GRAVITATIONAL WAVES FROM KNOWN PULSARS: RESULTS FROM THE INITIAL DETECTOR ERA
GRAVITATIONAL WAVES FROM KNOWN PULSARS: RESULTS FROM THE INITIAL DETECTOR ERA
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已知脉冲星的引力波：初始探测器时代的结果
DOI：
10.1088/0004-637x/785/2/119
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Aasi J
中科院分区：
文献类型：
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作者：
Aasi J
脉冲星是旋转的，磁化的中子星，旋转速率缓慢下降。在三轴椭球星星模型中，变形（可能来自星星固体部分的剪切应变，或来自磁应力）可以在星星旋转时表现为随时间变化的四极矩。观测到的旋转能量损失，称为自旋下降光度（由E= Izz给出）。| Ω| = 4π2Izzfrot| frot|其中Izz是围绕主轴（与旋转轴对齐）的惯性矩，frot是旋转频率，frot是旋转频率导数）提供了巨大的能量储存。沿着磁偶极辐射，这一储备的一部分可能通过引力波发射而消散（参见Shklovskii 1969; Ostriker &古恩1969; Ferrari & Ruffini 1969; Melosh 1969，其中有四个关于发现双星后不久的引力波发射的同期计算，或者例如Owen 2006对最近的发射机制计算的回顾）。已知的恒星通常具有精确确定的频率演化和天空位置，使它们成为引力波探测器的理想目标。如果通过电磁观测定期监测脉冲星，它可以产生相干相位模型，这使得引力波数据可以在数月或数年内进行相干积分。自激光干涉引力波天文台（LIGO）、Virgo和GEO 600的初始科学数据运行以来，人们已经对许多已知脉冲星的连续准单色引力波发射进行了搜索（Abbott等人，2004、2005、2007 a、2008、2010; Abadie等人，2011）。最近，利用LIGO第五次科学运行（S5; Abbott et al. 2010）的数据瞄准了116颗已知的恒星，并利用Virgo第二次科学运行（VSR 2）的数据瞄准了船帆座脉冲星（J 0835 − 4510）。这些搜索报告没有探测到，但提供了来自源的引力波振幅的上限，并超过了蟹状星云和船帆座星云的所谓自旋下降极限（见1.1节）。我们在这里的目标是寻找引力波发射从一个大的选择恒星，包括一些最大的自旋下的光度。由于探测器处的地震噪声在低频下引起灵敏度降低，因此不值得搜索旋转频率frot小于约10 Hz的磁共振，其对应于频率fgw= 2 frot小于20 Hz的引力波质量四极发射。这个引力波的精确值
Pulsars are spinning, magnetized neutron stars with slowly decreasing rotation rates. In the model of a triaxial ellipsoid star, a deformation (possibly from shear strains in the solid part (s) of the star, or from magnetic stresses) can appear as a time-varying quadrupole moment as the star rotates. The observed loss of rotational energy, known as the spin-down luminosity (given by E= IzzΩ| Ω|= 4π2Izzfrot| frot|, where Izz is the moment of inertia around the principal axis (aligned with the rotation axis), frot is the rotation frequency, and frot is the rotational frequency derivative) provides a huge reservoir of energy. Along with magnetic dipole radiation some fraction of this reservoir is potentially dissipated through gravitational wave emission (see Shklovskii 1969; Ostriker & Gunn 1969; Ferrari & Ruffini 1969; Melosh 1969 for four contemporaneous calculations of gravitational wave emission from soon after pulsars were discovered, or eg, Owen 2006 for a review of more recent emission mechanism calculations). Known pulsars usually have precisely determined frequency evolutions and sky-positions making them ideal targets for gravitational wave detectors. If a pulsar is monitored regularly through electromagnetic observations it can yield a coherent phase model, which allows gravitational wave data to be coherently integrated over months or years. Since the initial science data runs of the Laser Interferometric Gravitational-wave Observatory (LIGO), Virgo and GEO600, searches have been performed for continuous quasimonochromatic gravitational wave emission from many known pulsars (Abbott et al. 2004, 2005, 2007a, 2008, 2010; Abadie et al. 2011). Most recently 116 known pulsars were targeted using data from LIGO’s fifth science run (S5; Abbott et al. 2010), and the Vela pulsar (J0835− 4510) was targeted using data from Virgo’s second science run (VSR2). These searches reported no detections, but provided upper limits on the gravitational wave amplitude from the sources and surpassed the so-called spin-down limit (see Section 1.1) for the Crab and Vela pulsars. We aim here to search for gravitational wave emission from a large selection of stars including some of those with the largest spin-down luminosities. Due to the sensitivity reduction caused at low frequency by seismic noise at the detectors, it is not worthwhile to search for pulsars with rotational frequencies, frot, smaller than about 10 Hz, which corresponds to gravitational wave mass quadrupole emission at frequencies, fgw= 2 frot, smaller than 20 Hz. The exact value of this gravitational wave