The Radius of PSR J0740+6620 from NICER and XMM-Newton Data
The Radius of PSR J0740+6620 from NICER and XMM-Newton Data
复制标题
DOI：
10.3847/2041-8213/ac089b
复制
发表时间：
2021-09-01
影响因子：
7.9
通讯作者：
Stairs, I
中科院分区：
文献类型：
--
作者：
Miller, M. C.;Lamb, F. K.;Stairs, I
PSR J0740+6620的引力质量为2.08 +/- 0.07 m -圆点，这是所有中子星中可靠的最高质量。因此，对其半径的测量将为高密度中子星核心物质的特性提供独特的见解。本文报道了一种基于旋转热点模式与中子星内部成分探测器（NICER）和x射线多镜（XMM-Newton） x射线观测的拟合的半径测量。我们发现PSR J0740+6620的赤道周半径为13.7(-1.5)(+2.6)km（68%）。我们将我们的测量结果，结合先前对PSR J0030+0451的质量和半径测量，以及另外两颗类似于2 m圆点脉冲星的质量，以及两次引力波事件的潮汐变形性约束，应用于三种不同的状态方程建模框架，并在类似于1.5-5倍核饱和密度的情况下发现了一致的结果。对于给定的框架，当包括所有测量时，1.4 m圆点中子星的半径已知为+/- 4%（68%可信度），2.08 m圆点中子星的半径已知为+/- 5%。在三个框架中，所有半径估计的+/- 1s可信区间的全半径范围为1.4 m圆点中子星12.45 +/- 0.65 km， 2.08 m圆点中子星12.35 +/- 0.75 km。
PSR J0740+6620 has a gravitational mass of 2.08 +/- 0.07 M-circle dot, which is the highest reliably determined mass of any neutron star. As a result, a measurement of its radius will provide unique insight into the properties of neutron star core matter at high densities. Here we report a radius measurement based on fits of rotating hot spot patterns to Neutron Star Interior Composition Explorer (NICER) and X-ray Multi-Mirror (XMM-Newton) X-ray observations. We find that the equatorial circumferential radius of PSR J0740+6620 is 13.7(-1.5)(+2.6) km (68%). We apply our measurement, combined with the previous NICER mass and radius measurement of PSR J0030+0451, the masses of two other similar to 2 M-circle dot pulsars, and the tidal deformability constraints from two gravitational wave events, to three different frameworks for equation-of-state modeling, and find consistent results at similar to 1.5-5 times nuclear saturation density. For a given framework, when all measurements are included, the radius of a 1.4 M-circle dot neutron star is known to +/- 4% (68% credibility) and the radius of a 2.08 M-circle dot neutron star is known to +/- 5%. The full radius range that spans the +/- 1s credible intervals of all the radius estimates in the three frameworks is 12.45 +/- 0.65 km for a 1.4 M-circle dot neutron star and 12.35 +/- 0.75 km for a 2.08 M-circle dot neutron star.