This is the first in a series of posts introducing and providing essential facts about each of the Frontier Fields.
Abell 2744, also known as Pandora’s Cluster, is a giant pile-up of four smaller galaxy clusters. Abell 2744, and its neighboring parallel field, are among the first targets of the Frontier Fields program.
The Abell catalogue of galaxy clusters was first compiled by astronomer George O. Abell in 1958, with over 2,700 galaxy clusters observable from the Northern Hemisphere. The Abell catalogue was updated in 1989 with galaxy clusters from the Southern Hemisphere.
The locations of Hubble’s observations of the Abell 2744 galaxy cluster (left) and the adjacent parallel field (right) are plotted over a Digital Sky Survey (DSS) image. The blue boxes outline the regions of Hubble’s visible-light-observations, and the red boxes indicate areas of Hubble’s infrared-light observations. A scale bar in the lower left corner of the image indicates the size of the image on the sky. The scale bar corresponds to approximately 1/30th the apparent width of the full moon as seen from Earth. Astronomers refer to this unit of measurement as one arcminute, denoted as 1′.Credit: Digitized Sky Survey (STScI/NASA) and Z. Levay (STScI).