Epoch of reionization read more at here www.spinonews.com/index.php/item/1220-epoch-of-reionization

The epoch when the very first stars appeared is a key period of cosmic history. These stars began the manufacture of the chemical elements and their light began the re-ionization of the neutral cosmic gas.

These stars mark the dawn of the universe as we know it today and the start of the Epoch of Reionization. The term "re-ionization" refers to the process whereby these atoms are prompted to shed some of their electrons. Astronomers estimate that this period occurred a few hundred million years or so after the big bang.

Neutral hydrogen atoms were the dominant element in the universe from the time they first arose, until the Epoch of Reionization. Now, astronomers are constructing facilities like the radio telescope Murchison Wide-field Array (MWA), to search for light from the hydrogen atoms at the dawn of this Epoch.

Center for Astrophysics (CfA) astronomers were members of a large team of scientists that used the MWA during its early commissioning phase of operations to develop a catalog of foreground sources that could be likely sources of confusion.

The MWA currently consists of 128 groupings ("tiles") of sixteen antennae each arranged in four-by-four squares and sensitive to radiation around a meter in wavelength.

The unusual telescope pattern meant that the team had to learn how to properly reduce and analyze the complex resulting data, and much of the effort in this research was devoted to these tasks.

The astronomers successfully identified 7394 extra galactic sources which could be confused with earlier-epoch galaxies in their first field of the sky under study. Nearly all of these objects were associated with previously known galaxies, but twenty-five of them are previously unknown, and all of them have now been characterized.