What high resolution imaging spectroscopy with XRISM reveals about the cycle of interstellar dust
Abstract
The high resolution imaging spectroscopic capabilities of XRISM, enabled by micro-calorimeters, will have a high impact for studying extended emission from diffuse gas. Of particular interest will be the properties of the nearby interstellar medium (ISM), which serves as a template for measuring the gas properties in every other galaxy. Yet much about the cycle of metals and dust in the Milky Way is not well understood. For example, what is the role of supernovae in producing and processing dust? Such questions are answered by fully measuring the size distribution and composition of existing interstellar dust, which reveals the formation conditions and eventual fate of dust in harsh environments. Light from bright Galactic X-ray binaries is scattered by interstellar dust, producing a 10-arcminute scale 'halo' image. High resolution spectroscopy of the scattering halo will reveal photoelectric resonances from the intervening dust, revealing grain mineralogy in fine detail. Spectroscopy of dust scattering halos also probes the constituent elements of large dust grains, which are relatively invisible in absorption and inaccessible at other wavelengths. XRISM will thereby provide a leap in our understanding of the origin, phase, and exchange of metals across the interstellar, circumgalactic, and intergalactic medium.
- Publication:
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AAS/High Energy Astrophysics Division
- Pub Date:
- March 2019
- Bibcode:
- 2019HEAD...1711303C