偏置极冠$B$场几何中的高能脉冲星光变曲线
High-energy pulsar light curves in an offset polar cap $B$-field geometry
摘要：
自费米大天区望远镜（LAT）$γ$射线任务取得巨大成功以来的八年中，已经对200多个$γ$射线天体的光变曲线和光谱特性进行了无与伦比的详细测量。我们进行了几何脉冲星光变曲线建模使用静态，延迟真空，和偏移极帽（PC）偶极子$B$ -字段（后者的特点是由一个参数$ε$），结合标准的两极焦散（TPC）和外间隙（OG）的发射几何。除了恒定发射率的几何模型，我们还考虑了一个槽隙（SG）$E$ -场与偏置PC偶极子$B$ -场，并发现它的夹杂物导致定性不同的光变曲线。因此，我们发现，假设的$B$场，特别是$E$场结构，以及发射几何（磁倾角和观察者的角度），有很大的影响脉冲星的可见性和它的高能量脉冲形状。我们将我们的模型光变曲线与船帆座脉冲星的高质量$γ$射线光变曲线（能量为$>100$ MeV）进行了比较。我们的总体最佳光变曲线拟合（具有最低的$χ^2$值）是针对延迟真空偶极场和OG模型的。我们发现，较小的值的$ε$有利于偏置PC偶极场时，假设恒定的发射率，和较大的$ε$值有利于可变的发射率，但不显着。当我们增加相对较低的SG $E$场时，我们发现光变曲线拟合得到改善，在这种情况下，推断的脉冲星几何形状更接近独立研究的最佳拟合。特别是，我们发现，这样一个较大的SG $E$ -场（导致可变发射率）给出了第二个整体最佳拟合。该指示和其他指示指向实际的$E$场可能大于SG模型预测的。
英文摘要：
The light curves and spectral properties of more than 200 $γ$-ray pulsars have been measured in unsurpassed detail in the eight years since the launch of the hugely successful Fermi Large Area Telescope (LAT) $γ$-ray mission. We performed geometric pulsar light curve modelling using static, retarded vacuum, and offset polar cap (PC) dipole $B$-fields (the latter is characterized by a parameter $ε$), in conjunction with standard two-pole caustic (TPC) and outer gap (OG) emission geometries. In addition to constant-emissivity geometric models, we also considered a slot gap (SG) $E$-field associated with the offset-PC dipole $B$-field and found that its inclusion leads to qualitatively different light curves. We therefore find that the assumed $B$-field and especially the $E$-field structure, as well as the emission geometry (magnetic inclination and observer angles), have a great impact on the pulsar's visibility and its high-energy pulse shape. We compared our model light curves to the superior-quality $γ$-ray light curve of the Vela pulsar (for energies $>100$ MeV). Our overall optimal light curve fit (with the lowest $χ^2$ value) is for the retarded vacuum dipole field and OG model. We found that smaller values of $ε$ are favoured for the offset-PC dipole field when assuming constant emissivity, and larger $ε$ values are favoured for variable emissivity, but not significantly so. When we increased the relatively low SG $E$-fields we found improved light curve fits, with the inferred pulsar geometry being closer to best fits from independent studies in this case. In particular, we found that such a larger SG $E$-field (leading to variable emissivity) gives a second overall best fit. This and other indications point to the fact that the actual $E$-field may be larger than predicted by the SG model.
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。
