Pratten Geraint, Schmidt Patricia, Hinderer Tanja
School of Physics and Astronomy and Institute for Gravitational Wave Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 9TT, United Kingdom.
Universitat de les Illes Balears, Crta. Valldemossa km 7.5, E-07122, Palma, Spain.
Nat Commun. 2020 May 21;11(1):2553. doi: 10.1038/s41467-020-15984-5.
Gravitational waves (GWs) from binary neutron stars encode unique information about ultra-dense matter through characterisic signatures associated with a variety of phenomena including tidal effects during the inspiral. The main tidal signature depends predominantly on the equation of state (EoS)-related tidal deformability parameter Λ, but at late times is also characterised by the frequency of the star's fundamental oscillation mode (f-mode). In General Relativity and for nuclear matter, Λ and the f-modes are related by universal relations which may not hold for alternative theories of gravity or exotic matter. Independently measuring Λ and the f-mode frequency enables tests of gravity and the nature of compact binaries. Here we present directly measured constraints on the f-mode frequencies of the companions of GW170817. We also show that future GW detector networks will measure f-mode frequencies to within tens of Hz, enabling precision GW asteroseismology with binary inspiral signals alone.
来自双中子星的引力波通过与包括旋进期间的潮汐效应在内的各种现象相关的特征信号，编码了关于超致密物质的独特信息。主要的潮汐特征主要取决于与状态方程（EoS）相关的潮汐形变参数Λ，但在后期也由恒星基本振荡模式（f模式）的频率来表征。在广义相对论中，对于核物质，Λ和f模式通过普遍关系相关联，而这些关系对于替代引力理论或奇异物质可能不成立。独立测量Λ和f模式频率能够对引力和致密双星的性质进行检验。在此，我们给出了对GW170817伴星f模式频率的直接测量约束。我们还表明，未来的引力波探测器网络将把f模式频率测量到几十赫兹以内，仅通过双星旋进信号就能实现精确的引力波星震学。
