Cannibal Galaxy Eats its Neighbours
As a galaxy in the early universe feeds off its smaller neighbours, the energy released from the massive influx of material creates the brightest light known in the Universe...
The brightest lights in our universe are called quasars and as Dr George Lansbury, from the Institute of Astronomy in Cambridge explains, "what you have there is a supermassive black hole at the centre of the galaxy and material within the galaxy, so gas, dust and stars, is plummeting towards that supermassive black hole."
This releases a huge amount of energy, which is observed as an exceptionally bright source of light. But where does this massive amount of material come from? What fuels a quasar?
An international team of scientists have used telescopes in Chile, Hawaii and in space to scan the sky and look into the past. By doing this they have detected light from the most luminous quasar known. This light was emitted about 12.5 billion years ago and travelled for almost as long as the age of the universe to reach these telescopes.
The new analysis published in the journal Science reveals how the merging of galaxies can not only provide the vast amount of material necessary to power highly luminous quasars, but can also supply the large quantity of dust that may obscure it.
Lansbury was part of the team working on this discovery. "Something we want to know is how galaxies like our Milky Way come to be the so called ‘red and dead’ galaxies.”
These "red and dead" galaxies have stopped making new stars. When galaxies in the early universe merge and crash into each other, like the system of galaxies investigated in this study, gas and dust is funnelled towards the centre of the galaxy. The result is "a kind of dust enshrouded phase of intense star formation and intense quasar activity and this intensity of activity may actually disturb the galaxy to such an extent that future star formation just cannot occur, so you end up with a ‘red and dead’ system."