditions are listed in column 3 of Table 2 in Sec 7.1. With this orbit choice, we started numerical orbit design and used the CGC ephemeris to numerically optimize the orbit configuration in [85] as we have done for ASTROD-GW orbit [134][135][136]139,86,87 design.…”

“…With this orbit choice, we started numerical orbit design and used the CGC ephemeris to numerically optimize the orbit configuration in [85] as we have done for ASTROD-GW orbit [134][135][136]139,86,87 design. In this subsection, we review and summarize the procedure following [85].…”

Gravitational wave astronomy: the current status

“…Since then we have worked out the same things numerically for LISA [305], eLISA/NGO [306], NGO-LISAtype with 2 × 10 6 km arm length [306], ASTROD-GW with no inclination [307,308], and ASTROD-GW with inclination [309]. Schematic orbit configuration of ASTROD-GW mission design [309] and LISA-type mission design (http://sci.esa.int/lisa/35596-schematic-of-lisa-orbit/) are shown in Figures 39 and 40.…”