SPINNING DUST EMISSION: EFFECTS OF IRREGULAR GRAIN SHAPE, TRANSIENT HEATING, AND COMPARISON WITH WILKINSON MICROWAVE ANISOTROPY PROBE RESULTS
SPINNING DUST EMISSION: EFFECTS OF IRREGULAR GRAIN SHAPE, TRANSIENT HEATING, AND COMPARISON WITH WILKINSON MICROWAVE ANISOTROPY PROBE RESULTS
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旋转粉尘排放：不规则颗粒形状、瞬态加热的影响以及与威尔金森微波各向异性探头结果的比较
DOI：
10.1088/0004-637x/741/2/87
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
B. Draine
中科院分区：
文献类型：
--
作者：
Thiem C. Hoang;A. Lazarian;B. Draine
普朗克预计将回答有关早期宇宙的关键问题，但它也提供了对异常微波辐射的进一步理解。旋转尘埃颗粒的电偶极子发射仍然是对反常微波发射的有利解释。本文提出了一种计算具有转动惯量I1、⩾、I2、⩾、I3的不规则形状小颗粒的转动辐射的方法。我们证明了具有给定角动量的无扭矩旋转的不规则颗粒以多个频率模式辐射。由此产生的旋转尘埃光谱具有峰值频率和发射率随着颗粒形状不规则性程度的增加而增加，其定义为I1：I2：I3。我们讨论了偶极矩在物体坐标中的取向如何影响内部热涨落的不同区域的旋转尘埃光谱。结果表明，在强热涨落的情况下，旋转尘埃发射率对方向的敏感度比在弱热涨落的情况下要小。我们计算了气体密度和偶极矩范围内的自旋尘埃光谱。研究了可压缩湍流对旋转粉尘排放的影响。结果表明，当声速马赫数M S从2增加到7时，湍流介质中的辐射比均匀介质中的辐射增加了1倍。最后，通过将我们改进的模型与H-α关联和100-μm关联发射谱的5年Wilkinson微波各向异性探测器互相关前景谱进行拟合，约束了旋转尘埃参数。
Planck is expected to answer crucial questions on the early universe, but it also provides further understanding on anomalous microwave emission. Electric dipole emission from spinning dust grains continues to be the favored interpretation of anomalous microwave emission. In this paper, we present a method to calculate the rotational emission from small grains of irregular shape with moments of inertia I1 ⩾ I2 ⩾ I3. We show that a torque-free rotating irregular grain with a given angular momentum radiates at multiple frequency modes. The resulting spinning dust spectrum has peak frequency and emissivity increasing with the degree of grain shape irregularity, which is defined by I1:I2:I3. We discuss how the orientation of the dipole moment in body coordinates affects the spinning dust spectrum for different regimes of internal thermal fluctuations. We show that the spinning dust emissivity for the case of strong thermal fluctuations is less sensitive to the orientation of than in the case of weak thermal fluctuations. We calculate spinning dust spectra for a range of gas density and dipole moment. The effect of compressible turbulence on spinning dust emission is investigated. We show that the emission in a turbulent medium increases by a factor from 1.2 to 1.4 relative to that in a uniform medium, as the sonic Mach number M s increases from 2 to 7. Finally, spinning dust parameters are constrained by fitting our improved model to five-year Wilkinson Microwave Anisotropy Probe cross-correlation foreground spectra, for both the Hα-correlated and 100-μm-correlated emission spectra.
旋转尘埃辐射的改进模型
DOI：
10.1111/j.1365-2966.2009.14599.x
发表时间：
2009
影响因子：
4.8
作者：
Ali-Haïmoud Y
通讯作者：
Ali-Haïmoud Y