Hubble reveals surprising facts about far-off galaxy’s halo
Astronomers using the NASA/ESA Hubble Space Telescope have probed the extreme outskirts of the stunning elliptical galaxy Centaurus A. The galaxy’s halo of stars has been found to extend much further from the galaxy’s centre than expected and the stars within this halo seem to be surprisingly rich in heavy elements. This is the most remote portion of an elliptical galaxy ever to have been explored.
A team of astronomers recently used the Hubble Space Telescope to explore the most remote section of an elliptical galaxy ever studied.
The scientists, including McMaster’s Bill Harris, probed beyond Centaurus A’s bright, glowing centre and looked at the dim “halo” of stars at its edge.
These expansive haloes are important components of a galaxy. The halo of our own galaxy, the Milky Way, preserves signatures of both its formation and its evolution.
But scientists know little about other galaxy’s haloes as their faint and spread-out nature makes exploring them difficult.
By using the NASA/ESA Hubble Telescope, the team was able to determine that the halo surrounding Centaurus A spreads further into space than expected.
They also found the stars within the halo are surprisingly rich in heavy elements, which suggests a past merger with a large spiral galaxy.
That event would have ejected stars from the spiral galaxy’s disc, which are now seen as part of Centaurus A’s outer halo.
The results of the study will appear in the August 10 issue of Astrophysical Journal.
