A Tale of Two Star Cities
How do we reproduce what happened previously in a galaxy-galaxy interaction when all we have is one snapshot in time?
How do we reproduce what happened previously in a galaxy-galaxy interaction when all we have is one snapshot in time?
Every galaxy is thought to contain a black hole at the centre – but why are some active and some not? What process has ‘switched-on’ these active galaxies? Theorists suggest that major galaxy mergers could play a part for the highly luminous active galaxies but we’re currently lacking conclusive observational evidence to support this theory.
Astronomers have long wished to probe the number of galaxies containing bar structures to ever increasing redshifts. This paper discusses the first results from the Galaxy Zoo Hubble classifications of galaxies out to redshifts of z = 1, in order to study how the fraction of galaxies containing a bar has changed over a cosmic time that has previously not been explored.
Galaxy Zoo is a citizen science project that uses volunteers to classify galaxies from the Sloan Digitial Sky Survey as spiral or elliptical. Now the Galaxy Zoo 2 catalogue has gone public, with even more detailed classifications of galaxies, including bars, bulges, spiral arms, and round and squashed ellipticals.
We know that some spiral galaxies have central bars, and some don’t. But do we know why? In this paper, the authors explain some of the factors that influence the creation of spiral bars.
A beautiful structure at the center of our galaxy shows off Hershel’s abilities.