Constraints on cosmic-ray efficiency in the supernova remnant RCW 86 using multi-wavelength observations

Abstract

Several young supernova remnants (SNRs) have recently been detected in the high-energy and very-high-energy gamma-ray domains. As exemplified by RX J1713.7-3946, the nature of this emission has been hotly debated, and direct evidence for the efficient acceleration of cosmic-ray protons at the SNR shocks still remains elusive. We analyzed more than 40 months of data acquired by the Large Area Telescope (LAT) on-board the Fermi Gamma-Ray Space Telescope in the HE domain, and gathered all of the relevant multi-wavelength (from radio to VHE gamma-rays) information about the broadband nonthermal emission from RCW 86. For this purpose, we re-analyzed the archival X-ray data from the ASCA/Gas Imaging Spectrometer (GIS), the XMM-Newton/EPIC-MOS, and the RXTE/Proportional Counter Array (PCA). Beyond the expected Galactic diffuse background, no significant gamma-ray emission in the direction of RCW 86 is detected in any of the 0.1-1, 1-10 and 10-100 GeV Fermi-LAT maps. In the hadronic scenario, the derived HE upper limits together with the HESS measurements in the VHE domain can only be accommodated by a spectral index Gamma <= 1.8, i.e. a value in-between the standard (test-particle) index and the asymptotic limit of theoretical particle spectra in the case of strongly modified shocks. The interpretation of the gamma-ray emission by inverse Compton scattering of high energy electrons reproduces the multi-wavelength data using a reasonable value for the average magnetic field of 15-25 muG. For these two scenarios, we assessed the level of acceleration efficiency. We discuss these results in the light of existing estimates of the magnetic field strength, the effective density and the acceleration efficiency in RCW 86.

Accepted for publication in A&A; 10 pages and 4 figures

References in corpus (8)

• Primary particle acceleration above 100 TeV in the shell-type Supernova Remnant RX J1713.7-3946 with deep H.E.S.S. observations
• Analytical solutions for energy spectra of electrons accelerated by nonrelativistic shock-waves in shell type supernova remnants
• The Molonglo Galactic Plane Survey (MGPS-2): Compact Source Catalogue
• Observations of the young supernova remnant RX J1713.7-3946 with the Fermi Large Area Telescope
• Cosmic X-ray background and Earth albedo Spectra with Swift/BAT
• Measuring the cosmic ray acceleration efficiency of a supernova remnant
• Fermi LAT Observations of the Vela Pulsar
• Modeling the Multi-Wavelength Emission of Shell-Type Supernova Remnant RX J1713.7-3946

Cited by in corpus (30)

• 2FHL: The Second Catalog of Hard Fermi-LAT Sources
• The 1st Fermi Lat Supernova Remnant Catalog
• The gas-to-extinction ratio and the gas distribution in the Galaxy
• Space- and Ground-Based Gamma-Ray Astrophysics
• The many sides of RCW 86: a type Ia supernova remnant evolving in its progenitor's wind bubble
• Evolution of high-energy particle distribution in Supernova Remnants
• Study of TeV shell supernova remnants at gamma-ray energies
• The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
• Proper Motions of H-alpha filaments in the Supernova Remnant RCW 86
• Are Starburst Galaxies Proton Calorimeters?
• Acceleration of cosmic rays by young core-collapse supernova remnants
• Fermi Large Area Telescope Detection of Supernova Remnant RCW 86
• A hydrodynamical study of outflows in starburst galaxies with different driving mechanisms
• Deep morphological and spectral study of the SNR RCW 86 with Fermi-LAT
• Detailed spectral and morphological analysis of the shell type SNR RCW 86
• Prediction of the diffuse neutrino flux from cosmic ray interactions near Supernova Remnants
• TeV cosmic ray nuclei acceleration in shell-type supernova remnants with hard $\gamma$-ray spectra
• Quantitative Age Estimation of Supernova Remnants and Associated Pulsars
• The Refined Shock Velocity of the X-Ray Filaments in the RCW 86 Northeast Rim
• Starburst and post-starburst high-redshift protogalaxies: The feedback impact of high energy cosmic rays
• Interactions between Ultra-High-Energy Particles and Protogalactic Environments
• Fermi Large Area Telescope observations of the supernova remnant HESS J1731-347
• The SNR Puppis A Revisited with Seven Years of Fermi Large Area Telescope Observations
• Characterising the signatures of star-forming galaxies in the extra-galactic $\gamma$-ray background
• Observational constraints on the maximum energies of accelerated particles in supernova remnants: low maximum energies and a large variety
• Electron Acceleration in Middle-age Shell-type $\gamma$-Ray Supernova Remnants
• Study on the escape timescale of high-energy particles from supernova remnants through thermal X-ray properties
• Hadronic Interactions of Energetic Charged Particles in Protogalactic Outflow Environments and Implications for the Early Evolution of Galaxies
• The origin of Cosmic-Rays from SNRs: confirmations and challenges after the first direct proof
• The structure of TeV-bright shell-type supernova remnants