The Neutron Star Interior Composition Explorer (NICER) recently measured the mass and equatorial radius of the isolated neutron star PSR J0030+0451. We use these measurements to infer the moment of inertia, the quadrupole moment, and the surface eccentricity of an isolated neutron star for the first time, using relations between these quantities that are insensitive to the unknown equation of state of supranuclear matter. We also use these results to forecast the moment of inertia of neutron star $A$ in the double pulsar binary J0737-3039, a quantity anticipated to be directly measured in the coming decade with radio observations. Combining this information with the measurement of the tidal Love number with LIGO/Virgo observations, we propose and implement the first theory-agnostic and equation-of-state-insensitive test of general relativity. Specializing these constraints to a particular modified theory, we find that consistency with general relativity places the most stringent constraint on gravitational parity violation to date, surpassing all other previously reported bounds by 7 orders of magnitude and opens the path for a future test of general relativity with multimessenger neutron star observations.

中文翻译：

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Multimessenger中子星观测的天体物理和理论物理意义

最近，中子星内部成分探测仪（NICER）测量了孤立中子星PSR J0030 + 0451的质量和赤道半径。我们使用这些测量值来推断惯性矩，四极矩和孤立中子星的表面偏心率，这是首次使用这些量之间的关系进行的，这些量对上核物质的未知状态方程不敏感。我们还使用这些结果来预测中子星的惯性矩$\mathrm{一种}$在双脉冲星二进制J0737-3039中，预计未来十年将通过无线电观测直接测量该量。将这些信息与使用LIGO / Virgo观测值进行的潮汐洛夫数测量相结合，我们提出并实施了广义相对论的第一个与理论无关和状态不敏感的检验。将这些约束专门用于特定的修正理论，我们发现与广义相对论的一致性是迄今为止对重力奇偶性违反最严格的约束，比以前报道的所有其他边界都超出了七个数量级，这为以后的广义相对论检验开辟了道路用多信使中子星观测。