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2021-12-17 Abstract

Title:  Shining light on the properties of interstellar silicate dust
 
Speaker:  Sascha Zeegers
 
Date: Dec 17 at 14:30
 
Location: R124, Physics Building
 
Abstract:
Cosmic dust plays an important role in the life cycle of stars and galaxies. Although well studied, it is not clear how dust survives in the harsh environment of the galactic diffuse interstellar medium (DISM). My research focuses on providing a deeper understanding of these processes by performing a global study of silicate dust, a major constituent of the DISM. Dust grains absorb and scatter light from stars. The wavelength dependence of this extinction is governed by fundamental grain properties: size, shape, chemical composition, and lattice structure. Distinctive resonances can be identified, for example in the infrared and X-ray bands, due to vibrational or electronic bonds in the dust grains. These spectral features are therefore important tools to map the processing of silicate dust in the DISM. They can be observed in the spectra of distant, bright stars. We can probe the intervening dust along their line of sight and by selecting stars in different regions of the Galaxy, we can compare unassociated environments. In this talk, I will show how we can learn more about the silicate dust properties by combining infrared data from my JWST Cycle 1 program with archival X-ray to infrared data. From the X-ray side, I will also include a look into the future with the upcoming facilities Athena and XRISM.
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