Impact of signal clusters in wide-band searches for continuous gravitational waves
Impact of signal clusters in wide-band searches for continuous gravitational waves
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DOI：
10.1103/physrevd.106.042009
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发表时间：
2022-08
影响因子：
5
通讯作者：
L. Pierini;P. Astone;C. Palomba;Aidan Nyquist;S. Dall’Osso;S. D’Antonio;S. Frasca;I. La Rosa;P. Leaci;F. Muciaccia;O. Piccinni;L. Rei
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作者：
L. Pierini;P. Astone;C. Palomba;Aidan Nyquist;S. Dall’Osso;S. D’Antonio;S. Frasca;I. La Rosa;P. Leaci;F. Muciaccia;O. Piccinni;L. Rei
.在本文中，我们提出了一个层次的频率霍夫（FH）管道，用于在LIGO和Virgo合作的宽参数空间搜索的连续引力波（CW）发射，例如，旋转中子星（NS）的一些相关步骤的研究。由于CW的预期振幅较弱，迄今为止尚未发现CW。这些步骤，即谱估计、峰值图构造和在FH平面中选择候选者的程序，是关键的，因为它们有助于确定最终搜索灵敏度。在这里，我们感兴趣的是研究它们在信号簇（目前相当）极端情况下的行为，由于许多强CW源，在小（即< 1 Hz宽）频率范围内发射引力波（GW）。这可能发生在下一代探测器可探测到的某些CW源上，如丽莎，爱因斯坦望远镜和宇宙探测器。此外，这种可能性最近已经提出，即使是目前的地球上的探测器，在某些情况下，连续波发射的超轻玻色子云周围的恒星质量黑洞（BH）。我们定量评估的FH分析程序，旨在最大限度地减少单个CW信号的损失，信号集群的异常情况下的鲁棒性。结果主要取决于信号的振幅和频率的密集程度，以及它们覆盖的频率范围。我们表明，确实一个小的灵敏度损失可能会发生在一个非常高的平均信号密度的存在下，一个频率范围内的顺序为一赫兹，而当信号簇覆盖的频率范围的十分之一赫兹，或更少，我们实际上可能有一个灵敏度增益。总体而言，我们证明了FH是强大的，即使在存在中到大的信号集群。
. In this paper we present a study of some relevant steps of the hierarchical frequency-Hough (FH) pipeline, used within the LIGO and Virgo Collaborations for wide-parameter space searches of continuous gravitational waves (CWs) emitted, for instance, by spinning neutron stars (NSs). Because of their weak expected amplitudes, CWs have not been still detected so far. These steps, namely the spectral estimation, the peakmap construction and the procedure to select candidates in the FH plane, are critical as they contribute to determine the final search sensitivity. Here, we are interested in investigating their behavior in the (presently quite) extreme case of signal clusters, due to many and strong CW sources, emitting gravitational waves (GWs) within a small (i.e. < 1 Hz wide) frequency range. This could happen for some kinds of CW sources detectable by next generation detectors, like LISA, Einstein Telescope and Cosmic Explorer. Moreover, this possibility has been recently raised even for current Earth-based detectors, in some scenarios of CW emission from ultralight boson clouds around stellar mass black holes (BHs). We quantitatively evaluate the robustness of the FH analysis procedure, designed to minimize the loss of single CW signals, under the unusual situation of signal clusters. Results depend mainly on how strong in amplitude and dense in frequency the signals are, and on the range of frequency they cover. We show that indeed a small sensitivity loss may happen in presence of a very high mean signal density affecting a frequency range of the order of one Hertz, while when the signal cluster covers a frequency range of one tenth of Hertz, or less, we may actually have a sensitivity gain. Overall, we demonstrate the FH to be robust even in presence of moderate-to-large signal clusters.