WASHINGTON, 24 May 2011. An international team, of which NASA-funded researchers are part, used radio telescopes located throughout the Southern Hemisphere to produce the most detailed image to date of particle jets erupting from a supermassive black hole in a nearby galaxy. The new image shows a region less than 4.2 light-years across and radio-emitting features as small as 15 light-days, resulting in the highest-resolution view of galactic jets ever made.
Researchers for the TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) project using an intercontinental array of nine radio telescopes were able to zoom into the galaxy's innermost realm.
"Advanced computer techniques allow us to combine data from the individual telescopes to yield images with the sharpness of a single giant telescope, one nearly as large as Earth itself," says Roopesh Ojha at NASA's Goddard Space Flight Center in Greenbelt, Md.
"These jets arise as infalling matter approaches the black hole, but we don't yet know the details of how they form and maintain themselves," said Cornelia Mueller, the study's lead author and a doctoral student at the University of Erlangen-Nuremberg in Germany.
Mueller and her team targeted Centaurus A (Cen A) galaxy with a supermassive black hole weighing 55 million times the sun's mass. Also known as NGC 5128, Cen A is located roughly about 12 million light-years away in the constellation Centaurus, and is one of the first celestial radio sources identified with a galaxy. Seen in radio waves, Cen A is one of the biggest and brightest objects in the sky, nearly 20 times the apparent size of a full moon.
Detailed views of the jet's structure will help astronomers determine how they form.
NASA's Fermi Gamma-ray Space Telescope has detected much higher-energy radiation from Cen A's central region. "This radiation is billions of times more energetic than the radio waves we detect, and exactly where it originates remains a mystery," explains Matthias Kadler at the University of Wuerzburg inGermany and a collaborator of Ojha. "With TANAMI, we hope to probe the galaxy's innermost depths to find out."
Ojha is funded through a Fermi investigation on multiwavelength studies of Active Galactic Nuclei.
The astronomers credit continuing improvements in the Australian Long Baseline Array (LBA) with TANAMI's enormously increased image quality and resolution. The project augments the LBA with telescopes in South Africa, Chile, and Antarctica to explore the brightest galactic jets in the southern sky.
NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.
The Australia Long Baseline Array is part of the Australia Telescope National Facility, which is funded by the Commonwealth of Australia for operation as a National Facility managed by the Commonwealth Scientific and Industrial Research Organization.
