PASADENA, Calif. - Astronomers have unmasked hundreds of black holes
hiding deep inside dusty galaxies billions of light-years away.
The massive, growing black holes, discovered by NASA's Spitzer and
Chandra space telescopes, represent a large fraction of a long-sought
missing population. Their discovery implies there were hundreds of
millions of additional black holes growing in our young universe, more
than doubling the total amount known at that distance.
"Active, supermassive black holes were everywhere in the early
universe," said Mark Dickinson of the National Optical Astronomy
Observatory in Tucson, Ariz. "We had seen the tip of the iceberg before
in our search for these objects. Now, we can see the iceberg itself."
Dickinson is a co-author of two new papers appearing in the Nov. 10
issue of the Astrophysical Journal. Emanuele Daddi of the Commissariat
a l'Energie Atomique in France led the research.
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.
For decades, a large population of active black holes has 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. As the gas and dust are devoured by the black hole, they
heat up and shoot out X-rays. Those X-rays can be detected as a general
glow in space, but often the quasars themselves can't be seen directly
because dust and gas blocks them from our view.
"We knew from other studies from about 30 years ago that there
must be more quasars in the universe, but we didn't know where to find
them until now," said Daddi.
hiding deep inside dusty galaxies billions of light-years away.
The massive, growing black holes, discovered by NASA's Spitzer and
Chandra space telescopes, represent a large fraction of a long-sought
missing population. Their discovery implies there were hundreds of
millions of additional black holes growing in our young universe, more
than doubling the total amount known at that distance.
"Active, supermassive black holes were everywhere in the earlyuniverse," said Mark Dickinson of the National Optical Astronomy
Observatory in Tucson, Ariz. "We had seen the tip of the iceberg before
in our search for these objects. Now, we can see the iceberg itself."
Dickinson is a co-author of two new papers appearing in the Nov. 10
issue of the Astrophysical Journal. Emanuele Daddi of the Commissariat
a l'Energie Atomique in France led the research.
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.
For decades, a large population of active black holes has 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. As the gas and dust are devoured by the black hole, they
heat up and shoot out X-rays. Those X-rays can be detected as a general
glow in space, but often the quasars themselves can't be seen directly
because dust and gas blocks them from our view.
"We knew from other studies from about 30 years ago that there
must be more quasars in the universe, but we didn't know where to find
them until now," said Daddi.
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