Astronomers at Yale investigate how the number of galaxies at fixed inferred velocity dispersion (a probe of the total gravitational potential) changes as a function of time. Their results support a picture where star-forming galaxies are somehow “quenched” and transition to the non-star-forming galaxy population, consistent with leading ideas of galaxy evolution.
In the nearby Universe, massive galaxies contain very little interstellar gas and old stellar populations. But theoretical models predict that such galaxies should have much younger stellar populations. In order to solve this discrepancy models invoke quasar outflows in the early Universe. Such outflows would expel the gas from a galaxy and quench star formation. Presented here are the results from the first massive quasar outflow observer at z ~ 6.4189.
Active galactic nuclei are some of the most luminous objects in the universe. This paper explores how feedback from AGN could trigger star formation in their host galaxies.
Most simulations to date have implied that satellite galaxies traveling through galaxy clusters are stripped of gas for future star formation in a process known as “strangulation”. In contrast, the authors of this paper suggest that satellite galaxies may not be as cut off as some might think: instead, their simulations show that the cooler, stripped gas from the corona will mix with the surrounding intra-cluster medium and remain near the original galaxy as a potential new source of star-forming fuel.
Using a combination of spectra from gamma-ray burst afterglows and photometry and spectroscopy of nearby objects, astronomers have found the galaxy counterpart to at least one high-redshift absorption system, bumping the total number of such galaxies from nine to ten.
Tight relationships between galactic properties seem to depend on environment.