News Release Archive:

News Release 117 of 325

August 27, 2008 10:00 AM (EDT)

News Release Number: STScI-2008-32

A Clash of Clusters Provides New Clue to Dark Matter

Technical facts about this news release:

About the Object
Object Name: MACS J0025.4−1222
Object Description: Galaxy Cluster
Position (J2000): R.A. 00h 25m 29s.80
Dec. -12° 22' 46".99
Constellation: Cetus
Distance: This object has a redshift of z = 0.586. It is on the order of billions of light-years away.
Dimensions: This image is 3.2 arcminutes (4.2 million light-years or 1.3 million parsecs) wide.
About the Data
Science Team: This image was created from HST data from proposals 10703: PI H. Ebeling, University of Hawaii) and 11100: PI M. Bradac (University of California, Santa Barbara). It was composited with X-ray data from the Chandra X-ray Observatory's Advanced CCD Imaging Spectrograph, from proposals: 3251 and 5010: PI S. Allen (Stanford University). The science team includes M. Bradac (University of California, Santa Barbara), S. Allen (Stanford University), T. Treu (University of California, Santa Barbara), H. Ebeling (University of Hawaii), R. Massey (Royal Observatory, Edinburgh), and G. Morris, A. von der Linden, and D. Applegate (Stanford University).
Instrument: ACS and WFPC2
Exposure Date(s): November 5, 2006 and June 6, 2007
Filters: F450W (B), F555W (V), and F814W (I)
About the Release
Image Credit: NASA, ESA, CXC, M. Bradac (University of California, Santa Barbara), and S. Allen (Stanford University)
Release Date: August 27, 2008
Color: The image is a composite of separate exposures made by Hubble Space Telescope ACS and WFPC2 detectors and the Chandra ACIS detector. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are:
X-ray violet
F450W (B) blue
F555W (V) and F814W (I) yellow/cyan