A Record of the Discovery Ghost Light of Dead Galaxies Through the Hubble Space Telescope
Hubble Spies Spooky 'Ghost Light' Of Dead Galaxies
The Hubble Space Telescope’s Frontier Areas, a multiyear undertaking to map six faraway galaxy clusters in beautiful detail, is changing that. The first ever to be imaged is definitely Abell 2744, a cluster that had already attained the nickname Pandora’s Cluster because of its violent past. It is the blog of a near-simultaneous pile-up of four smaller clusters. Light from its a huge selection of galaxies has traveled 3.5 billion years to attain Earth.
Now Mireia Montes and Ignacio Trujillo (University of La Laguna, Spain) have used Hubble’s extended stare to create visible-light and near-infrared color pictures of the cluster. They split these color images by brightness, in order that they can examine the colour not only of the luminous galaxies but also of the many fainter intracluster light.
“The authors state that the intracluster light is normally a not-well defined amount, observationally speaking,” says theorist Emanuele Contini (University of Trieste, Italy). “I'd say that observers usually do not have many other alternatives!” While theorists can monitor every star as they style a galaxy cluster’s evolution, observational astronomers must determine intracluster light as any light below some threshold in surface brightness.
Given the amazingly faint threshold, few telescopes can handle saying much about intracluster light besides that it exists. However in these Hubble observations, Montes and Trujillo may use the colour of the cluster’s faintest glow to uncover the ghost stars’ age.
Compared to stars included with the cluster’s galaxies,