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arXiv 1808.06808astro-ph.HEnucl-th
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中子物质的相对论参数化及其对中子星的意义

Relativistic parameterizations of neutron matter and implications for neutron stars

Nadine Hornick, Laura Tolos, Andreas Zacchi, Jan-Erik Christian, Jürgen Schaffner-Bielich

摘要:

我们构造的相对论平均场模型的参数集适合于最近的约束的不对称能量$J$和斜率参数$L$的纯中子物质。我们发现了非物质行为的案例,即对于具有低有效质量值$m^*/m$的刚性参数集,出现负压。在某些情况下,纯中子物质的物态方程超出了手征有效场论的允许范围。对于所有可接受的参数集的中子星的质量-半径关系表明,超过$2M_\odot$的最大质量与脉冲星质量测量兼容。考虑到手征有效理论对低密度区模型的限制,我们发现$1.4M_\odot$中子星的半径几乎与$L$的值无关.这与以前的一些主张形成对比,这些主张认为斜率参数与中子星的半径有很强的联系。事实上,质量-半径关系只取决于对称物质的等熵参数。讨论了GW 170817对潮汐变形能力和半径的限制。

英文摘要:

We construct parameter sets of the relativistic mean-field model fitted to the recent constraints on the asymmetry energy $J$ and the slope parameter $L$ for pure neutron matter. We find cases of unphysical behaviour, i.e.\ the appearance of negative pressures, for stiff parameter sets with low values of the effective mass $m^*/m$. In some cases the equation of state of pure neutron matter turns out to be outside the allowed band given by chiral effective field theory. The mass-radius relations of neutron stars for all acceptable parameter sets shows a maximum mass in excess of $2M_\odot$ being compatible with pulsar mass measurements. Given the constraints on the model in the low-density regime coming from chiral effective theory, we find that the radius of a $1.4M_\odot$ neutron star is nearly independent on the value of $L$. This is in contrast to some previous claims for a strong connection of the slope parameter with the radius of a neutron star. In fact, the mass-radius relation turns out to depend only on the isoscalar parameters of symmetric matter. The constraints of GW170817 on the tidal deformability and on the radius are also discussed.

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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