Hubble spies curious galaxy moving a little closer

This Hubble image stars Messier 90, a beautiful spiral galaxy located roughly 60 million light-years from the Milky Way in the constellation of Virgo (the Virgin). The galaxy is part of the Virgo Cluster, a gathering of galaxies ...

Elliptical galaxies shed new light on dark matter

In the 1930s, it was first noticed that the dynamics of astrophysical objects (galaxies, galaxy clusters and the universe itself) required an invisible and unknown form of mass, known now as dark matter. Strong mass discrepancies ...

Suppressed star formation in the early universe

Massive clusters of galaxies, some with more mass than a hundred Milky Way galaxies, have been detected from cosmic epochs as early as about three billion years after the big bang. Their ongoing star formation makes them ...

A new filter to better map the dark universe

The earliest known light in our universe, known as the cosmic microwave background, was emitted about 380,000 years after the Big Bang. The patterning of this relic light holds many important clues to the development and ...

Image: Hubble snaps a crowded cluster

This sparkling burst of stars is Messier 75. It is a globular cluster: a spherical collection of stars bound together by gravity. Clusters like this orbit around galaxies and typically reside in their outer and less-crowded ...

Four questions: Here there be monsters

On April 10, the world got to see the first image taken of a black hole in space, taken by the Event Horizon Telescope, a worldwide collaboration of astronomers and astrophysicists including a substantial team at the University ...

Ultra-sharp images make old stars look absolutely marvelous

Using high-resolution adaptive optics imaging from the Gemini Observatory, astronomers have uncovered one of the oldest star clusters in the Milky Way Galaxy. The remarkably sharp image looks back into the early history of ...

Hubble and Gaia accurately weigh the Milky Way

In a striking example of multi-mission astronomy, measurements from the NASA/ESA Hubble Space Telescope and the ESA Gaia mission have been combined to improve the estimate of the mass of our home galaxy the Milky Way: 1.5 ...

Discovery of many new ultra-diffuse galaxies in galaxy clusters

In preparation for the new multi-object survey spectrograph, WEAVE, on the 4.2m William Herschel Telescope, the astronomical community is working on deep imaging surveys to identify the astronomical objects that will be studied ...

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Galaxy groups and clusters

Galaxy groups and clusters are the largest known gravitationally bound objects to have arisen thus far in the process of cosmic structure formation. They form the densest part of the large scale structure of the universe. In models for the gravitational formation of structure with cold dark matter, the smallest structures collapse first and eventually build the largest structures, clusters of galaxies. Clusters are then formed relatively recently between 10 billion years ago and now. Groups and clusters may contain from ten to thousands of galaxies. The clusters themselves are often associated with larger groups called superclusters.

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