ESA astronomers have turned the Fermi,Swift and Integral telescopes towards a distant supermassive blackhole, using an opportune gravitational lens to make observations thatwould otherwise have been impossible. The findings represent the first timethat gamma rays have been observed using a cosmic lens.
While the current crop of spacetelescopes are capable of providing some seriously breathtaking viewsof the universe, they're not powerful enough to image the innerregions of black holes, where high speed gamma rays are emitted.
Well, not under their own steam they'renot, anyway. The team of ESA researchers took advantage of analignment of the supermassive black hole PKS 1830-211 (itself billions of light-yearsdistant) and a star – the latter of which sits directly between thetelescopes and the target.
The effect is known as gravitationallensing, wherein the gravity of the obscuring object causes the lightfrom the target to flow around it, much like a gigantic magnifyingglass. Astronomers have made use of such cosmic lenses multiple times, using them to observe colliding galaxies, supernova explosions and more.
The team equates the sheer distancebetween the Earth and the black hole in question as being likeattempting to spot an ant on the moon, with the width of the distantpatch of sky measuring around 100 times the distance between theEarth and Sun.
The observations show that the gammarays are emitted directly from the vicinity of the black hole, givingscientists key information about the nature of the huge jets ofhigh-energy photons.
Three space telescopes workedtogether to make the observations, building a complete picture of thegamma rays streaming out of the black hole region. NASA's Fermiobservatory gathered data on the highest energy rays emitted at thebase of the jets, while ESA's own Integral was used to look atthe less energetic particles in the surrounding area. Integral alsoteamed up with the Swift telescope to study emitted X-rays in theregion surrounding the black hole.
Overall, the observations could have abig effect on our understanding of supermassive black holes,providing new, unique information about the high-energy processespresent.
"This black hole is one of themost powerful known objects of its kind," says ESA's Integral project scientist Erik Kuulkers. "Fully characterizing itsemission will hopefully give us real insight into how these jetsform."
Source: ESA
