Is Supernova Remnant Cassiopeia A a PeVatron?
文献类型：期刊论文
| 作者 | Zhang,Xiao1,2; Liu,Siming3
|
| 刊名 | The Astrophysical Journal
 |
| 出版日期 | 2019-03-27 |
| 卷号 | 874期号:1 |
| 关键词 | ISM: individual objects (G111.7-2.1=Cassiopeia A) ISM: supernova remnants radiation mechanisms: non-thermal |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/ab09fe |
| 英文摘要 | Abstract Cassiopeia A, a well-observed young core-collapse supernova remnant (SNR), is considered to be one of the best candidates for studying very high-energy particle acceleration up to PeV via the diffusive shock mechanism. Recently, MAGIC observations revealed a γ-ray spectral cutoff at ～ 3.5 TeV , suggesting that if the TeV γ-rays have a hadronic origin, SNR Cas A can only accelerate particles to tens of TeV. Here, we propose a two-zone emission model for regions associated with the forward (zone 1) and inward/reverse shocks (zone 2). Given the low density in zone 1, it dominates the high-frequency radio emission, soft X-ray rim via the synchrotron process, and TeV γ-ray via the inverse Comptonization. With a relatively softer particle distribution and a higher cutoff energy for electrons, emissions from zone 2 dominate the low-frequency radio, hard X-ray via the synchrotron process and GeV γ-ray via hadronic processes. There is no evidence for high-energy cutoffs in the proton distributions implying that Cas A can still be a PeVatron. Hadronic processes from zone 1 dominate very high-energy gamma-ray emission. Future observations in the hundreds of TeV range can test this model. |
| 语种 | 英语 |
| WOS记录号 | IOP:0004-637X-874-1-AB09FE |
| 出版者 | The American Astronomical Society |
| 源URL | [http://libir.pmo.ac.cn/handle/332002/23969]  |
| 专题 | 中国科学院紫金山天文台 |
| 作者单位 | 1.School of Astronomy & Space Science, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, People's Republic of China; xiaozhang@nju.edu.cn 2.Key Laboratory of Modern Astronomy and Astrophysics, Nanjing University, Ministry of Education, Nanjing 210023, People's Republic of China 3.Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, 8 Yuanhua Road, Nanjing 210034, People's Republic of China; liusm@pmo.ac.cn |
| 推荐引用方式 GB/T 7714 | Zhang,Xiao,Liu,Siming. Is Supernova Remnant Cassiopeia A a PeVatron?[J]. The Astrophysical Journal,2019,874(1). |
| APA | Zhang,Xiao,&Liu,Siming.(2019).Is Supernova Remnant Cassiopeia A a PeVatron?.The Astrophysical Journal,874(1). |
| MLA | Zhang,Xiao,et al."Is Supernova Remnant Cassiopeia A a PeVatron?".The Astrophysical Journal 874.1(2019). |
入库方式： OAI收割
来源：紫金山天文台
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