论文标题
psr j0740+6620的半径来自更好的背景估计值
The Radius of PSR J0740+6620 from NICER with NICER Background Estimates
论文作者
论文摘要
我们报告了对大量毫秒脉冲星PSR J0740+6620的半径，质量和热表面区域进行的修订分析，此前曾与Riley等人的关节拟合与Newto和XMM-Newton数据进行了研究。 （2021）和Miller等。 （2021）。我们对脉搏核模型参数执行类似的贝叶斯估计，除非我们使用XMM-Newton数据同时拟合，我们使用最好的更好的背景估计来限制从源检测到的光子数量。这种方法消除了这两种仪器之间交叉校准的任何潜在问题，从而独立检查了分析的鲁棒性。获得的中子星参数约束与已经发布的结果兼容，略微依赖于强加的背景限制的保守程度。更紧密的下限会导致推断的半径增加，并且更紧密的上限会导致其减小。我们还扩展了对推断的发射几何形状的研究，以检查偏离热区域的抗肌的偏差程度。我们表明，对抗斑点的构型存在显着偏移，这主要是由于两个发射点的非半循环方位角分离。从抗卵石上的偏移角度为25度以上，概率为84％。这似乎排除了PSR J0740+6620中的中心 - 偶极磁场。
We report a revised analysis for the radius, mass, and hot surface regions of the massive millisecond pulsar PSR J0740+6620, studied previously with joint fits to NICER and XMM-Newton data by Riley et al. (2021) and Miller et al. (2021). We perform a similar Bayesian estimation for the pulse-profile model parameters, except that instead of fitting simultaneously the XMM-Newton data, we use the best available NICER background estimates to constrain the number of photons detected from the source. This approach eliminates any potential issues in the cross-calibration between these two instruments, providing thus an independent check of the robustness of the analysis. The obtained neutron star parameter constraints are compatible with the already published results, with a slight dependence on how conservative the imposed background limits are. A tighter lower limit causes the inferred radius to increase, and a tighter upper limit causes it to decrease. We also extend the study of the inferred emission geometry to examine the degree of deviation from antipodality of the hot regions. We show that there is a significant offset to an antipodal spot configuration, mainly due to the non-half-cycle azimuthal separation of the two emitting spots. The offset angle from the antipode is inferred to be above 25 degrees with 84% probability. This seems to exclude a centered-dipolar magnetic field in PSR J0740+6620.
