Counting the number of galaxies at a given mass in a region of space gives you the number density – something that can be really easily compared to simulations. But do our observations and theory match up? And how does looking out to higher and higher redshifts help us to better understand our Universe…
Observations of dwarf galaxies show that sites of active star formation have fewer metals. These galaxies may have been diluted by the impact of pristine gas from the cosmic web.
Although magnetic fields exist virtually everywhere, we still do not know quite a lot about the role they play in the evolution of our Universe. On galaxy scales and larger, they can be difficult to observe, but may play a crucial role in how they evolve. Today’s astrobite discusses work done to try and understand how initially weak fields in the early Universe can affect galaxy evolution over time.
The evolution of a galaxy is strongly dependent upon the environment the galaxy lives in. Galaxies moving through galaxy groups and galaxy clusters can get stripped of their gas that would otherwise be used to form stars. Today’s astrobite discusses simulations of the stripping and removal of the hot, gaseous coronae that surround galaxies.
The Milky Way grew by accreting many smaller galaxies. What did these doomed galaxies leave behind, and what could they say about the Milky Way’s early past?
Reproducing the observed star formation history of galaxies in simulations is a fantastic test of our understanding of galaxy evolution. This is regulated strongly by “feedback”, for example, from supernova. Today’s astrobite discusses feedback from high mass X-ray binaries.