Gamma ray bursts (GRBs), the brightest explosions in the universe, can reveal information about our young universe, and may also fuel star formation.
An explosion known as GRB 090323 was detected by NASA’s Fermi Gamma-ray Space Telescope, and then studied in detail with the European Southern Observatory’s (ESO) Very Large Telescope (VLT).
The VLT showed that the burst’s intense light passed through its host galaxy and another nearby galaxy, both seen as they existed around 12 billion years ago, an event rarely detected.
“When we studied the light from this gamma-ray burst we didn’t know what we might find,” said lead researcher Sandra Savaglio at the Max-Planck Institute for Extraterrestrial Physics in Garching, Germany, in a press release. “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.”
“These galaxies have more heavy elements than have ever been seen in a galaxy so early in the evolution of the Universe,” she added. “We didn’t expect the Universe to be so mature, so chemically evolved, so early on.”
Light passing through the galaxies from the GRB was filtered by their gas, and absorbed at certain wavelengths. Analysis of these spectra revealed the chemical composition of the cool gas in these distant galaxies, including the abundance of heavy elements.
Galaxies in our early universe are thought to contain fewer heavy elements than present day galaxies like the Milky Way due to enrichment by stellar evolution. Knowing a galaxy’s chemical composition can yield information about its life cycle phase.
However, the VLT data showed that some ancient galaxies were surprisingly rich in heavy elements less than two billion years after the alleged big bang, indicating intense star formation.
These two newly discovered galaxies could be colliding, which would trigger vigorous star formation, suggesting that GRBs may be linked with this process.
“We were very lucky to observe GRB 090323 when it was still sufficiently bright, so that it was possible to obtain spectacularly detailed observations with the VLT,” Savaglio concluded.
“Gamma-ray bursts only stay bright for a very short time and getting good quality data is very hard. We hope to observe these galaxies again in the future when we have much more sensitive instruments, they would make perfect targets for the European Extremely Large Telescope.”
The findings will be published in Monthly Notices of the Royal Astronomical Society.
An explosion known as GRB 090323 was detected by NASA’s Fermi Gamma-ray Space Telescope, and then studied in detail with the European Southern Observatory’s (ESO) Very Large Telescope (VLT).
The VLT showed that the burst’s intense light passed through its host galaxy and another nearby galaxy, both seen as they existed around 12 billion years ago, an event rarely detected.
“When we studied the light from this gamma-ray burst we didn’t know what we might find,” said lead researcher Sandra Savaglio at the Max-Planck Institute for Extraterrestrial Physics in Garching, Germany, in a press release. “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.”
“These galaxies have more heavy elements than have ever been seen in a galaxy so early in the evolution of the Universe,” she added. “We didn’t expect the Universe to be so mature, so chemically evolved, so early on.”
Light passing through the galaxies from the GRB was filtered by their gas, and absorbed at certain wavelengths. Analysis of these spectra revealed the chemical composition of the cool gas in these distant galaxies, including the abundance of heavy elements.
Galaxies in our early universe are thought to contain fewer heavy elements than present day galaxies like the Milky Way due to enrichment by stellar evolution. Knowing a galaxy’s chemical composition can yield information about its life cycle phase.
However, the VLT data showed that some ancient galaxies were surprisingly rich in heavy elements less than two billion years after the alleged big bang, indicating intense star formation.
These two newly discovered galaxies could be colliding, which would trigger vigorous star formation, suggesting that GRBs may be linked with this process.
“We were very lucky to observe GRB 090323 when it was still sufficiently bright, so that it was possible to obtain spectacularly detailed observations with the VLT,” Savaglio concluded.
“Gamma-ray bursts only stay bright for a very short time and getting good quality data is very hard. We hope to observe these galaxies again in the future when we have much more sensitive instruments, they would make perfect targets for the European Extremely Large Telescope.”
The findings will be published in Monthly Notices of the Royal Astronomical Society.
