A montage of images showing an artist's concept of NuSTAR (top); a color
image of one of the galaxies targeted by NuSTAR (lower left); and
artist's concept of a hidden black hole. Image credit: Top:
NASA/JPL-Caltech. Lower-left: Hubble Legacy Archive, NASA, ESA.
Bottom-right: NASA/ESA. › Full image and caption
Some of the "biggest and baddest" black holes around are buried under
thick blankets of gas and dust. These monsters in the middle of
galaxies are actively devouring material, but their hidden nature makes
observing them a challenge.
NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) recently caught
a glimpse of five of these secluded beasts. While hidden from view from
most other telescopes, NuSTAR can spot them by detecting the
highest-energy X-rays, which can penetrate through the enshrouding gas
and dust.
The research, led by astronomers at Durham University, United
Kingdom, supports the theory that potentially millions of supermassive
black holes exist in the universe hidden from view. The findings were
presented today, July 6, at the Royal Astronomical Society's National
Astronomy Meeting in Llandudno, Wales.
The scientists pointed NuSTAR at nine galaxies where supermassive
black holes were thought to be extremely active but largely obscured.
Five of these candidates were found to contain hidden supermassive black
holes, feasting on surrounding material. What's more, the objects were
observed to be more active than previously thought.
Such observations were not possible before NuSTAR, which launched in
2012 and is able to detect much higher-energy X-rays than previous
satellite observatories.
"Thanks to NuSTAR, for the first time, we have been able to clearly
identify these hidden monsters that are predicted to be there, but have
previously been elusive because of their surrounding cocoons of
material," said George Lansbury of Durham University, lead author of the
findings accepted for publication in The Astrophysical Journal.
"Although we have only detected five of these hidden supermassive
black holes, when we extrapolate our results across the whole universe,
then the predicted numbers are huge and in agreement with what we would
expect to see."
Daniel Stern, the project scientist for NuSTAR at NASA's Jet
Propulsion Laboratory in Pasadena, California, added: "High-energy
X-rays are more penetrating than low-energy X-rays, so we can see deeper
into the gas burying the black holes. NuSTAR allows us to see how big
the hidden monsters are, and is helping us learn why only some black
holes appear obscured."
The research is funded by the Science and Technology Facilities Council.
NuSTAR is a Small Explorer mission led by the California Institute of
Technology in Pasadena and managed by NASA's Jet Propulsion Laboratory,
also in Pasadena, for NASA's Science Mission Directorate in Washington.
The spacecraft was built by Orbital Sciences Corporation, Dulles,
Virginia.
For more information, visit: http://www.nasa.gov/nustar - http://www.nustar.caltech.edu
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Jet Propulsion Laboratory, Pasadena, California
818-354-4673
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Source: NASA/JPL-Caltech