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)| About The Object | |
|---|---|
| Object Name | Abell 2744, Pandora's Cluster |
| Object Description | Galaxy Cluster and Gravitational Lens |
| R.A. Position | 00h 14m 21s.2 |
| Dec. Position | -30° 23' 50".1 |
| Constellation | Sculptor |
| Distance | 3.5 billion light-years |
| About The Data | |
| Data Description | Data 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). |
| Instrument | HST>ACS/WFC and HST>WFC3/IR |
| Exposure Dates | October 2009; August 2013 - July 2014 |
| Filters | ACS/WFC: F435W (B), F606W (V), F814W (I) WFC3/IR: F105W (Y), F125W (J), F140W (JH), F160W (H) |
| About The Image | |
| Color Info | This 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 |
| Compass Image |  |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
