Hubble image archive
Galaxy Cluster MACS J0717
This composite image shows the massive galaxy cluster MACS J0717.5+3745 (MACS J0717, for short), where four separate galaxy clusters have been involved in a collision – the first time such a phenomenon has been documented. Hot gas is shown in an image from NASA's Chandra X-ray Ob...
- Date
- Jan 1, 2009
- Mission
- Hubble Space Telescope
- Archive ID
- hubblesite-images-2009-17-2539-image
This composite image shows the massive galaxy cluster MACS J0717.5+3745 (MACS J0717, for short), where four separate galaxy clusters have been involved in a collision – the first time such a phenomenon has been documented. Hot gas is shown in an image from NASA's Chandra X-ray Observatory, and galaxies are shown in an optical image from NASA's Hubble Space Telescope. The hot gas is color-coded to show temperature, where the coolest gas is reddish purple, the hottest gas is blue, and the temperatures in between are purple.
The repeated collisions in MACS J0717 are caused by a 13-million-light-year-long stream of galaxies, gas, and dark matter – known as a filament – pouring into a region already full of matter. A collision between the gas in two or more clusters causes the hot gas to slow down. However, the massive and compact galaxies do not slow down as much as the gas does, and so move ahead of it. Therefore, the speed and direction of each cluster's motion – perpendicular to the line of sight – can be estimated by studying the offset between the average position of the galaxies and the peak in the hot gas.
MACS J0717 is located about 5.4 billion light-years from Earth. It is one of the most complex galaxy clusters ever seen. Other well-known clusters, like the Bullet Cluster and MACS J0025.4-1222, involve the collision of only two galaxy clusters and show much simpler geometry.
Credits
NASA, ESA, CXC, C. Ma, H. Ebeling, and E. Barrett (University of Hawaii/IfA), et al., and STScIImage Details
| About The Object | |
|---|---|
| Object Name | MACS J0717.5+3745 |
| Object Description | Cluster of Galaxies |
| R.A. Position | 07h 17m 33.79s |
| Dec. Position | 37° 45' 20.01" |
| Constellation | Auriga |
| Distance | 5.4 billion light-years or 1.7 billion parsecs |
| Dimensions | The image is roughly 4.5 arcminutes (7.7 million light-years or 2.4 megaparsecs) wide. |
| About The Data | |
| Data Description | Chandra Data: Chandra data used were from proposal . Hubble Data: The Hubble images were created from HST data from proposal : PI: Dr. H. Ebeling (University of Hawaii), I. Smail (University of Durham, UK), J.-P. Kneib (Laboratoire d'Astrophysique de Marseille, France), G. Smith (University of Birmingham, UK), and D. Donovan and E. Barrett (University of Hawaii). |
| Instrument | CXO>ACIS and HST>ACS/WFC |
| Exposure Dates | January 10, 2003 (CXO) and January 24, 2005 - February 9, 2005 (HST) |
| Filters | ACS: F606W (V) and F814W (I) ACIS Energies: 5 - 25 T(keV) |
| About The Image | |
| Color Info | The image is a composite of separate exposures made by the ACS instrument on the Hubble Space Telescope and the ACIS instrument onboard the Chandra X-ray Observatory. Two filters were used to sample broad wavelength ranges. A continuous energy band was used to sample the X-ray data. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are: Cyan: F606W (V) Yellow: F814W (I) Blue - Violet (temperature map): 5 - 25 T(keV) |
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Image and source material are credited to the official mission archive linked below.
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