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Supernovae |
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Supernovae |
Apart from the Big Bang, the disintegration of massive stars into supernova (SN) explosions are the energetically most violent short-lived phenomena in the universe. During the supernova explosion, the gravitational binding energy of the entire star is released within a few seconds. Hence, SNe are spectacular events especially in the optical, sometimes brighter than an entire galaxy over periods of weeks.
The interaction of the expanding supernova shell with circumstellar matter, however, gives radiation predominantly in the X-ray range. In order to conclude on the physics of this interaction, we perform X-ray observations of both known X-ray bright and previously unknown supernovae with orbiting X-ray observatories. Previous studies with the ROSAT satellite included the supernovae 1979C, 1993J and 1994I. With our ongoing program to monitor the X-ray emission from a number of supernovae, and given the superior spatial and spectral capabilities of the Chandra and XMM-Newton observatories, we expect a significant breakthrough in understanding one of the most violent processes in the universe.
From the analysis of the X-ray emission, we can derive the amount of the pre-supernova mass loss rate as well as the density and velocity profile including element abundances of the supernova ejecta. The most likely X-ray emission mechanism is thermal radiation from the collision of the high velocity supernova gas with mass lost from the progenitor star prior to the explosion. This interaction produces a fast shock wave in the circumstellar wind and a reverse shock wave into the outer supernova ejecta. The shocked region is a likely site for radio, late-time optical, ultraviolet, and, most importantly, X-ray emission.