Contribution of the Cygnus bubble to the Galactic cosmic ray spectrum and diffuse $γ$-ray emissions

Fuente: arXiv
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Autori principali: Nie, Lin, Qian, Xiang-Li, Guo, Yi-Qing, Liu, Si-Ming
Natura: Preprint
Pubblicazione: 2024
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author Nie, Lin
Qian, Xiang-Li
Guo, Yi-Qing
Liu, Si-Ming
author_facet Nie, Lin
Qian, Xiang-Li
Guo, Yi-Qing
Liu, Si-Ming
contents Since the discovery of cosmic rays (CRs) over a century ago, their origin has remained a mystery and a key research question. Recently, the LHAASO experiment identified the first CR super-acceleration source, the Cygnus bubble, which can accelerate CRs to energies exceeding 10 PeV. A pertinent question is: how much does the Cygnus bubble contribute to the CR spectrum observed on Earth? With the aim of answering that question, a 3D propagation analysis was conducted on CRs in this study. The Cygnus bubble was incorporated into our propagation model in order to determine its contributions to the observed spectra. First, we calculated the spectrum and spatial morphology of the Cygnus bubble to reproduce the observed LHAASO data. Subsequently, we calculated the diffuse $γ$-ray emissions produced by the CRs from the Cygnus bubble and the energy spectrum of the cosmic ray particles near Earth after propagation. Finally, we utilized a CR spatial-dependent propagation model to calculate the large-scale CR energy spectrum and the resulting diffuse $γ$-ray emissions. Our results indicate that: (1) the Cygnus bubble contributes minimally to the CR spectrum observed on Earth, (2) the emissions produced by the CR particles from the Cygnus bubble dominates the diffuse $γ$-ray emissions in that region, (3) the structural fluctuations of the diffuse $γ$-ray emissions observed by LHAASO are likely due to the local CR halo. We anticipate that LHAASO will identify more CR halo sources to validate our model.
format Preprint
id arxiv_https___arxiv_org_abs_2408_01693
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Contribution of the Cygnus bubble to the Galactic cosmic ray spectrum and diffuse $γ$-ray emissions
Nie, Lin
Qian, Xiang-Li
Guo, Yi-Qing
Liu, Si-Ming
High Energy Astrophysical Phenomena
Since the discovery of cosmic rays (CRs) over a century ago, their origin has remained a mystery and a key research question. Recently, the LHAASO experiment identified the first CR super-acceleration source, the Cygnus bubble, which can accelerate CRs to energies exceeding 10 PeV. A pertinent question is: how much does the Cygnus bubble contribute to the CR spectrum observed on Earth? With the aim of answering that question, a 3D propagation analysis was conducted on CRs in this study. The Cygnus bubble was incorporated into our propagation model in order to determine its contributions to the observed spectra. First, we calculated the spectrum and spatial morphology of the Cygnus bubble to reproduce the observed LHAASO data. Subsequently, we calculated the diffuse $γ$-ray emissions produced by the CRs from the Cygnus bubble and the energy spectrum of the cosmic ray particles near Earth after propagation. Finally, we utilized a CR spatial-dependent propagation model to calculate the large-scale CR energy spectrum and the resulting diffuse $γ$-ray emissions. Our results indicate that: (1) the Cygnus bubble contributes minimally to the CR spectrum observed on Earth, (2) the emissions produced by the CR particles from the Cygnus bubble dominates the diffuse $γ$-ray emissions in that region, (3) the structural fluctuations of the diffuse $γ$-ray emissions observed by LHAASO are likely due to the local CR halo. We anticipate that LHAASO will identify more CR halo sources to validate our model.
title Contribution of the Cygnus bubble to the Galactic cosmic ray spectrum and diffuse $γ$-ray emissions
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2408.01693