In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Se...In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein's first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan,which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravitational wave detection in the nanohertz frequency band using the technique of pulsar timing. Sect. 5 reviews the status of gravitational wave detection in the attohertz frequency band, detectable in the polarisation of the cosmic microwave background, and discusses the prospects for detection of primordial waves from the big bang. The techniques described in sects. 1–5 have already placed significant limits on the strength of gravitational wave sources. Sects. 6 and 7 review ambitious plans for future space based gravitational wave detectors in the millihertz frequency band. Sect. 6 presents a roadmap for development of space based gravitational wave detectors by China while sect. 7 discusses a key enabling technology for space interferometry known as time delay interferometry.展开更多
The light curve is one of the most important photometric characteristics of variable stars,which can supply physical information about many stars.So,light curves are the best candidate to inspect a theoretical model o...The light curve is one of the most important photometric characteristics of variable stars,which can supply physical information about many stars.So,light curves are the best candidate to inspect a theoretical model of binaries.One important feature of the light curve is the difference of two light minima of the light curve,namely the difference between the primary eclipse depth and the secondary eclipse depth(DED).In this paper,the secondary eclipse depths of theoretical and observational light curves are studied.Firstly,a method to calculate the theoretical light curves of an eclipsing binary with non-spherical components is proposed,which can be put into the HSB contact binary model [Huang R Q,et al.Chin J Astron Astrophys,2007,7:235-244;Song H F,et al.Chin J Astron Astrophys,2007,7:539-550].Theoretical light curves and the DED of the binary can be obtained at every evolutionary phase.The relationships of DED with mass and luminosity are presented and show special features for the contact binaries.Secondly,a large amount of observational data is collected,from which 11 massive,intermediate-mass contact binaries and 9 low-mass contact binaries are chosen and the two relationships are obtained using theoretical light curves.Finally,in order to check whether the HSB contact binary model can be used in contact binary systems with massive,intermediate-mass and low-mass components,a comparison is performed for the above mentioned relationships obtained from theoretical light curves with those from the astronomical observations.The results show a good agreement for contact binary systems with all different masses.展开更多
基金supported by the US National Science Foundation(Grant No.PHY-0757058)supported by the National Natural Science Foundation of China(Grant Nos.11443008 and 11503003)+2 种基金a Returned Overseas Chinese Scholars Foundation grant,and Fundamental Research Funds for the Central Universities(Grant No.2015KJJCB06)supported by the National Space Science Center,Chinese Academy of Sciences(Grant Nos.XDA04070400 and XDA04077700)Partial supports from the National Natural Science Foundation of China(Grant Nos.11305255,11171329 and 41404019)
文摘In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein's first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan,which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravitational wave detection in the nanohertz frequency band using the technique of pulsar timing. Sect. 5 reviews the status of gravitational wave detection in the attohertz frequency band, detectable in the polarisation of the cosmic microwave background, and discusses the prospects for detection of primordial waves from the big bang. The techniques described in sects. 1–5 have already placed significant limits on the strength of gravitational wave sources. Sects. 6 and 7 review ambitious plans for future space based gravitational wave detectors in the millihertz frequency band. Sect. 6 presents a roadmap for development of space based gravitational wave detectors by China while sect. 7 discusses a key enabling technology for space interferometry known as time delay interferometry.
基金supported by the National Natural Science Foundation of China (Grant No. 10933002)
文摘The light curve is one of the most important photometric characteristics of variable stars,which can supply physical information about many stars.So,light curves are the best candidate to inspect a theoretical model of binaries.One important feature of the light curve is the difference of two light minima of the light curve,namely the difference between the primary eclipse depth and the secondary eclipse depth(DED).In this paper,the secondary eclipse depths of theoretical and observational light curves are studied.Firstly,a method to calculate the theoretical light curves of an eclipsing binary with non-spherical components is proposed,which can be put into the HSB contact binary model [Huang R Q,et al.Chin J Astron Astrophys,2007,7:235-244;Song H F,et al.Chin J Astron Astrophys,2007,7:539-550].Theoretical light curves and the DED of the binary can be obtained at every evolutionary phase.The relationships of DED with mass and luminosity are presented and show special features for the contact binaries.Secondly,a large amount of observational data is collected,from which 11 massive,intermediate-mass contact binaries and 9 low-mass contact binaries are chosen and the two relationships are obtained using theoretical light curves.Finally,in order to check whether the HSB contact binary model can be used in contact binary systems with massive,intermediate-mass and low-mass components,a comparison is performed for the above mentioned relationships obtained from theoretical light curves with those from the astronomical observations.The results show a good agreement for contact binary systems with all different masses.
