Amsterdam, Nov 26 : New observations made by radio telescopes have revealed that the bizarre astronomical object known as "Hanny's voorwerp", which is a huge green irregular cloud of gas, is being generated by a massive black hole at the centre of a nearby galaxy.
The Voorwerp was discovered by Hanny van Arkel, a Dutch school teacher and an enthusiastic volunteer of the Galaxy Zoo project.
While surfing through hundreds of images, Hanny noticed a huge green irregular cloud of gas of galactic scale, located about 60,000 light years from a nearby galaxy, IC2497.
Astronomers have been baffled by this mysterious object for over a year now.
The extent of the cloud is enormous and the gas is extremely hot, with temperatures exceeding 15000 degrees Celsius, but paradoxically, it is devoid of stars.
Now, an international team of astronomers, led by Professor Mike Garrett, and including Hanny van Arkel herself, have observed IC2497 and the Voorwerp with the Westerbork Synthesis Radio Telescope (WSRT) and an e-VLBI array, in which the WSRT also participated.
The picture that is emerging from these data is that a jet of highly energetic particles is being generated by a massive black hole at the centre of IC2497.
"It looks as though the jet emanating from the black hole clears a path through the dense interstellar medium of IC 2497 towards Hanny's Voorwerp", said Garrett.
"This cleared channel permits the beam of intense optical and ultraviolet emission associated with the black hole, to illuminate a small part of a large gas cloud that partially surrounds the galaxy," he added. he optical and ultraviolet emission heats and ionises the gas cloud, thus creating the phenomena known as Hanny's voorwerp.
"There is a lot of gas out there. The WSRT observations detect a huge stream of gas that is extended across hundreds of thousands of light years", said Dr. Gyula Jozsa, another member of the team.
The total mass of gas is about 5000 million times the mass of the sun, according to Jozsa.
"It has all the hallmarks of an interacting system. The gas probably arises from a tidal interaction between IC 2497 and another galaxy, several hundred million years ago", said Dr. Tom Oosterloo.
According to Oosterloo, "The stream of gas ends three hundred thousand light years westwards of IC2497. All the evidence points towards a group of galaxies at the tip of the stream being responsible for this freak cosmic accident".