论文标题
连贯曲率辐射引起的脉冲星谱之间的光谱变化
Spectral variation across Pulsar Profile due to Coherent Curvature Radiation
论文作者
论文摘要
脉冲星的特征是两个不同的发射成分，即核心和锥体。 pulsar无线电发射光束的标准模型源自偶极磁场，将核心放在中心，周围是内部和外圆锥组件的同心层。与锥体相比，核心发射的光谱有望更陡。我们对核心发射和圆锥发射之间的光谱相对差异进行了详细分析，从大量脉冲星的大量脉冲显示在100 MHz和10 GHz之间的频率范围内。认为核心比锥体陡峭得多，特别是在100 MHz和1 GHz之间，光谱指数$Δα__{core/Cone} \ SIM $ -1.0之间的相对差。此外，我们还发现外部圆锥成分的光谱比内锥具有陡峭的圆锥体，该圆锥体的光谱指数$Δα__{in/out} \ sim $ +0.5。随着磁场线的曲率，从磁轴向开放线区域边缘的光谱扁平是从带电的Soliton束的相干曲率辐射的自然结果，并解释了核心和锥体之间光谱的差异。此外，由于相对论的光束效果，仅当辐射在狭窄的角度$θ\ leq 1/γ$上针对观察者时才可见，其中$γ$是流出的等离子体云的Lorentz因子。这限制了发射，尤其是从外锥中，这些锥与曲率较大的田间线相关，从而使光谱比内锥更陡。
The pulsar profile is characterised by two distinct emission components, the core and the cone. The standard model of a pulsar radio emission beam originating from dipolar magnetic fields, places the core at the centre surrounded by concentric layers of inner and outer conal components. The core emission is expected to have steeper spectra compared to the cones. We present a detailed analysis of the relative differences in spectra between the core and conal emission from a large sample of 53 pulsars over a wide frequency range between 100 MHz and 10 GHz. The core was seen to be much steeper than the cones particularly between 100 MHz and 1 GHz with a relative difference between the spectral index $Δα_{core/cone}\sim$ -1.0. In addition we also found the spectra of the outer conal components to be steeper than the inner cone with relative difference in the spectral index $Δα_{in/out}\sim$ +0.5. The flattening of the spectra from the magnetic axis towards the edge of the open field line region with increasing curvature of the field lines is a natural outcome of the coherent curvature radiation from charged soliton bunches, and explains the difference in spectra between the core and the cones. In addition due to the relativistic beaming effect, the radiation is only visible when it is directed towards the observer over a narrow angle $θ\leq 1/γ$, where $γ$ is the Lorentz factor of the outflowing plasma clouds. This restricts the emission particularly from outer cones, that are associated with field lines with larger curvature thereby making the spectra steeper than the inner cones.
