Phenomenon May Trigger Creation Of New Stars, Planets
A powerful jet from a super massive
black hole is blasting a nearby galaxy, according to new data from
NASA observatories. This never-before witnessed galactic violence
may have a profound effect on planets in the jet's path, and
trigger a burst of star formation in its destructive wake.
Known as 3C321, the system contains two galaxies in orbit around
each other. Data from NASA's Chandra X-ray Observatory show both
galaxies contain super massive black holes at their centers, but
the larger galaxy has a jet emanating from the vicinity of its
black hole. The smaller galaxy apparently has swung into the path
of this jet.
This "death star" galaxy was discovered through the combined
efforts of both space and ground-based telescopes. NASA's Chandra
X-ray Observatory, Hubble Space Telescope, and Spitzer Space
Telescope were part of the effort. The Very Large Array telescope
in Socorro, NM, and the Multi-Element Radio Linked Interferometer
Network (MERLIN) telescopes in the United Kingdom also were needed
for the finding.
"We've seen many jets produced by black holes, but this is the
first time we've seen one punch into another galaxy like we're
seeing here," said Dan Evans, a scientist at the
Harvard-Smithsonian Center for Astrophysics and leader of the
study. "This jet could be causing all sorts of problems for the
smaller galaxy it is pummeling."
Jets from super massive black holes produce high amounts of
radiation, especially high-energy X-rays and gamma-rays, which can
be lethal in large quantities. The combined effects of this
radiation and particles traveling at almost the speed of light
could severely damage the atmospheres of planets lying in the path
of the jet. For example, protective layers of ozone in the upper
atmosphere of planets could be destroyed.
Jets produced by super massive black holes transport enormous
amounts of energy far from black holes and enable them to affect
matter on scales vastly larger than the size of the black hole.
Learning more about jets is a key goal for astrophysical
research.
"We see jets all over the universe, but we're still struggling
to understand some of their basic properties," said co-investigator
Martin Hardcastle of the University of Hertfordshire in the United
Kingdom. "This system of 3C321 gives us a chance to learn how
they're affected when they slam into something like a galaxy and
what they do after that."
The effect of the jet on the companion galaxy is likely to be
substantial, because the galaxies in 3C321 are extremely close at a
distance of only about 20,000 light years apart. They lie
approximately the same distance as Earth is from the center of the
Milky Way galaxy.
A bright spot in the Very Large Array and MERLIN images shows
where the jet has struck the side of the galaxy, dissipating some
of the jet's energy. The collision disrupted and deflected the
jet.
Another unique aspect of the discovery in 3C321 is how
relatively short-lived this event is on a cosmic time scale.
Features seen in the Very Large Array and Chandra images indicate
that the jet began impacting the galaxy about one million years
ago, a small fraction of the system's lifetime. This means such an
alignment is quite rare in the nearby universe, making 3C321 an
important opportunity to study such a phenomenon.
It is possible the event is not all bad news for the galaxy
being struck by the jet. The massive influx of energy and radiation
from the jet could induce the formation of large numbers of stars
and planets after its initial wake of destruction is complete.
The results from Evans and his colleagues will appear in The
Astrophysical Journal. NASA's Marshall Space Flight Center,
Huntsville, AL, manages the Chandra program for the agency's
Science Mission Directorate. The Smithsonian Astrophysical
Observatory controls science and flight operations from the Chandra
X-ray Center in Cambridge, MA.