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arXiv 0710.0801astro-ph
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星系团中的宇宙射线和射电晕:来自射电观测的新约束

Cosmic rays and Radio Halos in galaxy clusters : new constraints from radio observations

G. Brunetti, T. Venturi, D. Dallacasa, R. Cassano, K. Dolag, S. Giacintucci, G. Setti

摘要:

星系团是带电粒子加速的场所和非热辐射源。本文报道了对星系团内介质(ICM)中宇宙射线数量的新限制,这些宇宙线是通过对一个相当大的、X射线发光的、红移范围为0.2- 0.4的大质量星系团样本的射电观测获得的。观测到的大部分星系团在星系团中心没有显示出任何兆秒差距尺度的同步辐射(射电晕)。我们得到了固体上限的弥漫无线电发射,并讨论了它们的影响模型的起源无线电晕。我们的测量使我们能够得出ICM中宇宙射线质子含量的限制。假设这些质子的光谱指数δ =2.1-2.4和微G水平的磁场,从旋转措施,这些限制是一个数量级深于目前的EGRET上限,而他们是不太严格的陡峭的光谱和较低的磁场。

英文摘要:

Clusters of galaxies are sites of acceleration of charged particles and sources of non-thermal radiation. We report on new constraints on the population of cosmic rays in the Intra Cluster Medium (ICM) obtained via radio observations of a fairly large sample of massive, X-ray luminous, galaxy clusters in the redshift interval 0.2--0.4. The bulk of the observed galaxy clusters does not show any hint of Mpc scale synchrotron radio emission at the cluster center (Radio Halo). We obtained solid upper limits to the diffuse radio emission and discuss their implications for the models for the origin of Radio Halos. Our measurements allow us to derive also a limit to the content of cosmic ray protons in the ICM. Assuming spectral indices of these protons delta =2.1-2.4 and microG level magnetic fields, as from Rotation Measures, these limits are one order of magnitude deeper than present EGRET upper limits, while they are less stringent for steeper spectra and lower magnetic fields.

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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