A medium-resolution search for polarimetric structure: Moderately reddened sightlines
A medium-resolution search for polarimetric structure: Moderately reddened sightlines
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DOI：
10.1086/117833
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发表时间：
1996-02-01
影响因子：
5.3
通讯作者：
Nook, MA
中科院分区：
文献类型：
--
作者：
Wolff, MJ;Nordsieck, KH;Nook, MA
星际偏振曲线的表征已广泛使用宽带偏振测量。因此，在高达几百埃尺度的极化曲线中可能存在未被发现的特征或结构。以前寻找这种结构的努力一般都产生了消极的结果。为了在更大的尺度上研究Wolstencroft和Smith的极化结构报告[MNRAS， 208,461(1984)]，我们提出了威斯康星大学Pine Bluff天文台（PBO）的高信噪比、多历元光谱极化观测结果。我们的样本由九个适度变红的视线组成，其构造是为了最大化合理大小的样本的极化信噪比。我们发现，在p（max）的1%水平下，所有视线都没有共同的结构。在4000-7000埃范围内，单个视线没有显示出令人信服的结构，最高为4%的p（5个视线为2%）。没有证据表明非常宽带结构（VBS）的极化特征，这意味着它的载流子至少比产生连续极化的晶粒差2到4倍。此外，我们没有发现Wolstencroft和Smith在HD 36371、HD 149757和HD 198478的偏振曲线中所声称的特征（等于或高于上述报道的水平）的佐证。(C) 1996年美国天文学会。
Characterization of the interstellar polarization curve has made extensive use of broadband polarimetry measurements. Consequently, features or structure in the polarization curve of up to several hundred Angstroms in scale may exist undetected. Previous efforts to search for such structure have generally produced negative results. In an effort to investigate the report of polarimetric structure on a larger scale by Wolstencroft & Smith [MNRAS, 208, 461 (1984)], we present high signal-to-noise, multiepoch spectropolarimetric observations at the University of Wisconsin's Pine Bluff Observatory (PBO). Our sample, which consists of nine moderately reddened sightlines, is constructed to maximize the polarimetric signal-to-noise for a reasonably sized sample. We find the that there is no structure common to all sightlines down to a level of 1% of p(max). The individual sightlines show no convincing structure over the range 4000-7000 Angstrom to a level of 4% of p(max) (to 2% for five of the sightlines). No evidence is seen for a polarimetric signature of very broadband structure (VBS), which implies that its carriers are at least two to four times less well aligned than the grains producing the continuum polarization. In addition, we find no corroboration for the claims of features (at or above the levels reported above) in the polarization curves of HD 36371, HD 149757, and HD 198478 by Wolstencroft and Smith. (C) 1996 American Astronomical Society.