Multifrequency VLA observations of the Crab Nebula at different epochs: expansion and radio spectra of filaments
Multifrequency VLA observations of the Crab Nebula at different epochs: expansion and radio spectra of filaments
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蟹状星云不同历元的多频 VLA 观测：细丝的膨胀和射电谱
DOI：
10.1093/mnras/255.2.210
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发表时间：
1992
影响因子：
4.8
通讯作者：
V. R. Venugopal
中科院分区：
文献类型：
--
作者：
T. Velusamy;D. Roshi;V. R. Venugopal
本文给出了1989.1，1983.9和1984.5历元的蟹状星云的高分辨率射电结构图，这些射电图是用327，1400和4800 MHz的VLA数据制作的。外部区域的暗条显示出与星云膨胀相一致的大的自行，尽管在西北边界可以看到一些异常运动或结构变化。暗条的射电频谱在远离中心的地方变陡，在中心100弧秒内的射电频谱为0.3，在外围区域为0.4。在6厘米处的偏振表明磁场是沿着灯丝，特别是在环和拱中，可能起源于星云的环形磁场。光谱显示，虽然弥漫星云的辐射来自脉冲星产生的电子，但外层区域的灯丝包含脉冲星和冲击波加速产生的电子
High-resolution radio maps of the filamentary structure of the Crab Nebula made using VLA data at 327, 1400 and 4800 MHz at epochs 1989.1, 1983.9 and 1984.5 are presented. The filaments in the outer regions show large proper motions consistent with the expansion of the nebula, although some anomalous motions or structural changes are seen in the north-western boundary. The radio spectrum of the filament steepens away from the centre, with ∼ 0.3 within 100 arcsec of the centre and ∼ 0.4 in the outer regions. The polarization at 6 cm suggests that the magnetic field is along the filaments, especially in the loops and arches, having a possible origin in the toroidal magnetic field of the nebula. The spectrum suggests that, while the diffuse nebular emission is from pulsar-generated electrons, the filaments in the outer regions contain electrons generated by both pulsar and shock acceleration