Astronomers discover supermassive black holes
Washington: Astronomers, using NASA’s Spitzer Space Telescope, have discovered two of the earliest and most primitive supermassive black holes known.
The discovery will provide a better understanding of the roots of our universe, and how the very first black holes, galaxies and stars all came to be.
“We have found what are likely first-generation quasars, born in a dust-free medium and at the earliest stages of evolution,” said Linhua Jiang, a research associate at the University of Arizona’s Steward Observatory.
Quasars are basically hungry supermassive black holes.
As grimy and unkempt as our present-day universe is today, scientists believe the very early universe didn’t have any dust, which tells them that the most primitive quasars should also be dust-free.
But nobody had seen such pristine quasars - until now.
Spitzer has identified two such immaculate quasars – the smallest quasars on record - about 13 billion light-years away from Earth.
The two quasars, called J0005-0006 and J0303-0019, were first unveiled by Xiaohui Fan, a UA professor of astronomy who coauthored the paper.
NASA’s Chandra X-ray Observatory had also observed X-rays from one of the objects.
X-rays, ultraviolet and optical light stream out from quasars as the gas surrounding them is swallowed.
“As surrounding gas is swallowed by the supermassive black hole, it emits an enormous amount of light, making those quasars detectable literally at the edge of the observable universe,” said Fan.
When Jiang and his colleagues set out to observe J0005-0006 and J0303-0019 with Spitzer between 2006 and 2009, their targets didn’t stand out much from the usual quasar bunch.
Spitzer measured infrared light from the objects along with 18 others, all belonging to a class of the most distant quasars known.
Each quasar is anchored by a supermassive black hole weighing more than 100 million suns.
The Spitzer data showed that, of the 20 quasars, J0005-0006 and J0303-0019 lacked characteristic signatures of hot dust.
“We think these early black holes are forming around the time when the dust was first forming in the universe, less than one billion years after the Big Bang,” Fan said.
“The primordial universe did not contain any molecules that could coagulate to form dust. The elements necessary for this process were produced and pumped into the universe later by stars,” he added.