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Gamma-ray emission concurrent with the nova in the symbiotic binary V407 Cygni
1, A A Abdo, M Ackermann
1Space Science Division, Naval Research Laboratory, Washington, DC 20375, USA.
Science (New York, N.Y.)
|August 14, 2010
Summary
Astronomers detected unexpected gamma-ray emissions from a nova, V407 Cygni, challenging previous models. This nova
Area of Science:
- Astrophysics
- High-energy astrophysics
- Stellar evolution
Background:
- Novae are stellar explosions resulting from white dwarf accretion.
- X-ray emission is expected from nova shells, but higher energy emissions are not.
- V407 Cygni is a symbiotic star system with a recent optical nova.
Purpose of the Study:
- To report the detection of gamma-ray emission from the nova V407 Cygni.
- To investigate the origin of this unexpected high-energy emission.
Main Methods:
- Fermi Large Area Telescope observations.
- Analysis of variable gamma-ray emission (0.1 to 10 GeV).
Main Results:
- Detection of variable gamma-ray emission from V407 Cygni.
- Emission spans energies from 0.1 to 10 GeV.
Conclusions:
- Proposed mechanism: interaction of nova shell with red giant's dense medium accelerates particles.
- Proton-proton interactions may produce pi(0) decay gamma-rays.
- Inverse Compton scattering of red giant radiation is a possible, though not confirmed, emission source.
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