Since ancient times, astronomers love order - everything is counted, classified and identified. However, the night sky never ceases to amaze attentive observers and constantly throws new and unknown objects into star catalogs. Quasars, discovered just 40 years ago, have seriously puzzled scientists with their phenomenal brightness and compact size. And only recently have astrophysicists been able to understand where these “dinosaurs of the Universe” get the energy necessary to shine in the starry sky with such amazing brightness.

In the photo: a star caught in the gravitational field of a massive black hole is first torn apart by tidal forces, and then, in the form of a brightly glowing, highly ionized gas, is absorbed by the black hole. After such an “acquaintance,” all that remains of the star is a small, rarefied cloud rotating around the black hole.

"Unnecessary" discovery

In 1960, astronomers T. Matthews and A. Sandage, working on a 5-meter telescope located on Mount Palomar in California, discovered an unremarkable 13th magnitude star, barely visible in an amateur telescope, observed in the constellation Virgo. And it was from this spark that the flame ignited!

It all started with the fact that in 1963 Martin Schmidt discovered that this object (according to catalog 3C 273) has a very large redshift. This means that it is located extremely far from us and is very bright. Calculations showed that 3C 273 is located at a distance of 620 megaparsecs, and is moving away at a speed of 44 thousand km/s. You cannot see an ordinary star from such a distance, and the quasar, being very small, did not look like a large star system, such as a galaxy.

Also in 1963, 3C 273 was identified with a powerful radio source. Radio telescopes then were not as accurate in determining the direction of arrival of radio waves as they are now, so the stellar coordinates of the quasar 3C 273 were determined by observing its lunar occultation at the Parksky Observatory in Australia. Thus, a completely unusual object appeared before the amazed eyes of astrophysicists, sparkling brightly in the visible and radio range of electromagnetic waves. At the moment, more than 20 thousand such star-like objects have been discovered, some of which are also clearly visible in the X-ray and radio range.

Moscow astronomers A. Sharov and Yu. Efremov decided to find out how the luminosity of 3C 273 changed in the past. They found 73 photographs of the object, the earliest of which dated back to 1896. It turned out that object 3C 273 changed its brightness several times by almost 2 times, and sometimes, for example, in the period from 1927 to 1929, by 3-4 times.

It must be said that the phenomenon of variable brightness was discovered even earlier. Thus, studies carried out at the Pulkovo Observatory in 1956 showed that the nucleus of the galaxy NGC 5548 changes its brightness quite strongly over time.

Now experts understand the importance of this observation, but several decades ago scientists were convinced that radiation from galactic nuclei in the optical range is provided exclusively by billions of stars located there, and even if several thousand of them go out for some reason, this will be noticeable from Earth will not be. This means, scientists reasoned, that most stars in the galactic core should “blink” synchronously! Although, of course, no conductor can manage such an orchestra. Thus, precisely because of its absolute incomprehensibility, this discovery did not attract much attention.

Further observations showed that changes in the intensity of radiation over a period of several months are a common phenomenon for quasars, and the size of the radiation region does not exceed the distance that the light travels over these very few months. And in order for changes at all points in the region to occur synchronously, it is necessary that information about the beginning change has time to reach all points. It is clear that the matter of a quasar emits light not by command, but due to the processes occurring on it, but the fact of synchronicity, that is, simultaneity, changes in conditions and magnitude of radiation indicates the compactness of this quasi-stellar object. The diameter of most quasars, apparently, does not exceed one light year, which is 100 thousand times smaller than the size of the galaxy, and they sometimes shine as much as a hundred galaxies.

Who is who

As is usually the case, immediately after the discovery of quasars, attempts began to introduce new laws of physics, although at first it was not even clear what kind of substance they consist of, the emission spectrum of quasars was so unusual. However, very little time passed, and the chemical composition of the emitting regions of quasars was identified from the spectral lines of known chemical elements. Hydrogen and helium on quasars are identical to those on Earth, but their emission spectra, as it turns out, are strongly red-shifted due to their high escape velocity.

Today, the most common point of view is that a quasar is a supermassive black hole that sucks in surrounding matter (matter accretion). As charged particles approach a black hole, they accelerate and collide, resulting in intense light emission. If the black hole has a powerful magnetic field, then it additionally twists the falling particles and collects them into thin beams, jets, flying away from the poles.

Under the influence of powerful gravitational forces created by a black hole, matter rushes towards the center, but does not move along a radius, but along tapering circles - spirals. In this case, the law of conservation of angular momentum forces the rotating particles to move faster and faster as they approach the center of the black hole, simultaneously collecting them into an accretion disk, so that the entire “structure” of the quasar is somewhat reminiscent of Saturn with its rings. In an accretion disk, particle velocities are very high, and their collisions produce not only energetic photons (X-rays), but also other wavelengths of electromagnetic radiation. During collisions, the energy of particles and the speed of circular motion decrease, they slowly approach the black hole and are absorbed by it. Another part of the charged particles is directed by the magnetic field to the poles of the black hole and flies out from there at enormous speed. This is how the jets observed by scientists are formed, the length of which reaches 1 million light years. Particles in the jet collide with interstellar gas, emitting radio waves.

At the center of the accretion disk the temperature is relatively low, reaching 100,000K. This area emits X-rays. A little further from the center, the temperature is still a little lower - about 50,000K, where ultraviolet radiation is emitted. As one approaches the boundary of the accretion disk, the temperature drops and in this region the radiation of electromagnetic waves of increasing length occurs, up to the infrared range.

We must not forget that the light from distant quasars comes to us very “reddened”. Astronomers use the letter z to quantify the degree of reddening. It is the expression z+1 that shows how many times the wavelength of electromagnetic radiation that has flown from the source (quasar) to the Earth has increased. So, if a message appears that a quasar with z=4 has been detected, this means that its ultraviolet radiation with a wavelength of 300 nanometers is converted into infrared radiation with a wavelength of 1,500 nanometers. By the way, this is a great success for researchers on Earth, because the ultraviolet part of the spectrum is absorbed by the atmosphere and these lines would never have been observed. Here, the wavelength increased due to the red shift, as if specifically in order to pass through the earth’s atmosphere and be recorded in instruments.

According to another point of view, quasars are the first young galaxies, and we are simply observing the process of their birth. However, there is also an intermediate, although it would be more accurate to say a “united” version of the hypothesis, according to which a quasar is a black hole that absorbs the matter of a forming galaxy. One way or another, the assumption of a supermassive black hole in the center of the galaxy turned out to be fruitful and capable of explaining many of the properties of quasars.

For example, the mass of a black hole located at the center of a typical galaxy is 10 6 -10 10 solar masses and, therefore, its gravitational radius varies between 3 × 10 6 -3 × 10 10 km, which is consistent with previous estimates of the size of quasars .

The latest data also confirms the compactness of the areas from which the glow emanates. For example, 5 years of observations made it possible to determine the orbits of six stars rotating around a similar center of radiation located in our galaxy. One of them recently flew from a black hole at a distance of only 8 light hours, moving at a speed of 9,000 km/s.

Absorption dynamics

As soon as matter in any form appears around a black hole, the black hole begins to emit energy, absorbing matter. At the initial stage, when the first galaxies were forming, there was a lot of matter around the black holes, which was a kind of “food” for them, and the black holes glowed very brightly - here they are, quasars! By the way, the energy that an average quasar emits per second would be enough to provide the Earth with electricity for billions of years. And one record holder with the number S50014+81 emits light 60 thousand times more intense than our entire Milky Way with its hundred billion stars!

When there is less matter in the vicinity of the center, the glow weakens, but nevertheless the core of the galaxy continues to remain its brightest region (this phenomenon, called the “Active Galactic Nucleus,” has been known to astronomers for a long time). Finally, a moment comes when the black hole absorbs the bulk of the matter from the surrounding space, after which the radiation almost stops and the black hole becomes a dim object. But she is waiting in the wings! As soon as new matter appears in the vicinity (for example, during a collision of two galaxies), the black hole will shine with renewed vigor, greedily absorbing stars and particles of the surrounding interstellar gas. So, a quasar manages to become noticeable only due to its surroundings. Modern technology already makes it possible to distinguish individual stellar structures around distant quasars, which are a breeding ground for insatiable black holes.

However, in our time, when galactic collisions are rare, quasars cannot arise. And apparently, this is indeed the case - almost all observed quasars are located at a very significant distance, which means that the light arriving from them was emitted a very long time ago, back in the days when the first galaxies were born. That is why quasars are sometimes called “dinosaurs of the Universe,” hinting not only at their extremely respectable age, but also at the fact that they, figuratively speaking, “went extinct.”

Habitat

Such powerful sources of radiant energy as quasars are dangerous neighbors, so we, earthlings, can only rejoice in the fact that they are absent in our Galaxy and in the nearest cluster of galaxies. They are found mainly at the very edge of the visible part of our Universe, thousands of megaparsecs from the Earth. But here, willy-nilly, a natural question arises: does this observation contradict the widespread opinion about the homogeneity of the Universe? How did it happen that quasars exist in some galaxies, but not in others? In order to answer these questions, it is necessary to remember that the light from the quasars we observe has traveled for billions of years. This means that quasars appear to the eyes of earthlings in their “primordial” form, the way they were billions of years ago, and today they have most likely lost their former power. Consequently, those galaxies that are located close to quasars “see” much weaker light sources. But then, if the Universe is homogeneous, the same should apply to our Galaxy! And here it remains to take a closer look at the cosmic structures closest to us, in an attempt to find objects that resemble cooled quasars, a kind of ghost quasars. It turns out that such objects really exist. Quasars, which are one of the most ancient formations, were born almost simultaneously with the Universe, that is, approximately 13 billion years ago. Moreover, they are not only extremely distant from our Galaxy - according to Hubble’s law of expansion (the further an object is from us, the faster it moves away), the distance between us continues to steadily increase. So, the most distant quasars “run away” from us at a speed of only 5% less than the speed of light.

Variable brightness

The brightest quasars emit as much light energy every second as a hundred ordinary galaxies like our Milky Way (this is approximately 10 42 Watts). To ensure the release of such an amount of energy, every second the black hole absorbs a mass equal to the mass of the Earth, and about 200 solar masses are “eaten” in a year. Such a process cannot take place indefinitely - someday the surrounding matter will dry up, and the quasar will either stop functioning or begin to emit relatively weakly.

So, the glow of a quasar decreases over time, but what can cause it to increase in brightness from time to time? To understand the mechanism of this process, remember that a black hole absorbs any matter, not just elementary particles. In a galaxy whose center is occupied by a black hole, there is no special order. Of course, in general, stars rotate around the center, but there are always those single stars or small clusters of them that violate the established order. They are the ones who are punished - they are captured and swallowed by a black hole. Moreover, if a star is “swallowed” whole, without preliminary destruction, then little light is released. The reason is that no matter how big a star is, its electrical charge is zero. Therefore, it does not actively emit light and does not quickly lose energy and angular momentum, emitting mainly gravitational waves into the surrounding space. This means that it revolves around the black hole for a long time, slowly falling towards it. But if a star, when approaching the so-called Schwarzschild horizon of a black hole - the gravitational radius, the passage of which closes the path back forever - is destroyed by tidal forces, then the additional radiation can be very noticeable. After absorbing the disruptor, the quasar's glow returns to normal.

Until recently, it was believed that black holes are one of the final stages of the existence of stars, and then, over time, these black holes merge into supermassive ones. But then where did massive black holes come from during the formation of the first galaxies? The problem is easily resolved within the framework of models of primordial black holes, that is, those that appeared before the onset of star formation. Another point of view is also possible - black holes and stars are formed almost simultaneously and according to the same scenario. Clouds of hydrogen and dark matter are compressed by gravitational forces. Small clouds form stars, and large clouds form massive black holes.

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Having understood in general terms the structure of quasars, scientists are trying to use them as a tool for space exploration. For example, by observing the microlensing effect, one can detect dark objects with a mass approximately equal to the mass of Jupiter. They give themselves away by deflecting the light of the quasar so that we see a short-term increase in its brightness. If such bodies are discovered, the problem of dark matter may be solved. Now, for many scientists, the discovery of a new quasar means the discovery of a new black hole. Thus, studies of a recently discovered quasar at redshift z=6.43 indicate that the black hole at the heart of this quasar is very massive—about a billion solar masses. Consequently, massive black holes appeared very early. This conclusion is extremely important for cosmology. Scientists recently realized that the energy of the vacuum, although extremely small, is different from zero. This revolutionary conclusion for science was first made based on a study of the rate of removal of quasars. It turned out that the red shift, and therefore the speed of space objects, increases even faster as they move away from the Earth than required by Hubble's law. Then other observations, including cosmic microwave background radiation, further confirmed the scientific community in the correctness of this conclusion. So it turns out that our Universe is not just expanding gradually, but is flying apart at an ever-increasing speed. The discovery of quasars greatly influenced cosmology, giving rise to many new models of the origin and development of the Universe. And today scientists are almost sure that black holes play a significant role in the formation of galaxies and their subsequent fate.

Sergey Rubin, Doctor of Physical and Mathematical Sciences

The first quasars were discovered by scientists in the early 60s of the last century. To date, about 2 thousand have already been discovered. They are the brightest objects in the Universe and have a luminosity 100 times greater than all the stars in the Milky Way galaxy. The dimensions of the quasar are approximately equal to the diameter of the solar system - 9 billion km. it has a mass equal to 2 billion solar masses or more. Quasars are the central stars of galaxies and large star systems of various sizes. They are located at a distance from 2 to 10 billion light years from Earth. Quasars generate energy jets in different directions of the plane of their galaxies, the radiation energy of which is tens of thousands of times more per second than that of the largest galaxies. What functions do quasars perform in the Universe?

Answer

Scientists do not know what source of colossal energy supports the glow of the quasar and why the radiation of jets of such enormous power is needed. A quasar is a special type of star, similar to black holes at the center of galaxies, which has enormous gravity and converts absorbed matter into energy and elementary particles, but has additional capabilities for emitting it into space. Quasars, like quasars, absorb matter, but not only from their galaxy, but also from nearby ones. As in a regular black hole, inside a quasar any absorbed matter decays into elementary particles and energy, and is then emitted in the form of light quanta, infrared and x-rays, gamma rays, radio waves and a huge range of elementary particles, including neutrinos.

The quasar radiates all this energy and matter into space in the form of two opposite jets. Both jets contain the matter of time in the form of gamma radiation, neutrinos and other particles, which are directed differently into the past and into the future to replenish their energy. The rest of the energy and elementary particles are absorbed by intergalactic space, which is dark matter. To understand this process, one can imagine how a galaxy with a quasar in the center moves through the Universe at a speed of 0.6 - 0.85 of the speed of light and emits enormous energy in the form of 2 jets several billion km long. This energy is absorbed, which uses it to build new types of matter, new stars and galaxies.

Any level of intelligence can be created by the Creator in any type of matter or energy. Intelligent quasars convert matter into energy and elementary particles and transmit it using radiation from intelligent dark matter, which, according to programs set by the Creator of the Universe, creates new matter with the necessary properties and parameters for new experiments. Therefore, quasars and dark matter are the Creator’s tools for creating new worlds in the Universe.

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A quasar is a galaxy at the initial stage of its development, in the center of which there is a huge supermassive black hole, the mass of which is billions of times greater than the mass of our sun. Quasars emit so much radiation that they outshine all other objects in the Universe. For this reason, quasars are very difficult to study - the emitted radiation does not allow these objects to be seen in detail.

On average, a quasar produces about 10 trillion times more energy per second than our Sun. The black hole inside the quasar sucks in absolutely everything that is within its reach. Cosmic dust, asteroids, comets, planets and even huge stars - all this becomes fuel for this giant.

Today it is very difficult to determine the exact number of discovered quasars, which is explained, on the one hand, by the constant discovery of new quasars, and on the other hand, by the lack of a clear boundary between quasars and other types of active galaxies. In 1987, 3,594 quasars were known. By 2005, this figure had increased to 195,000. The most distant quasars, due to their incredible luminosity, hundreds of times greater than the luminosity of ordinary galaxies, are recorded using radio telescopes at a distance of more than 12 billion light years. Recent observations have shown that most quasars are located near the centers of huge elliptical galaxies.

Quasars are compared to the lighthouses of the Universe. They are visible from vast distances and explore the structure and evolution of the Universe. The quasar's radiation spectrum represents all wavelengths measured by modern detectors, from radio waves to hard gamma radiation with a quantum energy of several teraelectronvolts. Quasars are usually surrounded by a ring of cosmic dust, and depending on its location, there are two types of quasars. The first type is when the ring is located so that it does not block the quasar from the observer. Quasars of the second type are protected from telescope lenses by the “wall” of the ring.

Not long ago, using a huge telescope in Chile, scientists were able to study one of the quasars, which belongs to the second type. They discovered that this quasar is surrounded by a nebula of ionized gas that extends over 590,000 light-years, about six times the diameter of the Milky Way. The nebula serves as a bridge connecting the quasar to a neighboring galaxy, and this fact can be considered as support for the hypothesis that quasars use nearby star clusters as “fuel”.

Scientists have suggested that quasar activity is caused by galaxy collisions. First, galaxies collide and their black holes merge into the universe. In this case, the black hole finds itself in the center of the dust cocoon formed as a result of the collision, and begins to intensively absorb matter. After about 100 million years, the glow from the hole's surroundings becomes so strong that emissions of radiation begin to break through the cocoon. As a result, a quasar appears. After another 100 million years, the process stops, and the central black hole begins to behave calmly again.
Just recently, scientists were able to photograph colliding quasars for the first time. As part of the work, scientists were interested in a double quasar, which is located at a distance of 4.6 billion light years from Earth in the constellation Virgo.

The term “quasar” itself is derived from the words quas istell a r and r adiosource, literally meaning: , like a star. These are the brightest objects in our Universe, having very strong . They are classified as active galactic nuclei - these do not fit into the traditional classification.

Many consider them to be huge, intensely absorbing everything that surrounds them. The substance, approaching them, accelerates and heats up very much. Under the influence of the magnetic field of a black hole, particles are collected into beams that fly away from its poles. This process is accompanied by a very bright glow. There is a version that quasars are galaxies at the beginning of their lives, and in fact, we see their appearance.

If we assume that a quasar is some kind of superstar that burns the hydrogen that makes it up, then it should have a mass of up to a billion solar!

But this contradicts modern science, which believes that a star with a mass of more than 100 solar masses will necessarily be unstable and, as a result, will disintegrate. The source of their gigantic energy also remains a mystery.

Brightness

Quasars have enormous radiation power. It can exceed the radiation power of all the stars in an entire galaxy by hundreds of times. The power is so great that we can see an object billions of light years away from us with a regular telescope.

The half-hour radiation power of a quasar can be comparable to the energy released during a supernova explosion.

The luminosity can exceed the luminosity of galaxies by thousands of times, and the latter consist of billions of stars! If we compare the amount of energy produced per unit time by a quasar, the difference will be 10 trillion times! And the size of such an object can be quite comparable to the volume.

Age

The age of these superobjects is tens of billions of years. Scientists have calculated: if today the ratio of quasars and galaxies is 1: 100,000, then 10 billion years ago it was 1: 100.

Distances to quasars

Distances to distant objects in the Universe are determined using. All observed quasars are characterized by a strong redshift, that is, they are moving away. And the speed of their removal is simply fantastic. For example, for object 3C196 the speed was calculated to be 200,000 km/sec (two-thirds the speed of light)! And before it there are about 12 billion light years. For comparison, galaxies fly at maximum speeds of “only” tens of thousands of km/sec.

Some astronomers believe that both the energy flows from quasars and the distances to them are somewhat exaggerated. The fact is that there is no confidence in the methods of studying ultra-distant objects; for all the time of intensive observations, it was not possible to establish the distances to quasars with sufficient certainty.

Variability

The real mystery is the variability of quasars. They change their luminosity with extraordinary frequency; galaxies do not have such changes. The period of change can be calculated in years, weeks and days. The record is considered to be a 25-fold change in brightness in one hour. This variability is characteristic of all quasar emissions. Based on recent observations, it turns out that O Most quasars are located near the centers of huge elliptical galaxies.

By studying them, we become more clear about the structure of the Universe and its evolution.

Quasar(English) quasar) is a particularly powerful and distant active galactic nucleus. Quasars are among the brightest objects in the Universe. The radiation power of a quasar is sometimes tens and hundreds of times higher than the total power of all the stars in galaxies like ours.

Quasars were initially identified as high redshift objects ( redshift- shift of the spectral lines of chemical elements to the red (long-wave) side) and electromagnetic radiation, having very small angular dimensions. For this reason, they could not be distinguished from stars for a long time, because extended sources are more consistent with galaxies. It was only later that traces of parent galaxies were discovered around quasars.

Term quasar stands for "star-like". According to one theory, quasars are galaxies at the initial stage of development, in which a supermassive black hole absorbs surrounding matter.

The first quasar, 3C 48, was discovered in the late 1950s by Alan Sandage and Thomas Matthews during a radio sky survey. In 1963, 5 quasars were already known. In the same year, Dutch astronomer Martin Schmidt proved that the lines in the spectra of quasars are strongly redshifted.

Recently, it has been accepted that the source of radiation is the accretion disk of a supermassive black hole located in the center of the galaxy and, therefore, the red shift of quasars is greater than the cosmological one by the amount of gravitational shift predicted by A. Einstein in the general theory of relativity (GTR). To date, more than 200,000 quasars have been discovered. The distance to it is determined by the redshift and brightness of the quasar. For example, one of the closest quasars and the brighter one, 3C 273, is located at a distance about 3 billion light years. Recent observations show that most quasars are located near the centers of huge elliptical galaxies, and the irregular variability of quasar brightness on time scales of less than a day indicates that region of generation of their radiation has a small size comparable to the size of the solar system.

On average, a quasar produces about 10 trillion times more energy per second than our Sun (and a million times more energy than the most powerful known star), and exhibits emission variability across all wavelength ranges.

The physical mechanism responsible for the generation of such powerful radiation in a relatively small volume is not yet reliably known. The processes occurring in quasars are the subject of intensive theoretical research.

Narrow absorption lines of hydrogen and ions of heavy elements were discovered in the spectra of distant quasars. The nature of the narrow absorption lines remains unclear. The absorbing medium can be extensive coronas of galaxies or individual clouds of cold gas in intergalactic space. It is possible that such clouds may be remnants of the diffuse medium from which galaxies were formed.