A cannibal galaxy with a powerful core has been revealed by two new images from the Herschel Space Observatory and the XMM-Newton x-ray satellite.
The European Space Agency's space observatories' multi-wavelength view of the "mysterious" elliptical galaxy Centaurus A, show that it's a result of two galaxies colliding, with one being subsumed by the other.
Professor Christine Wilson of McMaster University, Canada, who is leading the study of Centaurus A with Herschel, said: "Centaurus A is the closest example of a galaxy to us with massive jets from its central black hole. Observations with Herschel, XMM-Newton and telescopes at many other wavelengths allow us to study their effects on the galaxy and its surroundings."
The powerful core revealed by the ESA's new images feature two massive jets of material streaming from a massive black hole in its heart. The jets stretch for up to a million light years.
Using x-rays, the ESA has determined that the two jets of material contain extremely hot gas. While the second jet itself is not seen by XMM-Newton, the gas it streams into is shocked and heated to very high temperatures, creating a bright x-ray glow.
"XMM-Newton is the observatory most suited to detecting extended weak X-ray emission, often allowing us to see halos around galaxies for the first time," notes Norbert Schartel, XMM-Newton Project Scientist.
Centaurus A is 12 million light years from earth, and the closest large elliptical galaxy to the Milky Way.
First discovered in the 19th century, it was been hidden behind a thick lane of dust until a century later, when its elliptical nature was revealed.
This elliptical shape of Centaurus A tells ESA scientists that one galaxy consumed another in a cosmic collision in the distant past. The formation of young stars heats the resulting dust to cause the infrared glow seen by Herschel.
"The apparent alignment of two clumps with the two jets now seems to be a cosmic coincidence, and it appears that the dust originated from one of the colliding galaxies." explained Dr Robbie Auld, of Cardiff University.
"Unlike most dust Herschel sees, which is heated by nearby star formation, the dust in these clumps is being heated by old stars in Centaurus A itself, up to 50,000 light years away."
"This could be due to intense x-rays destroying the tiny dust grains, or due to the way the warped ring of dust is affecting star formation" said Prof Wilson.
"Either way, Centaurus A is the ideal place to study the extreme processes that occur near super-massive black holes".
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