NASA Mystery:- Brilliant Flash from Deep Space
Baffles Astronomers "Unlike Any Ever Seen Before" (VIDEO)
A mysterious X-ray source discovered
in Chandra Deep Field-South data, giving the deepest X-ray image ever made,
became 1,000 times brighter over a few hours before fading dramatically in
about a day. Hubble and Spitzer data indicate this source is likely located in
a small galaxy about 10.7 billion light years from Earth. Evidence points to
this being some sort of destructive event but perhaps unlike any ever seen
before.
Scientists have discovered a
mysterious flash of X-rays using NASA's Chandra X-ray Observatory, in the
deepest X-ray image ever obtained, as reported in our latest press release. The
X-ray source is located in a region of the sky known as the Chandra Deep
Field-South (CDF-S), which is shown in the main panel of this graphic. Over the
17 years Chandra has been operating, the telescope has observed this field many
times, resulting in a total exposure time of 7 million seconds, equal to two
and a half months. In this CDF-S image, the colors represent different bands of
X-ray energy, where red, green, and blue show the low, medium, and high-energy
X-rays that Chandra can detect.
The mysterious source that scientists
discovered, shown in the inset box, has remarkable properties. Prior to October
2014, this source was not detected in X-rays, but then it erupted and became at
least a factor of 1,000 brighter in a few hours. After about a day, the source
had faded completely below the sensitivity of Chandra.
Thousands of hours of legacy data from
the Hubble and Spitzer Space Telescopes helped determine that the event came
from a faint, small galaxy about 10.7 billion light years from Earth. For a few
minutes, the X-ray source produced a thousand times more energy than all the
stars in this galaxy.
While scientists think this source
likely comes from some sort of destructive event, its properties do not match
any known phenomenon. This means this source may be of a variety that
scientists have never seen before.
The researchers do, however, have some
ideas of what this source could be. Two of the three main possibilities to
explain the X-ray source invoke gamma-ray burst (GRB) events, which are jetted
explosions triggered either by the collapse of a massive star or by the merger
of a neutron star with another neutron star or a black hole. If the jet is
pointing towards the Earth, a burst of gamma-rays is detected. As the jet
expands, it loses energy and produces weaker, more isotropic radiation at X-ray
and other wavelengths.
Possible explanations for the CDF-S
X-ray source, according to the researchers, are a GRB that is not pointed
toward Earth, or a GRB that lies beyond the small galaxy. A third possibility
is that a medium-sized black hole shredded a white dwarf star.
Thousands of hours of legacy data from
the Hubble and Spitzer Space Telescopes helped determine that the event came
from a faint, small galaxy about 10.7 billion light years from Earth. For a few
minutes, the X-ray source produced a thousand times more energy than all the
stars in this galaxy.
The mysterious X-ray source was not seen
at any other time during the two and a half months of exposure time Chandra has
observed the CDF-S region. Moreover, no similar events have yet been found in
Chandra observations of other parts of the sky.
This X-ray source in the CDF-S has
different properties from the as yet unexplained variable X-ray sources
discovered in the elliptical galaxies NGC 5128 and NGC 4636 by Jimmy Irwin and
collaborators. In particular, the CDF-S source is likely associated with the
complete destruction of a neutron star or white dwarf, and is roughly 100,000
times more luminous in X-rays. It is also located in a much smaller and younger
host galaxy, and is only detected during a single, several-hour burst.
Additional highly targeted searches
through the Chandra archive and those of ESA's XMM-Newton and NASA's Swift
satellite may uncover more examples of this type of variable object that have
until now gone unnoticed. Future X-ray observations by Chandra and other X-ray
telescopes may also reveal the same phenomenon from other objects.
A paper describing this result appears
in the June 2017 issue of the Monthly Notices of the Royal Astronomical Society
and is available online. NASA's Marshall Space Flight Center in Huntsville,
Alabama, manages the Chandra program for NASA's Science Mission Directorate in
Washington. The Smithsonian Astrophysical Observatory in Cambridge,
Massachusetts, controls Chandra's science and flight operations.
Image credit: oneindia.com