Hubble Telescope Spots a few of the Oldest Galaxies in the Known Universe

May give clues to the formation of the universe. With the new data, the scientists said they could conclude the universe became fully transparent around 700 million years after the Big Bang.

As part of the Hubble Frontier Fields program, a three-year space project which explores the farthest parts of the universe, researchers examined images of galaxy clusters through gravitational lensing effects.

The light from these galaxies, which has taken over 13 billion years to reach us, is believed to have played a major role in one of the most mysterious periods of the universe’s early history – the epoch of reionisation.

“We also needed to add in the contribution of a more abundant population of faint dwarf galaxies”, said Hakim Atek of the Ecole Polytechnique Fédérale de Lausanne. The energetic electromagnetic radiation (including ultraviolet light) they released reionized the neutral atoms of hydrogen, and the fog cleared, letting light could travel to the vast corners of the universe.

This awesome collection of ancient galaxies is fainter than anything previously seen by the Earth-orbiting space telescope.

In addition to discovering new galaxies, an Atek’s team also concluded that these small, faint galaxies did produce enough light and radiation, along with bigger and brighter galaxies, to remove the veil of hydrogen that shrouded the early universe.

Furthermore, the tiniest, but most abundant galaxies in this study played a major role in maintaining the universe’s transparency.

The team of astronomers is worldwide and Swiss lead and it has discovered the smallest and faintest first generation dwarf galaxies.

The findings were part of the Hubble Frontier Fields program, and publication of the research in the Astrophysical Journal is pending. The galaxy clusters had accumulated and produced gravitational fields that magnified light from nearby faint galaxies found behind the clusters. Other co-authors represent the Observatoire de Lyon, Aix Marseille Université, and CNRS, in France; the Université de Genève, in Switzerland; the University of Hawaii; and the University of Arizona. Being super-massive, the galaxy clusters can bend spacetime. Peering out into deep space with the Hubble, astronomers use galaxies’ gravitational forces as a lens to see even farther. Often, the images of distant lensed galaxies are seen as arcs, or in very rare cases, complete circles (such as Einstein Rings – where the galactic light is completely warped into a full circle around the lensing galactic cluster). Earlier this year, it celebrated its 25 years in space since its launch in 1990.

“Clusters in the Frontier Fields act as powerful natural telescopes and unveil for us these faint dwarf galaxies that would otherwise be invisible”, said the EPFL’s Jean-Paul Kneib, co-author of the study.