Zeeman tomography of magnetic white dwarfs - I. Reconstruction of the field geometry from synthetic spectra
Zeeman tomography of magnetic white dwarfs - I. Reconstruction of the field geometry from synthetic spectra
复制标题
磁性白矮星的塞曼断层扫描 - I. 从合成光谱重建场几何
DOI：
10.1051/0004-6361:20020726
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发表时间：
2002
影响因子：
6.5
通讯作者：
F. Hessman
中科院分区：
文献类型：
--
作者：
F. Euchner;S. Jordan;K. Beuermann;B. Gänsicke;F. Hessman
我们计算了磁场强度在 10 到 200 MG 之间、有效温度在 8000 到 40 000 K 之间的磁性白矮星的光学塞曼光谱。它们形成了一个包含 20 628 组通量和圆偏振光谱的数据库。基于进化策略的最小二乘优化代码可以从旋转磁性白矮星的相位分辨合成塞曼光谱中恢复相对复杂的磁场拓扑。我们考虑不对齐且偏心的偶极子和四极子分量。模型几何结构包括具有单个高场点和间隔 90 的两个点的恒星。恢复的场结构的精度随着输入光谱的信噪比的增加而增加，并且如果除了通量谱之外还包括圆偏振谱，则恢复的场结构的精度会显着提高。我们讨论了迄今为止提出的解开磁性白矮星场几何形状的策略。
We have computed optical Zeeman spectra of magnetic white dwarfs for field strengths between 10 and 200 MG and eective temperatures between 8000 and 40 000 K. They form a database containing 20 628 sets of flux and circular polarization spectra. A least-squares optimization code based on an evolutionary strategy can recover relatively complex magnetic field topologies from phase-resolved synthetic Zeeman spectra of rotating magnetic white dwarfs. We consider dipole and quadrupole components which are non-aligned and shifted o-centre. The model geometries include stars with a single high-field spot and with two spots separated by90. The accuracy of the recovered field structure increases with the signal-to-noise ratio of the input spectra and is significantly improved if circular polarization spectra are included in addition to flux spectra. We discuss the strategies proposed so far to unravel the field geometries of magnetic white dwarfs.