News Release Archive:

News Release 9 of 109

March 2, 2012 09:00 AM (EST)

News Release Number: STScI-2012-10

Dark Matter Core Defies Explanation in Hubble Image

Technical facts about this news release:

About the Object

Object Name:	Abell 520
Object Description:	Merging Galaxy Cluster
Position (J2000):	R.A. 04h 54m 18s.99 Dec. +02° 56' 48".8
Constellation:	Orion
Distance:	2.4 billion light-years (740 million parsecs)

About the Data

Data Description:	The image was created from Hubble data from proposal 11221: J. Dalcanton (University of Washington, Seattle), A. Mahdavi (San Francisco State University), H. Hoekstra (Leiden Observatory), and A. Babul (University of Victoria, BC). The science paper is led by M.J. Jee (University of California, Davis).
Instrument:	WFPC2
Exposure Date(s):	August 19-22, 2008
Exposure Time:	11 hours
Filters:	F814W (I)

About the Release

Credit:

NASA, ESA, CFHT, CXO, M.J. Jee (University of California, Davis), and A. Mahdavi (San Francisco State University)

Release Date:

March 2, 2012

Color:

This image is a composite of separate exposures acquired by the HST/WFPC2 instrument, the Canada-France-Hawaii Telescope (CFHT), and the Chandra X-ray Observatory. Several filters were used to sample various wavelength and energy ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are:

Visible: CFHT (B), CFHT (V), and HST/WFPC2 F814W (I)	white
Luminosity derived from CFHT	red
Mass derived from HST/WFPC2	blue
Chandra X-ray Observatory	green

Orientation/Scale: