Hubble Space Telescope's high resolution allows astronomers to classify galaxies in a cluster (CL 0939+4713) that existed four billion years ago, when the universe was two- thirds of its present age.
The galaxies in this mosaic are arranged according to the well-established system developed by American astronomer Edwin Hubble in the 1920s. Despite the cluster's great distance of four billion light-years, the Space Telescope pictures are sharp enough to distinguish between various forms galaxies.
The top three rows show familiar types of galaxies which are found today in nearby clusters: elliptical galaxies and lens shaped galaxies (SO) which may be transition objects between spiral and elliptical galaxies.
Rows 4 through 7 show spiral galaxies categorized by the openness of their pinwheel- shaped arms (Hubble classification Sa, Sb, Sc, Sd). Many of these have since disappeared through possibly a variety of processes: merger, disruption, and fading. In particular the spirals in row 7 (Sd) show peculiar morphologies.
The bottom row shows galaxies apparently merging into single systems.
Space Telescope reveals that star-forming galaxies were far more prevalent in the clusters of the younger universe than in modern clusters, a result having important implications for theories of galaxy evolution.
The image was taken with HST's Wide Field/Planetary Camera in Wide Field Camera mode, and required a six-hour exposure.
Credits
Alan Dressier, Carnegie Institution, and NASA Co-investigators: Augustus Oemler (Yale Urnversfty), James E. Gunn (Princeton Universfty), Harvey Butcher (the Netherlands Foundation for Research in Astronomy).| About The Object | |
|---|---|
| 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 |
|
| 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. |
