• Recent observations of supernova remnants (SNRs) hint that they accelerate cosmic rays to energies close to similar to 10(15) electron volts. However, the nature of the particles that produce the emission remains ambiguous. We report observations of SNR W44 with the Fermi Large Area Telescope at energies between 2 x 10(8) electron volts and 3 x 10(11) electron volts. The detection of a source with a morphology corresponding to the SNR shell implies that the emission is produced by particles accelerated there. The gamma-ray spectrum is well modeled with emission from protons and nuclei. Its steepening above similar to 10(9) electron volts provides a probe with which to study how particle acceleration responds to environmental effects such as shock propagation in dense clouds and how accelerated particles are released into interstellar space.

Ämnesord

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Nyckelord

shocked molecular gas

pulsar wind nebula

very-high-energy

particle-acceleration

streaming instability

wave dissipation

rx

j1713.7-3946

area telescope

galactic plane

cosmic-rays

Astronomy and astrophysics

Astronomi och astrofysik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)