共查询到20条相似文献，搜索用时 31 毫秒
1.
郭越凡 CAPOCASA Eleonora EISENMANN Marc FLAMINIO Raffaele LEONARDI Matteo TACCA Matteo 肇宇航 李木子 吕振伟 《天文学进展》2019,(1):73-85
随着技术的发展,下一代引力波探测器的激光功率将得到进一步提高。大光斑半径的应用也将使探测器的热噪声进一步降低,因此,量子噪声将成为在全频段限制引力波探测器灵敏度的首要因素。作为目前最有保障的一种降低量子噪声的技术,频率相关压缩态很可能将被应用于下一代所有引力波探测器中[1]。频率相关压缩态可以通过将频率不相关压缩态与滤波腔相结合而产生。基于滤波腔具有的频率响应特性,这一技术的应用可以使低频波段的辐射压噪声有效降低,同时实现高频波段散粒噪声的降低,从而实现全探测频段灵敏度的提升。基于日本KAGRA引力波探测器的设计,我们预计将9dB压缩度的压缩态与周损失为8×10-5的300m滤波腔相结合,可以使探测器灵敏度在全探测频段提高1倍。此实验于2015年开始,目前滤波腔的安装调试已经基本完成,得到的结果基本与实验前的模拟相符合。与频率不相关压缩态光学实验台的安装过程也已经过半,通过温度和控制回路的调制,二次谐波腔的转化率已经超过50%。 相似文献
2.
José Antonio de Freitas Pacheco 《中国天文和天体物理学报》2010,10(11)
Large ground-based laser beam interferometers are presently in operation both in the USA(LIGO) and in Europe(VIRGO) and potential sources that might be detected by these instruments are revisited.The present generation of detectors does not have a sensitivity high enough to probe a significant volume of the universe and,consequently,predicted event rates are very low.The planned advanced generation of interferometers will probably be able to detect,for the first time,a gravitational signal.Advanced LIGO and... 相似文献
3.
Nils Andersson & Kostas D. Kokkotas 《Monthly notices of the Royal Astronomical Society》1998,299(4):1059-1068
We present new results for pulsating neutron stars. We have calculated the eigenfrequencies of the modes that one would expect to be the most important gravitational wave sources: the fundamental fluid f mode, the first pressure p mode and the first gravitational wave w mode, for twelve realistic equations of state. From these numerical data we have inferred a set of 'empirical relations' between the mode frequencies and the parameters of the star (the radius R and the mass M ). Some of these relations prove to be surprisingly robust, and we show how they can be used to extract the details of the star from observed modes. The results indicate that, should the various pulsation modes be detected by the new generation of gravitational wave detectors that come online in a few years, the mass and the radius of neutron stars can be deduced with errors no larger than a few per cent. 相似文献
4.
F. BastiF. Frasconi E. MajoranaL. Naticchioni M. PerciballiP. Puppo P. Rapagnani F. Ricci 《Astroparticle Physics》2011,35(2):67-75
Thermal noise is a limiting factor of interferometric gravitational wave detectors sensitivity in the low and intermediate frequency range. A concrete possibility for beating this limit, is represented by the development of a cryogenic last stage suspension to be integrated within a complex seismic isolation system. To this purpose a last stage payload prototype has been designed and built. It has been suspended within a dedicated cryostat with the same technique adopted for the VIRGO payload and making use of two thin wires in a cradle configuration to support a mirror made of silicon.The cooling strategy, the thermal behaviour and the system mechanical response have been deeply studied while a measurement characterization campaign has been performed both at room temperature and at cryogenic temperature. In this paper, the preliminary results obtained together with the first cooling down of the 300 kg overall mass payload at about 25 K, are reported. This study will play a driving role in the design of the third generation gravitational wave detector. 相似文献
5.
M. Benacquista D. M. Sedrakian M. V. Hairapetyan K. M. Shahabasyan A. A. Sadoyan 《Astrophysics》2004,47(3):324-334
Rotating white dwarfs undergoing quasi-radial oscillations can emit gravitational radiation in a frequency range from 0.1-0.3 Hz. Assuming that the energy source for the gravitational radiation comes from the oblateness of the white dwarf induced by the rotation, the strain amplitude is found to be 10-25 for a white dwarf at 50 pc. We had calculated thermal energy losses through a magneto-hydrodynamic mechanism and found it smaller than estimated before. The galactic population of these sources is estimated to be 107 and may produce a confusion-limited foreground for proposed advanced detectors in the frequency band between space-based and ground-based interferometers. Nearby oscillating white dwarfs may provide a clear enough signal to investigate white dwarf interiors through gravitational wave astroseismology. 相似文献
6.
引力波理论和实验的新进展 总被引：3，自引：0，他引：3
引力波的存在是爱因斯坦在广义相对论理论中提出的一个重要预言．由于目前技术水平的限制,无法在实验室产生足以被探测到的引力波,因此宇宙中大量的大质量剧烈活动的天体成为科学家研究引力波的首选,从而诞生了引力波天文学．引力波探测将开启研究宇宙的新窗口,是继电磁辐射、宇宙线和中微子探测后探索宇宙奥秘的又一重要手段,对天文学研究有着极为重要的意义.新一代应用了高灵敏度的迈克耳逊干涉仪装置的长基线引力波探测仪正在建造中．该综述从引力波理论出发,阐述了目前研究较多的可探测引力波源,给出了目前观测上的最新进展,并展望了今后的发展前景． 相似文献
7.
Recently, a configuration using atomic interferometers(AIs) had been suggested for the detection of gravitational waves. A new AI with some additional laser pulses for implementing large momentum transfer was also put forward, in order to reduce the effect of shot noise and laser frequency noise. We use a sensitivity function to analyze all possible configurations of the new AI and to distinguish how many momenta are transferred in a specific configuration. By analyzing the new configuration,we further explore a detection scheme for gravitational waves, in particular, that ameliorates laser frequency noise. We find that the amelioration occurs in such a scheme,but novelly, in some cases, the frequency noise can be canceled completely by using a proper data processing method. 相似文献
8.
Gravitational waves from mergers of black holes and neutron stars are now being detected by LIGO. Here we look at a new source of gravitational waves, i.e., a class of dark matter objects whose properties were earlier elaborated. We show that the frequency of gravitational waves and strains on the detectors from such objects (including their mergers) could be within the sensitivity range of LIGO. The gravitational waves from the possible mergers of these dark matter objects will be different from those produced by neutron star mergers in the sense that they will not be accompanied by electromagnetic radiation since dark matter does not couple with radiation.
相似文献9.
The polarization vector (PV) of an electromagnetic wave (EW) will experience a rotation in a region of spacetime perturbed by gravitational waves (GWs). Based on this consideration, Cruise's group has built an annular waveguide to detect GWs. We give detailed calculations of the rotations of polarization vector of an EW caused by incident GWs from various directions and in various polarization states, and then analyze the accumulative effects on the polarization vector when the EW passes n cycles along the annular waveguide. We reexamine the feasibility and limitation of this method to detect GWs of high frequency around 100 MHz, in particular the relic gravitational waves (RGWs). By comparing the spectrum of RGWs in the accelerating universe with the detector sensitivity of the current waveguide, it is found that the amplitude of the RGWs is too low to be detected by the waveguide detectors currently operating. Possible ways of improvements on detection are suggested. 相似文献
10.
在精确宇宙学的时代, 多信使、高精度、小尺度的宇宙学观测在帮助人们从更加深刻的层面理解宇宙极早期的同时, 也给基于线性近似和微扰展开宇宙学扰动理论带来了新的挑战. 近年来, 对原初引力波和原初黑洞的搜寻使得研究人员们对早期宇宙在小尺度上的非线性非微扰过程产生了浓厚的研究兴趣. 综述了在宇宙学小尺度上关于原初黑洞产生以及引力波研究取得的诸多进展, 重点关注了使用Mathieu方程的共振效应来研究小尺度功率谱放大以及诱导产生可观测的原初引力波的方法. 此外, 还尝试探讨了非高斯尾巴对原初黑洞形成的影响. 发现Mathieu方程所具备的共振效应可以提供一种有效的方法来刻画原初宇宙中小尺度的非微扰动力学过程, 从而能够更好地理解原初黑洞的形成以及相关的引力波产生机制. 同时, 非微扰的非高斯性在原初黑洞形成中可能会产生不可忽视的影响. 相似文献
11.
D. M. Sedrakian M. Benacquista K. M. Shahabassian A. A. Sadoyan M. V. Hairapetyan 《Astrophysics》2003,46(4):445-454
Undamped quasiradial fluctuations of rotating neutron stars and the gravitation radiation generated by them are discussed. Two possible sources of energy for maintaining these fluctuations are mentioned: the energy of deformation of the decelerating neutron star (spin down) and the energy released during a jump in the star's angular velocity (glitch). Expressions are derived for the intensity of the gravitational radiation and the amplitude of a plane gravitational wave for an earthbound observer. Estimates of these quantities are obtained for the Vela and Crab pulsars, for which the secular variation in the angular velocity is most often accompanied by irregular variations. It is shown that gravitational waves from these pulsars could be detected by the new generation of detectors. 相似文献
12.
Shin'ichirou Yoshida Yoshiharu Eriguchi 《Monthly notices of the Royal Astronomical Society》2000,316(4):917-922
We have investigated the influence of the r-mode instability on hypercritically accreting neutron stars in close binary systems during their common envelope phases, based on the scenario proposed by Brown et al. On the one hand, neutron stars are heated by the accreted matter at the stellar surface, but on the other hand they are also cooled down by the neutrino radiation. At the same time, the accreted matter transports its angular momentum and mass to the star. We have studied the evolution of the stellar mass, temperature and rotational frequency.
The gravitational-wave-driven instability of the r-mode oscillation strongly suppresses spinning up of the star, the final rotational frequency of which is well below the mass-shedding limit, in fact typically as low as 10 per cent of that of the mass-shedding state. On a very short time-scale the rotational frequency tends to approach a certain constant value and saturates there, as long as the amount of accreted mass does not exceed a certain limit to collapse to a black hole. This implies that a similar mechanism of gravitational radiation to that in the so-called 'Wagoner star' may work in this process. The star is spun up by accretion until the angular momentum loss by gravitational radiation balances the accretion torque. The time-integrated dimensionless strain of the radiated gravitational wave may be large enough to be detectable by gravitational wave detectors such as LIGO II. 相似文献
The gravitational-wave-driven instability of the r-mode oscillation strongly suppresses spinning up of the star, the final rotational frequency of which is well below the mass-shedding limit, in fact typically as low as 10 per cent of that of the mass-shedding state. On a very short time-scale the rotational frequency tends to approach a certain constant value and saturates there, as long as the amount of accreted mass does not exceed a certain limit to collapse to a black hole. This implies that a similar mechanism of gravitational radiation to that in the so-called 'Wagoner star' may work in this process. The star is spun up by accretion until the angular momentum loss by gravitational radiation balances the accretion torque. The time-integrated dimensionless strain of the radiated gravitational wave may be large enough to be detectable by gravitational wave detectors such as LIGO II. 相似文献
13.
Ernazar B. Abdikamalov Harald Dimmelmeier Luciano Rezzolla John C. Miller 《Monthly notices of the Royal Astronomical Society》2009,392(1):52-76
An increase in the central density of a neutron star may trigger a phase transition from hadronic matter to deconfined quark matter in the core, causing it to collapse to a more compact hybrid star configuration. We present a study of this, building on previous work by Lin et al.. We follow them in considering a supersonic phase transition and using a simplified equation of state, but our calculations are general relativistic (using 2D simulations in the conformally flat approximation) as compared with their 3D Newtonian treatment. We also improved the treatment of the initial phase transformation, avoiding the introduction of artificial convection. As before, we find that the emitted gravitational wave spectrum is dominated by the fundamental quasi-radial and quadrupolar pulsation modes but the strain amplitudes are much smaller than suggested previously, which is disappointing for the detection prospects. However, we see significantly smaller damping and observe a non-linear mode resonance which substantially enhances the emission in some cases. We explain the damping mechanisms operating, giving a different view from the previous work. Finally, we discuss the detectability of the gravitational waves, showing that the signal-to-noise ratio for current or second generation interferometers could be high enough to detect such events in our Galaxy, although third generation detectors would be needed to observe them out to the Virgo cluster, which would be necessary for having a reasonable event rate. 相似文献
14.
The gravitational radiation of n = 1 polytropes undergoing quasiradial pulsations is examined. The intensity of the gravitational
radiation and the gravitational wave amplitudes are calculated for polytropic models of white dwarfs and neutron stars when
the energy of rotation of the object serves as the source of the radiated energy. Calculations of h0 show that objects with a polytropic equation of state can describe the expected gravitational radiation from white dwarfs
and neutron stars. The gravitational radiation of polytropic models of galactic nuclei and quasars is also examined. These
objects can create a high enough background of gravitational radiation at frequencies of 10-8–10-11 Hz for gravitational wave detectors operating in this frequency range.
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Translated from Astrofizika, Vol. 48, No. 4, pp. 603–612 (November 2005). 相似文献
15.
极端质量比旋进系统是空间引力波探测器最重要的波源之一。对引力波的探测需要高精度波形模版。当前主流的极端质量比旋进系统引力波计算模型中,人们一般将小质量天体当作试验粒子进行计算,而忽略了其结构及自身引力对背景引力场的影响。利用Mathisson-Papapetrou-Dixon方程研究延展体在弯曲时空中的运动,以及小天体自旋和质量多极矩对引力波信号识别产生的影响。结果表明,质量比在10?6-10?4范围的旋进系统,其自旋达到很大时,自旋对延展体的轨道运动有不可忽略的影响;在质量比10?4-10?2区间内,需要考虑中心黑洞潮汐作用导致的白矮星形变;在质量比大于10?4,且白矮星自旋很大时,其自旋产生的形变会对小天体轨道运动产生不可忽略的影响。大质量黑洞潮汐作用导致的恒星级黑洞或中子星产生的形变可以忽略,中子星和黑洞的自旋会对轨道运动产生不可忽略的影响,而自旋产生的四极矩对轨道运动不产生影响。 相似文献
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The ASTROD-GW (ASTROD [Astrodynamical Space Test of Relativity Using Optical Devices] Optimized for Gravitation Wave Detection), the mission of the laser astrodynamical gravitational wave detection, is the scheme of optimality of the gravitational wave detection on which the ASTROD is concentrated. Its spacecraft orbits form a triangular array close to an equilateral triangle in the vicinity of the solar-terrestrial Lagrangian points L3, L4 and L5. The length of the interference arm is about 2.6 × 108 km and the detectable wavelength of the gravitational wave is 52 times larger than that detected by the LISA (Laser Interferometer Space Antenna). In this article, the design and optimization method of the ASTROD-GW orbit are summarized. After the orbit is optimized, the variation in the arm length difference (which can be called the interference difference in laser interferometry) within 10 years is in the order of magnitude of 10−4 AU. The Doppler velocities in the three arm length directions are smaller than 4 m/s, and all of them are less than that required by the LISA. Therefore the laser ranging techniques developed by the LISA can be applied to the ASTROD-GW. 相似文献
19.
Several experiments have been performed in many countries to observe gravitational waves or neutrino bursts. Since their simultaneous emission may occur in stellar collapses, we evaluate the effect of neutrino bursts on gravitational wave antennas and suggest the usefulness of a time correlation among the different detectors. 相似文献