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arXiv 0810.5416astro-ph
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银河系盘分子气体的亚毫米/毫米研究; TeV gamma ray SNR RXJ1713 .7-3946和W28高质量恒星形成区

Sub-mm/mm studies of the molecular gas in the Galactic disk; the TeV gamma ray SNR RXJ1713.7-3946 and the W28 high mass star forming region

Yasuo Fukui

摘要:

星际分子云是伽马射线源,通过与宇宙射线质子相互作用,随后产生中性π介子,衰变为伽马射线。本文介绍了在12 CO J=2-1,4-3和7-6发射谱线上对TeV γ射线SNR RXJ1713.7-3946和W28区的NANTEN 2新观测。在RXJ1713.7-3946中,我们证实了速度约为-10 km/s的局部分子气体与SNR具有非常好的空间相关性。结果表明,在整个SNR范围内,X射线峰与分子气体有很好的相关性,并表明SNR与分子气体之间的相互作用通过包括磁场压缩在内的多种方式对宇宙线加速起着重要作用. CO J=4-3向C峰的分布显示出一个紧凑而致密的云核,其大小约为1 pc,以及一个宽翼。核心显示出显着的反相关与朱雀X射线图像,也与硬伽马射线与HESS观察。基于这些发现,我们提出了一个图片,峰C是一个分子团幸存下来的冲击波的SN和周围的高能电子发射的X射线。TeV的伽马射线分布,另一方面,更扩展到分子气体,支持强子起源的伽马射线生产。W28是通过比较NANTEN CO数据集和HESS伽马射线源发现的最杰出的恒星形成区之一,展示出TeV伽马射线。在W_(28)区,我们给出了CO_(J)=2-1的分布以及两个TeV γ射线峰的详细图象。其中一个显示出强烈的CO J=7-6发射,表明在这个高质量恒星形成核心的高激发条件。对产生伽马射线的详细机制的追求正在进行中。

英文摘要:

Interstellar molecular clouds are gamma ray sources through the interactions with cosmic ray protons followed by production of neutral pions which decay into gamma rays. We present new NANTEN2 observations of the TeV gamma ray SNR RXJ1713.7-3946 and the W28 region in the 12CO J=2-1, 4-3 and 7-6 emission lines. In RXJ1713.7-3946 we confirm that the local molecular gas having velocities around -10 km/s shows remarkably good spatial correlations with the SNR. We show that the X ray peaks are well correlated with the molecular gas over the whole SNR and suggest that the interactions between the SNR and the molecular gas play an important role in cosmic ray acceleration via several ways including magnetic field compression. The CO J=4-3 distribution towards peak C shows a compact and dense cloud core having a size of about 1 pc as well as a broad wing. The core shows a notable anti-correlation with the Suzaku X ray image and is also associated with hard gamma rays as observed with HESS. Based on these findings, we present a picture that peak C is a molecular clump survived against the impact of the SN blast waves and is surrounded by high energy electrons emitting the X ray. The TeV gamma ray distribution is, on the other hand, more extended into the molecular gas, supporting the hadronic origin of gamma ray production. W28 is one of the most outstanding star forming regions exhibiting TeV gamma rays as identified through a comparison between the NANTEN CO dataset and HESS gamma ray sources. In the W28 region, we show the CO J=2-1 distribution over the whole region as well as the detailed image of the two TeV gamma ray peaks. One of them show strong CO J=7-6 emission, suggesting high excitation conditions in this high mass star forming core. A pursuit for the detailed mechanism to produce gamma rays is in progress.

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