Third generation of Gravitational Wave detectors like the Einstein Telescope or the
Cosmic Explorer will be Michelson interferometers with Fabry-Perot cavities in the arms,
using mirror test masses with diameter at the limit of technical feasibility. Unlike other
detectors, the Einstein Telescope will have a 60° angle between the arms. Because of its
larger incidence angle, at any given...
The DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space mission with 1,000 km arm cavities. One of the main objectives of DECIGO is the detection of primordial gravitational waves (PGWs) produced in the inflation period. We should improve DECIGO’s target sensitivity, which is limited by quantum noise, to enhance the possibility of the detection of...
Improvement of the sensitivity of gravitational-waves (GWs) detectors at lower frequencies is still challenging on account of displacement noise sources, such as thermal noise, seismic noise, and radiation pressure noise. One of the solutions is the displacement-noise-free interferometer (DFI). At frequencies lower than 1Hz, however, the DFI has less sensitivity to GWs because the propagation...
Pulsars are expected to be strong sources of low frequency gravitational waves in ground based interferometers. The knowledge of their distances is a key parameter to estimate the gravitational emission. The pulsar distances are usually estimated using dispersion measure. The Gaia data release provides information on the distance, kinematic and photometric properties of nearly two billions...
An observation of gravitational waves is a trigger of the multi-messenger search of an astronomical event. A combination of the data from two or three gravitational wave detectors indicates the location of a source and low-latency data analysis is key to transferring the information to other detectors sensitive at different wavelengths. In contrast to the current method, which relies on the...
The DECi-hertz Interferometer Gravitational-Wave Observatory (DECIGO) is a space gravitational wave (GW) detector. DECIGO was originally designed to be sensitive enough to observe primordial GW background (PGW). However, due to the lowered upper limit of the PGW by the Planck observation, further improvement of the target sensitivity of DECIGO is required. In the previous studies, DECIGO’s...
The DECi-hertz Interferometer for Gravitational-wave Observatory(DECIGO) aims mainly at the detection of primordial gravitational waves (PGWs) originating from inflation. Recent observations by the Planck satellite and others have lowered the upper limit of PGWs. Thus, it is necessary to improve the target sensitivity of DECIGO. A newly proposed method to reduce the quantum noise of DECIGO is...
Atom-interferometer gravitational-wave (GW) observatory, as a new design of ground-based GW detector for the near future, is sensitive at a relatively low frequency for GW observations. Taking the proposed atom interferometer Zhaoshan Long-baseline Atom Interferometer Gravitation Antenna (ZAIGA), and its illustrative upgrade (Z+) as examples, we investigate how the atom interferometer will...
Recently, Tamanini & Danielski discussed the possibility of detecting circumbinary exoplanets (CBPs) orbiting double white dwarfs (DWDs) with the Laser Interferometer Space Antenna (LISA). Extending their methods and criteria, we discuss the prospects for detecting exoplanets around DWDs not only by LISA, but also by Taiji, a Chinese space-borne gravitational-wave (GW) mission. We first...
We investigated the detection and localization of binary neutron star (BNS) populations with decihertz gravitational-wave observatories in a realistic detecting strategy, including real-time observations and early warnings. Assuming 4 years' operation of B-DECIGO, we found that the detected BNSs can be divided into three categories: (a) sources that merge within 1 year, which could be...
DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO) is a future Japanese space gravitational-wave antenna with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at detection of primordial gravitational waves, which could have been produced during the inflationary period right after the birth of the universe. There are many other scientific objectives of DECIGO, including the...
B-DECIGO is a space gravitational wave antenna mission. While it is a precursor mission of DECIGO, we can expect fruitful sciences with B-DECIGO. One of the most exciting science cases is detection of compact binary system before merger. It will enlarge the possibility of multi-messenger astronomy with electro-magnetic wave observations at the time of merger. In this presentation , we will...
Torsion-bar antenna (TOBA) is a ground-based gravity gradiometer proposed for measurement of gravity gradient fluctuations such as gravitational waves and gravity gradient noise. TOBA consists of two perpendicular torsion pendulum, and the low mechanical resonant frequency of torsion pendulums enables us to measure gravity gradient of frequencies around 0.1 Hz. TOBA aims to achieve the...
Einstein Telescope (ET) will be the third generation of gravitational wave interferometer to be built in Europe. One of the sites candidates to host ET is located in Sardinia (Italy), near the Sos Enattos mine, where a seismometer’s net already proves the quietness of the site. The Sar-Grav laboratory, a seed of ET, aims to host underground experiments, cryogenic payloads, low frequency and...
The problem of mitigating scattered light noise within interferometer arm
tubes has been addressed via the insertion of baffles that intercept the
stray rays which after interacting with the tube walls may be reinjected in
the Fabry-Perot resonator, carrying the vibrational noise of the walls.
Such a problem has been dealt with conical, serrated, baffles that may
still be source of noise...
Broadband mitigation of quantum noise in interferometric gravitational-waves detectors can be achieved via frequency dependent squeezing (FDS) of the vacuum field at the dark port of the interferometer. This allows to reduce the vacuum field phase fluctuations at high frequency, where quantum shot noise dominates, and the amplitude fluctuation at low frequency, where the contribution of...
Large-scale, high-end, scientific instruments see their performances significantly impaired by residual ground motion at low frequencies. Namely, recent development of gravitational wave detectors aims to detect gravitational waves whose strain is as low as 10-20 Hz-1/2 in the sub-Hz frequency range, while seismic noise can be 10 times larger in this frequency range. High performance active...
As part of the second phase of Advanced Virgo update program, instrumented baffles are being constructed to be installed around the end mirrors in the main FP cavities, in continuation of what has been implemented for the input mode cleaner end mirror during phase I. According to the current design, these baffles will be equipped with more than 200 photosensors, allowing for real-time...
The cryogenic environment of gravitational-wave detectors, such as Einstein Telescope (ET), can be used in combination with superconducting materials to open up pathways to low-loss actuators and sensor mechanics.
We are developing a Cryogenic Superconducting Inertial Sensor (CSIS) with a displacement sensitivity of several fm/√Hz at 0.5 Hz. Such highly sensitive device can monitor the...
As straylight is a dominating limitation for the sensitivity of gravitational wave detectors, we
investigate the use of tunable coherence in the form of phase modulation following a pseudo-random-sequence on the interferometer laser to break the coherence of the delayed straylight. Thereby, we aim to reduce its intrusive impact on the measurement by effectively realizing a pseudo white-light...
