Scientists using observations from two ESA’s spacecrafts have created a multi-wavelength view of cataclysmic events taking place within the giant galaxy of Centaurus A.
Centaurus A is the closest giant elliptical galaxy to Earth, lying at a distance of about 12 million light years. It stands out for harboring a massive black hole at its core and emitting intense blasts of radio waves.
While previous images taken in visible light have hinted at a complex inner structure in Centaurus A, data from ESA’s observatories reveal the unusual structure in much greater detail.
New images taken with the Herschel Space Observatory with unprecedented resolution at far-infrared wavelengths reveal the giant black scar of obscuring dust crossing the centre of Centaurus A all but disappears.
The Herschel data also uncover evidence for intense star birth towards the centre of the galaxy along with two jets emanating from the galaxy’s core – one of them 15000 light years long. Newly-discovered clouds co-aligned with the jets can also be seen in the far-infrared.
“The sensitivity of the Herschel observations enables us to see not only the glow from dust in and around the galaxy, but also emission from electrons in the jets spiraling in magnetic fields at velocities close to the speed of light,” said Dr. Göran Pilbratt, a Herschel project scientist.
ESA’s XMM-Newton X-ray observatory recorded the high-energy glow from one of the jets, extending over 12000 light years away from the galaxy’s bright nucleus. The X-ray view shows not only the way that the jet interacts with the surrounding interstellar matter, but also the galaxy’s intensely active nucleus, and its large gaseous halo.
“XMM-Newton is well suited to detecting extended weak X-ray emission, often allowing us to see halos around galaxies for the first time,” explained Dr. Norbert Schartel, a XMM-Newton project scientist.
The jets seen by both satellites are evidence of the supermassive black hole – ten million times the mass of our Sun – at the centre of the galaxy.
The new data also strengthen the view that the galaxy may have been created by the cataclysmic collision of two older galaxies.