did not find dark matter In two galaxies that occurs, new on the website at all

Published: 15.4.2019
in two galaxies at all did not find dark matter that occurs

Just as the ripples in a pond indicate that someone threw a stone, ran a hydrometer or the frog jumped, existence of mysterious substance - dark matter - is determined by its extensive influence on space. Astronomers cannot observe it directly, however gravitation of dark matter defines the birth, a form and the movement of galaxies. It makes a discovery of last year absolutely unexpected: in the strange, diffusion galaxy did not find dark matter at all. Do you think, on it all? Kind of not so.

Results of work of Danielle were presented to

at a conference on dark matter in Princeton University and will be published in Astrophysical Journal Letters.

Today nobody definitely found dark matter, despite decades of active search. The lack of proofs induced some astrophysicists to look for alternative ways of a molding of galaxies and management of their movement for the account of emergence of hypotheses like "emerdzhentny gravitation" and "the modified Newtonian dynamics". Supporters of these hypotheses claim that most of astronomers believes that dark matter can be the phenomenon which arises from physics which we do not understand fully. But in that case these strange galaxies will speak well for the fact that alternatives are incorrect and that dark matter can really be the cause.

"It became possible thanks to new devices which arrived to the biggest telescopes on the planet. And, frankly speaking, a year ago it was not obvious to me that it will be feasible. A year ago I was not ready to tell that I this system will be direct surely strange because it seemed to me that measurements are not supported by data fully. But now, when there are two different teams which measured the range of speeds of stars, I think, it became obvious that the strangeness is".

Two galaxies interesting us very dim also are far from Earth: photons from their star clusters began to travel towards our planet in the last days of board of dinosaurs, about 65 million years ago. The first galaxy of NGC 1052-DF2 of the size of the Milky Way, but contains 100 times less stars. The new galaxy of NGC 1052-DF4 is in the same site of the sky and by the sizes and weight approximately same.

In general, its research assumes that there is the whole class of such poor dark matter of galaxies.

Well, time will tell. Do not forget to subscribe for our canal with news to see dark matter the first.

Meanwhile, Eric Emsellem from the European southern observatory and his colleague explored the galaxy by means of Very Big Telescope in the Chilean Atacama Desert. They also found low-speed dispersion which supports the scenario of the absent dark matter.

"To our own surprise, we measured extremely narrow spectral lines which leave very few place for bigger weight, except the weight brought by stars in the galaxy", speaks to Danielle. There is no dark matter just the place.

In March of last year scientific led by Chanйe Danielle and Peter van Dokkum from Yale University published a research in which estimated the NGC 1052-DF2 size, observing its star light and also movements of star clusters which surround it. If NGC 1052-DF2 contained so much dark matter how many astronomers usually expect from it, dark matter would increase orbital speeds of these star phenomena. But they move inertly that says that dark matter is absent. Critics object that speeds of these star clusters were incorrectly calculated - and even if their calculations correct, the amount of selection of only 10 star clusters was too modest for reliable definition of a reserve of dark matter in NGC 1052-DF2.

In terms of information, star light contains much it. Dividing light into the colors which are it (it is called spectroscopy), scientists can determine structure of a star, its age, the direction of the movement in space and speed. The most part of this information is transferred in a view of spectral lines - the linear elements which are built in a star range owing to radiation or absorption of various chemical elements. The Keka tool measured a range about 10 million stars in the galaxy of DF2. The extent of dispersion between the fastest and slowest stars in the galaxy gives an idea of that how many matter interacts with them. The bigger matters - dark or still what - the dispersion in speeds of stars is more.

And here, the initial team got the additional proofs confirming its initial opening. Besides, the second galaxy with similar symptoms was found. Where there was one ultradiffusion galaxy free from dark matter (at first sight), now their two earlier.

"One object can always be written off as a unicorn, but as soon as you find two unicorns, you begin to think of possible existence of unicorns", Michael Boylan-Kolchin, the astronomer of the University of Texas at Austin who did not take part in this research says. "And then you begin to think of that from where they undertook what their properties and as far as they are widespread".

One clear for certain: if no powerful doubts appear, the lack of dark matter in galaxies will convincingly show that this substance is separable from stars, gas, dust and other usual matter. And it, in turn, will strengthen an argument in favor of existence of dark matter.

Some scientists welcomed this opening. Others expressed the doubts, having criticized measurement of distances and the movement of the galaxy. Rates are high: if in this galaxy there is really not enough dark matter, it paradoxically will confirm existence of this substance.

In October of Danielle decided to deal with this issue, using other equipment. It took Keck Cosmic Web Imager, the new tool which is recently installed behind a huge 10-meter main mirror of the Keka telescope in Hawaii. This device can measure light from very weak objects with extremely high resolution that does it by the ideal tool for studying of ultradiffusion galaxies, such as NGC 1052-DF2. This tool was so good that Danielle had not to study movements of a star cluster any more to determine the mass of the galaxy. Instead she could receive weight directly, directly using star light of the galaxy.

Nicholas Martin, the astronomer from the Strasbourg university in France, was one of critics of original article. In the subsequent work published last year it claimed that it is too difficult to estimate the mass of the galaxy of DF2 on the basis of movements of a surrounding star cluster. But Martin says that he was calmed by the last results of Danielle and Emsell.

Some astronomers puzzle over how such galaxies could be formed and where dark matter got to. Boylan-Kolchin says that one of opportunities is the gravitational attraction of the neighboring, much larger galaxy separated from dark matter. Or DF2 and DF4 can be not galaxies at all, and the modest meetings of stars masking under galaxies; in this case these isolated groups of stars can be formed of the facing jets of the gas flowing from other place. Or there can be even more boring scenarios, for example, orientation of galaxies concerning Earth which adversely influences receiving exact spectral measurements of their movements.

Source: http://photo-rai.ru

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