Low-Frequency Gravitational Waves from Massive Black Hole Binaries: Predictions for LISA and Pulsar Timing Arrays
Low-Frequency Gravitational Waves from Massive Black Hole Binaries: Predictions for LISA and Pulsar Timing Arrays
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DOI：
10.1086/375187
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发表时间：
2002-11
期刊：
影响因子：
--
通讯作者：
J. Wyithe;A. Loeb;A. Loeb
中科院分区：
文献类型：
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作者：
J. Wyithe;A. Loeb;A. Loeb
星系合并导致的大质量黑洞(BH)双星的合并提供了一个主要的低频引力辐射来源，可以通过脉冲星计时测量和拟议的激光干涉空间天线(LISA)天文台探测到。我们通过将预测的银晕合并率与最近测量的BH质量、MBH和其宿主星系σ的速度弥散之间的关系结合起来，计算了来自所有红移源的预期引力辐射信号。我们的主要发现如下：(1)NHZ频率背景主要是红移为z≲2的BH双星，来自脉冲星计时数据的现有限制严格限制了MBH-σ关系的归一化和幂定律斜率或BH双星合并的比例；(2)LISA可探测到的所有离散MHz大质量BH源中有一半以上可能起源于红移z≳7；(3)只要BH形成是由星系中的气体冷却触发的，那么再电离后每年单位红移的LISA源的数量应该会大幅下降。对每年数百个可探测事件中最高红移源的研究将提供关于星系中黑洞增长的物理和历史的独特信息。
The coalescence of massive black hole (BH) binaries due to galaxy mergers provides a primary source of low-frequency gravitational radiation detectable by pulsar timing measurements and by the proposed the Laser Interferometry Space Antenna (LISA) observatory. We compute the expected gravitational radiation signal from sources at all redshifts by combining the predicted merger rate of galactic halos with recent measurements of the relation between BH mass, MBH, and the velocity dispersion of its host galaxy, σ. Our main findings are as follows: (1) the nHz frequency background is dominated by BH binaries at redshifts z ≲ 2, and existing limits from pulsar timing data place tight constraints on the allowed normalization and power-law slope of the MBH-σ relation or on the fraction of BH binaries that proceed to coalescence; (2) more than half of all discrete mHz massive BH sources detectable by LISA are likely to originate at redshifts z ≳ 7; (3) the number of LISA sources per unit redshift per year should drop substantially after reionization as long as BH formation is triggered by gas cooling in galaxies. Studies of the highest redshift sources among the few hundred detectable events per year will provide unique information about the physics and history of black hole growth in galaxies.