VERITAS Observations of the Galactic Center Region at Multi-TeV Gamma-Ray Energies
VERITAS Observations of the Galactic Center Region at Multi-TeV Gamma-Ray Energies
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DOI：
10.3847/1538-4357/abf926
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发表时间：
2021-04
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影响因子：
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通讯作者：
J. Ryan
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文献类型：
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作者：
J. Ryan
银河系中心(GC)区域拥有各种强大的天文学来源和罕见的天体物理过程，它们发出大量的非热辐射。内部375pc×600pc区域被称为中央分子带，是超大质量黑洞射手座A*、大质量云复合体和超新星残留物(SNR)等粒子加速器的所在地。我们介绍了我们使用非常高能辐射成像望远镜阵列系统成像-大气切伦科夫望远镜在2010至2018年间获取的125小时数据对来自GC的高于2TeV的甚高能伽马射线发射的改进分析结果。与人马座A*位置一致的中心源VJ1745290在背景水平(38σ)之上的显著意义上被探测到，我们报告了它的光谱和光曲线。其微分光谱符合指数截止值的幂规律，谱指数为5.3TeV，通量归一化为TeV−1 cm−2 S−1，截止能量为TeV。我们还给出了GC附近扩散发射的结果，这些结果是通过合并GC脊线上多个区域的数据获得的，累积重要性为9.5σ。弥散的GC脊谱符合幂定律，硬指数为2.19±0.20，没有证据表明截止到40TeV。这加强了在GC中存在潜在的PeV宇宙射线加速器的证据。我们还提供了我们视野中具有重要探测的其他源的光谱，复合SNR G0.9+0.1和Hess J1746-285。
The Galactic Center (GC) region hosts a variety of powerful astronomical sources and rare astrophysical processes that emit a large flux of nonthermal radiation. The inner 375 pc × 600 pc region, called the Central Molecular Zone, is home to the supermassive black hole Sagittarius A*, massive cloud complexes, and particle accelerators such as supernova remnants (SNRs). We present the results of our improved analysis of the very-high-energy gamma-ray emission above 2 TeV from the GC using 125 hr of data taken with the Very Energetic Radiation Imaging Telescope Array System imaging-atmospheric Cerenkov telescope between 2010 and 2018. The central source VER J1745–290, consistent with the position of Sagittarius A*, is detected at a significance of 38 standard deviations above the background level (38σ), and we report its spectrum and light curve. Its differential spectrum is consistent with a power law with exponential cutoff, with a spectral index of , a flux normalization at 5.3 TeV of TeV−1 cm−2 s−1, and cutoff energy of TeV. We also present results on the diffuse emission near the GC, obtained by combining data from multiple regions along the GC ridge, which yield a cumulative significance of 9.5σ. The diffuse GC ridge spectrum is best fit by a power law with a hard index of 2.19 ± 0.20, showing no evidence of a cutoff up to 40 TeV. This strengthens the evidence for a potential accelerator of PeV cosmic rays being present in the GC. We also provide spectra of the other sources in our field of view with significant detections, composite SNR G0.9+0.1, and HESS J1746–285.