The interstellar and intergalactic media, ISM and IGM, consist of gas, dust, magnetic fields, interstellar radiation fields, and energetic cosmic rays, inside and outside of galaxies. By being both the source and aftermath of star formation, the ISM/IGM and their physical processes are of key importance for many aspects of galaxy evolution.
The Astronomy Department at UW-Madison has historically played an important and visible role in ISM/IGM studies, pioneering the law of interstellar reddening (Whitford 1958), the size distribution of dust grains (Mathis, Rumpl & Nordsieck 1977), the extended layer of ionized gas in the Milky Way (Reynolds 1991), to just mention a few prominent contributions.
The Department of Astronomy covers a broad range of scientific topics, include the following.
- How do galaxies acquire their gas? How does IGM interact with galactic halos?
- What are the physical properties of the multi-phase ISM and IGM?
- What are the origin and properties of interstellar turbulence?
- What is the importance of magnetic fields for star formation and galaxy evolution?
- What are the initial conditions for star formation in galaxies?
- How does star formation feedback affect galaxy evolution?
Researchers in the Astronomy department study these questions through a confluence of theory, numerical simulations, and observations over a wide range of wavelengths. Some of the facilities used are: the 305m Arecibo radio observatory, the Expanded Very Large Array, the Spitzer Space Telescope, Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, the Hubble Space Telescope, the WIYN telescope, the Southern African Large Telescope etc.