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arXiv 1111.0325astro-ph.HE
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脉冲星辐射几何与加速场强

Pulsar Emission Geometry and Accelerating Field Strength

Megan E. DeCesar, Alice K. Harding, M. Coleman Miller, Ioannis Contopoulos, Constantinos Kalapotharakos, Damien Parent

摘要:

高质量的Fermi LAT观测为理解γ射线源高能辐射的产生机制打开了一扇新的窗口。高统计允许对光曲线特征的仔细建模以及相位分辨光谱建模。我们模拟的LAT光变曲线的船帆座和CTA 1的恒星与模拟的高能量光变曲线产生的几何表示的外部间隙和槽隙的排放模型,在真空延迟偶极子和无力场。马尔可夫链蒙特卡罗极大似然方法被用来探索相空间的磁倾角,视角,最大发射半径,和间隙宽度。我们还使用测量的光谱截止能量来估计加速平行电场对半径的依赖性,假设高能量发射主要由曲率辐射和几何形状(发射半径和最小曲率半径的磁场线)是由每个模型的最佳拟合光变曲线确定。我们发现,从真空场的光变曲线更紧密地匹配所观察到的光变曲线和多波长的限制,并计算出的平行电场可以放置额外的约束的发射几何形状。

英文摘要:

The high-quality Fermi LAT observations of gamma-ray pulsars have opened a new window to understanding the generation mechanisms of high-energy emission from these systems. The high statistics allow for careful modeling of the light curve features as well as for phase resolved spectral modeling. We modeled the LAT light curves of the Vela and CTA 1 pulsars with simulated high-energy light curves generated from geometrical representations of the outer gap and slot gap emission models, within the vacuum retarded dipole and force-free fields. A Markov Chain Monte Carlo maximum likelihood method was used to explore the phase space of the magnetic inclination angle, viewing angle, maximum emission radius, and gap width. We also used the measured spectral cutoff energies to estimate the accelerating parallel electric field dependence on radius, under the assumptions that the high-energy emission is dominated by curvature radiation and the geometry (radius of emission and minimum radius of curvature of the magnetic field lines) is determined by the best fitting light curves for each model. We find that light curves from the vacuum field more closely match the observed light curves and multiwavelength constraints, and that the calculated parallel electric field can place additional constraints on the emission geometry.

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