Current status of space gravitational wave antenna DECIGO and B-DECIGO

Abstract

Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) is the future Japanese space mission with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at the detection of primordial gravitational waves, which could be produced during the inflationary period right after the birth of the universe. There are many other scientific objectives of DECIGO, including the direct measurement of the acceleration of the expansion of the universe, and reliable and accurate predictions of the timing and locations of neutron star/black hole binary coalescences. DECIGO consists of four clusters of observatories placed in the heliocentric orbit. Each cluster consists of three spacecraft, which form three Fabry-Perot Michelson interferometers with an arm length of 1,000 km. Three clusters of DECIGO will be placed far from each other, and the fourth cluster will be placed in the same position as one of the three clusters to obtain the correlation signals for the detection of the primordial gravitational waves. We plan to launch B-DECIGO, which is a scientific pathfinder of DECIGO, before DECIGO in the 2030s to demonstrate the technologies required for DECIGO, as well as to obtain fruitful scientific results to further expand the multi-messenger astronomy.

Scalar Induced Gravitational Waves Review

“…Interestingly, the corresponding induced GWs to the PBHs in the LIGO window fall in the PTA band. 24 Coincidentally, the NANOGrav collaboration reported a possible SGWB in such range [18], but is yet to be confirmed. We discuss more on NANOGrav a bit later.…”

“…For example, Pulsar Timing Arrays (PTA) [13][14][15][16][17][18], cover around 10 −9 ∼10 −7 Hz, LIGO, VIRGO, KAGRA and ET [19], are sensitive roughly for 10∼10 3 Hz. In between, we will have LISA [20,21], DECIGO [22][23][24], AION/MAGIS [25], Taiji [26] and Tainqin [27]. For an illustration see Figure 1.…”

Chiral gravitational waves and primordial black holes in UV-protected Natural Inflation

“…The Laser Interferometer Space Antenna (LISA) [110] is mostly sensitive to frequencies 10 −4 f 10 −1 Hz, corresponding to momenta 10 11 Mpc −1 k 10 14 Mpc −1 or an e-fold range 22 N 28. The Deci-hertz Interferometer Gravitational wave Observatory (DECIGO) [111,112], the advanced LIGO detector (aLIGO) [113] and the Einstein Telescope (ET) [114] extend this range all the way up to ∼ 10 2 -10 3 Hz, corresponding to scales around k ∼ 10 17 -10 18 Mpc −1 and N ∼ 15. Note that, although our GW spectra display generically a "knee" rather than a peak structure, they are maximally chiral and non-Gaussian, which could serve as a smoking gun for this mechanism and facilitate their discrimination against astrophysical backgrounds (see e.g.…”

Fundamental Tone and Overtones of Quasinormal Modes in Ringdown Gravitational Waves: A Detailed Study in Black Hole Perturbation

“…), and it was a mainstream strategy for the ringdown GW data analysis (see, e.g., Ref. [41], in the context of multiband GW observation with B-DECIGO [42][43][44][45]).…”