Netherlands Research School for Astronomy (NOVA) | 2018 Aug 07
After nearly twenty years, the record of the most distant radio galaxy ever discovered has been broken. A team led by Leiden PhD student Aayush Saxena has found a radio galaxy from a time when the universe was only 7% of its current age, at a distance of 12 billion light years.
- This picture shows the near-infrared image in K band taken using the Large Binocular Telescope in Arizona, with radio emission overlaid in white. The fact that the host galaxy was not detected at infrared wavelengths from where the radio emission originates helped independently confirm the record distance of this galaxy.
The team used the Giant Meter wave Radio Telescope (GMRT) in India to initially identify the radio galaxy. The distance to this galaxy was then determined using the Gemini Telescope on Hawaii and the Large Binocular Telescope (LBT) in Arizona by measuring the redshift of the galaxy. The redshift of z = 5.72 means that the galaxy is perceived as it looked when the universe was only a billion years old. This also means that the light from this galaxy is almost 12 billion years old. ...
Radio galaxies are very rare objects in the Universe. They are colossal galaxies with a super massive black hole in their center that actively accretes gas and dust from its surroundings. This activity initiates the launch of high-energy jet streams, which are capable of accelerating charged particles around the super massive black hole to almost the speed of light. These jets are very clearly observed at radio wavelengths.
The fact that such galaxies exist in the distant Universe has surprised astronomers. The discovery of such galaxies at extremely large distances is important for our understanding of the formation and evolution of galaxies. Studying these radio galaxies in detail also sheds light on the formation of primordial black holes, which have driven and regulated the growth of galaxies. ...
Discovery of a Radio Galaxy at z = 5.72 ~ A. Saxena et al