Colloquium

"An X-ray View of the Dusty Universe"

A significant fraction of the heavy elements produced by stars spend some time in the interstellar medium as dust grains. These heavy metal transporters influence gas cooling during star formation, eventually becoming the seeds for planet formation. Much like quasar spectra are used to probe intergalactic gas, observations of X-ray bright Galactic compact objects can yield key insights to the mineralogy and evolution of dust grains in the Milky Way. With high resolution X-ray spectroscopy, we can directly measure the state of metals and the mineral composition of dust in the interstellar medium. In addition, dust scattering produces a diffuse halo image around bright X-ray objects, revealing information about dust grain sizes and their spatial distribution. I will review the most recent exciting dust scattering discoveries, which draw on multi-wavelength observations. Finally, I will discuss open questions regarding our X-ray view of the ISM that can be addressed with lab experiments and future X-ray observatories.