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arXiv 2204.12166astro-ph.HE
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用HAWC探测河外中红外背景

Probing the extragalactic mid-infrared background with HAWC

Mateo Fernandez Alonso

摘要:

河外背景光(EBL)包含了恒星和致密天体自复合时代以来由核过程和吸积过程发射的全部辐射。直接测量EBL密度是具有挑战性的,特别是在近红外到远红外波段,主要是由于黄道光前景。相反,伽马射线天文学提供了一种可能性,通过研究遥远耀变体的甚高能量(VHE:$>$ 100 GeV)光谱中伽马射线吸收的影响,间接地对EBL设定限制。高海拔水切伦科夫伽马射线天文台(HAWC)是少数对能量超过10 TeV的伽马射线敏感的仪器之一。这提供了探测近/中IR区域中的EBL的机会:$λ$ = 1 $μ$ m - 100 $μ$ m。在这项研究中,我们适合物理激发的排放模型费米大面积望远镜(LAT)的GeV数据外推的本征TeV光谱的耀变体。然后,我们模拟了大量的吸收光谱不同的随机生成的EBL模型形状和计算贝叶斯可信带的EBL强度空间的比较和测试的吸收光谱和HAWC河外观测的两个耀变体之间的协议。得到的频带与当前EBL下限和上限一致,显示出在先前测量中也观察到的朝向更高波长值$λ>10\, μ$ m的下降趋势。

英文摘要:

The extragalactic background light (EBL) contains all the radiation emitted by nuclear and accretion processes in stars and compact objects since the epoch of recombination. Measuring the EBL density directly is challenging, especially in the near- to far-infrared waveband, mainly due to the zodiacal light foreground. Instead, gamma-ray astronomy offers the possibility to indirectly set limits on the EBL by studying the effects of gamma-ray absorption in the very high energy (VHE:$>$100 GeV) spectra of distant blazars. The High Altitude Water Cherenkov gamma ray observatory (HAWC) is one of the few instruments sensitive to gamma rays with energies above 10 TeV. This offers the opportunity to probe the EBL in the near/mid IR region: $λ$ = 1 $μ$m - 100 $μ$m. In this study, we fit physically motivated emission models to Fermi Large Area Telescope (LAT) GeV data to extrapolate the intrinsic TeV spectra of blazars. We then simulate a large number of absorbed spectra for different randomly generated EBL model shapes and calculate Bayesian credible bands in the EBL intensity space by comparing and testing the agreement between the absorbed spectra and HAWC extragalactic observations of two blazars. The resulting bands are in agreement with current EBL lower and upper limits, showing a downward trend towards higher wavelength values $λ>10\, μ$m also observed in previous measurements.

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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