blue horizontal-branch (BHB) stars tagged posts

Astronomers from the University of Cambridge, U.K., have detected a number of narrow streams and diffuse debris clouds around 2 nearby irregular dwarf galaxies called the Magellanic Clouds. The research also implies that one of these dwarf galaxies – the Large Magellanic Cloud (LMC) could be more massive than previously thought.

“Even though a prominent gaseous stream emanating from the clouds has been known and studied for some time, no obvious stellar streams had been found until recently,” Vasily Belokurov. Belokurov, together with colleague Sergey Koposov, used the Dark Energy Survey (DES) to track down stellar debris on the outskirts of the Magellanic Clouds. They were searching for the Magellanic stellar halo substructure using blue horizontal-branch (BHB) stars as tracers...

This chronographic map of the Milky Way’s halo system shows a color gradient that is associated with an age difference of roughly 2-2.5 G yrs

The 1st chronographic (age) map of the halo of the Milky Way galaxy has been created. The halo, along with the disk and bulge, are the primary components of the galaxy. Using a sample of 4,700 blue horizontal-branch (BHB) stars from the Sloan Digital Sky Survey, the research team showed that the oldest stars are concentrated in the central region of the galaxy, confirming predictions from numerical simulations of galaxy assembly. The researchers have also shown that chronographic maps such as theirs can also be used to identify complex structures of stars still in the process of being added to the halo system of our galaxy.

The researchers used the...