FERMI-LAT STUDY OF GAMMA-RAY EMISSION IN THE DIRECTION OF SUPERNOVA REMNANT W49B
- Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
- W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy)
- Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France)
- Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy)
- Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy)
- Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy)
- Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy)
- Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France)
We present an analysis of the gamma-ray data obtained with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope in the direction of SNR W49B (G43.3-0.2). A bright unresolved gamma-ray source detected at a significance of 38{sigma} is found to coincide with SNR W49B. The energy spectrum in the 0.2-200 GeV range gradually steepens toward high energies. The luminosity is estimated to be 1.5 x 10{sup 36} (D/8 kpc){sup 2} erg s{sup -1} in this energy range. There is no indication that the gamma-ray emission comes from a pulsar. Assuming that the supernova remnant (SNR) shell is the site of gamma-ray production, the observed spectrum can be explained either by the decay of neutral {pi} mesons produced through the proton-proton collisions or by electron bremsstrahlung. The calculated energy density of relativistic particles responsible for the LAT flux is estimated to be remarkably large, U{sub e,p}>10{sup 4} eV cm{sup -3}, for either gamma-ray production mechanism.
- OSTI ID:
- 21464621
- Journal Information:
- Astrophysical Journal, Vol. 722, Issue 2; Other Information: DOI: 10.1088/0004-637X/722/2/1303; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
BREMSSTRAHLUNG
COSMIC GAMMA SOURCES
ENERGY DENSITY
ENERGY SPECTRA
GAMMA RADIATION
GEV RANGE
PHOTON EMISSION
PIONS NEUTRAL
PROTON-PROTON INTERACTIONS
PULSARS
RELATIVISTIC RANGE
SUPERNOVA REMNANTS
TELESCOPES
BARYON-BARYON INTERACTIONS
BOSONS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EMISSION
ENERGY RANGE
HADRON-HADRON INTERACTIONS
HADRONS
INTERACTIONS
IONIZING RADIATIONS
MESONS
NUCLEON-NUCLEON INTERACTIONS
PARTICLE INTERACTIONS
PIONS
PROTON-NUCLEON INTERACTIONS
PSEUDOSCALAR MESONS
RADIATIONS
SPECTRA