Which occupy a borderline position between dwarf and normal galaxies, the first dwarf galaxies were discovered by H. Shapley in the late 1930s, while conducting a survey of the sky in the vicinity South Pole world for statistical research of galaxies at the Harvard University Observatory in South Africa. First, Shapley discovered a previously unknown cluster of stars in the constellation Sculptor, containing about 10 thousand stars 18-19.5 m. A similar cluster was soon discovered in the constellation Fornax. After using the 2.5 m telescope at Mount Wilson Observatory to study these clusters, it was possible to find Cepheids in them and determine the distances. It turned out that both unknown clusters are located outside our galaxy, that is, they represent new type low surface brightness galaxies.

Discoveries of dwarf galaxies became widespread after the Palomar Sky Survey was carried out in the 1950s using the 120 cm Schmidt Camera at Mount Palomar Observatory. It turned out that dwarf galaxies are the most common galaxies in the Universe.

Formation of dwarf galaxies

Local dwarfs

Morphology

There are several main types of dwarf galaxies:

• Dwarf elliptical galaxy ( dE) - similar to elliptical galaxies
  • Dwarf spheroidal galaxy ( dSph) - subtype dE characterized by particularly low surface brightness
• Dwarf irregular galaxy ( dIr) - similar to irregular galaxies, has a ragged structure
• Dwarf blue compact galaxy ( dBCG or BCD) - has signs of active star formation
• Ultracompact dwarf galaxies ( UCD) - a class of very compact galaxies containing about 10 8 stars with a characteristic transverse size of about 50 pc. Presumably, these galaxies are the dense remnants (nuclei) of dwarf elliptical galaxies that flew through the central parts of rich galaxy clusters. Ultracompact galaxies were discovered in the galaxy clusters in Virgo, Fornax, Coma Berenices, Abel 1689, etc.
• A dwarf spiral galaxy is an analogue of spiral galaxies, but, unlike normal galaxies, is extremely rare

Hobbit galaxies

The recently coined term Hobbit Galaxies was used to refer to galaxies that are smaller and fainter than dwarf galaxies.

The problem of the shortage of dwarf galaxies

A detailed study of such galaxies and especially the relative velocities of individual stars in them, allowed astronomers to assume that the powerful ultraviolet radiation giant young stars at one time “blew out” most of the gas from such galaxies (that’s why there are few stars there), but left dark matter, which is why it now predominates. Astronomers propose to search for some of these dim dwarf galaxies with an overwhelming predominance of dark matter by indirect observations: along the “wake” in the intergalactic gas, i.e. by the attraction of gas jets to this “invisible” galaxy.

Partial list of dwarf galaxies

See also

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Notes

1. Linda S. Sparke, John S. Gallagher III. Galaxies in the Universe: An Introduction. - 2nd ed. - Cambridge University Press, 2007. - P. 410. - 442 p. - ISBN 978-0-521-85593-8.
2. Zasov, A. V. Dwarf galaxies (New in life, science, technology). - M.: Knowledge, 1984. - 64 p. - (Cosmonautics, astronomy).
3. Shapley, Harlow. Two Stellar Systems of a New Kind // Nature. - 1938. - T. 142. - pp. 715-716.
5. Astronomy: XXI century / Ed.-comp. V.G. Surdin. - 2nd ed. - Fryazino: Century 2, 2008. - P. 373. - ISBN 978-5-85099-181-4.
7. arXiv :astro-ph/0307362 Galaxies and Overmerging: What Does it Take to Destroy a Satellite Galaxy? July 21, 2003
8. arXiv :astro-ph/0406613 Ultra Compact Dwarf galaxies in Abell 1689: a photometric study with the ACS. June 28, 2004
9. SPACE.com
11. Simon, J. D. and Geha, M. (Nov 2007). "The Kinematics of the Ultra-faint Milky Way Satellites: Solving the Missing Satellite Problem." The Astrophysical Journal 670 (1): 313–331. arXiv:0706.0516. DOI:10.1086/521816. Bibcode:.
12. September 27, 2007.
13. January 17, 2011.

Bound by gravitation Not gravitationally bound Visually connected

Species Structure Active cores Interaction Phenomena and processes Lists

Excerpt characterizing the Dwarf Galaxy

The horses were brought in.
“Bonjour, messieurs, [Here: farewell, gentlemen.],” said Dolokhov.
Petya wanted to say bonsoir [good evening] and could not finish the words. The officers were whispering something to each other. Dolokhov took a long time to mount the horse, which was not standing; then he walked out of the gate. Petya rode beside him, wanting and not daring to look back to see whether the French were running or not running after them.
Having reached the road, Dolokhov drove not back into the field, but along the village. At one point he stopped, listening.
- Do you hear? - he said.
Petya recognized the sounds of Russian voices and saw the dark figures of Russian prisoners near the fires. Going down to the bridge, Petya and Dolokhov passed the sentry, who, without saying a word, walked gloomily along the bridge, and drove out into the ravine where the Cossacks were waiting.
- Well, goodbye now. Tell Denisov that at dawn, at the first shot,” said Dolokhov and wanted to go, but Petya grabbed him with his hand.
- No! - he cried, - you are such a hero. Oh, how good! How great! How I love you.
“Okay, okay,” Dolokhov said, but Petya did not let him go, and in the darkness Dolokhov saw that Petya was bending down towards him. He wanted to kiss. Dolokhov kissed him, laughed and, turning his horse, disappeared into the darkness.

X
Returning to the guardhouse, Petya found Denisov in the entryway. Denisov, in excitement, anxiety and annoyance at himself for letting Petya go, was waiting for him.
- God bless! - he shouted. - Well, thank God! - he repeated, listening to Petya’s enthusiastic story. “What the hell, I couldn’t sleep because of you!” Denisov said. “Well, thank God, now go to bed.” Still sighing and eating until the end.
“Yes... No,” said Petya. – I don’t want to sleep yet. Yes, I know myself, if I fall asleep, it’s over. And then I got used to not sleeping before the battle.
Petya sat for some time in the hut, joyfully recalling the details of his trip and vividly imagining what would happen tomorrow. Then, noticing that Denisov had fallen asleep, he got up and went into the yard.
It was still completely dark outside. The rain had passed, but drops were still falling from the trees. Close to the guardhouse one could see black figures of Cossack huts and horses tied together. Behind the hut were two black wagons with horses standing, and in the ravine the dying fire was red. The Cossacks and hussars were not all asleep: in some places, along with the sound of falling drops and the nearby sound of horses chewing, soft, as if whispering voices were heard.
Petya came out of the entryway, looked around in the darkness and approached the wagons. Someone was snoring under the wagons, and saddled horses stood around them, chewing oats. In the darkness, Petya recognized his horse, which he called Karabakh, although it was a Little Russian horse, and approached it.
“Well, Karabakh, we’ll serve tomorrow,” he said, smelling her nostrils and kissing her.
- What, master, aren’t you sleeping? - said the Cossack sitting under the truck.
- No; and... Likhachev, I think your name is? After all, I just arrived. We went to the French. - And Petya told the Cossack in detail not only his trip, but also why he went and why he believes that it is better to risk his life than to make Lazar at random.
“Well, they should have slept,” said the Cossack.
“No, I’m used to it,” answered Petya. - What, you don’t have flints in your pistols? I brought it with me. Isn't it necessary? You take it.
The Cossack leaned out from under the truck to take a closer look at Petya.
“Because I’m used to doing everything carefully,” said Petya. “Some people just don’t get ready, and then they regret it.” I don't like it that way.
“That’s for sure,” said the Cossack.
“And one more thing, please, my dear, sharpen my saber; dull it... (but Petya was afraid to lie) it was never sharpened. Can this be done?
- Why, it’s possible.
Likhachev stood up, rummaged through his packs, and Petya soon heard the warlike sound of steel on a block. He climbed onto the truck and sat on the edge of it. The Cossack was sharpening his saber under the truck.
- Well, are the fellows sleeping? - said Petya.
- Some are sleeping, and some are like this.
- Well, what about the boy?
- Is it spring? He collapsed there in the entryway. He sleeps with fear. I was really glad.
For a long time after this, Petya was silent, listening to the sounds. Footsteps were heard in the darkness and a black figure appeared.
- What are you sharpening? – the man asked, approaching the truck.
- But sharpen the master’s saber.
“Good job,” said the man who seemed to Petya to be a hussar. - Do you still have a cup?
- And over there by the wheel.
The hussar took the cup.
“It’ll probably be light soon,” he said, yawning, and walked off somewhere.
Petya should have known that he was in the forest, in Denisov’s party, a mile from the road, that he was sitting on a wagon captured from the French, around which the horses were tied, that the Cossack Likhachev was sitting under him and sharpening his saber, that there was a big black spot to the right is a guardhouse, and a bright red spot below to the left is a dying fire, that the man who came for a cup is a hussar who was thirsty; but he knew nothing and did not want to know it. He was in a magical kingdom in which there was nothing like reality. A large black spot, perhaps there was definitely a guardhouse, or perhaps there was a cave that led into the very depths of the earth. The red spot might have been fire, or maybe the eye of a huge monster. Maybe he is definitely sitting on a wagon now, but it may very well be that he is sitting not on a wagon, but on a terribly high tower, from which if he fell, he would fly to the ground for a whole day, a whole month - keep flying and never reach it . It may be that just a Cossack Likhachev is sitting under the truck, but it may very well be that this is the kindest, bravest, most wonderful, most excellent person in the world, whom no one knows. Maybe it was just a hussar passing for water and going into the ravine, or maybe he just disappeared from sight and completely disappeared, and he was not there.
Whatever Petya saw now, nothing would surprise him. He was in a magical kingdom where everything was possible.
He looked at the sky. And the sky was as magical as the earth. The sky was clearing, and clouds were moving quickly over the tops of the trees, as if revealing the stars. Sometimes it seemed that the sky was clearing and black was showing, clear sky. Sometimes it seemed that these black spots were clouds. Sometimes it seemed as if the sky was rising high, high above your head; sometimes the sky dropped completely, so that you could reach it with your hand.
Petya began to close his eyes and sway.
Drops were dripping. There was a quiet conversation. The horses neighed and fought. Someone was snoring.
“Ozhig, zhig, zhig, zhig...” the saber being sharpened whistled. And suddenly Petya heard a harmonious choir of music playing some unknown, solemnly sweet hymn. Petya was musical, just like Natasha, and more than Nikolai, but he had never studied music, did not think about music, and therefore the motives that unexpectedly came to his mind were especially new and attractive to him. The music played louder and louder. The melody grew, moving from one instrument to another. What was called a fugue was happening, although Petya did not have the slightest idea what a fugue was. Each instrument, sometimes similar to a violin, sometimes like trumpets - but better and cleaner than violins and trumpets - each instrument played its own and, not yet finishing the tune, merged with another, which started almost the same, and with the third, and with the fourth , and they all merged into one and scattered again, and again merged, now into the solemn church, now into the brightly brilliant and victorious.
“Oh, yes, it’s me in a dream,” Petya said to himself, swaying forward. - It's in my ears. Or maybe it's my music. Well, again. Go ahead my music! Well!.."
He closed his eyes. And from different sides, as if from afar, sounds began to tremble, began to harmonize, scatter, merge, and again everything united into the same sweet and solemn anthem. “Oh, what a delight this is! As much as I want and how I want,” Petya said to himself. He tried to lead this huge choir of instruments.
“Well, hush, hush, freeze now. – And the sounds obeyed him. - Well, now it’s fuller, more fun. More, even more joyful. – And from an unknown depth arose intensifying, solemn sounds. “Well, voices, pester!” - Petya ordered. And first, male voices were heard from afar, then female voices. The voices grew, grew in uniform, solemn effort. Petya was scared and joyful to listen to their extraordinary beauty.

Messier 32, or M32, is a type of dwarf galaxy with an elliptical shape. Located in the constellation Andromeda. M32 has an apparent magnitude of 8.1 with an angular size of 8 x 6 arcminutes. The galaxy is 2.9 million light years away from our planet. According to Equinox 2000, the following coordinates are derived: right ascension 0 hours 42.8 minutes; declination +40 ° 52′. Thanks to this, the galaxy can be seen throughout the fall.

Messier 32 refers to the two elliptical satellite galaxies of Andromeda Magna that can be seen in the provided images. Along the lower edge of object M31, galaxy M32 is the closest galaxy, while object M110 is the most distant galaxy along the upper right edge. M31 is a large Andromeda galaxy, represented by a bright celestial object that can be observed with the naked eye. Messier 31, Messier 32 and Messier 110 belong to the Local Group of galaxies. It also includes the Triangulum Galaxy and Milky Way.

The images provided show uncompressed photographs of all three objects - M31, M32 and M110. All photos were taken using a Takahashi E-180 astrograph. Nearby is a 3x magnification image of the center of the Messier 32 galaxy.

The object was included in Messier's catalog, but was discovered by the French scientist Le Gentil in 1749. Based on data from advanced researchers in 2010, it is possible to calculate approximate data for this galaxy. The distance from Earth to Messier 32 is 2.57 million light-years, the approximate mass varies between 300,000,000 solar masses, and its diameter reaches 6,500 light-years.

Observations

M32 is a small galaxy, but has a bright elliptical shape. When amateurs look at the Andromeda Nebula, this particular object will seem strange to them. Even the most ordinary telescope will reveal the features of the diffuse nature of the galaxy. It is located half a degree south of the center of the M31 galaxy. If you look at M32 with a medium-quality telescope, you can see a star-shaped core and a compact oval halo that gradually decreases in brightness.

Nearby objects from the Messier catalog

The first neighbor of the M32 galaxy is its physical satellite, the Andromeda Nebula. This is a spiral supergiant galaxy. The second neighboring galaxy is the elliptical M110, and the third is M31, a satellite that is on the other side of Messier 32.

Thanks to the Dwarf Galaxy, you can see the globular cluster G156. It belongs to object M31. The best tool A telescope with an aperture of 400 mm will be used for observation.

Description of Messier 32 in the catalog

August 1764

Below Andromeda's belt for a few minutes there is a small starless nebula. Compared to the belt, this small nebula has a dimmer light. It was discovered by Le Gentil on October 29, 1749, and in 1757 it was seen by Messier.

Technical details of the Messier 32 photo

Object: M32

Other designations: NGC 221

Object type: Dwarf elliptical galaxy

Position: Bifrost Astronomical Observatory

Mount: Astro-Physics 1200GTO

Telescope: Hyperbolic astrograph TakahashiEpsilon 180

Camera: Canon EOS 550D (Rebel T2i) (Baader UV/IR filter)

Exposure: 8 x 300s, f/2.8, ISO 800

Original photo size: 3454 × 5179 pixels (17.9 MP); 11.5″ x 17.3″ @ 300 dpi

Dwarf galaxies may be very small, but they have a phenomenal power that can give birth to new stars. New observations from the Hubble Space Telescope show that star formation in dwarf galaxies plays a larger role in the early universe than is currently believed.

And while galaxies across the universe are still forming new stars, most of them were formed between two and six billion years after the Big Bang. Studying this early era the history of the universe is key if we want to understand how the first stars appeared and how the first galaxies grew and developed.

This image shows a patch of sky marked with dwarf galaxies that are experiencing bursts of star formation. The image was taken as part of the GOODS (Great Observatories Origins Deep Survey) program and shows only one frame from the entire survey. Source: NASA, ESA, the GOODS Team and M. Giavalisco (STScI/University of Massachusetts)

New research from Hubble and its Wide Field Camera 3 (WFC3) has allowed astronomers to take a step forward in understanding that era by studying various types dwarf galaxies of the early Universe and, in particular, selecting from them only those with obvious processes of active star formation. Such galaxies are usually called starburst galaxies. In such objects, new stars form much faster than usual in other galaxies. Previous studies have focused primarily on medium- and high-mass galaxies and have not taken into account the huge number of dwarf galaxies that existed during this active era. But the fault here lies not so much with the scientists who did not want to explore dwarf galaxies. This is most likely due to the inability to see these small objects, since they are very far away from us. Until recently, astronomers could observe small galaxies at smaller distances or large galaxies over long distances.

However, now, using grism, astronomers have been able to peer at low-mass dwarf galaxies in the distant universe and take into account the contribution of their star formation bursts, approximating the information to the possible number of small galaxies that then existed. A grism is an objective prism, a combination of a prism and a diffraction grating, which transmits light without shifting its spectrum. The letter “G” in the name comes from grating.

“We've always assumed that starburst dwarf galaxies would have a significant effect on new star formation in the young universe, but this is the first time we've been able to measure the effect they actually have. And, apparently, they played a significant, if not key role,” Hakim Atek from the Swiss Polytechnic University.

“These galaxies form stars so quickly that they could actually double their entire stellar mass in just 150 million years. By comparison, stellar masses for ordinary galaxies double on average every 1-3 billion years,” adds co-author Jean-Paul Kneib.

An image of galaxies in grism mode using the example of the Wide Field Camera 3 installed on Hubble and operating in this spectroscopy mode. Extended rainbow lines are nothing more than galaxies caught in the lens, but in grism mode they are presented as a rainbow spectrum. Thanks to this, scientists are able to evaluate chemical composition space objects.

Most galaxies, like our Milky Way, are surrounded by dozens of small satellites that orbit around them. These satellites are extremely dim - of them, only the brightest and closest ones were seen in the vicinity of our Galaxy and its closest neighbor, the Andromeda Galaxy. But these dwarf satellite galaxies do not fly chaotically: they are all located approximately in the same plane, which seems to us to be a straight line.

The coplanarity seems unexpected. Computer models of galaxy evolution showed that in each direction of the celestial sphere there should be approximately the same number of satellite galaxies. This spherically symmetrical distribution was long thought to be a natural consequence of the existence of dark matter, a mysterious substance that interacts with ordinary matter only through gravity. Astronomers believe that dark matter dominates the Universe and plays a key role in the formation of galaxies and the expansion of space.

However, the mystery of the coplanarity of dwarf galaxies has haunted some astronomers, including Krupa, to question whether dark matter exists at all. “The dark matter hypothesis has been shown to be untenable,” he said, interrupting my report, “because its predictions that satellites should be distributed spherically symmetrically around the Milky Way are in direct contradiction to what we observe.”

I presented another way of looking at the problem, one that attempts to explain the strange arrangement of galactic satellites by the presence of cosmic dark matter structures larger than our Milky Way. While a small number of skeptics like Krupa remain unconvinced, recent work, including mine, shows how a giant web of dark matter could explain the unique arrangement of satellite galaxies in the sky.

Missing Matter

The dark matter hypothesis at the center of this controversy was first proposed to explain other mysterious properties of galaxies. In the 1930s The great astronomer Fritz Zwicky wanted to “weigh” the Coma cluster, a giant group of almost a thousand galaxies. He began by measuring the speeds at which the galaxies in this cluster were moving. To his surprise, he discovered enormous speeds—thousands of kilometers per second—fast enough to tear the cluster apart. Why didn't it break into pieces? Zwicky suggested that the cluster is filled with some invisible substance that holds the galaxies together by the force of its gravity. This missing substance was later called dark matter.

Since Zwicky first proposed his proposal 80 years ago, the specter of dark matter has been popping up here and there throughout the Universe, in almost every galaxy studied. In our own - the Milky Way - astronomers have identified its existence based on the nature of the movement of stars on the outskirts of the galaxy. Like the galaxies in the Coma cluster, these stars are moving too fast to be supported by all visible matter. And a dozen dwarf galaxies near the Milky Way appear to be richer in dark matter.

The omnipresence of dark matter has strengthened confidence in its existence. Indeed, most cosmologists believe that dark matter makes up about 84% of all matter, outweighing normal atoms by a ratio of about five to one.

This abundance of dark matter suggests that it appears to play a unique role in the evolution of the Universe. One way to study this evolution is to use computer models. Since the 1970s. Scientists in the field of computational cosmology have attempted to model the history of the Universe using computer programs. The technique is simple: define an imaginary rectangular volume; place imaginary point particles there at the nodes of an almost perfect lattice, which in this model simulate clumps of dark matter; calculate the gravitational attraction of each particle from all the others and let them move in accordance with the gravitational field acting on them: trace this process over an interval of 13 billion years.

Since the 1970s Strategies of this kind have evolved significantly and become much more complex, but at their core this method is still used today. Forty years ago, the program could only work with a few hundred particles. Modern methods Computer simulations make it possible to calculate the behavior of billions of particles in a volume approaching the size of the observable Universe.

Computer simulations of the universe have proven to be an incredibly useful way to study individual galaxies, but they have also raised some challenging mysteries. For example, computer models indicate that the dark matter filling the halo around the Milky Way pulls gas and dust into separate clumps. These clumps should collapse under the influence of gravity, forming stars and dwarf galaxies. Surrounded by dark matter, there should be thousands of small galaxies around the Milky Way. However, when observing the night sky, we see only a few dozen of them. The failure of all attempts to detect them became apparent in the 1990s, and since then it has been called the “missing satellite problem.”

Over the years, astronomers have come up with several possible explanations for this dilemma. The first and most convincing is that not all satellites appearing in computer models strictly correspond to real-life satellite galaxies. The masses of the smallest clumps of dark matter (and their gravitational pull) may not be enough to trap gas and form stars. Continuing this line of reasoning, one might speculate that the observed satellite galaxies are just the visible tip of a dark iceberg: perhaps hundreds, if not thousands, of dark, starless satellite galaxies exist nearby. We just don't see them.

Second, even if stars have formed in small clumps of dark matter, they may be too dim for us to see with our telescopes. Then, as technology develops and the sensitivity of telescopes increases, astronomers will discover new satellite galaxies. Indeed, over the past few years, the number of known satellite galaxies orbiting the Milky Way has doubled.

In addition, the disk of our galaxy itself probably prevents us from seeing some satellites. This disk is essentially a dense, flat collection of stars, so bright that to the naked eye it appears as a strip of white liquid (hence the name “Milky Way”). It is very difficult to detect satellites hiding behind the disk, as difficult as seeing the Moon during the day - the dim light of the satellite galaxy is drowned in the glow of the Milky Way.

All these arguments taken together solve the problem of missing satellite galaxies and convince most astrophysicists. They rescue the idea of ​​dark matter by defending it against the most serious observational counterarguments. However, the strange spatial arrangement of satellite galaxies still baffles scientists.

New Dwarf Threat

In several articles published in the late 1970s and early 1980s, Donald Lynclen-Bell. an astrophysicist at the University of Cambridge, noted that many of the satellite galaxies orbiting the Milky Way appear to be located on the water plane. How to explain this strange picture? In 2005, Krupa and his team at the University of Bonn convinced the world that this coplanar arrangement could not be a coincidence. They suggested that dark matter moons were evenly distributed around the Milky Way, as computer simulations predicted, and that only one in a hundred of these dwarfs was large enough to form stars and become visible in a telescope. Given these perfectly reasonable assumptions, they asked the question: How often can we expect to find a system like the Milky Way with its luminous moons lined up around it? The answer created an explosion in cosmology: the probability of this is less than one in a million.

“If dark matter controlled the formation of galaxies,” Krupa argues. “then the satellite galaxies would never line up along the plane.” Describing your results in the article. Krupa offered his own solution. “The only way out,” he wrote. - to suggest that the satellites of the Milky Way were not formed as a result of the aggregation of dark matter." Dark matter, he argued. does not exist.

Being a good theorist. Krupa offered an alternative. He believes that the satellites are fragments of a large progenitor galaxy, which once flew near the Milky Way in the past. Just as an asteroid breaks up and leaves behind a tail of debris as it passes through Earth's atmosphere, it is possible that the Milky Way's moons arose from material taken from a larger ancestor.

When we look at the Universe, says Krupa, some colliding galaxies we see long bridges stellar matter called tidal arms. Tidal arms often contain small satellite galaxies that were formed as a result of the compression of trapped material. Under suitable conditions, the detachment process itself causes the trapped material to collect on the water plane, similar to the satellites of the Milky Way.

Krupa's explanation was elegant, simple, and most importantly, non-controversial. It quickly came under a barrage of attacks. For example, the stars in the Milky Way's satellite galaxies move too fast for ordinary matter alone. Dark matter must be holding them together, just as it holds all parts of the Milky Way. (Indeed, observations indicate that the dwarf satellites of the Milky Way are the galaxies with the highest content of dark matter in the Universe.) And the tidal scenario for the formation of dwarf galaxies suggests that they do not contain dark matter, leaving open the question of what prevents them from flying apart .

Second, just as a collision damages another car, collisions between disk galaxies destroy the disks. Almost always end result collisions of galaxies - a shapeless clump of stars. The Milky Way has a clearly defined structure and a rather thin disk. We see no indication that it has been damaged by any collision or merger in the recent past.

Dark Web

An alternative solution to the puzzle of the unusual alignment of dwarf galaxies requires looking further into the depths of space. Numerical modeling efforts that began in the 1970s have not easily studied the evolution of individual galaxies, but have simulated gigantic volumes of the Universe. When we do this on the largest scales, we see that the galaxies are not randomly distributed. On the contrary, they tend to unite into a strictly defined thread-like structure called the cosmic web. We can clearly discern the predicted structure when we look at spatial distribution maps of real galaxies.

This cosmic web consists of majestic layers filled with millions of galaxies and stretching over hundreds of millions of light years. These layers are connected by cigar-shaped threads. In the spaces between the filaments there are voids in which there are no galaxies. Large galaxies like ours tend to be located at points in the web where many threads intersect.

As a graduate student at Durham University in England, I built computer models of these dense regions. One day I brought a printout latest results to my office scientific supervisor Carlos Frenk. The model I was working on traced the formation of the Milky Way and its environs over 13 billion years of the universe's history—Frank stared at the computer drawing for a few seconds, then waved a piece of paper and exclaimed, “Leave the rest!” The satellite galaxies that you study, every single one of them, lie in that same incredible Krupa plane!” Our model did not reproduce the results of previous computer models - the uniform distribution of satellite galaxies in the halo of the Milky Way. Instead, the computer predicted the formation of water-plane satellites—very close to what astronomers observe. We felt that our model would begin to unravel the mystery of how the dwarf satellites were able to arrange themselves so strangely in space.

“Why don’t you trace the evolution of satellites back in time to see where they came from?” - Frank suggested. We had the end result; now the time has come to explore the intermediate stages of evolution.

When we looked back at the simulation, we saw that dwarf galaxies did not form in the regions immediately adjacent to the Milky Way. As a rule, they were grouped a little further, inside the threads of the cosmic web. Threads are areas of more high density than space voids. This is probably why they attract nearby dust and gas and collect them into nascent galaxies.

The image shows Dwarf galaxy in the constellation Sculptor Dwarf Galaxy. The image was taken by the Wide Field Imager, which is installed on the 2.2-meter MPG/ESO telescope at the European Southern Observatory in La Silla. This galaxy is one of the neighbors of our Milky Way. But, despite such close proximity to each other, these two galaxies have absolutely various history emergence and evolution, we can say that their characters are completely different. The Sculptor dwarf galaxy is much smaller and older than the Milky Way, making it a very valuable object for studying the processes that led to the birth of new stars and other galaxies in the early Universe. However, due to the fact that it emits very little light, its study is very difficult.

The dwarf galaxy in the constellation Sculptor belongs to the subclass of dwarf spheroidal galaxies and is one of fourteen satellite galaxies that orbit the Milky Way. They are all located close to each other in the halo region of our Galaxy, which is a spherical region extending far beyond the boundaries of the spiral arms. As its name suggests, this dwarf galaxy is located in the constellation Sculptor and lies at a distance of 280,000 light years from Earth. Despite its proximity, it was only discovered in 1937 with the advent of new powerful instruments, since its component stars are very faint and seem to be scattered throughout the sky. Also, do not confuse this galaxy with NGC 253, which is located in the same constellation Sculptor, but looks much brighter and is a barred spiral.

Dwarf galaxy in the constellation Sculptor. Source: ESO

Photo information

Photo information

Although difficult to detect, this dwarf galaxy was among the first faint dwarf objects discovered in the region around the Milky Way. Its strange shape has given astronomers pause since its discovery to this day. But in our time, astronomers have become accustomed to spheroidal galaxies and have realized that such objects allow us to look far into the past of the Universe.

It is believed that the Milky Way, like all large galaxies, was formed as a result of mergers with smaller objects during the early years of the Universe. And if some of these small galaxies still exist today, then they must contain many extremely old stars. That is why the Dwarf Galaxy in the constellation Sculptor meets all the requirements that apply to primordial galaxies. It is these ancient stars that can be observed in this image.

Astronomers have learned to determine the age of stars in a galaxy by the characteristic signatures that are present in their light flux. This radiation carries very little evidence of the presence of heavy heavy metals in these objects. chemical elements. The point is that such chemical compounds tend to accumulate in galaxies as generations of stars change. Thus, low concentrations of heavy molecules indicate that middle age The stars in this spheroidal galaxy are quite high.

The area of ​​sky around the dwarf galaxy in the constellation Sculptor.