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arXiv 0705.0987astro-ph
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奥尔特云畸变对CMB各向异性的影响

Imprint of Distortions in the Oort Cloud on the CMB Anisotropies

Daniel Babich, Abraham Loeb

摘要:

我们研究了近距离接触的一个路过的明星的内部奥尔特云的形状的效果,使用脉冲近似。受扰奥尔特云偏离球形,增加了彗星热辐射引起的宇宙微波背景(CMB)亮度的角起伏。根据太阳附近恒星的丰度和速度色散,如果与一颗质量为太阳质量的恒星相遇,碰撞参量为$1750 \au$,就会产生四极矩,其大小为$C_2 = 4.5 \times 10^{-15}, 6.7 \times 10^{-12}, 1.1 \times 10^{-9}$的部分CMB强度波动在$ν= 30, 353, 545 \GHz$的平方(这些是即将发射的普朗克卫星的频段)。我们还量化了散射盘产生的四极光谱失真,无论奥尔特云的任何扰动和随后的形状如何,这种失真都将存在。相比之下,目前的宇宙学模型预测的平方分数温度波动四极矩是$C_2 = 1.76 \times 10^{-10}$,它对应于$ν= 30, 353, 545 \GHz$的$C_2 = 2.9 \times 10^{-10}, 6.8 \times 10^{-9}, 1.6 \times 10^{-8}$的CMB强度波动。最后,我们讨论了如何测量的各向异性光谱失真可以用来约束最近的恒星飞的轨迹。

英文摘要:

We study the effect of a close encounter of a passing star on the shape of the inner Oort Cloud, using the impulse approximation. The deviation of the perturbed Oort Cloud from sphericity adds angular fluctuations to the brightness of the Cosmic Microwave Background (CMB) due to thermal emission by the comets. An encounter with a solar-mass star at an impact parameter of $1750 \au$, as expected based on the abundance and velocity dispersion of stars in the solar neighborhood, leads to a quadrupole moment in the square of the fractional CMB intensity fluctuation of $C_2 = 4.5 \times 10^{-15}, 6.7 \times 10^{-12}, 1.1 \times 10^{-9}$ at $ν= 30, 353, 545 \GHz$ (these being the frequency bands of the upcoming Planck satellite). We also quantify the quadrupole spectral distortions produced by the Scattered Disc, which will exist regardless of any perturbation and the subsequent shape of the Oort Cloud. For comparison, the square fractional temperature fluctuation quadrupole moment predicted by the current cosmological model is $C_2 = 1.76 \times 10^{-10}$, which corresponds to fluctuations in the CMB intensity of $C_2 = 2.9 \times 10^{-10}, 6.8 \times 10^{-9}, 1.6 \times 10^{-8}$ at $ν= 30, 353, 545 \GHz$. Finally, we discuss how a measurement of the anisotropic spectral distortions could be used to constrain the trajectory of the closest stellar fly-by.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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