[Music throughout]
From its perch on the International Space Station,
NASA's NICER X-ray telescope has helped map
a mysterious cosmic event for the first time.
It happened in a galaxy 300 million light-years away.
Astronomers call this system Ansky.
Ansky produces a type of recurring X-ray outburst
called a QPE or quasi-periodic eruption.
These events were just recently discovered.
Ansky is only the eighth known QPE emitter and is the most energetic to date.
Some scientists think QPEs occur when a lower mass object
orbits a supermassive black hole in the center of a galaxy.
When the smaller object passes through the disk of gas around the
monster black hole, it produces a cloud of debris
that causes an X-ray outburst.
The low mass object isn't on a circular orbit,
and its motion is affected
by the distortion of space-time near the black hole,
so the eruptions don't repeat over the same exact time frame,
which is what makes them quasi-periodic.
Ansky’s outbursts are the longest of all the QPEs astronomers have studied,
with eruptions every 4.5 days or so that last approximately one and a half days.
That may be caused by a larger disk engulfing an object farther away.
NICER’s observations of Ansky allowed scientists
to probe the gas ejected from the disk after each collision.
They show that it's expelling around a Jupiter’s worth of gas each time.
The gas expands, reaching velocities about 15%
the speed of light
and produces the X-rays we see as QPEs.
NICER and other missions will continue to study Ansky
and other QPEs,
helping astronomers reveal their secrets.
[NASA]