Astronomers have been waiting for such an event for many years

Nov 2, 2011 15:23 GMT  ·  By

In a recent study, an international collaboration of astronomers was able to analyze a bright gamma-ray burst (GRB) that occurred in the distant Universe. The reason why this particular flash of light is so important is because it passes through two very old galaxies before finally making its way to Earth.

In essence, the GRB acted as a backlight for these two objects. When it passed through them, the gamma-ray photons making it up collected a large amount of information about the chemical components that made up the galaxies, and delivered them faithfully to our doorsteps.

Instances of such events are tremendously rare, and astronomers jumped at the opportunity to analyze them. The study was largely conducted on data used by the Very Large Telescope (VLT) at the Paranal Observatory, in Chile. The facility is operated by the European Southern Observatory (ESO).

What was extremely fortunate for the researchers was the fact that the light flash pierced both galaxies, as illustrated in this artist's impression. Even though the event was very brief, it provided sufficient data to keep astronomers busy for a long time.

The GRB originated in one of the galaxies, passed through its entire length, and then moved onwards through a neighboring galaxy, before finally setting on the course that took it here, Space reports.

The most significant discovery was the fact that both these galaxies – which started developing when the Universe was just a fraction of its current age – contain significantly higher amounts of heavy chemical elements than the Sun does, about 4.6 billion years after its birth.

Past studies had suggested that early galaxies were poor in heavy chemicals. In astronomical terms, heavy elements are those heavier than the basic building blocks of the Cosmos, hydrogen and helium, Space reports.

“When we studied the light from this gamma-ray burst we didn't know what we might find. It was a surprise that the cool gas in these two galaxies in the early universe proved to have such an unexpected chemical make-up,” Sandra Savaglio explains.

“These galaxies have more heavy elements than have ever been seen in a galaxy so early in the evolution of the Universe. We didn't expect the Universe to be so mature, so chemically evolved, so early on,” adds the expert.

She holds an appointment as a research scientists with the Max-Planck Institute for Extraterrestrial Physics in Garching, Germany, and was the lead author of the new investigation.