Detailed Investigation of the Gamma-Ray Emission in the Vicinity of SNR W28 with FERMI-LAT
Detailed Investigation of the Gamma-Ray Emission in the Vicinity of SNR W28 with FERMI-LAT
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使用 FERMI-LAT 详细研究 SNR W28 附近的伽马射线发射
DOI：
10.1088/0004-637x/786/2/145
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
R.
中科院分区：
文献类型：
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作者：
Hanabata;Y.;Katagiri;H.;Hewitt;J. W.;Ballet;J.;Fukazawa;Y.;Fukui;Y.;Hayakawa;T.;Lemoine-Goumard;M.;Pedaletti;G.;Strong;A. W.;Torres;D. F.;Yamazaki;R.
本文详细研究了超新星遗迹W28（G6）附近的γ射线辐射。4− 0.1）由费米伽马射线太空望远镜上的大面积望远镜（LAT）观测到。我们探测到了与TeV源HESS J1800− 240 A、B和C在空间上一致的大量γ射线发射，这些源位于SNR的射电边界之外。它们在2-100 GeV波段的谱与TeV源幂律谱的外推一致。我们还确定了一个新的GeV辐射源，称为源W，它位于TeV源的边界之外，与W28西部的射电辐射相吻合。所有的GeV γ射线源在0 ~ 20 km s− 1的速度范围内都与分子云重叠。假设HESS J1800− 240 A、B和C的γ射线发射来自于分子云和从W28逃逸的宇宙射线（CR）之间相互作用的π 0衰变，它们可以自然地用一个单一的模型来解释，其中CR扩散系数小于星际空间中的理论预期。通过同样的模型计算，从W28逃逸的CRs的总能量被限制在102 × 1049 erg以上。来自源W的发射也可以用相同的CR逃逸情景来解释。
We present a detailed investigation of the γ-ray emission in the vicinity of the supernova remnant (SNR) W28 (G6. 4− 0.1) observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. We detected significant γ-ray emission spatially coincident with TeV sources HESS J1800− 240A, B, and C, located outside the radio boundary of the SNR. Their spectra in the 2–100 GeV band are consistent with the extrapolation of the power-law spectra of the TeV sources. We also identified a new source of GeV emission, dubbed Source W, which lies outside the boundary of TeV sources and coincides with radio emission from the western part of W28. All of the GeV γ-ray sources overlap with molecular clouds in the velocity range from 0 to 20 km s− 1. Under the assumption that the γ-ray emission toward HESS J1800− 240A, B, and C comes from π 0 decay due to the interaction between the molecular clouds and cosmic rays (CRs) escaping from W28, they can be naturally explained by a single model in which the CR diffusion coefficient is smaller than the theoretical expectation in the interstellar space. The total energy of the CRs escaping from W28 is constrained through the same modeling to be larger than∼ 2× 10 49 erg. The emission from Source W can also be explained with the same CR escape scenario.