14 DAY TRIAL // Following the biggest and most comprehensive study to date on gamma-ray bursts, experts have now made sense of the factors that make some of the most energetic events in the entire Universe to appear dim when seen in visible light wavelengths.
When looking at this energetic light in the gamma-ray portion of the electromagnetic spectrum, they simply light up the sky, and are immediately obvious from the cosmic background.
However, this doesn't happen when astronomers use optical telescopes to look for them. This has puzzled experts for many years, but the new study was able to crack the mystery.
The team that conduct the research used the GROND instrument for the job. It is mounted on the 2.2-meter MPG/ESO telescope at the La Silla facility, in Chile. The European Southern Observatory manages the scientific installation.
Astrophysicists say that gamma-ray bursts (GRB) are some of the most energetic and intense events in the known Universe, adding that they can last between seconds and minutes. This gives suitable telescopes ample time to observe them.
But, ever since dark GRB were found, researchers have been fascinated by their dimness in optical wavelengths. Apparently, many factors conspire to yield this result.
Some 13 years ago, experts discovered that the vast majority of GRB have afterglows, which are basically residues of the initial event, that emit X-ray radiation.
But only less than half of afterglows emit visible light. Theories to explain this have stated that some of the light residues may be too far away, or that they belong to different class of GRB.
Apparently, the explanation is a lot simpler. “Studying afterglows is vital to further our understanding of the objects that become gamma-ray bursts and what they tell us about star formation in the early Universe,” says Jochen Greiner.
The expert, who holds an appointment at the Garching bei München, Germany-based Max-Planck Institute for Extraterrestrial Physics, was the lead author of the new investigation.
After analyzing GROND data, the team concluded that vast amounts of dust located between Earth and the GRB afterglows are what obscure our view. Cosmic dust is renowned for absorbing a large portion of the electromagnetic spectrum, letting only certain radiation pass through.
“Compared to many instruments on large telescopes, GROND is a low cost and relatively simple instrument, yet it has been able to conclusively resolve the mystery surrounding dark gamma-ray bursts,” the team leader says of the instrument that made the finding possible.