This is a NASA Hubble Space Telescope image of a portion of a remote cluster of galaxies (CL 0939+4713) that existed when the universe was two-thirds of its present age (redshift z = 0.4). Hubble's high resolution allows astronomers to study, for the first time, the shapes of galaxies which existed long ago. The Space Telescope pictures are sharp enough to distinguish between various forms of spiral galaxies, as well as galaxies in collision, some tearing material from each other, some merging into single systems. The HST picture confirms that billions of years ago, clusters of galaxies contained not only the types of galaxies dominating their descendant clusters today, but also several times as many spiral galaxies. These spiral galaxies have since disappeared through possibly a variety of processes: merger1 disruption, and fading. The Hubble images provide the first unambiguous evidence for the influence of environment on the form of a galaxy. The image was taken with HST's Wide Field/Planetary Camera in Wide Field Camera mode, and required a six-hour exposure.
Credits
Photo Credit: Alan Dressier, Carnegie Institution, and NASA Co-investigators: Augustus Oemler (Yale Universfty), James E. Gunn (Princeton University), Harvey Butcher (the Netherlands Foundation for Research in Astronomy).| About The Object | |
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| Object Name | CL 0939+4713 |
| R.A. Position | 09h 42m 56.59s |
| Dec. Position | 46° 59' 21.99" |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
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| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
