Hubble image archive

Hubble Sees 'Ghost Light' from Dead Galaxies in Galaxy Cluster Abell 2744

The massive galaxy cluster Abell 2744, nicknamed Pandora's Cluster, takes on a ghostly look in this Hubble Space Telescope view where the total starlight from the cluster has been artificially colored blue. This plot reveals that not all the starlight is contained within the citi...

Date
Jan 1, 2014
Mission
Hubble Space Telescope
Archive ID
hubblesite-images-2014-43-3431-image
By

The massive galaxy cluster Abell 2744, nicknamed Pandora's Cluster, takes on a ghostly look in this Hubble Space Telescope view where the total starlight from the cluster has been artificially colored blue. This plot reveals that not all the starlight is contained within the cities of stars – the galaxies – which appear as bright blue-white blobs. A fraction of the starlight is dispersed throughout the cluster, as seen in the darker blue regions. This light comes from "dead" galaxies. The galaxies were torn apart long ago by the cluster's gravitational forces, and their stars were scattered into "intracluster" space – the space between the galaxies. These orphaned stars roam the cluster, without being gravitationally tethered to any single galaxy. Because these extremely faint stars are brightest at near-infrared wavelengths of light, this type of observation could only be accomplished with Hubble's infrared sensitivity to extraordinarily dim light.

The galaxies that are not colored blue lay either in the foreground or background and are not part of the cluster.

The intracluster light was detected as part of the Frontier Fields program, an ambitious three-year effort, begun in 2013, that teams Hubble with NASA's other Great Observatories – the Spitzer Space Telescope and the Chandra X-ray Observatory – to probe the early universe by studying large galaxy clusters. Abell 2744 resides about 3.5 billion light-years away.

Credits

NASA, ESA, M. Montes (IAC), and J. Lotz, M. Mountain, A. Koekemoer, and the HFF Team (STScI)

Image Details

About The Object
Object NameAbell 2744, Pandora's Cluster
Object DescriptionGalaxy Cluster and Gravitational Lens
R.A. Position00h 14m 21s.2
Dec. Position-30° 23' 50".1
ConstellationSculptor
Distance3.5 billion light-years
About The Data
Data DescriptionData of Abell 2744 were obtained as part of the HST proposals : R. Dupke (Eureka Scientific, Inc.) et al., : S. Rodney (JHU) et al., and : J. Lotz (STScI) and the Frontier Fields Team. The science team includes: M. Montes and I. Trujillo (Instituto de Astrofísica de Canarias/Universidad de La Laguna, Tenerife, Spain).
InstrumentHST>ACS/WFC and HST>WFC3/IR
Exposure DatesOctober 2009; August 2013 - July 2014
FiltersACS/WFC: F435W (B), F606W (V), F814W (I) WFC3/IR: F105W (Y), F125W (J), F140W (JH), F160W (H)
About The Image
Color InfoThis image is a composite of separate exposures acquired by the ACS and WFC3 instruments on the Hubble Space Telescope. Several filters were used to sample broad wavelength 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: Blue: F435W (B) + F606W (V) Green: F814W (I) + WFC3/IR F105W (Y) Red: WFC3/IR F125W (J) + F140W (JH) + F160W (H) Blue: J-band Surface Brightness

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