Astronomers follow twin jets to the center of an active galaxy

BONN, Germany, Sept. 19 (UPI) -- Astronomers have developed a new method for locating the heart of an active galaxy. In a new study, researchers with the Max Planck Society traced the origin of a pair of relativistic jets by measuring the magnetic field surrounding a supermassive black hole.

Previously, researchers have located the centers of galaxies by tracing the wavelengths of relativistic jets to their convergence point. Relativistic jets are the streams of X-rays emitted along the axis of rotation of a black hole and its accretion disk.

Unfortunately, measuring the physical properties of twin jets is prohibitively difficult in many active galaxies. Scientists say their new method, called very-long-baseline interferometry, may offer a more reliable way to locate the heart of an active galaxy.

Instead of measuring the wavelengths of a pair of jets, researchers measured the magnetic fields surrounding them. Astronomers recently used the method to pinpoint the activity center of NGC1052, an elliptical galaxy located 60 million light-years away.

Scientists measured the magnetic field by imaging the compactness and brightness of the galaxy's central region, using a series of radio telescopes at observatories all over the world -- a collection known as the Global mm-VLBI Array.

"It yields unprecedented image sharpness, and is soon to be applied to get event-horizon scales in nearby objects," MPI astronomer Eduardo Ros said in a news release.

The symmetry of the magnetic field lines surrounding the galactic center allowed astronomers to track the relativistic jets to a base point.

The research, detailed in the journal Astronomy & Astrophysics, marks the most precise location of a supermassive black hole outside the Milky Way. The findings may also help astronomers understand how relativistic jets are formed and powered by the magnetic energy generated by the rotation of a black hole and its accretion disk.