Hidden black holes discovered inside far-off galaxies

Washington, Oct 26 : Recent observations by NASA’s Spitzer Space Telescope and the Chandra X-ray observatory indicates the possibility of hundreds of hidden black holes inside far off galaxies.

For decades, a large population of active black holes have been considered missing.

These highly energetic structures belong to a class of black holes called quasars.  A quasar consists of a doughnut-shaped cloud of gas and dust that surrounds and feeds a budding supermassive black hole.

Agency astronomers say the discovery implies that there are hundreds of millions of additional black holes growing in our young universe, more than doubling the total amount known at that distance.

They say the findings are also the first direct evidence that most, if not all, massive galaxies in the distant universe spent their youths building monstrous black holes at their cores.

“Active, supermassive black holes were everywhere in the early universe,” said Mark Dickinson of the National Optical Astronomy Observatory in Tucson, Arizona.

Lead researcher Emanuele Daddi of the Commissariat a l'Energie Atomique in France and his team initially set out to study 1,000 dusty, massive galaxies that were busy making stars and were thought to lack quasars.

The galaxies are about the same mass as our own spiral Milky Way galaxy, but are irregular in shape.

When the astronomers peered more closely at the galaxies with the Spitzer telescope, they noticed that about 200 of the galaxies gave off an unusual amount of infrared light.

X-ray data from Chandra, and a technique called “stacking”" revealed the galaxies were, in fact, hiding plump quasars inside.

Scientists say the newfound quasars are helping answer fundamental questions about how massive galaxies evolve.

For now, astronomers know that most massive galaxies steadily build up their stars and black holes simultaneously until they get too big and their black holes suppress star formation.

The researchers say the observations also suggest that collisions between galaxies might not play as large a role in galaxy evolution as previously believed.

The new observations were made as part of the Great Observatories Origins Deep Survey, which surveys the distant universe at multiple wavelengths. (ANI)

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