Scanning the heavens for the first time since the successful December 1999 servicing mission, NASA's Hubble Space Telescope has imaged a giant, cosmic magnifying glass, a massive cluster of galaxies called Abell 2218. This "hefty" cluster resides in the constellation Draco, some 2 billion light-years from Earth.
The cluster is so massive that its enormous gravitational field deflects light rays passing through it, much as an optical lens bends light to form an image. This phenomenon, called gravitational lensing, magnifies, brightens, and distorts images from faraway objects. The cluster's magnifying powers provides a powerful "zoom lens" for viewing distant galaxies that could not normally be observed with the largest telescopes.
This useful phenomenon has produced the arc-shaped patterns found throughout the Hubble picture. These "arcs" are the distorted images of very distant galaxies, which lie 5 to 10 times farther than the lensing cluster. This distant population existed when the universe was just a quarter of its present age. Through gravitational lensing these remote objects are magnified, enabling scientists to study them in more detail. This analysis provides a direct glimpse of how star-forming regions are distributed in remote galaxies and yields other clues to the early evolution of galaxies.
The picture is dominated by spiral and elliptical galaxies. Resembling a string of tree lights, the biggest and brightest galaxies are members of the foreground cluster. Researchers are intrigued by a tiny red dot just left of top center. This dot may be an extremely remote object made visible by the cluster's magnifying powers. Further investigation is needed to confirm the object's identity.
The Hubble telescope first viewed this cluster in 1994, producing one of the most spectacular demonstrations of gravitational lensing up to that time. Scientists who analyzed that black-and-white picture discovered more than 50 remote, young galaxies. Hubble's latest multicolor image of the cluster will allow astronomers to probe in greater detail the internal structure of these early galaxies. The color picture already reveals several arc-shaped features that are embedded in the cluster and cannot be easily seen in the black-and-white image.
The colors in this picture yield clues to the ages, distances, and temperatures of stars, the stuff of galaxies. Blue pinpoints hot young stars. The yellow-white color of several of the galaxies represents the combined light of many stars. Red identifies cool stars, old stars, and the glow of stars in distant galaxies. This view is only possible by combining Hubble's unique image quality with the rare lensing effect provided by the magnifying cluster.
The picture was taken Jan. 11 to 13, 2000, with the Wide Field and Planetary Camera 2.
Credits
NASA, Andrew Fruchter and the ERO Team [Sylvia Baggett (STScI), Richard Hook (ST-ECF), Zoltan Levay (STScI)] (STScI)| About The Object | |
|---|---|
| Object Name | Abell 2218 |
| Object Description | Galaxy Cluster, Gravitational Lens |
| R.A. Position | 16h 35m 53.99s |
| Dec. Position | 66° 13' 0.0" |
| Constellation | Draco |
| Distance | 2 billion light-years (600 million parsecs) |
| About The Data | |
| Data Description | Principal Astronomers: A. Fruchter (STScI), C. Christian (STScI), A. Kinney (NASA), A. Fruchter (STScI), S. Baggett (STScI), R. Hook (ST-ECF), Z. Levay (STScI) |
| Instrument | HST>WFPC2 |
| Exposure Dates | January 11 - 13, 2000, Exposure Time: 9.4 hours |
| Filters | F450W (Wide B), F606W (Wide V), and F814 W (I) |
| 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. |
