Exploring Galaxy Halos and the Cosmic Web through X-Ray Spectroscopy

About 90 of the metals produced in the universe and 50 of the baryons are unaccounted for through UV-IR and radio studies of stars and gas. This large amount of gas and metals likely lies in a hot phase 0.5-10E6 K and must be enriched to about 0.2-0.3 of the solar metallicity, so it should be a good absorber of X-rays in the resonance lines of common elements. X-ray absorption lines against background AGNs should show hot extended halos around galaxies out to the virial radius, if not beyond. The outer parts of galaxy groups and some cosmic filaments are other potential sources of absorption. For the Milky Way, high X-ray spectral resolution allows us to determine the dynamics of the hot halo, including the rotation as a function of radius as well as the accretion or outflow rate.Session 3: Cycles of Baryons Chair: Giuseppina Fabbian