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One islightIts scientific appearance is similar to that of stars and strong radio sources with huge redshift in the radiation spectrum. The other is the radio quiet quasar system.The ultraviolet radiation of the quasar radio source is strong and blue.Since the discovery of quasars in 1963, more than 1000 quasars have been discovered by 1979, of which more than 300 are strong radio quasar radio sources.Some researchers believe that the quasar radio source is a short stage in the evolution of long-lived quasar systems.
If you pressHubble's lawTo calculate the distance of quasi stellar radio sources, they must be very distant objects, so the corresponding radio power is very large.One atcosmologyThe magnitude of output power of typical quasi stellar radio source in distance is 1047 ergs per second, and the brightness is equivalent to the brightest specialRadio galaxy。If these energies are completely generated from nuclear fusion, the required productivity mass is 1010 solar masses.If the quasar radio source is considered to be located not far from the Milky Way, the required output power is 1043 ergs per second.The total energy of a quasar radio source can reach 1062 ergs.With a resolution of a few thousandths of a secondVery long baseline interferometerThe structure of quasi stellar radio sources is observed directly (or by using the lunar mask method). It is found that they are similar to radio star systems and have a certain spacing of twin sources. This structure is a typical radio structure of quasi stellar radio sources.The maximum distance between the two sub sources can reach several hundred thousand light years (for example, the distance between the sub sources of 3C47 is 680000 light years).In addition, the intensity changes of different parts of the quasar radio source at different times are also measured.Radio has power law spectrumSv∝vForm, whereSvIs the flow density of the source,vIs the frequency,αIs the spectrum index,αThe average value of is 0.75.There are some relations between the properties of radio spectrum and other properties.For example, the radio spectrum of quasi stellar radio sources with sub sources is mostly steep, while the quasi stellar radio sources with sub sources that cannot be distinguished in the radio structure are often flat spectrum.The relationship between the frequency spectrum and the quasar radio source over time is that the frequency spectrum of the quasar radio source without optical or radio changes is mostly steep spectrum, while the frequency spectrum of the variable source is often flat spectrum or even inverted spectrum.The flow density of the quasar radio source is less than 100 cm, and is almost variable, especially at the high-frequency end.This change is irregular, sometimes increasing several times suddenly within a few weeks.Since the output power of the radio source is already very large, a few times increase means that a great amount of energy is released.And because the change takes place within a few weeks, the change source must be less than the length of the radio wave (about 1016~1017 cm) in a few weeks.
Einstein shift
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The distance of quasar radio source is far away, and the radial retrogression velocity v is very large. The red shift z should be calculated with the following formula:, wherecIs the speed of light, λ is the wavelength of the spectral line measured in the laboratory,Δλ is the difference between the observed wavelength and the wavelength measured in the laboratory.The spectrum of all quasar radio sources has a large red shift, most of which are greater than 1.The red shift of the quasar radio source OQ172 is as high as 3.53, which is equivalent to the retrogression speed of 91% of the speed of light, that is, 273000 kilometers per second.
Model
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So far, many models have been proposed according to the observation data.The quasar radio source can be divided into at least four parts: ① the main central source has continuous radiation, and the linearity does not exceed 1016~1017 cm (assuming that the quasar radio source is located at the cosmological distance); ②The diameter of the gas shell containing fiber or ionized gas spots is more than 1019~1020 cm; ③The high-frequency part of the quasar radio source is usually variable, and its diameter is no more than 1019~1020 cm; ④The low-frequency part of the quasar radio source is relatively stable, accounting for about 1021~1024 cm in diameter.The above scale refers to the average value. In fact, there are large differences between the sources.The statistical results of the evolution relationship between the two sub sources show that the distance between the two sub sources is an important parameter for the evolution of the quasi stellar radio source.With the increase of the distance between the two sub sources, the optical luminosity and radio luminosity decrease.In the evolution process, the radio spectrum type, that is, the spectrum index, basically remains unchanged.Radio radiation is non thermalSynchrotron radiationOptical radiation is mainly non thermal radiation, but with the evolution of quasi stellar radio sources, the composition of thermal radiation gradually increases (seeThermal radiation and non thermal radiation）。The quasar radio source may be the early stage of the galaxy, but there is no statistical data indicating that the quasar radio source was generated at the same time.
Large redshifts and rapid changes are the most important characteristics of quasi stellar radio sources, which can provide new information for the research of astrophysics and celestial evolution.As for why so much radiant energy is emitted from such a small area in such a short time?Further research is needed.
Bibliography
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G.L.Verschuur and K.I.Kellermann,Galactic andExtragalactic Radio Astronomy, Springer-Verlag,Berlin,1974.
F.Golden, Quasars, Pulsars and Black Holes, Charles Scribner's Sons,New Jersey,1976.
