Leaked GeV CRs from a broken shell: Explaining 9 years Fermi-LAT data of SNR W28

Abstract

Supernova remnant (SNR)\,W28 is well known for its classic hadronic scenario, in which the TeV cosmic rays (CRs) released at the early stage of this mid-aged SNR are illuminating nearby molecular clouds (MCs). Overwhelming evidences have shown that the northeast of the SNR (W28-North) has already encountered with the MC clumps. Through this broken shell -- W28-North, we believe the CRs with energy down to $<$1\,GeV to be able to be injected into nearby MCs. To further testify this hadronic scenario, we first analyse the 9 years Fermi-LAT data in/around W28 with energy down to 0.3\,GeV. Our Fermi-LAT analysis display a 10-200 GeV skymap which spatially matches well with the known TeV sources -- HESS\,J1801-233 (W28-North), HESS\,J1800-240\,A,\,B\,\&\,C (240\,A\,B\,\&\,C). At low energy band, we has discovered a 0.5-1\,GeV blob located to the south of 240\,B\,\&\,C, and a low flux of 0.3-1\,GeV at 240\,A. A hadronic model is build to explain our analysis results and previous multi-wavelength observations of W28. Our model consists of three CR sources: The run-away CRs escaped from a strong shock; The leaked GeV CRs from the broken shell -- W28-North; And the local CR sea. Through modelling the SNR evolution, CR acceleration\,\&\,releasing, we have explained the GeV-TeV emission in/around SNR\,W28 (except for 240\,A) in one model. Both the damping of the magnetic waves by the neutrals and the decreased acceleration efficiency are taken into account in our model due to the mid-age of SNR W28.

arXiv commentThis paper has 25 pages, 9 figures and 5 tables

References in corpus (37)

• Progenitors of core-collapse supernovae
• Neutron Star Cooling
• Simulations of Ion Acceleration at Non-relativistic Shocks. I. Acceleration Efficiency
• Development of the Model of Galactic Interstellar Emission for Standard Point-Source Analysis of Fermi Large Area Telescope Data
• Young core collapse supernova remnants and their supernovae
• Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W28 (G6.4-0.1) field
• Transport of Cosmic Rays in Chaotic Magnetic Fields
• Supernova Remnants in Molecular Clouds
• Toward Understanding the Cosmic-ray Acceleration at Young Supernova Remnants Interacting with Interstellar Clouds: Possible Applications to RX J1713.7-3946
• On the spectrum of high-energy cosmic rays produced by supernova remnants in the presence of strong cosmic-ray streaming instability and wave dissipation
• Discovery of 35 New Supernova Remnants in the Inner Galaxy
• Fermi LAT Observations of the Supernova Remnant W28 (G6.4-0.1)
• Gamma rays from molecular clouds illuminated by cosmic rays escaping from interacting supernova remnants
• Diffusive Shock Acceleration with Magnetic Amplification by Non-resonant Streaming Instability in SNRs
• Shocked Molecular Gas in the Supernova Remnants W 28 and W 44: Near-infrared and millimeter-wave observations
• Shock Excited Maser Emission from the Supernova Remnant W28
• Gamma rays from molecular clouds illuminated by accumulated diffusive protons from supernova remnant W28
• Investigation of the large-scale neutral hydrogen near the supernova remnant W28
• Spitzer spectral line mapping of supernova remnants: I. Basic data and principal component analysis
• Star Forming Dense Cloud Cores in the TeV γ-ray SNR RX J1713.7-3946
• ROSAT/Asca Observations of the Mixed-Morphology Supernova Remnant W28
• Cosmic ray induced ionisation of a molecular cloud shocked by the W28 supernova remnant
• Numerical simulations of diffusive shock acceleration in SNRs
• Infrared Spectroscopy of Molecular Supernova Remnants
• Discovery of New Interacting Supernova Remnants in the Inner Galaxy
• Detailed Investigation of the Gamma-Ray Emission in the Vicinity of SNR W28 with FERMI-LAT
• The Sizes of 1720 MHz OH Masers: VLBA and MERLIN Observations of the Supernova Remnants W44 and W28
• A 7mm line survey of the shocked and disrupted molecular gas towards the W28 field TeV gamma-ray sources
• A young SNR illuminating nearby Molecular Clouds with cosmic rays
• An XMM-Newton study of the mixed-morphology supernova remnant W28 (G6.4-0.1)
• 12mm line survey of the dense molecular gas towards the W28 field TeV gamma-ray sources
• High Energy Cosmic-ray Diffusion in Molecular Clouds: A Numerical Approach
• X-ray Spectroscopy of the Mixed Morphology Supernova Remnant W28 with XMM-Newton
• Ammonia excitation imaging of shocked gas towards the W28 gamma-ray source HESS J1801-233
• Studying the SGR 1806-20/Cl* 1806-20 region using the \emph{Fermi} Large Area Telescope
• Imaging of Four Galactic Supernovae Remnants in the Mid-Infrared, and their Interaction with the Interstellar Medium
• Gamma-ray Emission of the Kes 73/1E 1841-045 Region Observed with the Fermi Large Area Telescope

Cited by in corpus (24)

• Discovery of the Ultra-high energy gamma-ray source LHAASO J2108+5157
• Gamma rays as probes of cosmic-ray propagation and interactions in galaxies
• Cosmic-ray acceleration and escape from post-adiabatic Supernova remnants
• Multi-wavelength study of the galactic PeVatron candidate LHAASO J2108+5157
• Using Interstellar Clouds to Search for Galactic PeVatrons: Gamma-ray Signatures from Supernova Remnants
• Constraining the cosmic ray spectrum in the vicinity of the supernova remnant W28: from sub-GeV to multi-TeV energies
• Observational constraints on the maximum energies of accelerated particles in supernova remnants: low maximum energies and a large variety
• Uniform distribution of the extremely overionized plasma associated with the supernova remnant G359.1-0.5
• Interaction between Molecular Clouds and MeV-TeV Cosmic-ray Protons Escaped from Supernova Remnants
• Study on the escape timescale of high-energy particles from supernova remnants through thermal X-ray properties
• Searches for Pulsar-like Candidates from Unidentified Objects in the Third Catalog of Hard Fermi-LAT (3FHL) sources with Machine Learning Techniques
• Detection of gamma rays around SNR HB9 and its implication to the diffusive shock-acceleration history
• Intrusion of MeV-TeV Cosmic-Rays into Molecular Clouds Studied by Ionization, the Neutral Iron Line, and Gamma-Rays
• Multiwavelength studies of G298.6$-$0.0: An old GeV supernova remnant interacting with molecular clouds
• Supernova remnant G46.8-0.3, a new case of interaction with molecular material
• Is the SNR HESS J1731-347 colliding with molecular clouds?
• High-velocity interstellar absorption associated with the supernova remnant W28
• Spatially decomposed $\gamma$-ray features surrounding SNR Kes 79 & PSR J1853+0056
• The population of Galactic supernova remnants in the TeV range
• Discovery of an Extended $\gamma$-ray Emission around the Supernova Remnant Candidate associated with PSR J0837$-$2454
• Regions of suppressed diffusion around supernova remnants?
• HESS J1858+020: A GeV-TeV source possibly powered by CRs from SNR G35.6-0.4
• A Complete X-ray View of Supernova Remnant W28 with Einstein Probe: Spatial Distribution of Parameters and Origin of the Thermal-Composite Morphology
• Examining a hadronic $\gamma$-ray scenario for the radiative shell & molecular clouds of the old GeV supernova remnant G298.6$-$0.0