What is a galactic halo?
A galactic halo is an extended, roughly spherical component of a galaxy which extends beyond the main, visible component. This structure surrounds most disk galaxies and some elliptical galaxies of type cD.
Questions about Galactic halo
Short answers, pulled from the story.
How does the Milky Way's stellar halo differ from other components?
The Milky Way's stellar halo contains globular clusters and RR Lyrae stars with low metallicity. Most stars within this population are older than 12 billion years old and have an observed radial velocity dispersion of about 200 kilometres per second.
What is a galactic corona?
A galactic corona is a distribution of gas extending far away from the center of the galaxy that can be detected by its distinct emission spectrum. It shows the presence of atomic neutral hydrogen known as the H I region and exists as a plasma stretching outward into space.
Why do astronomers study dark matter halos?
Astronomers study dark matter halos because their mass is far greater than the mass of the other components combined. The existence of this component is hypothesized to account for the gravitational potential determining dynamics within galaxies.
How did the Milky Way Galaxy form its current halo structure?
The halo of the Milky Way Galaxy is thought to derive from the Gaia Sausage event. This specific merger shaped the current structure we observe today through bottom-up evolution where large scale structures form starting with small objects.