Gravitational waves from type II axion-like curvaton model and its implication for NANOGrav result
Gravitational waves from type II axion-like curvaton model and its implication for NANOGrav result
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DOI：
10.1088/1475-7516/2021/05/023
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发表时间：
2021-01
影响因子：
6.4
通讯作者：
M. Kawasaki;Hiromasa Nakatsuka
中科院分区：
文献类型：
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作者：
M. Kawasaki;Hiromasa Nakatsuka
nanogravity最近的报道引起了人们的关注，因为它的信号可以用引力波（GWs）的随机背景来解释，引力波在参考频率f ~ 10-8上的丰度为ΩGW ~ 10-9。PBH形成场景是nanogravity信号的候选者之一，它可以同时解释在LIGO-Virgo合作中观测到的30M☉黑洞的双星合并事件。我们重点研究了PBH形成的ii型类轴子曲率模型。在II型模型中，相位部分为轴子的复场从势的原点向下滚动。研究发现，II型模型具有密度扰动的宽功率谱，能够同时解释LIGO-Virgo事件和nanogravity信号。我们还改进了模型中扰动的非高斯性处理，以准确估计诱导GWs的振幅。
The recent report of NANOGrav is gathering attention since its signal can be explained by a stochastic background of gravitational waves (GWs) with an abundance of ΩGW ∼ 10-9 at the reference frequency f ∼ 10-8. The PBH formation scenario is one of the candidates for the NANOGrav signal, which can simultaneously explain the observed 30M☉ black holes in the binary merger events in LIGO-Virgo collaboration. We focus on the type-II axion-like curvaton model of the PBH formation. In the type II model, the complex field whose phase part is the axion rolls down from the origin of the potential. It is found that type II model achieves the broad power spectrum of the density perturbations and can simultaneously explain the LIGO-Virgo events and the NANOGrav signal. We also improve the treatment of the non-Gaussianity of perturbations in our model to accurately estimate the amplitude of the induced GWs.