By combining the VLBA radio telescopes and instruments involved in gamma, astronomers have observed the central black hole of the famous radio galaxies M87 more precisely than ever . They have concluded that it is in their immediate environment the powerful gamma eruptions occurs.

When a black hole is surrounded by a disk of matter spiraling toward the event horizon (surface defining the region of space-time occupied by this star and where not even light can escape),  large amounts of gravitational energy can be converted into bursts of radiation in the radio operator fields, X and gamma.

In the case of a central black hole in a galaxy, the energy released by the accretion process becomes monstrous and, coupled with the processes of relativistic magnetohydrodynamics complex due to the rotation of the black hole, it explains the power of active galactic nuclei as quasars.

The radio galaxy M87 is one of the most studied by astronomers and astrophysicists. It is located at 55 million light-years or so and it boasts a powerful jet of material emitted by its central black hole whose mass is estimated at six billion solar masses. It has to be 120 hours of observations conducted using radio telescopes of the Very Long Baseline Array (VLBA) and three other instruments examining the secrets of the cosmos in gamma.

VLBA radio telescopes

By combining radio telescopes around the Globe, it is possible to obtain images at very high resolution, as if we had an antenna of several thousand kilometers in diameter. The objective of the researchers was to try to locate where exactly in M87 the eruptions in the gamma field occurred, which we knew they were associated with bursts of radio waves of longer periods.

It was of course natural to imagine that these emissions, intense but short, of photons of the thousands of billion times energy than the Sun in the visible range should occur in the accretion disc of the black hole of supermassive black hole M87, or at least in its draft energy particles.

A diagramatic representation of the disk of dust and gas spiraling toward a giant black hole rotation. Two jets of matter particles and photons at different wavelengths are emitted. The black dot in the center of the accretion disc is the black hole

But sometimes the universe defies theories the most rational and logical. From January to May 2008, the three most sensitive instruments in the field of gamma photons of extremely high energies, Veritas, HESS and Magic observed M87 for a total of 120 hours, jointly with the VLBA.

Two gamma-ray bursts have been detected in M87 and, as in the case of the first observations of this kind in 1998, followed by those of 2006, a variability of gamma photon flux for a few days was measured. This implies that the size of the source can not be itself, to the maximum as the magnitude of the distance traveled by light during this period. This was therefore consistent with the hypothesis that it was in close connection with the central black hole of this elliptical galaxy where the gamma eruptions occur.

As the images obtained with the extraordinary power of resolution of the VLBA radio is actually very close to the black hole where the generation of gamma photons and radio bursts occur. The accuracy obtained is such that astronomers now know that flares occur are only 50 times the size of the horizon of the supermassive black hole in M87.

Researchers now believe that gamma erruption and radio start with the ejection of a burst of particles traveling at nearly the speed of light in the jet of M87 matter. As the burst of particles dissolved in the jet, the gamma emissions cease fairly quickly but the radio increases in intensity for at least two months.

A short video regarding the M87 elliptical galaxy.