Smears and streaks of light punctuate this Hubble image of an enormous cluster of galaxies called Abell 370. These weird shapes are the warped appearances of galaxies that are not part of the cluster but lie far beyond it. The immense gravity of the galaxy cluster causes these far-off galaxies to look distorted.
Albert Einstein's general theory of relativity tells us that gravity can change the course of not just physical objects but light as well. As light from a distant galaxy travels toward us, through the Abell 370 galaxy cluster, the cluster's gravitational force bends and magnifies the distant galaxy's light like a lens. This quirk of nature is called gravitational lensing. Abell 370 is one of the first galaxy clusters in which astronomers saw the effects of gravitational lensing.
This view from Hubble, captured with the Advanced Camera for Surveys, uncovers far more detail in the numerous streaks and arcs scattered throughout Abell 370 than telescopes on the ground could provide. For example, Hubble's fine resolution reveals that the source of the large, bright streak in the upper right is a faraway spiral galaxy with a red central bulge, blue spiral arms, and clumps of active star formation.
Johan Richard of Durham University in the United Kingdom and his colleagues studied Hubble's images of Abell 370 and identified ten distant galaxies lensed by the cluster, including six that hadn't been spotted before. How these background galaxies appear to us depends on the amount and location of mass in the cluster. So Richard and his team analyzed Hubble's observations of the lensed galaxies to improve estimates of Abell 370's total mass, including what we can see (galaxies and gas) and what we cannot (mysterious stuff known as dark matter). They found that Abell 370 contains two large, separate clumps of dark matter. This, along with other evidence, suggests that Abell 370 is the product of two smaller galaxy clusters that are merging together.
Constellation: Cetus
Distance: 4.9 billion light-years (1.5 billion parsecs)
Instrument: Advanced Camera for Surveys/WFC
Image Filters: F475W (g), F625W (r), F814W (I)
| About The Object | |
|---|---|
| Object Name | Abell 370 |
| 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. |
