Galaxy Centaurus A, “hid” very interesting secret. Astronomers have discovered that around this giant galaxy in the same plane rotate several dwarf galaxies, how the planets revolve around stars or stars that revolve around galactic centers. The interest of this discovery is due to the fact that it brings scientists to review their attitude to the theory that dwarf galaxies revolve around larger in all directions, for example, like bees around the hive, that is more chaotic, not more systematically how objects (planets and stars), described above. About their work, the researchers shared in the journal Science.
Galaxy Centaurus A is located approximately 10 to 16 million light years from the Solar system and is located in the constellation of Centaurus. It is very close, but nevertheless not part of the Local group of galaxies and is the nearest active galaxy, which means that she is very bright and is a very powerful source of radio emission. In addition, it has an unusual shape is a lenticular galaxy with a polar ring. And now the Centauri A was also the first galaxy beyond the Local group, which scientists have discovered a dwarf galaxy satellites rotating in the same plane.
The milky Way and Andromeda, too, are dwarf galaxies, rotating them in the same plane, however, the cosmological model built on the standard model Lambda-CDM, predict that they are often more compact galaxy revolve around the bigger it randomly, moving in all directions, which in turn makes the milky Way and Andromeda is an exception to this rule. However, the new observation of Centaurus A refutes this conclusion.
“Model of the Lambda-CDM has forced astronomers to believe that the most studied galaxy in the Universe – the milky Way and Andromeda – stand out among all the other” — explains the researcher Helmut Jerjen from the Australian national University research school of astronomy and astrophysics.
“But it looks like our milky Way and Andromeda are quite a normal, and galaxies rotating in the same plane with other galaxies, in fact, quite common in the Universe.”
And yet the rotation of galaxies-satellites is somewhat different from the rotation of planets around their stars. The latter, as a rule, wrapped around the equator of their bodies. As for galaxies-satellites, such as those that revolve around Centauri A, as, however, and around the milky Way, and Andromeda, they are circling around the larger galaxies perpendicular to their Equatorial plane, i.e. around the poles of the supermassive black holes located at their centers.
Model the rotation of dwarf galaxies around the galaxy Centaurus A
The researchers say that the detection of the galactic plane to the milky Way and Andromeda is quite simple. While on Earth, you need to take pictures of the sky every few years and to see where in this moment are the stars. From Andromeda is located about 2.5 million light-years, therefore, perpendicular to the plane of rotation of dwarf galaxies also find is not difficult.
With the plane of Centaurus A it’s more complicated. However, there is a huge amount of archival data collected about this galaxy allowed the team of scientists to detect information about at least 16 dwarf galaxies, orbiting around it. And the Doppler effect allowed us to determine the direction in which the dwarf galaxy is moving.
“We found that half of them have a redshift, meaning they are moving away from us, while the other half has a blue shift, which suggests that on the contrary, they are moving in our direction,” explains astronomer of Marcel Pawlowski of the University of California, Irvine (USA).
Based on this, researchers found that 14 of the 16 galaxies-satellites have the same plane of rotation. For example, the milky Way of the 11 galaxies, satellites only 8 rotate in the same perpendicular plane. And among the 27 detected galaxies around Andromeda is perpendicular to the plane of rotation have 15.
As the discussed phenomenon was observed for the third time, according to the researchers, the random factor can be safely discarded. In addition, it also suggests that this phenomenon needs to meet more often than previously thought – according to standard models, this feature should be only 0.5 per cent of our neighboring galaxies. But we see that it is not.
“This means that we missed something,” says Pawlowski.
“Either simulation models have some shortcomings or our conventional model actually turned out to be wrong. The results of this study can be a starting point in the search for alternative models to explain our observation.”
Head of research Oliver müller of Basel University (Switzerland) added that the results also support the idea that collisions between large galaxies (which happens quite often) can generate dwarf galaxies from discarded as a result of these collisions of matter, drawn by tidal forces.