Modeling of the Non-thermal Emission from the Cloudlet-dominated Vela SNR
Abstract
Supernova remnants (SNRs) are widely considered to be sites of Galactic cosmic-ray (CR) acceleration. Vela is is one of the nearest Galactic composite SNRs to the Earth, accompanied by the Vela pulsar and its pulsar wind nebula (PWN) Vela X, which is a powerful y-ray emitter. The Vela SNR is one of the most studied remnants and it benefits from precise estimates of various physical parameters such as distance and age. Therefore, it is a perfect object for a detailed study of physical processes in SNRs. The Vela SNR expands into the highly inhomogeneous cloudy interstellar medium (ISM) and its dynamics is determined by the heating and evaporation of ISM cloudlets. It features an asymmetrical X-ray morphology which is explained by the expansion into two media with different densities. This could occur if the progenitor of the Vela SNR exploded close to the edge of the stellar wind bubble of the nearby Wolf-Rayet star in the y2Velorum binary system and hence one part of the remnant expands into the bubble. The interaction of the main shock with ISM cloudlets causes formation of secondary shocks at which additional particle acceleration and magnetic field enhancement occurs. This leads to the close to uniform distribution of relativistic particles inside the remnant. We calculate the synchrotron radio emission within the framework of the new hydrodynamical model which assumes the supernova explosion at the edge of the stellar wind bubble. The simulated radio emission agrees well with the observed flux and complicated morphology of the remnant. We also give an estimate of the expected y-ray flux from the remnant generated in inelastic proton-proton interactions. A possibility of detection of the predicted y-ray emission with next generation instruments is discussed.
- Publication:
-
International Cosmic Ray Conference
- Pub Date:
- 2013
- Bibcode:
- 2013ICRC...33.3204S
- Keywords:
-
- Vela SNR;
- y2Velorum;
- radio radiation;
- cosmic rays;
- y-rays.