Decihertz Gravitational Waves from Double White Dwarf Merger Remnants
Decihertz Gravitational Waves from Double White Dwarf Merger Remnants
复制标题
DOI：
10.3847/1538-4357/abc7bd
复制
发表时间：
2020-09
期刊：
影响因子：
--
通讯作者：
S. Yoshida
中科院分区：
文献类型：
--
作者：
S. Yoshida
双白色矮星（DWD）的近距离双星通过发射引力波（GW）而螺旋并合并。其中一些双星的轨道运动预计将在低频波段观测到的星载激光干涉探测器的全球Ws。如果合并后的残余物质量足够大，它们可能会遭受热核失控并爆炸成超新星Ia。作为GW源，迄今为止很少有人研究残留物。在这里，我们提出了一个新的机制，GW发射DWD合并残留物，可以观察到计划GW探测器在一个分贝频带。由于合并过程的结果，一个残留物暂时预计会有高度的差异旋转。然后，它是不稳定的振荡模式，其方位角图案的速度与恒星旋转一致。我们解决了差分旋转残留物的特征值问题，并确定不稳定的本征模式，这可能是惯性模式。对引力波特征应变的估计表明，它们可能在室女座星系团的距离内被计划中的引力波观测站探测到。
Close binaries of double white dwarfs (DWDs) inspiral and merge by emitting gravitational waves (GWs). Orbital motion of some of these binaries is expected to be observed at a low-frequency band by space-borne laser interferometric detectors of GWs. The merger remnant may suffer thermonuclear runaway and explode as SNe Ia if they are massive enough. As GW sources, the remnants have so far been scarcely studied. Here we propose a new mechanism of GW emission from DWD merger remnants that may be observed by planned GW detectors in a decihertz frequency band. A remnant is temporarily expected to have a high degree of differential rotation as a consequence of the merger process. It is then unstable to oscillation modes whose azimuthal pattern speed coincides with the stellar rotation. We solve the eigenvalue problem of differentially rotating remnants and identify unstable eigenmodes, which may be categorized to inertial modes. The estimate of characteristic strain of GWs shows that they may be detectable within the distance of the Virgo cluster by planned gravitational wave observatories targeting the decihertz band.