ESO 550-IG025: ESO550-IG025 shows a pair of spiral galaxies, the larger nearly face-on and accompanied by a smaller, highly tilted partner. Tidal interaction from the smaller companion has clearly deformed one arm of the larger galaxy. Strong star formation continues both in the deformed arm and in a ring structure around the galaxy's core. The pair is surrounded by the glow of faintly shining stars and interstellar matter that has been smeared through space by the gravitational effects of the collision and the pull of a third nearby galaxy. This image is part of a large  collection of 59 images of merging galaxies taken by the Hubble Space Telescope and released on the occasion of its 18th anniversary on 24th April 2008.

Name: ESO 550-IG025
Type: Local Universe : Galaxy : Type : Interacting
Category: AnniversaryGalaxies
Constellation: Eridanus
Distance: 400 million light years
Release date: 24 April 2008, 15:00
Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)

Hubble studies compact galaxies loaded with stars: These images taken by the NASA/ESA Hubble Space Telescope show nine compact, ultra-dense galaxies as they appeared 11 billion years ago. The galaxies are only 5,000 light-years across and yet are 200 billion times more massive than the Sun. They are a fraction of the size of today's grownup galaxies but contain the same number of stars. Each galaxy could fit inside the central hub of our Milky Way Galaxy. Hubble's Near Infrared Camera and Multi-Object Spectrometer snapped these images between June 2006 and June 2007.

Name: 1030-1813, 1030-2559, 1256-0, 1256-142, 1256-1967, ECDFS-11490, ECDFS-5856, HDFS1-1849, HDFS2-2046
Type: Early Universe : Galaxy
Category: Galaxies
Release date: 29 April 2008, 15:00
Credit: NASA, ESA, P. van Dokkum (Yale University), M. Franx (Leiden University, The Netherlands), and G. Illingworth (University of California and Lick Observatory, Santa Cruz)

The Antennae moves closer: The Antennae Galaxies are among the closest known merging galaxies. The two galaxies, also known as NGC 4038 and NGC 4039, started to interact a few hundred million years ago, creating one of the most impressive sights in the night sky. They are considered by scientists as the archetypal merging galaxy system and are used as a standard with which to validate theories about galaxy evolution. The ground-based image (left) is taken by Robert Gendler and shows the two merging galaxies and their impressive long tidal tails. The Hubble Advanced Camera for Surveys image (right) shows a portion of the southern tidal tail. The main visible component consists of young blue stars recently formed out of the gas accumulating along the spine of the tail, and many red background galaxies can also be seen. The region is also filled by thousands of faint red stars, just visible when zooming on the image. By measuring the colours and brightnesses of red giant stars in the system, the scientists found that the Antennae Galaxies are much closer than previously thought: 45 million light-years instead of the previous best estimate of 65 million light-years. These red stars cannot be brighter than a certain threshold, and it is this luminosity threshold that was used to derive the new distance of the Antennae.

Name: Antennae Galaxies, NGC 4038, NGC 4039
Type: Local Universe : Galaxy : Type : Interacting
Category: Galaxies
Distance: 45 million light years
Release date: 9 May 2008, 12:00
Credit: NASA, ESA & Ivo Saviane (European Southern Observatory)/Robert Gendler

Stars in the tail of the Antennae: The Hubble ACS image shows a portion of the southern tidal tail of the Antennae galaxies. The main visible component consists of young blue stars recently formed out of the gas accumulating along the spine of the tail, and many red background galaxies can also be seen. The region is also filled by thousands of faint red stars, just visible when zooming on the image. The Antennae Galaxies are among the closest known merging galaxies. The two galaxies, also known as NGC 4038 and NGC 4039, started to interact a few hundred million years ago, creating one of the most impressive sights in the night sky. They are considered by scientists as the archetypal merging galaxy system and are used as a standard with which to validate theories about galaxy evolution. By measuring the colours and brightnesses of red giant stars in the system, the scientists found that the Antennae Galaxies are much closer than previously thought: 45 million light-years instead of the previous best estimate of 65 million light-years. These red stars cannot be brighter than a certain threshold, and it is this luminosity threshold that was used to derive the new distance of the Antennae.

Name: Antennae Galaxies, NGC 4038, NGC 4039
Type: Local Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Corvus
Distance: 45 million light years
Release date: 9 May 2008, 12:00
Credit: NASA, ESA & Ivo Saviane (European Southern Observatory)

Ground-based image of the Antennae Galaxies: This ground-based image was taken by Robert Gendler and shows the two merging Antennae Galaxies (NGC 4038 and NGC 4039) and their impressive long tidal tails.

Name: Antennae Galaxies, NGC 4038, NGC 4039
Type: Local Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Corvus
Distance: 45 million light years
Release date: 9 May 2008, 12:00
Credit: Robert Gendler

Wide-field view of the region around the Antennae Galaxies (ground-based image): This image is a colour composite made from exposures from the Digitized Sky Survey 2 (DSS2). The field of view is 2.8 x 2.8 degrees.

Name: Antennae Galaxies, NGC 4038, NGC 4039
Type: Local Universe : Galaxy : Type : Interacting
Category: Galaxies
Constellation: Corvus
Distance: 45 million light years
Release date: 9 May 2008, 12:00
Credit: ESA/Hubble and Digitized Sky Survey 2. Acknowledgements: Davide De Martin (ESA/Hubble)

The Coma Galaxy Cluster as seen by Hubble: Hubble's Advanced Camera for Surveys has viewed a large portion of the Coma Cluster, stretching across several million light-years across. The entire spherical cluster is more than 20 million light-years in diameter and contains thousands of galaxies. Most of the galaxies that inhabit the central portion of the Coma Cluster are elliptical galaxies. These featureless "fuzz-balls" are a pale golden brown in colour and contain populations of old stars. Both dwarf and giant ellipticals are found in abundance in the Coma Cluster.

Name: Abell 1656
Type: Local Universe : Galaxy : Grouping : Cluster
Category: Galaxies
Constellation: Coma Berenices
Distance: 300 million light years
Release date: 10 June 2008, 15:00
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA). Acknowledgment: D. Carter (Liverpool John Moores University) and the Coma HST ACS Treasury Team.

Coma Galaxy Cluster (Detail 1): On the right, a spiral galaxy in the Coma Cluster.

Name: Abell 1656
Type: Local Universe : Galaxy : Type : SpiralLocal Universe : Galaxy : Grouping : Cluster
Category: Galaxies
Constellation: Coma Berenices
Distance: 300 million light years
Release date: 10 June 2008, 15:00
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA). Acknowledgment: D. Carter (Liverpool John Moores University) and the Coma HST ACS Treasury Team.

Coma Galaxy Cluster (Detail 2): Varied galaxy types in the Coma Cluster.

Name: Abell 1656
Type: Local Universe : Galaxy : Grouping : Cluster
Category: Star Clusters
Constellation: Coma Berenices
Distance: 300 million light years
Release date: 10 June 2008, 15:00
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA). Acknowledgment: D. Carter (Liverpool John Moores University) and the Coma HST ACS Treasury Team.