scholarly journals Overview of KAGRA: KAGRA science

Author(s):  
T Akutsu ◽  
M Ando ◽  
K Arai ◽  
Y Arai ◽  
S Araki ◽  
...  

Abstract KAGRA is a newly build gravitational wave observatory, a laser interferometer with 3 km arm length, located in Kamioka, Gifu, Japan. In this paper, one of a series of articles featuring KAGRA, we discuss the science targets of KAGRA projects, considering not only the baseline KAGRA (current design) but also its future upgrade candidates (KAGRA+) for the near to middle term ($\sim$5 years).

2009 ◽  
Vol 72 (7) ◽  
pp. 076901 ◽  
Author(s):  
B P Abbott ◽  
R Abbott ◽  
R Adhikari ◽  
P Ajith ◽  
B Allen ◽  
...  

Author(s):  
Kun Chen ◽  
Xiaofeng Zhang ◽  
Tong Guo ◽  
Zhi-Ming Cai ◽  

The observation of gravitational wave enables human to explore the origin, formation and evolution of universe governed by the gravitational interaction and the nature of gravity beyond general theory of relativity. The groundbreaking discovery of Gravitational Wave by Laser Interferometer Gravitational-Wave Observatory provides a brand-new observation way. While detecting gravitational wave on ground is limited by noises and test scale, space detection is an optimized alternative to learn rich sources in range of 0.1 mHz–1 Hz. Considering the great significance of space gravitational wave detection, ESA proposed LISA project, CAS also proposed Taiji project. Due to the extremely weak gravitational wave signal and high measurement accuracy requirement, the spaceborne GW observation antenna is accomplished by three spacecrafts constitute isosceles triangle formation intersatellite interferometer. The arm length of the interferometer reaches millions of kilometers between them, and the measurement accuracy reaches pico-meter magnitude. There are many key technologies including pm magnitude space laser interferometer metrology, drag-free control using TM of Gravity Reference Sensor, [Formula: see text]N micro thruster, ultra-clean & ultra-stable spacecraft, etc. This paper focuses on key technologies of the ultra-clean & ultra-stable spacecraft, analyzing the design of mechanical, thermal control and magnetic clean. Moreover, it reports the preliminary results of the technological breakthrough.


2016 ◽  
Vol 12 (S324) ◽  
pp. 287-290
Author(s):  
Barbara De Lotto ◽  
Stefano Ansoldi ◽  
Angelo Antonelli ◽  
Alessio Berti ◽  
Alessandro Carosi ◽  
...  

AbstractThe year 2015 witnessed the first direct observations of a transient gravitational-wave (GW) signal from binary black hole mergers by the Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) Collaboration with the Virgo Collaboration. The MAGIC two 17m diameter Cherenkov telescopes system joined since 2014 the vast collaboration of electromagnetic facilities for follow-up of gravitational wave alerts. During the 2015 LIGO-Virgo science run we set up the procedure for GW alerts follow-up and took data following the last GW alert. MAGIC results on the data analysis and prospects for the forthcoming run are presented.


Author(s):  
Tony Yuan

The relative velocity between objects with finite velocity affects the reaction between them. This effect is known as general Doppler effect. The Laser Interferometer Gravitational-Wave Observatory (LIGO) discovered gravitational waves and found their speed to be equal to the speed of light c. Gravitational waves are generated following a disturbance in the gravitational field; they affect the gravitational force on an object. Just as light waves are subject to the Doppler effect, so are gravitational waves. This article explores the following research questions concerning gravitational waves: What is the spatial distribution of gravitational waves? Can the speed of a gravitational wave represent the speed of the gravitational field (the speed of the action of the gravitational field upon the object)? What is the speed of the gravitational field? Do gravitational waves caused by the revolution of the Sun affect planetary precession? Can we modify Newton’s gravitational equation through the influence of gravitational waves?


2017 ◽  
Vol 4 (5) ◽  
pp. 687-706 ◽  
Author(s):  
Rong-Gen Cai ◽  
Zhoujian Cao ◽  
Zong-Kuan Guo ◽  
Shao-Jiang Wang ◽  
Tao Yang

Abstract The direct detection of gravitational wave by Laser Interferometer Gravitational-Wave Observatory indicates the coming of the era of gravitational-wave astronomy and gravitational-wave cosmology. It is expected that more and more gravitational-wave events will be detected by currently existing and planned gravitational-wave detectors. The gravitational waves open a new window to explore the Universe and various mysteries will be disclosed through the gravitational-wave detection, combined with other cosmological probes. The gravitational-wave physics is not only related to gravitation theory, but also is closely tied to fundamental physics, cosmology and astrophysics. In this review article, three kinds of sources of gravitational waves and relevant physics will be discussed, namely gravitational waves produced during the inflation and preheating phases of the Universe, the gravitational waves produced during the first-order phase transition as the Universe cools down and the gravitational waves from the three phases: inspiral, merger and ringdown of a compact binary system, respectively. We will also discuss the gravitational waves as a standard siren to explore the evolution of the Universe.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mengxu Liu ◽  
Biping Gong

Abstract The gravitational wave (GW) has opened a new window to the universe beyond the electromagnetic spectrum. Since 2015, dozens of GW events have been caught by the ground-based GW detectors through laser interferometry. However, all the ground-based detectors are L-shaped Michelson interferometers, with very limited directional response to GW. Here we propose a three-dimensional (3-D) laser interferometer detector in the shape of a regular triangular pyramid, which has more spherically symmetric antenna pattern. Moreover, the new configuration corresponds to much stronger constraints on parameters of GW sources, and is capable of constructing null-streams to get rid of the signal-like noise events. A 3-D detector of kilometer scale of such kind would shed new light on  the joint search of GW and electromagnetic emission.


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