Radio astronomers have produced the most complete picture of radio broadcasts from one of the Milky Way’s closest supermassive black holes. The show is fed by the central black hole in the Centaurus A galaxy, about 12 million light years away, and whose manifestation of an eruption occupies on the celestial vault 16 times the size of the Moon.
It was in 1800 that theastronomer William Herschel discovered the first band of radiation beyond the visible for theeye human: theinfrared. The equally invisible ultraviolet band was discovered two years later by the physicist Johann Ritter. For the band radio, it was not until 1888 and the famous experience of Heinrich hertz. About half a century later, radio astronomy will take off and it is a more active field than ever, as shown by the collaboration of theEvent Horizon Telescope and the ongoing development of Square Kilometer Array (SKA).
The Centaurus A radiogalaxy has been studied in several wavelength bands for decades. This is what we can see in the visible, ultraviolet and near infrared with Hubble and what we can already deduce from it. To obtain a fairly accurate French translation, click on the white rectangle at the bottom right. The English subtitles should then appear. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Translate automatically”. Choose “French”. © Hubble, ESA
One of the very first steps towards the SKA has been taken for several years now with the commissioning of the Murchison Widefield Array, also known by the acronym MWA, a radio telescope bass frequencies giant located in Meekatharra in Western Australia. He has just delivered new images of a galaxy mythical that Futura had already spoken about in the previous article below and which has long been the subject of numerous observations both in the visible with Hubble than in the field of X-rays with Chandra : Centaurus A.
It turns out that Centaurus A in the constellation du Centaur was already known to the British astronomer John Herschel, William’s son. But he couldn’t have known that the galaxy that astronomers also call NGC 5128 is located approximately 12 millionlight years and that it is the radiogalaxy closest to the Milky Way. He also couldn’t have known that at its core is a supermassive black hole containing about 55 million people. masses solar (Sagittarius A * only contains around 4.3 million in our Galaxy) and that Centaurus A is probably the result of a past collision between a elliptical galaxy and a spiral. Its current appearance is that of a lenticular galaxy.
A video showing the Centaurus A radio galaxy, which hosts the active galaxy core with a black hole closest to Earth. The video shows the apparent size of the galaxy at visible, x-ray and submillimeter wavelengths of the Earth in relation to the Moon. It then zooms out to show the enormous extent of surrounding bubbles seen at radio wavelengths. © ESO / WFI (Visible) – MPIfR / ESO / APEX / A. Weiss et al. (Submillimeter) – Nasa / CXC / CfA / R.Kraft et al. (X-rays) – Ben McKinley, ICRAR / Curtin and Connor Matherne, Louisiana State University (Radio)
Centaurus A, a multi-wavelength laboratory for studying AGNs
Centaurus A is spectacular in the field of X-rays and even more in radio where we can see jets of matter relativistic spanning about a million light years that end in two bright radio lobes.
These jets originate from what is believed to be a central supermassive black hole and so this is a good example of active galaxy core (AGN) which is also a powerful radio source. The relative proximity of Centaurus A makes it an object of choice for studying this type ofstar cousin of quasars.
We therefore understand why we are trying to have more and more precise observations of Centaurus A and this is what a publication in Nature Astronomy which can also be viewed in free access on arXiv. The main author is theastrophysicist Benjamin McKinley of Curtin University, member of the International Center for Research in Radio Astronomy (ICRAR).
Seen from Earth, theeruption of matter and energy caused by the supermassive black hole of Centaurus is seen thanks to the MWA in unprecedented detail, and the radio-bright regions affected by the particle jets extend eight degrees across the sky, the length of 16 full moons placed side by side.
Combining multiple data wavelengths, not just radio, supports a theory of the growth in size of supermassive black holes in galaxies called ” accretion cold chaotic “(ACC for Chaotic Cold Accretion, in English). According to this theory, clouds Of gas cold condense in galactic halos and then rain down on central regions, fueling supermassive black holes.
We can make a connection with the cold matter filament theory which is the current paradigm of the theory of the joint growth of galaxies and their supermassive black holes.
” Overly greedy supermassive black holes. »All galaxies are home to a supermassive black hole at their center, with a mass of between a million and a few billion solar masses. There is a proportionality relationship between the mass of these black holes and the mass of the bulbous galaxies, which suggests that star formation and black hole feeding occur simultaneously. In a way, galaxies and their black holes grow in symbiosis. When gas falls towards the center of the galaxy, the black hole swallows as much as possible, but the mass it can absorb is limited. The fall of matter on the black hole releases a considerable amount of energy, in the form of radiation, and also in the form of kinetic energy. The core of the galaxy becomes active, either a Seyfert core or a quasar. Winds and plasma jets emitted by the black hole drag the surrounding interstellar gas. Flows of molecular gas have recently been detected around active nuclei, carrying so much mass that they can have a significant impact on the evolution of the host galaxy, regulating or even stopping the supply of gas for star formation. . Gluttonous black holes, by spitting out their food, regulate star formation. We will detail these phenomena, perhaps at the origin of the proportionality between masses of black holes and bulbs. Françoise Combes is an astronomer at the Paris Observatory at the Laboratory for the Study of Radiation and Matter in Astrophysics (Lerma). His current field of research concerns the formation and evolution of galaxies. © École normale supérieure – PSL
The new face of the nearest radiogalaxy, Centaurus A
Article by Laurent Sacco published on 02/01/2009
It is a remarkable image of the galaxy Centaurus A, practically in real life colors, what have just achieved ESO astronomers, using the telescope Atacama Pathfinder Experiment (Apex). It shows with unparalleled clarity the jets and radio lobes of the closest radiogalaxy to the Milky Way.
Located 13 million light-years away from the constellation Centauri, NGC 5128 is the product of the collision of an elliptical galaxy with a spiral galaxy. At its center, a black hole supermassive is therefore copiously supplied with gas and becomes a active galaxy core (NAG) ejecting material halfway through speed of light.
Centaurus A is not an object astrophysics new. The British astronomer John Herschel already knew of his existence in 1847. We have very good examples of him. photographs taken in the visible, in X-rays and especially in radio waves, as shown by the superb images presented here, obtained with the VLT and Chandra. Its record, particularly rich in dust, is striking.
Very active radio jets
Today is the turn of Atacama Pathfinder Experiment (Apex) to bring its harvest of details. This is a radio telescope similar to the prototype of the antennas that will equip the large radio interferometer Atacama Large Millimeter / submillimeter Array (Alma), currently being installed, and which should come into service in 2012.
With a diameter of 12 m, the Apex observes the Universe in the millimeter domain at an altitude of around 5,000 m, on the Chajnantor plateau in the famous Atacama region in Chile. At these wavelengths, and since September 25, 2005, this instrument has been informing us about the galaxies of the young Universe, the galactic jets, the formation of protostars as well in our Galaxy as in very distant galaxies and therefore early in the history of the Universe.
Centaurus A itself is the site of an outbreak of news stars and its central core is particularly bright, both in the field of X-rays and radio waves.
A first composite observation image at several wavelengths had already been given (see above). The news makes the emissions radio lobes created by the shock wave of jets of matter from the central supermassive black hole coming into contact with the intergalactic gas.
This black hole is believed to have at least a mass equivalent to 200 million times that of the Sun. It is notably with the instrument baptized Large APEX Bolometer Camera (Laboca), observing around 870 microns, that one can most clearly photograph the radio lobes. They can be seen in orange in the image below, as well as other details delivered by the radio telescope. In blue are represented the images provided by Chandra in X-rays. As for the rest of the image, more or less in true colors, it concerns the data delivered in the visible by the instrument. Wide Field Imager (WFI) telescope Max Planck Gesellschaft (MPG) 2.2 m from ESO.
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