Last year,
astronomers discovered an inactive black hole in a distant galaxy that explodes
after grate and consuming a passing star. Identified Researchers now have a
distinctive X-ray signal in the days Observed Following The explosion that
comes from matter on the edge of falling into the black hole.
This tell-tale
signal, called a quasi-periodic oscillation or QPO,
is a characteristic feature
of the accretion disks surrounds That Often The Most compact objects in the
universe - white dwarf stars, neutron stars and black holes. QPOs Have Been
Seen in Many stellar-mass black holes, and there is tantalizing evidence for
them in a few black holes middleweight that May have masses between 100 and
100.000 times the sun's.
Until the new
finding, had been detected QPOs around only one supermassive black hole - the
type Containing millions of solar masses and located at the centers of
galaxies. That object is the Sifter-type galaxy REJ 1034 +396, at a distance of
Which 576 million light-years relativamente lies nearby.
"This
discovery extends our reach to the innermost edge of a black hole located
billions of light-years away, which is really amazing. This gives us an
opportunity to explore the nature of black holes and test Einstein's relativity
at a Time When the universe was very different than it is today, "said
Rubens Reis, an Einstein Postdoctoral Fellow at the University of Michigan in
Ann Arbor. That Reis led the team uncovered the QPO signal using data from the
orbiting Suzuki and XMM-Newton X-ray telescopes, to finding Described in a
paper published today in Science Express.
The X-ray source
Swift J1644 +57 Known as - after its astronomical coordinates in the
constellation Draco - was discovered on March 28, 2011, by NASA's Swift
satellite. It was originally assumed to be a more common type of outburst
called a gamma-ray burst, but its gradual fade-out had been matched that
nothing seen before. Astronomers soon converged on the notion That They Were
seeing what was the aftermath of a truly extraordinary event - the awakening of
a distant galaxy's dormant black hole as it shredded and gobbled up a passing
star. The galaxy is so far away from the event that light had to travel 3.9
billion years before reaching Earth.
The star
experienced intense tides as it reached its closest point to the black hole and
was torn apart quickly. Some of its gas fell toward the black hole and formed a
disk around it. The innermost part of this disk was heated to temperatures of rapidly
millions of degrees, hot enough to emit X-rays. At the same time, through still
not fully Understood Processes, oppositely directed jets perpendicular to the
disk Formed near the black hole. These jets blasted outward at velocities
matter Greater than 90 percent the speed of light along the black hole's spin
axis. One of these jets happened to point straight just at Earth.
Nine days after
the outburst, Reis, Strohmayer and Their colleagues Observed Swift J1644 +57
using Suzuki, an X-ray satellite operated by the Japan Aerospace Exploration
Agency with NASA participation. About ten days later, then They Began to longer
monitoring campaign using the European Space Agency's XMM-Newton observatory.
"Because
matter in the jet was moving so fast and was angled nearly into our line of sight,
the effects of relativity boosted its X-ray signal enough That We Could catch
the QPO, Which Otherwise Would Be Difficult to detect at so great a distance,
"said Tod Strohmayer, an astrophysicist and co-author of the study at
NASA's Goddard Space Flight Center in Greenbelt, Md.
As hot gas in
the innermost disk spirals toward a black hole, astronomers point it Reaches to
refer to as the innermost stable orbit round (ISCO). Any closer to the black
hole and plunges into the gas rapidly event horizon, the point of no return.
The inward spiraling gas tends to pile up around the ISCO, where it becomes
tremendously heated and radiates a flood of X-rays. The brightness of These
X-rays varies in a pattern repeats that interval at a nearly regular basis,
creating the QPO signal.
The data show
That Swift J1644 +57' s QPO cycled every 3.5 minutes, Which places its source
region Between 2.2 and 5.8 million miles (4 million km to 9.3) from the center
of the black hole, the exact distance Depending on how fast the black hole is
rotating. To put this in perspective, the maximum distance is only about 6
times the diameter of our sun. The distance from the QPO region to the event
horizon depends on rotation speed Also, but for a black hole spinning at the
maximum rate Allows theory, the horizon is just inside the ISCO.
"QPOs send
us information from the very brim of the black hole, where the effects which is
of relativity Become Most Extreme," Reis said. "The Ability to gain
insight into These Processes Such a vast distance over is a truly beautiful and
holds great promise result."
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