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 a 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 influence magnetic field In a black hole, particles are collected into bundles 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 greater 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 red shift, 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.
However, this star, amazing in all respects, is like a 10-watt light bulb compared to the truly brightest objects in space, for example, the same quasars. These objects are blinding galactic cores, shining so intensely because of their hungry nature. At their centers there are supermassive black holes that devour any matter surrounding them. More recently, scientists have discovered the brightest representative. Its brightness exceeds that of the sun by almost 600 trillion times.
The quasar, which scientists write about in The Astrophysical Journal Letters and named J043947.08+163415.7, is significantly brighter than the previous record holder - it glows with the intensity of 420 trillion suns. By comparison, the brightest galaxy ever discovered by astronomers has the luminosity of “only” 350 trillion stars.
“We did not expect to find a quasar brighter than the entire observable Universe,” comments the head of the study, Xiaohui Fan.
It is logical to ask: how did astronomers miss such a bright object and only now discover it? The reason is simple. The quasar is located practically on the other side of the Universe, at a distance of about 12.8 billion light years. It was only discovered thanks to a strange physical phenomenon known as gravitational lensing.
Diagram showing how the gravitational lensing effect works
According to general theory Einstein's relativity, very massive objects in space, with the help of their gravitational force, have ways of bending the direction of movement of light waves, literally forcing them to bend around the source of gravity. In our case, the light from the quasar was distorted by a galaxy located almost halfway between us and the source, which increased its luminosity by almost 50 times. In addition, in the case of strong gravitational lensing, several images of a background object can be observed at once, since the light from the source comes to us in different ways and, accordingly, will arrive at the observer at different times.
“Without such a high level of magnification, we would never be able to see the galaxy in which it is located,” says Feige Wang, another author of the study.
“Thanks to this magnification effect, we can even follow the gas around the black hole and learn what effect the black hole has on its host galaxy overall.”
Gravitational lensing allows scientists to see an object in more detail. Thus, it was found that the main brightness of the object comes from highly heated gas and dust falling into the supermassive black hole at the center of the quasar. However, part of the brightness is also added by a rather dense cluster of stars near the galactic center. Astronomers have roughly estimated that the galaxy containing the brightest quasar produces about 10,000 new stars every year, which makes our Milky Way compared to her, a real lazy person. In our galaxy, astronomers say, on average only one star is born per year.
The fact that such a bright quasar has only now been detected once again shows how limited astronomers really are in their ability to detect these objects. The researchers say that due to their distances, most quasars are identified by their red color, but many may fall in the "shadow" of galaxies that lie in front of these objects. These galaxies make images of quasars blurrier and their color moves more into the blue range of the spectrum.
“We think we may have missed 10 to 20 similar objects by now. Simply because they might appear different from quasars to us due to their blueshift,” says Fan.
“This may indicate that our traditional way of searching for quasars may no longer work and we need to look for new ones capable of searching for and observing these objects. Perhaps relying on analysis of large data sets.”
The brightest quasar was confirmed using the telescope of the MMT Observatory (Arizona, USA), after data about it flashed during the infrared study of the sky by British specialists (UK Infrared Telescope Hemisphere Survey), observations of the Pan-STARRS1 telescope, as well as archival infrared data NASA WISE space telescope. Using the Hubble Space Telescope, scientists were able to confirm that they see the quasar using the effect of gravitational lensing.
Thanks to the duo of a natural lens and the Hubble Space Telescope, astronomers have discovered the brightest quasar in the early Universe, providing additional insight into the birth of galaxies less than one billion years after big bang. An article describing the discovery is presented in the journal The Astrophysical Journal Letters .
“If it were not for the natural space telescope, the light from the object reaching the Earth would be 50 times weaker. The discovery shows that strongly lensed quasars do exist, despite the fact that we have been looking for them for more than 20 years and have never seen them at such vast distances before,” says Xiaohui Fan, lead author of the study from the University of Arizona (USA).
Quasars are the extremely bright nuclei of active galaxies. The powerful glow of such objects is created by a supermassive black hole surrounded by an accretion disk. The gas falling into the space monster releases an incredible amount of energy that can be observed at all wavelengths.
The discovered object, cataloged as J043947.08 + 163415.7 (J0439+1634 for short), is no exception to this rule - its brightness is equivalent to about 600 trillion Suns, and the supermassive black hole that creates it is 700 million times more massive than our star .
However, even the keen eye of Hubble alone cannot see such a bright object located at a great distance from the Earth. And here gravity and luck come to his aid. A dim galaxy located directly between the quasar and the telescope bends the light from J0439+1634 and makes it 50 times brighter than it would be without the effect of gravitational lensing.
The data obtained in this way showed that, firstly, the quasar is located at a distance of 12.8 billion light years from us, and, secondly, its supermassive black hole not only absorbs gas, but also provokes the birth of stars at an amazing rate - up to 10,000 luminaries per year. By comparison, only one star is formed in the Milky Way during this period of time.
“The properties and remoteness of J0439+1634 make it a prime target for studies of the evolution of distant quasars and the role of supermassive black holes in star formation,” explained Fabian Walter, co-author of the study from the Max Planck Institute for Astronomy (Germany).
The Hubble Space Telescope image shows an intervening galaxy acting as a lens and enhanced light from quasar J0439+1634. Credit: NASA, ESA, X. Fan (University of Arizona)
Objects similar to J0439+1634 existed during the reionization era of the young Universe, when radiation from young galaxies and quasars heated hydrogen that had cooled in the 400,000 years since the Big Bang. Thanks to this process, the Universe turned from a neutral plasma to an ionized one. However, it is still not clear exactly what objects provided the reionizing photons, and quasars like the one discovered may help solve a long-standing mystery.
For this reason, the team continues to collect as much data as possible about J0439+1634. She is currently analyzing a detailed 20-hour spectrum taken by the European Southern Observatory's Very Large Telescope, which will allow them to identify chemical composition and the temperature of intergalactic gas in the early Universe. In addition, the ALMA radio telescope array, as well as the future NASA James Webb space telescope, will be used for observations. Using the collected data, astronomers hope to view the supermassive black hole's 150 light-year radius and measure the effect of its gravity on gas and star formation.
Thanks to the rapid development of technology, astronomers are making more and more interesting and incredible discoveries in the Universe. For example, the title of “the largest object in the Universe” passes from one discovery to another almost every year. Some open objects so huge that they baffle even the best scientists on our planet with their existence. Let's talk about the ten biggest ones.
Relatively recently, scientists discovered the largest cold spot in the Universe. It is located in the southern part of the constellation Eridanus. With a length of 1.8 billion light years, this spot has baffled scientists. They had no idea that objects of this size could exist.
Despite the presence of the word “void” in the name (from English “void” means “emptiness”), the space here is not completely empty. This region of space contains about 30 percent fewer galaxy clusters than the surrounding space. According to scientists, voids make up up to 50 percent of the volume of the Universe, and this percentage, in their opinion, will continue to grow due to super-strong gravity, which attracts all the matter surrounding them.
Superblob
In 2006, the discovery of a mysterious cosmic “bubble” (or blob, as scientists usually call them) received the title of the largest object in the Universe. True, he did not retain this title for long. This bubble, 200 million light years across, is a giant collection of gas, dust and galaxies. With some caveats, this object looks like a giant green jellyfish. The object was discovered by Japanese astronomers while studying one of the regions of space known for the presence of a huge volume of cosmic gas.
Each of the three “tentacles” of this bubble contains galaxies that are four times denser among themselves than usual in the Universe. Clusters of galaxies and balls of gas inside this bubble are called Lyman-Alpha bubbles. It is believed that these objects began to appear approximately 2 billion years after the Big Bang and are true relics ancient universe. Scientists suggest that the bubble in question formed when massive stars that existed back in the early times space, suddenly became supernovae and ejected gigantic volumes of gas into space. The object is so massive that scientists believe it is, by and large, one of the first cosmic objects to form in the Universe. According to theories, over time, more and more new galaxies will form from the gas accumulated here.
Shapley Supercluster
For many years, scientists have believed that our galaxy is being pulled across the Universe at a speed of 2.2 million kilometers per hour somewhere in the direction of the constellation Centaurus. Astronomers suggest that the reason for this is the Great Attractor, an object with such a gravitational force that it is enough to attract entire galaxies to itself. True, to find out what kind of object this is, scientists for a long time could not. This object is believed to be located beyond the so-called “zone of avoidance” (ZOA), an area in the sky obscured by the Milky Way galaxy.
However, over time, X-ray astronomy came to the rescue. Its development made it possible to look beyond the ZOA region and find out what exactly is the cause of such a strong gravitational attraction. True, what scientists saw put them in an even greater dead end. It turned out that beyond the ZOA region there is an ordinary cluster of galaxies. The size of this cluster did not correlate with the strength of the gravitational attraction exerted on our galaxy. But once scientists decided to look deeper into space, they soon discovered that our galaxy was being pulled toward an even larger object. It turned out to be the Shapley Supercluster - the most massive supercluster of galaxies in the observable Universe.
The supercluster consists of more than 8,000 galaxies. Its mass is about 10,000 times that of the Milky Way.
Great Wall CfA2
Like most of the sites on this list, the Great Wall (also known as the CfA2 Great Wall) once boasted the title of largest known space object in the Universe. It was discovered by American astrophysicist Margaret Joan Geller and John Peter Hunra while studying the redshift effect for the Harvard-Smithsonian Center for Astrophysics. According to scientists, its length is 500 million light years, width 300 million, and thickness 15 million light years.
The exact dimensions of the Great Wall still remain a mystery to scientists. It may be much larger than thought, spanning 750 million light years. The problem is the definition exact dimensions lies in the location of this gigantic structure. As with the Shapley Supercluster, the Great Wall is partially obscured by an "avoidance zone."
In general, this “zone of avoidance” does not allow us to see about 20 percent of the observable (reachable for current telescopes) Universe. It is located inside the Milky Way and contains dense accumulations of gas and dust (as well as a high concentration of stars) that greatly distort observations. To look through the avoidance zone, astronomers have to use, for example, infrared telescopes, which allow them to penetrate another 10 percent of the avoidance zone. What infrared waves cannot penetrate, radio waves, as well as near-infrared waves and x-rays, can penetrate. However, the virtual inability to view such a large region of space is somewhat frustrating for scientists. The "Zone of Avoidance" may contain information that could fill gaps in our knowledge of space.
Laniakea Supercluster
Galaxies are usually grouped together. These groups are called clusters. Regions of space where these clusters are more densely located among themselves are called superclusters. Previously, astronomers mapped these objects by determining their physical location in the Universe, but recently new way mapping local space. This made it possible to shed light on information that was previously unavailable.
The new principle of mapping local space and the galaxies located in it is based not on calculating the location of objects, but on observing the indicators of the gravitational influence exerted by objects. Thanks to the new method, the location of galaxies is determined and, based on this, a map of the distribution of gravity in the Universe is compiled. Compared to the old ones, new method is more advanced because it allows astronomers not only to spot new objects in the visible universe, but also to find new objects in places where they could not look before.
The first results of studying a local cluster of galaxies using a new method made it possible to detect a new supercluster. The importance of this research is that it will allow us to better understand where our place is in the Universe. It was previously thought that the Milky Way was located inside the Virgo Supercluster, but a new research method shows that this region is only part of the even larger Laniakea Supercluster - one of the largest objects in the Universe. It extends over 520 million light years, and somewhere within it we are.
Great Wall of Sloan
The Sloan Great Wall was first discovered in 2003 as part of the Sloan Digital Sky Survey, a scientific mapping of hundreds of millions of galaxies to identify the largest objects in the Universe. Sloan's Great Wall is a giant galactic filament consisting of several superclusters. They are like the tentacles of a giant octopus distributed in all directions of the Universe. With a length of 1.4 billion light years, the "wall" was once considered the largest object in the Universe.
The Sloan Great Wall itself is not as studied as the superclusters that lie within it. Some of these superclusters are interesting in their own right and deserve special mention. One, for example, has a core of galaxies that together from the outside look like giant tendrils. Inside another supercluster, there is a high gravitational interaction between galaxies - many of them are now undergoing a period of merger.
The presence of the “wall” and any other larger objects creates new questions about the mysteries of the Universe. Their existence contradicts a cosmological principle that theoretically limits how large objects in the universe can be. According to this principle, the laws of the Universe do not allow the existence of objects larger than 1.2 billion light years. However, objects like Sloan's Great Wall completely contradict this opinion.
Huge-LQG7 Quasar Group
Quasars are high-energy astronomical objects located at the center of galaxies. It is believed that the centers of quasars are supermassive black holes that attract surrounding matter. This leads to a huge emission of radiation, the energy of which is 1000 times greater than the energy produced by all the stars inside the galaxy. Currently in third place among the largest structural objects in the Universe is the Huge-LQG group of quasars, consisting of 73 quasars scattered over more than 4 billion light years. Scientists believe that such a massive group of quasars, as well as similar ones, are one of the reasons for the appearance of the largest structural ones in the Universe, such as, for example, the Great Wall of Sloan.
The Huge-LQG group of quasars was discovered after analyzing the same data that led to the discovery of Sloan's Great Wall. Scientists determined its presence after mapping one of the regions of space using a special algorithm that measures the density of quasars in a certain area.
It should be noted that the very existence of Huge-LQG is still a matter of debate. Some scientists believe that this region of space actually represents a single group of quasars, while other scientists are confident that quasars within this region of space are located randomly and are not part of one group.
Giant gamma ring
Stretching over 5 billion light years, the Giant GRB Ring is the second largest object in the Universe. In addition to its incredible size, this object attracts attention due to its unusual shape. Astronomers studying gamma-ray bursts (huge bursts of energy that result from the death of massive stars) discovered a series of nine bursts, the sources of which were the same distance from Earth. These bursts formed a ring in the sky 70 times larger than the diameter of the full Moon. Considering that gamma-ray bursts themselves are quite rare, the chance that they will form a similar shape in the sky is 1 in 20,000. This allowed scientists to assume that they are witnessing one of the largest structural objects in the Universe .
The “ring” itself is just a term that describes the visual representation of this phenomenon when observed from Earth. According to one assumption, the giant gamma ring may be a projection of a certain sphere around which all gamma radiation emissions occurred in a relatively short period of time, about 250 million years. True, here the question arises about what kind of source could create such a sphere. One explanation involves the idea that galaxies may cluster in groups around a huge concentration dark matter. However, this is just a theory. Scientists still do not know how such structures are formed.
Great Wall of Hercules - Northern Crown
The largest structural object in the Universe was also discovered by astronomers while observing gamma rays. This object, called the Great Wall of Hercules - Corona Borealis, extends over 10 billion light years, making it twice the size of the Giant Gamma-ray Ring. Because the brightest gamma-ray bursts come from larger stars, usually located in regions of space that contain more matter, astronomers metaphorically view each gamma-ray burst as a needle pricking something larger. When scientists discovered that a region of space in the direction of the constellations Hercules and Corona Borealis was experiencing excessive bursts of gamma rays, they determined that there was an astronomical object there, most likely a dense concentration of galaxy clusters and other matter.
Interesting fact: the name “Great Wall Hercules - Northern Crown” was invented by a Filipino teenager who wrote it down in Wikipedia (anyone who doesn’t know can make edits to this electronic encyclopedia). Shortly after the news that astronomers had discovered a huge structure in the cosmic horizon, a corresponding article appeared on the pages of Wikipedia. Despite the fact that the invented name does not accurately describe this object (the wall covers several constellations at once, and not just two), the world Internet quickly got used to it. This may be the first time that Wikipedia has given a name to something discovered and interesting. scientific point view of the object.
Since the very existence of this “wall” also contradicts the cosmological principle, scientists have to revise some of their theories about how the Universe actually formed.
Cosmic web
Scientists believe that the expansion of the Universe does not occur randomly. There are theories according to which all the galaxies of space are organized into one structure of incredible size, reminiscent of thread-like connections that unite dense regions with each other. These threads are scattered between less dense voids. Scientists call this structure the Cosmic Web.
According to scientists, the web was formed at a very early stages history of the Universe. At first, the formation of the web was unstable and heterogeneous, which subsequently helped the formation of everything that now exists in the Universe. It is believed that the “threads” of this web played big role in the evolution of the Universe - they accelerated it. It is noted that galaxies that are located inside these filaments have a significantly higher rate of star formation. In addition, these filaments are a kind of bridge for gravitational interaction between galaxies. After their formation within these filaments, galaxies move towards galaxy clusters, where they eventually die over time.
Only recently have scientists begun to understand what this Cosmic Web actually is. While studying one of the distant quasars, researchers noted that its radiation affects one of the threads of the Cosmic Web. The quasar's light went straight to one of the filaments, which heated the gases in it and made them glow. Based on these observations, scientists were able to imagine the distribution of filaments between other galaxies, thereby creating a picture of the “skeleton of the cosmos.”
The closest quasar is 3C 273, which is located in a giant elliptical galaxy in the constellation Virgo. Credit: ESA/Hubble & NASA.
Shining so brightly that they dwarf the ancient galaxies in which they reside, quasars are distant objects that are essentially a black hole with an accretion disk billions of times more massive than our Sun. These powerful objects have fascinated astronomers since their discovery in the middle of the last century.
In the 1930s, Karl Jansky, a physicist at Bell Telephone Laboratories, discovered “stellar noise” to be most intense toward the central part of the Milky Way. In the 1950s, astronomers, using radio telescopes, were able to discover a new type of object in our Universe.
Because this object looked like a point, astronomers called it a “quasi-stellar radio source” or quasar. However, this definition is not entirely correct, since, according to the National Astronomical Observatory of Japan, only about 10 percent of quasars emit strong radio waves.
It took years of study to realize that these distant specks of light that seemed to look like stars were created by particles accelerating to speeds approaching the speed of light.
“Quasars are among the brightest and most distant celestial objects known. They are crucial for understanding the evolution of the early Universe,” said astronomer Bram Venemans from the Institute of Astronomy. Max Planck in Germany.
It is assumed that quasars form in those regions of the Universe in which the overall density of matter is much higher than the average.
Most quasars have been found billions of light years away. Because it takes time for light to travel this distance, studying quasars is much like a time machine: we see the object as it was when the light left it, billions of years ago. Almost all of the more than 2,000 quasars known to date are found in young galaxies. Our Milky Way, like other similar galaxies, has probably already passed this stage.
In December 2017, the most distant quasar was discovered, which was located at a distance of more than 13 billion light years from Earth. Scientists have been watching this object, known as J1342+0928, with interest since it appeared just 690 million years after the Big Bang. These types of quasars can provide information about how galaxies evolve over time.
Bright quasar PSO J352.4034-15.3373 located at a distance of 13 billion light years. Credit: Robin Dienel/Carnegie Institution for Science. Quasars emit millions, billions, and perhaps even trillions of electronvolts of energy. This energy exceeds the total amount of light from all the stars in the galaxy, so quasars shine 10-100 thousand times brighter than, for example, the Milky Way.
If quasar 3C 273, one of the brightest objects in the sky, were 30 light-years from Earth, it would appear as bright as the Sun. However, the distance to quasar 3C 273 is actually at least 2.5 billion light years.
Quasars belong to a class of objects known as active galactic nuclei (AGNs). This also includes Seyfert galaxies and blazars. All these objects require supermassive black hole for existence.
Seyfert galaxies are the weakest type of AGN, generating only about 100 kiloelectronvolts of energy. Blazars, like them cousins- Quasars emit significantly larger amounts of energy.
Many scientists believe that all three types of AGN are essentially the same objects, but located at different angles to us.
