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北美退伍军人节(Veterans Day),12 日无更新
arXiv 0910.4881astro-ph.HEastro-ph.CO
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TeV-selected AGN的费米观测

Fermi observations of TeV-selected AGN

S. J. Fegan, D. Sanchez, Fermi LAT Collaboration, :, A. A. Abdo

摘要:

我们报告的观测TeV选择AGN在第一个5.5个月的观测与大面积望远镜(LAT)上的费米伽马射线太空望远镜(费米)。总共选择了96个活动星系核进行研究,每个活动星系核要么是(i)在TeV能量下探测到的源(28个源),要么是(ii)已经用TeV仪器研究过的物体,并且已经报告了上限(68个物体)。费米望远镜的观测结果清楚地显示了38个TeV选定的天体,其中21个是GeV-TeV联合源,29个不在第三个EGRET目录中。对于38个费米探测源,光谱和光变曲线。大多数可以用光谱指数大于2.0的幂律来描述,通常需要光谱中断来适应TeV测量。基于外推的费米光谱,我们确定的来源,以前没有检测到TeV的能量,这是有前途的目标TeV仪器。证据系统的演化的$γ$ -射线光谱红移的背景下,与EBL的相互作用进行了讨论。

英文摘要:

We report on observations of TeV-selected AGN made during the first 5.5 months of observations with the Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope (Fermi). In total, 96 AGN were selected for study, each being either (i) a source detected at TeV energies (28 sources) or (ii) an object that has been studied with TeV instruments and for which an upper-limit has been reported (68 objects). The Fermi observations show clear detections of 38 of these TeV-selected objects, of which 21 are joint GeV-TeV sources and 29 were not in the third EGRET catalog. For each of the 38 Fermi-detected sources, spectra and light curves are presented. Most can be described with a power law of spectral index harder than 2.0, with a spectral break generally required to accommodate the TeV measurements. Based on an extrapolation of the Fermi spectrum, we identify sources, not previously detected at TeV energies, which are promising targets for TeV instruments. Evidence for systematic evolution of the $γ$-ray spectrum with redshift is presented and discussed in the context of interaction with the EBL.

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