Why galaxies with strange appearanceCen A , there will be so much dust?The spectacular dust belt passing through the center of the galaxy isCen A These dust belts are so thick that they almost completely cover the core of the galaxy in visible light.Because Centaur A is a giantElliptical galaxyIt also has many red stars, which should reasonably contain a small amount of dust, so its dust belt is a very unusual feature.Centaurus A is also calledNGC 5128In addition to the dust belt mentioned above, it also contains a higher ratio of blue young stars compared with ordinary elliptical galaxies, and is a strong source of radio radiation.Evidence suggests that Centaurus A may be the product of the collision of two normal galaxies.During the collision, many young stars were born, but the details of how the unusual dust belt in Centaurus A formed still need further exploration.Centaurus A is only 13 million light-years away from us, so it is the nearest active galaxy.Centaurus A is located in Centaurus in the southern sky, about 60000 in sizeLight year, usingBinocularsYou can see it.
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About 12 million light years away from us, NGC 5128 is the nearest large-scaleElliptical galaxy。This unusual galaxy is one of the most widely studied objects in the southern sky.In the visible light image, we can see a wide dust belt in its center, which shows that it met and merged with another spiral galaxy billions of years ago.Recent studies have shown that it also swallowed up another smaller galaxy hundreds of millions of years ago.Astronomers also found that it has nearly 2000Globular cluster, which is much more than the number in our entire galaxy cluster.Some clusters are so huge that they are close to the mass of a dwarf galaxy.Astronomers suspect that these globular clusters may be the cores left behind by the swallowed dwarf galaxy.
Although NGC 5128, which is more than 60000 light-years in size, is already a huge galaxy, it is even more amazing in the radio image.It has a pair of giant radio valves nearly one million light years wide, spanning the sky more than ten degrees!In fact, NGC5128 is the strongest radio source in the southern sky, second only to Cygnus A in the north.So it is also called Centaurus A.The reason why such a strong radio wave is generated is that there is aSupermassive black hole。Astronomers estimate that the mass of this black hole is about 55 million suns!Use multiple groups on the earthradio telescopeAstronomers also carefully observed the super jet of the black hole.Because of some functions that have not yet been fully understood, when matter falls into a black hole, these strong jets are produced.These substances are ejected at a speed of up to half the speed of light and collide strongly with the nearby gas, generating a large amount of radio, X-ray and gamma ray radiation.
Cen A Is located inCentaurIt is about 14 million light years awayLenticular galaxy(elliptical galaxy).It is one of the radio wave sources closest to the earth and is widely studied by professional astronomersActive galactic nucleus。This galaxy is also the fifth brightest galaxy in the day, so even if this galaxy can only be seen in the low latitudes of the southern and northern hemispheres, it is still an ideal target for amateur astronomers.Relativistic jetIt is believed that the energy ofSuperheavy black holeThe nearby space ejects, radiatesX-rayandradio wavesThe wavelength of.By observing the radio waves of the jet at ten year intervals, astronomers determined that the moving speed of the inner part of the jet reachedlight speedHalf of.X-rays are produced when energetic particles in the jet collide with the surrounding gas at a further distance.
Maybe Centaurus A is classified asSpecial galaxySeen from Earth, this galaxy seems to be added with a dust beltBiconvex lens galaxyorElliptical galaxy。This particular galaxy was first discovered in 1847John Herschel Found and included inAtlas of special galaxies(Arp) (published in 1966), as the best example of galaxies with internal absorption interference.The strange shape of this galaxy is believed to be that two smaller galaxies aremergeThe results of the intermediate stages of the process.
The main member of this galactic nucleus sphere is the evolving redfixed star。The dusty disk is still in the near futureStar formationThe main site of;It has been confirmed that more than 100 stars are forming in the disk.
Supernova
One was found in Centaurus ASupernovaThis supernova is calledSN 1986G, is REvans found it in the dust belt in 1986, which was later identified as aIa supernova。Ia supernova is of the maximum massWhite dwarf, a supernova that explodes because it cannot support its own mass, usuallyConjoint starThe white dwarf star in the middle is formed by the gas accretion mass stripped from its companion star.The spectrum of SN 1986G is not exactly the same as that of Ia supernova used for identification. Maybe Ia supernovae change as their luminosity changes with time.
Information on neighboring galaxies and galaxy groups
Centaur A is located inCentaurus A/M83 Galaxy GroupThe central position of one of the two sub groups ofGalaxy cluster。M83(Southern Pinwheel ）At the center of another group, sometimes these two groups are considered as one group, and sometimes they are considered as two groups.However, the galaxy surrounding Centaurus A and M83 are actually very close, and there is mutual movement between the two groups.
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Centaur A is located inCentaur omega(A visibleGlobular cluster）About 4 ° north.Because of its high surface brightness and relatively large viewing angle, this galaxy is an ideal target for amateur astronomical observation.The bright nuclear sphere and the black dust belt are looking for astroscopes and largeBinocularsOther structures can only be seen with larger telescopes.
