Evidence for PeV Proton Acceleration from Fermi-LAT Observations of SNR G106.3+2.7

Abstract

The existence of a "knee" at energy ~1 PeV in the cosmic-ray spectrum suggests the presence of Galactic PeV proton accelerators called "PeVatrons". Supernova Remnant (SNR) G106.3+2.7 is a prime candidate for one of these. The recent detection of very high energy (0.1-100 TeV) gamma rays from G106.3+2.7 may be explained either by the decay of neutral pions or inverse Compton scattering by relativistic electrons. We report an analysis of 12 years of Fermi-LAT gamma-ray data which shows that the GeV-TeV gamma-ray spectrum is much harder and requires a different total electron energy than the radio and X-ray spectra, suggesting it has a distinct, hadronic origin. The non-detection of gamma rays below 10 GeV implies additional constraints on the relativistic electron spectrum. A hadronic interpretation of the observed gamma rays is strongly supported. This observation confirms the long-sought connection between Galactic PeVatrons and SNRs. Moreover, it suggests that G106.3+2.7 could be the brightest member of a new population of SNRs whose gamma-ray energy flux peaks at TeV energies. Such a population may contribute to the cosmic-ray knee and be revealed by future very high energy gamma-ray detectors.

14 pages, 7 figures. Editor's Suggestion in PRL

References in corpus (12)

• Parametrization of gamma-ray production cross-sections for pp interactions in a broad proton energy range from the kinematic threshold to PeV energies
• PINT: A Modern Software Package for Pulsar Timing
• Absorption of Very High Energy Gamma Rays in the Milky Way
• Fermi Large Area Telescope Fourth Source Catalog Data Release 2
• Hadronic gamma-rays from RX J1713.7-3946?
• Potential PeVatron supernova remnant G106.3+2.7 seen in the highest-energy gamma rays
• HAWC J2227+610 and its association with G106.3+2.7, a new potential Galactic PeVatron
• Parameterized total cross sections for pion production in nuclear collisions
• X-Ray Emission from the PeVatron-candidate Supernova Remnant G106.3+2.7
• Modeling the γ-ray Pulsar Wind Nebulae population in our Galaxy
• Revealing a peculiar supernova remnant G106.3+2.7 as a petaelectronvolt proton accelerator with X-ray observations
• A new method to perform data/model comparison in Fermi-LAT analysis

Cited by in corpus (14)

• MAGIC observations provide compelling evidence of the hadronic multi-TeV emission from the putative PeVatron SNR G106.3+2.7
• Where are Milky Way's Hadronic PeVatrons?
• Decomposing the Origin of TeV-PeV Emission from the Galactic Plane: Implications of Multi-messenger Observations
• Ultra-High-Energy Gamma-Ray Astronomy
• The LHAASO PeVatron bright sky: what we learned
• Search for Extended Sources of Neutrino Emission in the Galactic Plane with IceCube
• Electron slingshot acceleration in relativistic preturbulent shocks explored via emitted photon polarization
• Observation of gamma rays up to 320 TeV from the middle-aged TeV pulsar wind nebula HESS J1849$-$000
• Search for the Galactic accelerators of Cosmic-Rays up to the Knee with the Pevatron Test Statistic
• Detection of the extended $\gamma$-ray emission from the new supernova remnant G321.3-3.9 with Fermi-LAT
• Testing the Molecular Cloud Paradigm for Ultra-High-Energy Gamma Ray Emission from the Direction of SNR G106.3+2.7
• PeVatron Candidate SNR G106.3+2.7 in a Low-density Cavity: a Multiwavelength Test
• The Cosmic-ray Knee as a Local Signature of Nearby PeVatrons
• Can a single supernova remnant account for the gamma-ray emission of G106.3+2.7?