21/12/2017
What are quasars?
The expanses of the Universe do not cease to amaze terrestrial observers with a variety of mysterious objects, and one of the incredible discoveries of cosmology of the past century has become quasars!
General information.
These sparkling objects emit the most significant amount of energy found in the universe. Being at a colossal distance from the Earth, they demonstrate greater brightness than the cosmic bodies located 1000 times closer. According to the modern definition, a quasar is the active core of a galaxy, where processes that release a huge mass of energy take place. The term itself means "star-like radio source". Precisely because of electromagnetic radiation and a significant redshift, open objects were identified as new, located on the boundaries of the universe.
Quasars secrete 100 times more energy than the aggregate of all the stars in our galaxy. Most quasars and us share 10 billion light years, and reached the Earth their light was sent even before the process of its formation. Initially, it was assumed that all pseudo stars are powerful sources of radio emission, but by 2004 it became known that, it turns out, there are very few of these - about 10%, while the rest are considered radio-quiet.
The history of the discovery.
The first quasar was seen by American astronomers A. Sendij and T. Mathews, who observed the stars in the California observatory. In 1963, M. Schmidt, using a reflex telescope that collected electromagnetic radiation at one point, detected a deviation in the spectrum of the observed object to the red side, which determines that its source is moving away from our system. Subsequent studies have shown that the celestial body, recorded as 3C 273, is at a distance of 3 billion St. years and retreats at a tremendous speed - 240 000 km / s. Moscow scientists Sharov and Efremov studied the available early photographs of the object and found that he repeatedly changed his brightness. Irregular changes in the intensity of light assume a small size of the source.
Structure and theory of origin.
Quasars and the process of their powerful radiation are still not fully understood. Several versions are considered, explaining what they are in fact.
Most astrophysicists tend to assume that this is a black hole of a giant scale that absorbs the surrounding matter. Under the influence of attraction, the particles gain enormous speed, stumble against each other and strike, their temperature rises from this, a visible glow appears. The irresistible attraction of the energy of a black hole causes the substance to move to the center in a spiral and turn into an accretion disk - a structure that arises when falling particles turn to a massive cosmic body. The magnetic induction of a black hole sends a part of matter to the poles, where jets are created-narrow beams emitting radio waves. At the edges of the accretion disk, the temperature decreases, and the wavelength increases to the infrared spectrum.
Another hypothesis considers quasars to be young galaxies during their formation. There is an option combining two versions, according to which a black hole absorbs the incipient substance of the galaxy. The number of quasars found by 2005 was 195,000, but this process is continuous, new facilities are constantly being opened.
Unusual properties.
Quasar activity varies in all ranges: infrared and ultraviolet waves, visible light, X-rays, radio waves. The magnitude of its energy is 1 million times greater than that of any open star. Variations in the luminosity of an object occur at different time intervals, from one year to a week. Such oscillations are characteristic for cosmic bodies, the size of which is within the limits of the light year.
Interesting Facts.
To denote the degree of "reddening" of quasar light, the letter z (redshift) is used. In the early 80's, several extremely remote celestial objects were found, in which z = 4.0. Their radio signal started before the beginning of the birth of our galaxy. Recently, a quasar has been observed, having a displacement z = 6.42, that is, the distance to it is more than 13 billion light years. The energy emitted by a small pseudo-star can give Earth a supply of electricity a few billion years ahead. These are dangerous neighbors, and their bright light, which we see, is the glare from the substance of a young galaxy that has disappeared into the black hole. Fortunately, there is no question of a threat to our planet - such phenomena are not seen in the nearest galaxies. Observation of the oldest objects that have become coevals of the Universe has shown that it is not just increasing,
The Milky Way has a supermassive black hole in the center, and its food is over. It does not have an active galactic core, and therefore we do not seem to be a quasar for any distant galaxy. We could be in the past, and we can become in the future. In ten billion years or so, when the Milky Way encounters Andromeda, our supermassive black hole can return to life as a quasar, consuming all this new stuff.
