Photopolarimetry of BL Lac
Photopolarimetry of BL Lac
复制标题
BL Lac 的光偏振测定
DOI：
10.1007/bf00658383
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发表时间：
1993
影响因子：
1.9
通讯作者：
S. Kikuchi
中科院分区：
文献类型：
--
作者：
A. Sillanpää;L. Takalo;K. Nilsson;S. Kikuchi
本文介绍了我们在拉帕尔马的2.56米北欧光学望远镜和日本多代拉国家天文台的0.91米望远镜上对BLLac的监测结果。在拉帕尔马，我们使用了UBVRI-光偏振仪，它在所有五个颜色带上提供了真正同时的观测。在Dodaira，我们使用了光偏振仪，它可以同时提供ATB、Vandr波段和ATV波段的光度测量。我们在耀斑过程中观测到了BLLac，在此期间我们观察到了偏振位置角的明显旋转。在这些耀斑期间，偏振水平也发生了强烈的变化，物体失去了偏振位置角的首选方向。这种现象的原因仍不清楚，但有两种可能的解释：喷流中螺旋磁场的冲击几乎指向我们，或者在超大质量中心黑洞的吸积盘(几乎正面看到)内旋转的极化同步加速器耀斑。
This paper presents results of our monitoring of BL Lac at the 2.56 m Nordic Optical Telescope in La Palma and at the 0.91 m telescope at National Astronomical Observatory in Dodaira, Japan. On La Palma we used aUBVRI-photopolarimeter which gives truly simultaneous observations in all five colour bands. At Dodaira we used a photopolarimeter which gives simultaneously photometry atB, VandR-bands and polarimetry atV-band. We have observations of BL Lac during flare behaviour and during these times we have observed a clear rotation of the polarization position angle. During these flares the polarization level has also been strongly variable and the object has lost its preferred direction of the polarization position angle. The reason for this behaviour remains still unclear, but there are two possible explanations: shocks in the helical magnetic field in the jet pointing nearly towards us or polarized synchrotron flares rotating within the accretion disk (seen nearly face on) of the supermassive central black hole.