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arXiv 0910.3015astro-ph.CO
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漫同步辐射与大尺度结构的互相关

Cross-Correlation of Diffuse Synchrotron and Large-Scale Structures

Shea Brown, Damon Farnsworth, Lawrence Rudnick

摘要:

首次探索了利用射电同步辐射与大尺度结构示踪剂的互相关方法探测弥散IGM/WHIM。我们对两个红移切片(0.03 < z < 0.04和0.06 < z < 0.07)的34 x 34度区域的2 MASS星系与1.4 GHz波恩巡天的相应区域进行了互相关。在这个分析中,我们假设同步辐射表面亮度与星系的表面密度成线性比例。我们还抽样交叉关联函数使用24个相同大小的远场从波恩调查,以更好地评估噪声属性。虽然我们得到了零结果,但我们发现,通过添加由具有1(7)mK和7(49)mK的细丝(峰值)表面亮度的2 MASS图像加权的信号,将分别对0.03 < z < 0.04和0.06 < z < 0.07红移切片产生3 σ正相关。这些检测阈值对应于低至0.2 microG的最小能量磁场,接近于灯丝场值的一些理论预期。这种注入的信号也低于波恩调查的均方根噪声,并证明了这种技术的力量及其实用性,即将到来的敏感连续测量,如在阿雷西博的GALFACTS和那些计划与默奇森宽场阵列(MWA)。

英文摘要:

We explore for the first time the method of cross-correlation of radio synchrotron emission and tracers of large-scale structure in order to detect the diffuse IGM/WHIM. We performed a cross-correlation of a 34 x 34 degree area of 2MASS galaxies for two redshift slices (0.03 < z < 0.04 and 0.06 < z < 0.07) with the corresponding region of the 1.4 GHz Bonn survey. For this analysis, we assumed that the synchrotron surface brightness is linearly proportional to surface density of galaxies. We also sampled the cross-correlation function using 24 distant fields of the same size from the Bonn survey, to better assess the noise properties. Though we obtained a null result, we found that by adding a signal weighted by the 2MASS image with a filament (peak) surface brightness of 1 (7) mK and 7 (49) mK would produce a 3 sigma positive correlation for the 0.03 < z < 0.04 and 0.06 < z < 0.07 redshift slices respectively. These detection thresholds correspond to minimum energy magnetic fields as low as 0.2 microG, close to some theoretical expectations for filament field values. This injected signal is also below the rms noise of the Bonn survey, and demonstrates the power of this technique and its utility for upcoming sensitive continuum surveys such as GALFACTS at Arecibo and those planned with the Murchison Widefield Array (MWA).

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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