Galaxies reached their busiest star-making pace about 11 billion years ago, then slowed down. Scientists have puzzled for years over the question of what happened. Now researchers have found evidence supporting the argument that the answer was energy feedback from quasars within the galaxies where stars are born.
Quasars are the discs of hot gas that form around supermassive black holes at the centre of massive galaxies — they are hotter than the surface of the Sun, generating enough light to be seen across the observable universe. New research has revealed quasar wind speeds of 20 percent the speed of light near a supermassive black hole.
A strange new kind of galactic beast has been spotted in the cosmic wilderness. Dubbed “super spirals,” these unprecedented galaxies dwarf our own spiral galaxy, the Milky Way, and compete in size and brightness with the largest galaxies in the universe. The galaxies have long hidden in plain sight by mimicking the appearance of typical spirals.
An international team of astronomers led by Ivan Zolotukhin from Lomonosov Moscow State University is close to understanding one of the most important mysteries of modern astronomy — so-called intermediate-mass black holes. The researchers acknowledge the invaluable assistance of volunteer Russian computer programmers in the search.
You might think that astronomers could easily tell the difference between a black hole and a white dwarf — but nature can be deceptive. Astronomers from the Sloan Digital Sky Survey (SDSS) have just announced the results of a new study that reveals the true origin of puzzling light from nearby galaxies.
Astronomers can’t find any sign of the black hole at the centre of the quasar SDSS J1011+5442, and they couldn’t be happier. The black hole is still there, of course, but over the past ten years, it appears to have swallowed all the gas in its vicinity. With the gas consumed, researchers were unable to detect the spectroscopic signature of the quasar, which now appears as an otherwise normal galaxy.
Astronomers have created the first large-scale map that shows stellar ages in the Milky Way by determining the ages of nearly 100,000 red giant stars, at distances of up to 50,000 light-years from the galactic centre. Notably, the map confirms that our home galaxy has grown inside out: in the present epoch, most old stars can be found in the middle, more recently formed ones in the outskirts.
Researchers are sifting through an avalanche of data produced by one of the largest cosmological simulations ever performed. The simulation, run on the Titan supercomputer at the U.S. Department of Energy’s Oak Ridge National Laboratory, modelled the evolution of the universe from just 50 million years after the Big Bang to the present day.
Astronomers have found evidence for a faded electron cloud “coming back to life,” much like the mythical phoenix, after two galaxy clusters collided. This “radio phoenix,” so-called because the high-energy electrons radiate primarily at radio frequencies, is found in Abell 1033. This galaxy cluster collision is located about 1.6 billion light-years from Earth.
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