Near-Infrared Imaging Polarimetry of the Star-Forming Region NGC 2024
Near-Infrared Imaging Polarimetry of the Star-Forming Region NGC 2024
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DOI：
10.1093/pasj/59.3.487
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发表时间：
2007-02
影响因子：
2.3
通讯作者：
R. Kandori;M. Tamura;N. Kusakabe;Y. Nakajima;T. Nagayama;C. Nagashima;J. Hashimoto;A. Ishihara;T. Nagata;J. Hough
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文献类型：
--
作者：
R. Kandori;M. Tamura;N. Kusakabe;Y. Nakajima;T. Nagayama;C. Nagashima;J. Hashimoto;A. Ishihara;T. Nagata;J. Hough
我们对NGC2024进行了广视场JHKs成像偏振测量。我们在NGC2024上空发现了一个突出的、延伸的偏振星云，并通过偏振矢量分析确定了该星云的照明源位置。一颗大质量恒星IRS2b位于对称矢量图的中心。在我们的偏振图像上，我们发现了五个与YSOs有关的小偏振星云。这些星云负责星际物质的结构，通过尘埃散射产生强烈的偏振光。对于类点源，我们进行了软件孔径偏振测量，发现了5颗年轻的棕矮星，具有高度极化的积分发射。这些来源为棕矮星周围存在盘/包络系统提供了直接证据。通过二向色性极化测量研究了NGC2024的磁场结构。整个区域的投射磁场的平均位置角为110度。我们发现用近红外二向色极化和亚毫米/远红外尘埃发射极化得到的磁场结构具有很好的一致性，表明近红外波长的二向色极化跟踪致密分子云内部的磁场结构。
We conducted wide-field JHKs imaging polarimetry toward NGC 2024. We found a prominent and extended polarized nebula over NGC 2024, and constrained the location of illuminating source of the nebula through the analysis of polarization vectors. A massive star, IRS 2b, is located in the center of the symmetric vector pattern. Five small polarized nebulae associated with YSOs are discovered on our polarization images. These nebulae are responsible for the structures of circumstellar matter that produce strongly polarized light through dust scattering. For the point-like sources, we performed software aperture polarimetry in order to measure integrated polarizations, and found five young brown dwarfs with highly polarized integrated emission. These sources serve as direct evidence for the existence of disk/envelope system around brown dwarfs. We investigated the magnetic field structure of NGC 2024 through the measurements of dichroic polarization. The average position angle of projected magnetic fields across the region is found to be 110 degrees. We found a good consistency in magnetic field structures obtained using near-infrared dichroic polarization and sub-mm/far-infrared dust emission polarization, indicating that the dichroic polarizations at near-infrared wavelengths trace magnetic field structures inside dense molecular clouds.