After the death of stars

When a massive star runs out of thermonuclear fuel, it implodes with catastrophic consequences. The infalling material collides with the core of the star, bounces back and is then violently ejected at supersonic velocities. This spectacular process destroys the star in a supernova explosion, leaving behind a supernova remnant (SNR) that may be visible for a further 50,000 years. As seen below, SNRs appear as expanding circular shells of ejected stellar material that surround the location of the original star and which can shock nearby hydrogen gas clouds to trigger the formation of a new generation of stars.

Understanding the life history of SNRs is important in order to comprehend how stars evolve after the normal lifetimes; to probe the environment where new stars and planets are born; and to study the complex chemical cocktail from which life might eventually form. My research will make a census and images of known SNRs throughout our galaxy; search for new SNRs from a ‘missing’ population of SNRs that models suggest should be present, but as yet have remained undetected; and test models of how SNRs inject heavy elements into their surroundings.

The study will use new data from the Low Frequency Array Telescope (LOFAR) in the Netherlands, along with archival data from ground and space-based telescopes. LOFAR currently consists of 51 radio telescopes separated by thousands of kilometers across Europe, and operating at very low radio frequencies between 30 and 200 MHz. The low-frequency radio signals that LOFAR detects are emitted by energetic electrons accelerated within the SNR shock-fronts, making LOFAR the current world-leading facility for this kind of study.

This Leverhulme Emeritus Fellowship will make it possible to bring huge amounts of data together into this unique look at our cosmic environment, placing SNRs into the context of our own galactic eco-system and providing a template against which to understand how stars evolve in more distant galaxies.