The NANOGrav 11 yr Data Set: Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
The NANOGrav 11 yr Data Set: Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
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DOI：
10.3847/1538-4357/ab2236
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发表时间：
2019-08-01
影响因子：
4.9
通讯作者：
Zhu, W. W.
中科院分区：
文献类型：
--
作者：
Aggarwal, K.;Arzoumanian, Z.;Zhu, W. W.
观测表明，几乎所有星系的中心都有超大质量黑洞。当星系合并时，它们的组成黑洞形成SMBH双星（smbhb），它们发出低频引力波（GWs），可以被脉冲星定时阵列探测到。我们已经搜索了北美纳赫兹天文台11年的引力波数据集，这些数据集来自圆形轨道上单个smbhb的引力波。由于在我们的数据中没有发现GWs的有力证据，我们对来自这些来源的GWs的强度设置了95%的上限。在f(gw) = 8 nHz时，我们设置了h(0) < 7.3(3) x 10（-15）的天平均上限。我们还开发了一种技术来确定每个脉冲星中特定信号的重要性，使用“dropout”参数作为识别杂散信号的一种方式。根据这些上限，我们在我们最敏感的天空位置排除了120 Mpc内M = 10(9) M-圆点发射f(gw) = 8 nHz的gw的smbhb，以及在5.5 Gpc内M = 10(10) M-圆点发射f(gw) = 8 nHz的smbhb。我们还确定了室女座星系团中没有> 1.6 x 10(9) m圆点的smbhb，发射出f(gw) = 2.8-317.8 nHz的gw。最后，我们将我们的应变上限与模拟的smbhb种群进行了比较，该种群基于两微米全天巡天（Two Micron All-Sky Survey）中的星系和Illustris宇宙模拟项目中的合并率，发现在7.5万个局部宇宙中只有34个包含可探测的源。
Observations indicate that nearly all galaxies contain supermassive black holes at their centers. When galaxies merge, their component black holes form SMBH binaries (SMBHBs), which emit low-frequency gravitational waves (GWs) that can be detected by pulsar timing arrays. We have searched the North American Nanohertz Observatory for Gravitational Waves 11 yr data set for GWs from individual SMBHBs in circular orbits. As we did not find strong evidence for GWs in our data, we placed 95% upper limits on the strength of GWs from such sources. At f(gw) = 8 nHz, we placed a sky-averaged upper limit of h(0) < 7.3(3) x 10(-15). We also developed a technique to determine the significance of a particular signal in each pulsar using "dropout" parameters as a way of identifying spurious signals. From these upper limits, we ruled out SMBHBs emitting GWs with f(gw) = 8 nHz within 120 Mpc for M = 10(9) M-circle dot, and within 5.5 Gpc for M = 10(10) M-circle dot at our most sensitive sky location. We also determined that there are no SMBHBs with > 1.6 x 10(9) M-circle dot emitting GWs with f(gw) = 2.8-317.8 nHz in the Virgo Cluster. Finally, we compared our strain upper limits to simulated populations of SMBHBs, based on galaxies in the Two Micron All-Sky Survey and merger rates from the Illustris cosmological simulation project, and found that only 34 out of 75,000 realizations of the local universe contained a detectable source.