Hercules A is an elliptical galaxy about two billion light-years from the Milky Way. About 1,000 times more massive than our Galaxy, it features a central black hole 2.5 billion solar masses. We see in the visible in this photo taken by Hubble on which was superimposed a picture made in the field of radio waves by the VLA. Then reveal two radio lobes produced by relativistic jets of long terms of several million light years. It is this kind of objects that astronomers behind the Radio Galaxy Zoo want to identify in the observable universe to better understand the origin of supermassive black holes. © NASA, ESA
hunter supermassive black holes with Radio Galaxy Zoo – Photo 1
born supermassive black holes at the center of galaxies? Where do these monsters rotation containing a few million to a few billion solar masses and are at the origin of quasars and active galactic nuclei come from? We do not really know, although several theories have been proposed in recent decades. They are believed to evolve along with the host galaxies since they are often about a thousand times more massive than the compact stars giants.
For a long time it was thought that supermassive black holes grew larger during collisions between galaxies. Which resulted in the completion of the merger of two black holes they contained and brought fresh gas to the final black hole. The black hole thus produced is then surrounded by an accretion disk, and also flashed tremendous jets of relativistic material forming particularly bright lobes in the field of radio waves. This simple and plausible picture is blurred in recent years. We do not know very well what is the proportion of collisions between galaxies and the intergalactic filaments drop of cold material on the horizon of these black holes in their growth process.
A huntingactive galactic nuclei
To see more clearly, it would have a large number of observations of supermassive black holes in the process of accreting large amounts of material over a long period in the history of the observable universe. These black holes are reporting emissions by some infrared band and the presence of bright radio lobes, you should start looking for objects with these characteristics.
This video first shows a visible image of the giant elliptical galaxy Hercules A. We then see images of the radio lobes caused by jets of matter from the supermassive black hole at the heart of Hercules A. © NASA, ESA
The good news is that collection of images containing such objects have already been made. There was, for example, the observation campaign Faint Images of the Radio Sky at Twenty-Centimeters (First). It has provided about 175,000 pictures during a deep survey of a large part of the sky. First was conducted between 1993 and 2011 with 27 radio telescopes of the VLA (Very Large Array).
In the infrared range, supermassive black holes lurk in the data collected from 2009 to 2011 by Wise (Wide-Field Infrared Survey Explorer). Its 175,000 images can be compared with those of First. Spitzer, after exhausting its cooling system with helium, still remained able to perform infrared observations reveal the existence of supermassive black holes in the 6,000 pictures he has taken.
The bad news is that all radio sources are not lobes of active galactic nuclei. And it is not easy to associate with a computer, radio broadcasts an infrared source from a supermassive black hole.
Imagesradio to associate with infrared images of Wise
Fortunately, the capabilities of visual association of a human brain are much higher than those of computers for certain tasks and in particular to correlate the observations with those of First Wise and Spitzer. That is why astrophysicists are put online Radio Galaxy Zoo in the famous Zooniverse. This citizen science portal well known is an extension of the original Galaxy Zoo project, which invited users to classify galaxies. Recently, they were on the hunt for exoplanets that invited them all.
Today, you can help astrophysicists to discover supermassive black holes and especially to understand their origin and history, which is probably also the birth and evolution of galaxies. Just click on Radio Galaxy Zoo …
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