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Stalking the Elusive Molecular Cloud
Erik Rosolowsky, University of Alberta

We believe that the process of star formation is ultimately guided by the structure in the molecular interstellar medium (ISM). Historically, we have separated the molecular ISM into "clouds" and used this population of molecular clouds to describe the how diffuse ISM becomes new generations of stars. In this talk, I will review some of the successes of this approach in studying cloud evolution in nearby galaxies, highlighting the observational results that constrain the cloud formation process. I will then discuss the shortcomings of these approaches and present new ways to describe the molecular ISM structure that offer new insights. I will focus a new method for cloud identification based on dendrograms and graph theory. This approach offers a way to study the hardest problem in characterizing the molecular ISM, namely uniformly studying the molecular gas in the Milky Way

Dwarf Galaxies as ideal laboratories to study astrophysical processes
Gerhard Hensler, University of Vienna

From the predictions of Cold Dark Matter (CDM) cosmology low-mass DM sub-halos are expected to form at first and to feed the major galaxies hierarchically. Also dwarf galaxies (DGs) should have been formed early in the universe by the assembly of baryonic matter. Because of their morphological appearance DGs have been traditionally classified in analogy to the massive Hubble-type galaxies. Comprehensive and detailed studies of DGs, however, have spotted the existence of a much larger variety and complexity of their substructures as previously expected. Due to their low gravitation DGs are very sensitive to energetic influences by internal processes, like stellar feedback, as well as by environmental influences, exerted e.g. in galaxy groups and clusters. Both effects can account for morphological transitions. This talk will present a sample of wide activities in the Viennese research group of the speaker addressing presently most burning questions on the formation and morphological evolution of DGs from numerical models to observations, as there are:

- How does star formation occur at low rates?
- Can starbursts evacuate DGs of their gas by galactic winds, by this transforming irregular to elliptical DG?
- How uncertain are observationally derived star-formation rates and element abundances in star-forming DGs?
- Did strong baryonic outflows by means of galactic winds happened to relax their DM profiles from cuspy to cored ones?
- To what extent does ram pressure by an intergalactic medium strip off the gas from DGs and transform them morphologically? And how should one understand the morphological variety of elliptical DGs in galaxy clusters?
- What happens to the ram-pressure stripped gas tails?
- Is the formation of DGs in tidal tails of merger galaxies a viable path in cosmological galaxy formation and what are its consequences for galaxy structure and the CDM picture?