Images by Date
Images by Category
Solar System
White Dwarfs
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Galaxy Clusters
Cosmology/Deep Field
Images by Interest
Space Scoop for Kids
Sky Map
Photo Blog
Top Rated Images
Image Handouts
Fits Files
Image Tutorials
Photo Album Tutorial
False Color
Cosmic Distance
Look-Back Time
Scale & Distance
Angular Measurement
Images & Processing
Image Use Policy
Web Shortcuts
Chandra Blog
RSS Feed
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
NGC 5813 Animations
Click for low-resolution animation
Tour of NGC 5813
Quicktime MPEG With closed-captions (at YouTube)

Galaxy groups are families of galaxies that are bound together by gravity. They are very similar to their larger cousins, galaxy clusters. Instead of containing hundreds or even thousands of galaxies like clusters do, galaxy groups are typically comprised of 50 or fewer galaxies. Like galaxy clusters, groups of galaxies are enveloped by giant amounts of hot gas that emit X-rays. They also often contain a giant black hole at their center that can impact what's happening throughout the group.

Astronomers used NASA's Chandra X-ray Observatory to study this in the galaxy group NGC 5813, which is located about 105 million light years from Earth. They found three pairs of cavities, or bubbles, that have been carved into the hot gas. These cavities were produced by jets of material that blasted out of the central black hole, including multiple eruptions that lasted for some 50 million years. Similar to how air bubbles will rise to the surface of water, these cavities have moved away from the galaxy group's center toward the edge of the hot gas. By studying the details of these cavities, astronomers can get a better understanding of just how supermassive black holes affect their cosmic surroundings.
[Runtime: 01:35]

(Credit: NASA/CXC/A. Hobart)

Return to NGC 5813 (June 10, 2015)