The ‘ghost’ light of dead galaxies explains how he … – RTVE

RTVE.es/IAC

A ‘ghostly light’ (intracluster light) that is in a cluster located about 4,000 million light years from Earth provides clues about the formation and evolution of the universe.

This is a light that comes from Star in cluster that are not gravitationally bound to any galaxy in particular. According to the theoretical prediction, enormous tidal forces destroy galaxies and force their star clusters roam freely.

The big problem facing astronomers in studying This light is very weak , and therefore difficult to observe. However, researchers at the Instituto de Astrofísica de Canarias (IAC) and the University of La Laguna (ULL) have been studied for the first time in detail the properties of this light.

It has been possible using the deeper details of galaxy clusters achieved with the Hubble Space Telescope , up to distances of 350,000 light years away in the cluster Abell 2744, according to the IAC.

Depth unprecedented

For the results of this study, published in Astrophysical Journal have used data a new mapping-the Hubble Frontier Fields (Campos Border Hubble) – that the Hubble telescope is performing and includes six galaxy clusters with unprecedented depth

“It is a novel work involved a before and after in our understanding of the formation and evolution of galaxy clusters , and so far the intracluster light studies had received serious limitations in depth and spectral coverage to derive age and metallicity of stars that emit “ told Mireia Montes, first author of the paper.

These observations at various wavelengths (optical and infrared) are the deepest that have been made of clusters of galaxies to date.

Initially, the project Hubble Frontier Fields was designed for the study of very distant galaxies exploiting the gravitational properties of these clusters, which act as a kind of lens that magnifies small and faint objects that are behind.

“However warns Montes, the depth of these images allows a detailed study of the cluster itself , which makes them ideal images to analyze the intracluster light.”

Use pictures as deep drawing this allows diffused light over long distances and, therefore, prevent pollution from the outer parts of galaxies .

large galaxies from smaller structures

In addition, the combination of images from multiple wavelengths from the optical to the infrared, can discern the stellar populations contributing to this light.

“The result of the study shows that galaxies that can potentially create this intracluster light are very similar to the Milky Way and began to fall in Abell 2744 9.000 million years ago. The amount of mass that is observed in the form of this light is equivalent to the destruction of between 4 and 6 galaxies like ours, “ has explained Ignacio Trujillo, second author.

This result is consistent with current theories of galaxy formation where large structures tend to grow adding smaller structures (hierarchical model).