News Release Number: STScI-2008-07



ABOUT THIS IMAGE:

The elliptical galaxy NGC 1132 reveals the final result of what may have been a group of galaxies that merged together in the recent past. Another possibility is that the galaxy formed in isolation as a "lone wolf" in a universe ablaze with galaxy groups and clusters.

NGC 1132 is dubbed a "fossil group" because it contains enormous concentrations of dark matter, comparable to the dark matter found in an entire group of galaxies. NGC 1132 also has a strong X-ray glow from an abundant amount of hot gas that is normally only found in galaxy groups.

In visible light, however, it appears as a single, isolated, large elliptical galaxy. The origin of fossil-group systems remains a puzzle. They may be the end-products of complete merging of galaxies within once-normal groups. Or, they may be very rare objects that formed in a region or period of time where the growth of moderate-sized galaxies was somehow suppressed, and only one large galaxy formed.

Elliptical galaxies are smooth and featureless. Containing hundreds of millions to trillions of stars, they range from nearly spherical to very elongated shapes. Their overall yellowish color comes from the aging stars. Because ellipticals do not contain much cool gas, they no longer can make new stars.

This image of NGC 1132 was taken with Hubble's Advanced Camera for Surveys. Data obtained in 2005 and 2006 through green and near-infrared filters were used in the composite. In this Hubble image, NGC 1132 is seen among a number of smaller dwarf galaxies of similar color. In the background, there is a stunning tapestry of numerous galaxies that are much larger but much farther away.

NGC 1132 is located approximately 318 million light-years away in the constellation Eridanus, the River.

For more information, please contact:

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4514
villard@stsci.edu

Lars Lindberg Christensen
Hubble/ESA, Garching, Germany
011-49-89-3200-6306
lars@eso.org

Michael West
ESO, Santiago, Chile
011-56-2-463-3254
mwest@eso.org

Object Name: NGC 1132

Image Type: Astronomical


Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration

Acknowledgment: M. West (ESO, Chile)


Source: HubbleSite - Newsdesk

This image of the elliptical galaxy NGC 1132 and its surrounding region combines data from NASA's Chandra X-ray Observatory and the Hubble Space Telescope. The blue/purple in the image is the X-ray glow from hot, diffuse gas detected by Chandra. Hubble's data reveal a giant foreground elliptical galaxy, plus numerous dwarf galaxies in its neighborhood, and many much more distant galaxies in the background.

Chandra X-ray Image of NGC 1132 Astronomers have dubbed NGC 1132 a "fossil group" because it contains an enormous amount of dark matter, comparable to the dark matter found in an entire group of galaxies. Also, the large amount of hot gas detected by Chandra is usually found for groups of galaxies, rather than a single galaxy.

The origin of such fossil-group systems remains a puzzle. They may be the end-products of the complete merging of groups of galaxies. Or, they may be very rare objects that formed in a region or period of time where the growth of moderate-sized galaxies was somehow suppressed, and only one large galaxy formed.

Elliptical galaxies are smooth and featureless. Containing hundreds of millions to trillions of stars, they range from nearly spherical to very elongated shapes. Their overall yellowish color comes from the aging stars. Because elliptical galaxies do not contain much cool gas, they can no longer make large numbers of new stars.


Fast Facts for NGC 1132:

Credit X-ray: NASA/CXC/Penn State/G. Garmire; Optical: NASA/ESA/STScI/M. West
Scale Image is 3.26 arcmin across
Category Groups & Clusters of Galaxies
Coordinates (J2000) RA 02h 52m 51.9s | Dec -01° 16' 28.0''
Constellation Eridanus
Observation Dates 12/10/1999, 11/18/2004
Observation Time 15 hours
Obs. IDs 801, 3576
Color Code X-ray (blue); Optical (red, green, & white)
Instrument ACIS
Also Known As Wd 2
References Naze, Y. et al, 2008 A&A, accepted.
Distance Estimate 300 million light years
Release Date February 05, 2008


Source: Chandra - Photo Album

This image of elliptical galaxy NGC 1132 and its surrounding region shows the X-ray glow from hot, diffuse gas detected by Chandra. Astronomers have dubbed NGC 1132 a "fossil group" because it contains an enormous amount of dark matter, comparable to the dark matter found in an entire group of galaxies. Also, the large amount of hot gas detected by Chandra is usually found for groups of galaxies, rather than a single galaxy. Below, the white box represents the Hubble Space Telescope's field of view.
(Credit: X-ray: NASA/CXC/Univ. de Liege/Y. Naze et al; IR: NASA/JPL-Caltech/Univ. of Wisconsin/E. Churchwell)

Source: Chandra - Photo Album