A galaxy needs to constantly replenish its HI reservoir in order to continue to form stars over cosmic time. The majority of the baryons in the Universe are in an ionized gas phase outside of a galaxy and therefore must somehow cool and settle on to the galaxy's star forming region. I will discuss the observational evidence for the flow of gas between these two phases.
Cold interstellar clouds are a necessary step on the way to star formation. Yet, understanding how these clouds form out of the warm diffuse medium, and what fundamental processes regulate their atomic and molecular fractions, has been largely unexplored. We have recently completed the first statistical study of the properties of neutral gas over the entire temperature range $10-10^4\,{\rm...
We present the latest results from the HIX galaxy survey, which studies a sample of the most HI-rich (for their optical luminosity) and HI-massive spiral galaxies in the local universe. Given their large and massive HI discs, their high redshift counterparts might be among the first galaxies, we will detect in HI beyond the currently observable redshift range. A detailed examination of the...
In principle, QSO absorption lines studies can provide the most sensitive approach to studying galactic in-and outflows of gas. In reality, it has remained difficult to distinguish between the two, and theoretical prejudices have often driven the interpretation of absorption line results.
I shall present recent observations of the intergalactic medium (IGM) and galaxies, partly combining...
Damped Lya absorbers (DLAs) probe the neutral gas in the interstellar medium, extended rotating disks, and likely dense gaseous streams in galaxy halos. The large gas surface mass densities revealed in DLAs are comparable to what is seen in 21 cm observations of nearby star-forming galaxies, making DLAs a promising signpost of distant young galaxies. In this talk, I will present new damped...
