X Rays from the Perseus Cluster Core
7.12.2005

The Perseus Cluster of thousands of galaxies, 250 million light-years distant, is one of the most massive objects in the Universe and the brightest galaxy cluster in the x-ray sky. At its core lies the giant cannibal galaxy Perseus A (NGC 1275), accreting matter as gas and galaxies fall into it.

M44: The Beehive Cluster
22.02.2014

A mere 600 light-years away, M44 is one of the closest star clusters to our solar system. Also known as the Praesepe or the Beehive cluster its stars are young though, about 600 million years old compared to our Sun's 4.5 billion years.

M15: Dense Globular Star Cluster
4.08.2000

Life might get dull at the core of M15 but the sky would always be bright with stars! In fact, only 40,000 light-years away in the constellation Pegasus, M15 is one of the most densely packed globular star clusters in our Milky Way Galaxy.

The Matter of the Bullet Cluster
14.01.2017

What's the matter with the Bullet Cluster? This massive cluster of galaxies (1E 0657-558) creates gravitational lens distortions of background galaxies in a way that has been interpreted as strong evidence for the leading theory: that dark matter exists within.

Simulation TNG50: A Galaxy Cluster Forms
25.02.2019

How do clusters of galaxies form? Since our universe moves too slowly to watch, faster-moving computer simulations are created to help find out. A recent effort is TNG50 from IllustrisTNG, an upgrade of the famous Illustris Simulation.

Simulation TNG50: A Galaxy Cluster Forms
28.05.2022

How do clusters of galaxies form? Since our universe moves too slowly to watch, faster-moving computer simulations are created to help find out. A recent effort is TNG50 from IllustrisTNG, an upgrade of the famous Illustris Simulation.

Abell 1795: A Galaxy Cluster s Cooling Flow
7.12.2000

Throughout the Universe, galaxies tend to swarm in groups ranging from just a handful of members to casts of thousands. Astronomers have realized since the early 1970s that the larger swarms, immense clusters of galaxies millions of light-years across, are immersed within tenuous clouds of hot gas which glow strongly in x-rays.

Giant Cluster Bends, Breaks Images
14.06.1998

What are those strange blue objects? Many are images of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster galaxies here appear yellow and -- together with the cluster's dark matter -- act as a gravitational lens.

Young Star Clusters in an Old Galaxy
4.07.2002

Elliptical galaxy NGC 4365 is old, probably about 12 billion years old. Like most elliptical galaxies, this galaxy was thought to be full of old stars too, its burst of star forming activity having long since ended.

Giant Cluster Bends, Breaks Galaxy Images
3.05.1997

What are those strange blue objects? Many are images of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster galaxies here appear yellow and -- together with the cluster's dark matter -- act as a gravitational lens.