Session S3: Probing Galactic Astrophysics with Supernova Remnants

Observational Constraints on Cosmic Ray Acceleration in Supernova Remnants

Over the past few years, observations in the X-ray and gamma-ray bands, coupled with theoretical investigations, have led to important new insights into the process of particle acceleration at high speed shocks in supernova remnants. In this presentation I will review results largely from the X-ray band that reveal the presence of shock-accelerated relativistic electrons and amplified magnetic fields at these shock fronts. Evidence for shock-accelerated protons, although less direct, appears in the form of modifications to the dynamical evolution of young remnants, particularly SN1006 and the Tycho supernova remnant. As time permits, I will examine other observational topics bearing on the small-scale angular structure and temporal variations in the X-ray synchrotron emission, and particle acceleration at the reverse shocks of remnants.   

Gamma-Ray Emission from Supernova Remnants

The last few years have brought significant advances in our understanding of acceleration processes at work in shell-type as well as in plerionic Supernova remnants through observations from X-rays to VHE Gamma-rays. Unprecedented morphological studies of gamma-ray emission from shell-type Supernova remnants show a striking correlation to X-ray emission. Gamma-ray energy spectra of up to 100 TeV confirm particle acceleration up to the ``knee'' in the Cosmic ray spectrum at 1 PeV in these objects. All these measurements can now be complemented with data from the recently-launched Fermi-LAT, operating in the energy range between 20 MeV and 300 GeV. Fermi-LAT data will constrain gamma-ray emission models and allow studies of the parent population accelerated in these objects. I will review the current observational status of gamma-ray emission in supernova remnants.   

Supernova Remnants as Probes of Type Ia Nucleosynthesis

I will review our present understanding of Type Ia Supernovae (SN), with an emphasis on the open questions about the explosion mechanism and the identification of their elusive progenitors. The study of nearby supernova remnants (SNRs) originated by Type Ia SNe has the potential to shed new light onto these long-standing open questions. SNRs in our Galaxy and the Magellanic Clouds are much closer than the extragalactic SNe that are discovered by the hundreds every year, which means that we can study the composition of the ejected material in much greater detail. We can also examine the structure of the ambient medium and the stellar populations around Type Ia SNRs and put constraints on the mass-loss rates and properties of their progenitors. I will conclude with some thoughts about the future of X-ray observations of SNRs.