Descope of the ALIA mission

Abstract

The present work reports on a feasibility study commissioned by the Chinese Academy of Sciences of China to explore various possible mission options to detect gravitational waves in space alternative to that of the eLISA/LISA mission concept. Based on the relative merits assigned to science and technological viability, a few representative mission options descoped from the ALIA mission are considered. A semi-analytic Monte Carlo simulation is carried out to understand the cosmic black hole merger histories and the possible scientific merits of the mission options in probing the light seed black holes and their coevolution with galaxies in early Universe. The study indicates that, by choosing the armlength of the interferometer to be three million kilometers and shifting the sensitivity floor to around one-hundredth Hz, together with a very moderate improvement on the position noise budget, there are certain mission options capable of exploring light seed, intermediate mass black hole binaries at high redshift that are not readily accessible to eLISA/LISA, and yet the technological requirements seem to within reach in the next few decades for China.

Gravitational wave astronomy: the current status

“…During 2011-2013, a subsequent, more indepth study was made [275,276]. This time technological constraints were taken into account and we strived to obtain a balance between merits in science and viability in technologies.…”

“…The capability of the mission designs to detect lighter seed black holes at high redshifts is illustrated in Figure 28 [275].…”

“…A semi-analytic Monte Carlo simulation was also carried out to understand the cosmic black hole merger histories starting from intermediate mass black holes at high redshift as well as the possible scientific merits of the mission design in probing the light seed black holes and their coevolution with galaxies in early Universe (Figure 29) [275].…”

“…Presented in Table 6 is some event rate calculations for IMRIs in local Universe [275]. It should be remarked that estimate is model dependent and subject to many uncertainties and we should not attach too much importance to the precise numbers.…”

“…Expected globular cluster harbored IMBH-BH final inspirals and mergers detectable for year-long observation, scaled in unit of together with a very moderate improvement on the position noise budget, there are certain mission options capable of exploring light seed, intermediate mass black hole binaries at high redshift that are not readily accessible to eLISA/LISA [279,280], and yet the technological requirements seem to within reach in the next few decades for China [275,276].…”