We run hydrodynamical models of supernovae exploding in the pre-shaped medium of moving GalacticĬore-collapse progenitors. We investigate whether the initial mass and space velocity of these progenitors can be associated with asymmetric supernova Progenitor, and may lose energy, momentum and its spherical symmetry before expanding into the local interstellar medium (ISM). All of our results support that the X-ray flux decay in the remnant is mainly caused by the thermal components.Īfter the death of a runaway massive star, its supernova shock wave interacts with the bow shocks produced by its defunct The flux change rates in the whole remnant are $-$0.65$\pm$0.02 \% yr$^$). We found simultaneous decrease of Fe-K line and 4.2-6 keV continuum of Cassiopeia A with the monitoring data taken by Chandra in 2000-2013. I review the growing diversity of neutron stars from an observational perspective, then highlight recent and on-going theoretical and observational work attempting to address this diversity, particularly in light of their magnetic field evolution, energy loss mechanisms, and supernova progenitors' studies. In addition, some neutron stars act 'schizophrenic' in that they occasionally display properties that seem common to more than one of the defined subclasses. These two subclasses of high-energy objects, however, seem to be characterized by anomalously high or anomalously low surface magnetic fields (thus dubbed as 'magnetars' and 'anti-magnetars', respectively), and have pulsar characteristic ages that are often much offset from their associated SNRs' ages. The growing diversity of neutron stars includes the highly magnetized neutron stars (magnetars) and the Central Compact Objects shining in X-rays and mostly lacking pulsar wind nebulae. In this model, the acceleration of electrons is dominated by the reverse shock the required 1048 erg can be achieved under the assumption that the injection of electrons (positrons) is supported by the radioactive decay of 44Ti.Įver since the discovery of the Crab and Vela pulsars in their respective Supernova Remnants, our understanding of how neutron stars manifest themselves observationally has been dramatically shaped by the surge of discoveries and dedicated studies across the electromagnetic spectrum, particularly in the high-energy band.
At the same time, the model calculations do not provide extension of the maximum energy of accelerated protons beyond 100 TeV. Then, the acceleration efficiency in this source, despite the previous claims, should be very high 25% of the explosion energy (or approximately 3 × 1050 erg) should already be converted to cosmic rays, mainly by the forward shock. Although the TeV gamma-ray observations can be interpreted by interactions of both accelerated electrons and protons/ions, the measurements by Fermi Large Area Telescope at energies below 1 GeV give a tentative preference to the hadronic origin of gamma-rays. We show that the available multi-wavelength observations in the radio, X-ray, and gamma-ray bands can be best explained by invoking particle acceleration by both forward and reversed shocks.
Electrons, protons, and the oxygen ions accelerated by forward and reverse shocks are included in the numerical calculations. The model is based on spherically symmetric hydrodynamic equations complemented with transport equations for relativistic particles.
The processes responsible for the broadband radiation of the young supernova remnant Cas A are explored by using a new code that is designed for a detailed treatment of the diffusive shock acceleration of particles in the nonlinear regime.