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arXiv 2211.02437gr-qc
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各种状态方程的奇异星引力波回波

Gravitational wave echoes from strange stars for various equations of state

Jyatsnasree Bora, Umananda Dev Goswami

摘要:

最近,在GW170817事件中,频率约为$72\,Hz$的试验性引力波回波(GWE)被认为具有$4.2σ$显著性水平。GWEs可以作为研究超致密天体特性的工具。考虑到最后的超紧凑,合并后的物体是一颗奇怪的恒星,GWE频率可以计算出来。然而,GWEs只观察到那些紧凑的恒星结构,其紧凑性介于0.33和0.44之间。另外,GWE可以得到那些紧凑的恒星,其特点是光子球和紧凑性不跨越布赫达尔的极限半径$R_{B}=9/4M$。光子球是位于$R=3M$的表面,$R$是半径,$M$是超紧凑物体的总质量。最近,利用最简单的MIT Bag模型状态方程(EoS),已经报道了奇怪的恒星可以产生频率为几十千赫的GWEs。有鉴于此,为了进行比较研究,我们考虑了三种奇异星Eos模型,即,MIT袋模型、线性和多变EoS \cite{JB}。我们发现,不太僵硬的多变EoS不能发射GWE,而麻省理工学院的袋模型和线性EoS可以发射GWE在几十千赫的频率范围内。此外,GWE频率随着袋常数$B$的值的增加而增加,并且随着线性常数$b$的值的增加而减小。因此,GWE频率的模型依赖性被观察到。

英文摘要:

The tentative Gravitational Wave Echo (GWE) at a frequency of about $72\,Hz$ has been recently claimed at $4.2σ$ significance level in the GW170817 event. GWEs can be used as a tool to study the characteristics of ultra-compact stellar objects. Considering the final ultra-compact, post-merger object as a strange star, the GWE frequency can be calculated. However, GWEs are observed for only those compact stellar structures whose compactness lies in between 0.33 and 0.44. Alternatively, GWE can be obtained for those compact stars which feature a photon sphere and compactness not crossing the Buchdahl's limit radius $R_{B}=9/4M$. A photon sphere is a surface located at $R=3M$, $R$ being the radius and $M$ is the total mass of the ultra-compact object. Recently using the simplest MIT Bag model Equation of State (EoS) it has been reported that strange stars can produce GWEs with frequencies of tens of kilohertz. In view of this, for a comparative study, we have calculated the respective echo frequencies associated with strange stars by considering three models of strange star EoSs, viz., MIT bag model, linear and polytropic EoSs \cite{JB}. We found that, not being too stiff the polytropic EoS can not emit GWE, whereas the MIT Bag model and the linear EoSs can emit GWEs at a frequency range of about tens of kilohertz. Also, GWE frequency increases with the increase in values of bag constant $B$ and decreases with the increasing values of linear constant $b$. So a model-dependent nature of GWE frequencies is observed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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