Composition of gas surrounding quasars identified

Two University of Hawaii astronomers have using data from the Hubble Space Telescope, identified what makes at least some quasars shine.

Washington, Aug 4 : Two University of Hawaii astronomers have using data from the Hubble Space Telescope, identified what makes at least some quasars shine.

Scientists know that quasars, among the most powerful objects in the universe, lie at the centres of giant galaxies and consist of a massive black hole surrounded by a vortex of gas. Before the gas falls into the black hole, it spins faster and faster, and its temperature rises until it is hot enough to radiate up to a trillion times the power from the Sun.

Now, graduate student Hai Fu and astronomer Alan Stockton have using telescope-mounted spectroscope on Mauna Kea, the Big Island, found out what the gas is made of.

"We found that the gas that is spiralling into the black hole is almost pure hydrogen and helium, whereas the stars and other material in the surrounding giant galaxy are heavily contaminated by other elements such as carbon and oxygen," said Fu.

Fu says according to their theory, the infalling gas has recently come from outside the galaxy, most likely from another galaxy that is merging with the giant one.

A chaotic distribution of fast-moving patches of relatively pure hydrogen and helium scattered around the quasar, implies that black holes not only swallow things, but can also expel a large portion of their meal out to thousands of light-years away, likely through an energetic blast that happened millions of years ago, he said.

The study appears in the August 1 issue of the Astrophysical Journal Letters.

ANI