Scientific Seminars

The galaxy-halo connection: insights from the ALFALFA survey

Manolis Papastergis
Cornell University, USA

2012-06-20    16:00    Merate - POE

The ALFALFA survey is a blind, wide-area 21cm line survey conducted with the Arecibo radiotelescope. The public release of data from 40% of its final area ("?.40" catalog) has already produced the largest HI-selected sample to date, containing more than 11 000 galaxies. In contrast to optical surveys, ALFALFA detects galaxies based on their gas content and, due to its intrinsic spectroscopic nature, obtains automatically information about the dynamics of each detected galaxy. This new information affords more insight into the relationship between simulated dark matter halos and observed galaxies. In this talk I will discuss how ALFALFA can help find some of the "missing" Milky Way satellites, how it challenges our current picture for the formation of dwarf galaxies, and how it can be used to test the nature of dark matter. Lastly, the recently published correlation function of ALFALFA-detected galaxies demonstrates the potential of future larger surveys similar to ALFALFA to measure the acoustic scale, and constrain our cosmology.