Gravitational waves neutron stars. Astronomers for the first time heard gravitational waves from the merger of neutron stars. Where in the Universe, gold and other heavy elements are taken

Right holder illustration Getty Images Image Caption. The phenomenon was observed with the help of cosmic observatories and ground telescopes

Scientists for the first time managed to register gravitational waves from the merger of two neutron stars.

The waves were recorded by LIGO detectors in the United States and the Italian Virgo Observatory.

According to researchers, as a result of such mergers in the Universe, such elements like platinum and gold appear.

The discovery was made on August 17th. Two detectors in the United States registered the GW170817 gravitational signal.

Data from the third detector in Italy allowed to clarify the localization of the space event.

"This is what we all have been waiting for," said the executive director of Lago Labo David Rich, commenting on the discovery.

The merger occurred in the NGC4993 galaxy, which is at a distance of about 130 million light years from the Earth in the constellation Hydra.

The masses of stars were in the range from 1.1 to 1.6 mass of the Sun, which falls into the area of \u200b\u200bneutron stars. Their radius is 10-20 km.

The stars are called neutron, since in the process of gravitational compression protons and electrons inside the star merge, resulting in an object consisting almost exclusively from neutrons.

Such objects have an incredible density - a teaspoon of matter will weigh around a billion tons.

Right holder illustration NSF / LIGO / SONOMA STATE UNIVERSITY Image Caption. The fusion of neutron stars in the view of scientists looks like this (in the photo - a computer model)

LABO LABORATORY in Livingston in Louisiana is a small building from which two pipes are departed at a right angle - the shoulders of the interferometer. Inside each of them - a laser beam, fixing changes in the length of which can detect gravitational waves.

The LIGO detector established in the midst of extensive forests was created in order to fix gravitational waves that generate large-scale space cataclysms, such as the fusion of neutron stars.

Four years ago, the detector was upgraded by, since then, he collided four times a collision of black holes.

Gravitational waves that arise as a result of large-scale events in space lead to the occurrence of temporary spatial curvatures, something similar to ripples on the water.


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Opening of the year: how does the collision of neutron stars?

They stretch and squeeze all the matter through which they pass, at an almost insignificant degree - less than the width of one atom.

"I am delighted with what we did. For the first time, I started working on gravitational waves in Glasgow, being still a student. Since then, many years have passed, there were ups and downs, but now it all happened," says Worker LIGO, Professor Norna Robertson.

"Over the past few years, we first recorded the merge of" black holes ", and then - neutron stars, according to my feelings, we open a new field for research," it adds.

  • The existence of gravitational waves was predicted in the framework of the general theory of Einstein's relativity.
  • To develop the technology that allowed to fix the waves, decades went
  • Gravitational waves are distortion in time and space that arise as a result of large-scale events in space.
  • Radically accelerating matter generates gravitational waves that apply to light speed
  • Among the visible sources of the waves are called the mergers of neutron stars and "black holes"
  • Research of the waves opens a fundamentally new field for research

Scientists believed that the release of energy on a scale leads to the occurrence of rare elements - such as gold and platinum.

According to Dr. Kate Maguire from the Royal University of Belfast, which was engaged in analyzing the first outbreaks arising from the merger, now this theory is proved.

"With the most powerful in the world of telescopes, we found that as a result of this merger of neutron stars, a high-speed release of heavy chemical elements occurred, such as gold and platinum, in space," says Maguire.

"These new results helped to significantly move to the resolution of a long-time dispute about where the elements of the periodic table came from the periodic table," she adds.

New frontiers

Monitoring the collision of neutron stars also allowed to confirm the theory that it is accompanied by short emissions of gamma radiation.

Comparing the collected information about the resulting gravitational waves with data on light radiation, assembled using telescopes, scientists used previously not used in practice. Method to measure the expansion rate of the universe.

One of the most influential physicists of theoretics on the planet, Professor Stephen Hawking in a conversation with the BBC called it the "first step on the stairs" to a new method for measuring distances in the universe.

"A new way of observation of the universe as a rule leads to surprises, many of which cannot be foreseen. We still wipe your eyes, or rather, we can clean the ears after the sound of gravitational waves first heard," Hawking said.

Right holder illustration NSF. Image Caption. The Ligo Observatory complex in Livingston. From the building, "shoulders" - pipes, inside of which laser rays are held in vacuo

Now the equipment of the LIGO complex is upgraded. A year later, he will be twice as more sensitive, and can scan the segment of space, which is eight times the current one.

Scientists believe that in the future, observation of the collision of "black holes" and neutron stars will become the usual phenomenon. They also hope to learn to watch objects that can not even imagine today, and begin a new era in astronomy.

The collaboration of Ligo-Virgo together with astronomers of 70 observatories announced today about the observation of the merger of two neutron stars in gravitational and electromagnetic bands: they saw a gamma splash, as well as X-ray, ultraviolet, visible, infrared and radio radiation.

Illustration of a collision of neutron stars. Narrow emission diagonally is a flow of gamma rays. The luminous cloud around the stars is the source of visible light, which was observed by telescopes after the merger. Credit: NSF / LIGO / SONOMA STATE UNIVERSITY / AURORE SIMONNET

The joint observation of gamma burst, gravitational waves and visible light allowed to determine not only the area in the sky, where the event occurred, but also the Galaxy of the NGC 4993, to which the stars belonged.


Determination of the location in the sky with different detectors

What can we say about neutron stars?

Astronomers watched short gamma radiation bursts over the years, but did not know exactly how they arise. The main assumption was that this burst occurs as a result of the merger of neutron stars, and now the observation of gravitational waves from this event confirmed the theory.

When neutron stars face, the main part of their substance merges into one supermassive object, radiating the "fireball" from the gamma of radiation (the shortest gamma burst, registered in two seconds after gravitational waves). After that, the so-called kilonov occurs when the substance remaining after the collision of neutron stars is carried away from the collision site, radiating light. The observation of the spectrum of this radiation made it possible to determine that heavy elements, such as gold, are born as a result of kilon. Scientists were observed after-glow over weeks after the event, collecting data on the processes that took place in the stars, and this was the first reliable observation of Kilon.

Neutron stars are super-flat objects resulting from supernova explosion. The pressure in the star is so high that the atoms cannot exist separately, and inside the star is liquid "soup" from neutrons, protons and other particles. To describe a neutron star, scientists use the equation of a state that binds the pressure and the density of the substance. There are many options for possible equations of states, but scientists do not know which of them are correct, therefore gravitational observations can help resolve this issue. At the moment, the observed signal does not give an unequivocal response, but help to give interesting estimates on the shape of a star (which depends on the gravitational attraction to the second star).

An interesting discovery turned out that the observed short gamma surge is the closest to Earth, but at the same time too dim for such a distance. Scientists suggested several possible explanations: perhaps a ray of gamma-radiation was uneven brightness, or we saw only its very edge. In any case, the question arises: Earlier, astronomers did not assume that such dull bursts could be located so close, and could they then skip the same dull bursts, or would it be wrong to interpret them as more distant? Joint observations in the gravitational and electromagnetic range can help give an answer, but at this level of detectors sensitivity such observations will be quite rare - on average 0.1-1.4 per year.

In addition to gravitational and electromagnetic radiation, neutron stars emit neutrino streams during the fusion process. Neutrino detectors also worked on the search for these streams from the event, but did not record anything. In general, this result was expecting - as in the case of a gamma burst, an event is too dim (or we observe it at a big angle) so that the detectors can see it.

Speed \u200b\u200bof gravitational waves

Since gravitational waves and the light signal occurred from one source with a very high probability (5.3 SIGMA), and the first light signal came after 1.7 seconds after gravitational, we can limit the speed of propagation of gravitational waves with very great accuracy. Assuming that light and gravitational waves emitted simultaneously, and the delay between the signals occurred due to the fact that the gravity is faster, you can get the top rating. The lower estimate can be obtained from the merge models of neutron stars: assume that the light was emitted in 10 seconds after gravitational waves (at that moment all the processes should have completed accurately) and caught up with gravitational waves at the time of the Earth. As a result, gravity rate is equal to the speed of light with great accuracy

For the bottom assessment, it is possible to use a greater delay between radiation, and even to assume that the light signal was first emitted, which will reduce the accuracy proportionally. But even in this case, the assessment is extremely accurate.

Using the same knowledge of the delay between signals, it is possible to significantly increase the accuracy of estimates on the Lorenz invariance (difference between the behavior of gravity and light when the Lorentz transform) and the equivalence principle.

Scientists measured a permanent Hubble and in other ways to monitor the parameters of relic radiation on the planke telescope, and received another value of a constant Hubble, not consistent with the measurements of shoes. This distinction is too large to be statistical, but not yet known the causes of evaluations. Therefore, it is necessary to independent measurement.


Probability distribution for constant hubble using gravitational waves (blue). The dotted line indicates the intervals 1σ and 2σ (68.3% and 95.4%). For comparison, 1σ and 2σ intervals are shown for previous estimates: Planck (green) and shoes (orange) that do not converge with each other.

Gravitational waves in this case plays the role of standard candles (and are called standard sirens). Observing the amplitude of the signal on Earth and modeling its amplitude in the source, it is possible to evaluate how much it decreased, and thereby find out the distance to the source - regardless of any assumptions on the permanent Hubble or previous measurements. The observation of the light signal made it possible to determine the galaxy where a pair of neutron stars was located, and the removal rate of this galaxy was well known for previous measurements. The ratio between speed and distance is constant Hubble. It is important that such an assessment is completely independent of previous estimates or a space scale of distances.

One dimension was not enough to allow the riddle of differences in the estimates of the plank and shoes, but in general the assessment is already well corresponds to known values. Given that previous estimates are based on statistics collected over the years, this is a very significant result.

A little about Ligo and glitches



The top panel shows the glitch in Ligo-Livingston data, and also clearly demonstrates the presence of chirpa. The lower panel shows the dimensionless amplitude of the oscillations, "Strain" (the value we describe the value of the signal in Ligo and Virgo) at the time of the glitch. This is a short
(It lasts only about 1/4 seconds), but a very strong signal. Suppression reduces the glitch to an orange curve, which shows the level of background noise, always present in LIGO detectors.

Only one of the LIGO detectors saw a signal in automatic mode, since "glitch" occurred at the detector in Livingstone at the time of the event. This term is a splash of noise, similar to cotton static in the radio. Although the gravitational wave signal was obviously noticed by the human eye, the automation cuts out such data. Therefore, it took a cleaning of the signal from the glitch before the data could be used by the detector. The glitches appear in detectors all the time - about once a few hours. Scientists classify them in form and duration and use these knowledge to improve detectors. You can help them with this in the GravitySpy project, where users are looking for and classifying glitches in Ligo data to help scientists.

Questions without answers



Famous black holes, neutron stars and their mergers. There is an area of \u200b\u200bmedium mass, about the existence of compact objects with which we do not know anything. Credit: Ligo-Virgo / Northwestern / Frank Elavsky

We registered gravitational waves from two compact objects, and the observation of electromagnetic radiation suggests that one of them was a neutron star. But the second could be a black hole with a small mass, and although no one had seen such black holes, they couldoretically exist. From the observation of GW170817, it is impossible to determine exactly if it was a collision of two neutron stars, although it is more likely.

The second curious moment: what did this object become after the merger? He could be either a supermassive neutron star (the most massive from known) or the easiest of famous black holes. Unfortunately, the observation data is not enough to answer this question.

Conclusion

Observation of the merger of neutron stars in about all bands is a stunningly rich event. The amount of data received by scientists only for these two months has made it possible to prepare several dozen publications, and will be much more when the data becomes publicly available. Physics of neutron stars is much richer and more interesting than the physics of black holes - we can directly check the physics of the super-proper state of the substance, as well as the quantum mechanics under conditions of strong gravitational fields. This unique opportunity can help us finally find a link between the general theory of relativity and quantum physics, which still eluded us.

This discovery shows how much the work of many collaborations from thousands of people is important in modern physics.

Reddit AMA.

Traditionally, Reddit scientists from Ligo respond to user questions, I highly recommend!
It will happen from 18 hours in Moscow on October 17 and 18. The link to the event will be at the beginning of the beginning.
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    Surveillance results can shed light on the mystery of the structure of neutron stars and the formation of heavy elements in the Universe

    Artistic image of gravitational waves generated by the merge of two neutron stars

    Image: R. Hurt / Caltech-JPL

    Moscow. October 16. Website - scientists for the first time in history recorded gravitational waves from the confluence of two neutron stars - superlit objects with a mass with our sun and the size of Moscow, the site N + 1 reports.

    About 70 terrestrial and cosmic observatories that arose then have observed about 70 terrestrial and cosmic observatories - they were able to see the theoreticals of the synthesis of heavy elements, including gold and platinum, and confirm the rightness of the hypotheses about the nature of mysterious short gamma bursts, according to the press service of the collaboration LIGO / VIRGO, the European Southern Observatory and the Los Cumbrity Observatory. The results of observations can shed light on the mystery of the structure of neutron stars and the formation of heavy elements in the universe.

    Gravitational waves - waves of oscillations of the geometry of space-time, the existence of which was predicted by the general theory of relativity. For the first time on their reliable disclosure, LIGO collaboration reported in February 2016 - 100 years after Einstein's predictions.

    As reported, on the morning of August 17, 2017 (at 8:41 pm in the time of the east coast of the United States, when in Moscow it was 15:41) Automatic systems on one of the two detectors of the LIGO gravitational and wave observatory registered the parish of a gravitational wave from space. The signal received the designation GW170817, it was already the fifth case of fixing gravitational waves since 2015, from the moment they were first recorded. In just three days before that, the LIGO Observatory for the first time "heard" gravitational wave together with the European project Virgo.

    However, this time after two seconds after the gravitational event, the Fermi space telescope recorded the outbreak of gamma radiation in the southern sky. Almost at the same time, the outbreak saw the European-Russian Space Observatory Integral.

    Automatic data analysis systems of the LIGO observatory have concluded that the random coincidence of these two events is extremely unlikely. During the search for more information, it was found that the gravitational wave saw the second LIGO detector, as well as the European Gravitational Observatory Virgo. Astronomers of the whole world were raised "alarm" - a hunt for gravitational waves and gamma burst began many observatories, including the European Southern Observatory and the Hubble Space Telescope.

    The task was not easy - the combined data LIGO / VIRGO, FERMI and INTEGRAL made it possible to outline the area of \u200b\u200b35 square degrees - this is an exemplary area of \u200b\u200bseveral hundred lunar disks. Only after 11 hours a small SWOPE telescope with a meter mirror located in Chile, made the first shot of the intended source - it looked like a very bright star next to the elliptical NGC 4993 galaxy in the constellation Hydra. Over the next five days, the brightness of the source fell 20 times, and the color gradually shifted from blue to red. All this time, the object was observed with many telescopes in the ranges from X-ray to infrared, while in September the galaxy was not too close to the Sun, and it became unavailable for observations.

    Scientists concluded that the source of the outbreak was in the NGC 4993 galaxy at a distance of about 130 million light years from the Earth. It is incredibly close, so far gravitational waves have come to us from the distance in billions of light years. Thanks to this intimacy, we were able to hear them. The source of the wave was the merging of two objects with the masses in the range from 1.1 to 1.6 mass of the Sun - it could only be neutron stars.

    Localization of the source of gravitational waves in the NGC 4993 galaxy

    The splash itself "sounded" for a very long time - about 100 seconds, gave bursts lasting in a fraction of a second. A pair of neutron stars rotated around the common center of masses, gradually losing energy in the form of gravitational waves and approaching. When the distance between them has decreased to 300 km, the gravitational waves have become powerful enough to get into the sensitivity zone of the LIGO / VIRGO gravitational detectors. Neutron stars managed to make 1.5 thousand revolutions around each other. At the time of the merger of two neutron stars in one compact object (neutron star or black hole) there is a powerful flash of gamma radiation.

    Such gamma outbreaks of astronomers are called short gamma bursts, gamma telescopes fix them approximately once a week. A short gamma splash from the merger of neutron stars, which was reported, lasted 1.7 seconds.

    If the nature of long gamma bursts is more understandable (their sources - supernova), the unity of opinions about sources of short bursts was not. There was a hypothesis that they would give rise to the mergers of neutron stars.

    Now scientists were able to confirm this hypothesis for the first time, because thanks to the gravitational waves, we know a lot of spontaneous components, which proves that it is precisely neutron stars.

    "Decades We suspected that short gamma bursts generate the mergers of neutron stars. Now, thanks to the data Ligo and Virgo, we have an answer about this event. Gravitational waves tell us that the spontaneous objects had masses corresponding to neutron stars, and the gamma flash says These objects could hardly be black holes, since the collision of black holes should not generate radiation, "says Julie Mcanery, an employee of the Fermi project center of NASA namedrd.

    Gold and platinum source

    In addition, astronomers for the first time received an unambiguous confirmation of the existence of kilon (or "macronic") outbreaks, which are about 1 thousand times more powerful outbreaks of ordinary new ones. Theorists predicted that kilon can occur when the neutron stars or neutron stars and a black hole.

    In this case, the process of the synthesis of heavy elements is launched, based on the grip of neutron nuclei (R-process), as a result of which many of the heavy elements such as gold, platinum or uranium appeared in the universe.

    According to scientists, with one explosion, a kilon can arise a huge amount of gold - up to ten masses of the moon. Until now, only once an event was observed that could be a kilon explosion.

    Now the astronomers were able to watch not only the birth of kilon, but also the products of her "work". The spectra obtained using the Hubble and VLT telescope (Very Large Telescope) showed the presence of cesium, tellurium, gold, platinum and other heavy elements formed by the merger of neutron stars.

    11 hours after the collision, the temperature of Kilon was 8 thousand degrees, and its expansion speed reached about 100 thousand kilometers per second, N + 1 notes with reference to the data of the State Astronomical Institute named Sternberg (Gaish).

    ESO reported that the observation was practically ideally coincided with the forecast of the behavior of two neutron stars when merging.

    "While the data we received is greatly consistent with the theory. This is a triumph of theorists, confirmation of the absolute reality of events registered by LIGO and Virgo Observatory, and the wonderful achievement of ESO, which was able to obtain such Khonon observations," said Stefano Covino, the first author of one of Articles in Nature Astronomy.

    So the collision of neutron stars saw astronomers

    Scientists have no answer to the question that it remains after the merger of neutron stars - it can be both a black hole and a new neutron star, moreover, it is not quite clear why the gamma splash turned out to be relatively weak.

    On August 17, 2017, the laser-interferometric gravitational-wave Observatory Ligo and the Franco-Italian Virgo gravitational wave detector first recorded gravitational waves from the collision of two neutron stars. Approximately two seconds after that, the Space Gamma Telescope NASA "FERMI" and the Astrophysical Gamma Laboratory ESA "Integral" was observed a short gamma splash GRB170817A in the same sky area.

    "A scientist rarely falls the case to witness the beginning of a new era in science. This is one of these cases! " - Elena Pian said from the Astrophysical Institute of Italy, the author of one of the published in Nature. Articles.

    What is gravitational waves?

    Gravitational waves created by moving masses are markers of the most severe events in the universe and occur when a collision of dense objects, such as black holes or neutron stars.

    Their existence was predicted in 1916 by Albert Einstein in the general theory of relativity. However, fix the gravitational waves managed only after a hundred years, since only the most powerful of these waves, due to rapid changes in the speed of very massive objects, can be registered with modern receivers.

    Until today, 4 gravitational waves were caught: three times ligo fixed the "ripples" of space-time, and on September 14, 2017, for the first time, gravitational waves were caught in three detectors at once (two LIGO detectors in the United States and one Virgo detector in Europe).

    Four previous events have one common - all of them are caused by the merge of pairs of black holes, as a result of which their source is impossible. Now everything has changed.

    How to observatory around the world "caught" the source of gravitational waves

    The joint work of LIGO and Virgo allowed to position the source of gravitational waves within the extensive portion of the southern sky of several hundred discs of the full moon containing millions of stars. More than 70 observatories around the world, as well as the NASA Space Telescope "Hubble" began to observe this area of \u200b\u200bthe sky in search of new radiation sources.

    The first message about the discovery of the new light source came after 11 hours from the SWOPE meter telescope. It turned out that the object was very close to the Lenzoid Galaxy NGC 4993 in the constellation Hydra. Almost at the same time, the same source was registered by the telescope of the European South Observatory ESO "Vista" in infrared rays. As the night moved to the West to the West, the object was observed in the Hawaiian Islands "Pan-Starrs" and "Subaru" telescopes, and his quick evolution was noted.

    The flash from the collision of two neutron stars in the NGC 4993 galaxy is clearly visible on the image of the Hubble Space Telescope. Observations conducted from 22 to 28 August 2017 show how it gradually disappeared. Credit: NASA / ESA

    Estimates of the distance to the object, obtained from both gravitational and wave data and from other observations, gave the consistent results: GW170817 is located at the same distance from the Earth as the NGC 4993 galaxy, that is, in 130 million light years. Thus, it is closest to us from all detected sources of gravitational waves and one of the nearest ever observed sources of gamma bursts.

    Mysterious kilon

    After a massive star explodes in the form of a supernova, there remains a superproof choleloped kernel: a neutron star. The mergers of neutron stars are mainly explained by short gamma bursts. It is believed that this event is accompanied by an explosion a thousand times brighter than the typical new - so-called kilon.

    Artistic representation of the collision of two neutron stars in the NGC 4993 Galaxy, which has breeded the outbreak of kilon and gravitational waves. Credit: ESO / L. Calgada / m. Kornmesser

    "This is nothing like! The object very quickly became incredibly bright, and then began to disappear rapidly, moving from blue to red. It is incredible! " - tells Ryan Fowie from the University of California in Santa Cruz (USA).

    Almost simultaneous registration of gravitational waves and gamma rays from GW170817 gave rise to hope that this is a long wanted kilon. Detailed observations on ESO tools and the Hubble Space Telescope did found the properties of this object very close to theoretical predictions made more than 30 years ago. Thus, the first observational confirmation of the existence of kilon was obtained.

    It is still unclear which object gave rise to the merge of two neutron stars: a black hole or a new neutron star. Further data analysis should answer this question.

    As a result of the merger of two neutron stars and a kilon explosion, radioactive heavy chemical elements will release, flying out at a speed of one fifth light speed. For several days - faster than with any other star explosion - the color of Kilon is changing from bright blue to very red.

    "The data we received is greatly consistent with the theory. This is a triumph of theorists, confirmation of the absolute reality of events registered by the LIGO and Virgo installations, and the remarkable ESO achievement, which was able to obtain Kilon observations, "says Stefano Covino from the Astrophysical Institute of Italy, the author of one of the published in Nature Astronomyarticles.

    Some of the elements emitted into space when merging two neutron stars. Credit: ESO / L. Calçada / m. Kornmesser.

    The spectra obtained by the tools on a very large ESO telescope show the presence of cesium and tellurium, thrown into the space when merging neutron stars. These and other heavy elements are dissipated in space after kilon explosions. Thus, observations indicate the formation of elements of heavier than iron under nuclear reactions in the depths of superproof star objects. This process, called R-nucleosynthesis, was previously known only in theory.

    The importance of opening

    The discovery marked the dawn of the new era in cosmology: now we can not only listen, but also see events generating gravitational waves! In the short term, the analysis of new data will allow scientists to obtain a more accurate picture of neutron stars, and in the future, observation of such events will help to explain the continued expansion of the universe, the composition of the dark energy, as well as the origin of the most difficult elements in space.

    Studies describing the discovery are represented by a series of articles in magazines Nature., Nature Astronomy and Astrophysical Journal Letters..

    Moscow, October 16. / TASS /. LASER INTERFEROMETRIC GRAVITATIONAL WAVE OBSERVATORY, USA) and VIRGO (similar observatory in Italy) recorded gravitational waves from the merger of two neutron stars. This discovery is announced on Monday during the International Press Conference, held simultaneously in Moscow, Washington and a number of cities in other countries.

    "Scientists first recorded gravitational waves from the fusion of two neutron stars, and this phenomenon was observed not only on laser interferometers, registering gravitational waves, but also with the help of cosmic observatives (Integral, Fermi) and ground telescopes, registering electromagnetic radiation. In total, this phenomenon was observed. About 70 terrestrial and cosmic observatories around the world, including a network of robot telescopes Master (MSU. M.V. Lomonosov), "the press service of the Moscow State University says.

    When and how to registered

    The discovery of which scientists reported on Monday was made on August 17. Then both LIGO detectors registered a gravitational signal called GW170817. The information provided by the third detector of Virgo made it possible to significantly improve the localization of the space event.

    Almost at the same time, in about two seconds after gravitational waves, the NASA FERMI Space Gamma Telescope and the International Gamma-Ray Astrophysics Laboratory / Integral Observatory (International Gamma-Ray Astrophysics Laboratory / Integral) discovered gamma ray bursts. In the following days, scientists registered electromagnetic radiation in other ranges, including X-ray, ultraviolet, optical, infrared and radio waves.

    LIGO detectors showed that registered gravitational waves were emitted by two astrophysical objects rotating relative to each other and located on a relatively close distance - about 130 million light years - from the Earth. It turned out that objects were less massive than previously detected Ligo and Virgo double black holes. According to calculations, their masses were in the range of 1.1 to 1.6 mass of the Sun, which falls into the area of \u200b\u200bneutron stars, the smallest and most dense among stars. Their typical radius is only 10-20 km.

    If the signal from merging double black holes was usually in the ligo detector sensitivity range over a second, the signal, registered on August 17, lasted about 100 seconds. After about two seconds after the fusion of the stars, a flash of gamma radiation occurred, which was registered by space gamma telescopes.

    The rapid detection of gravitational waves by the Ligo-Virgo command in combination with the detection of gamma radiation allowed to launch observation of optical and radio telescope around the world.

    After receiving the coordinates, several observatories were able to start a search in the sky area after a few hours, where the event was supposedly occurred. A new light point resembling a new star was discovered by optical telescopes, and as a result, about 70 observatories on Earth and in space was observed this event in various wavelength ranges.

    In the following days, after a collision, electromagnetic radiation in X-ray, ultraviolet, optical, infrared and radio wavebands was registered.

    "For the first time, in contrast to the" single "mergers of black holes, a" Caleship "event is registered not only by gravitational detectors, but also with optical and neutrine telescopes. This is the first such dance of observations around the same event," said Professor of the Physics Faculty of Moscow State University Sergey Vyatchanin, Which is included in the group of Russian scientists who participated in the observation of the phenomenon, under the leadership of Professor of the Physical Faculty of Moscow State University Valery Mitrofanov.

    Theorists predict that in the collision of neutron stars, gravitational waves and gamma rays should be erased, as well as erupt the powerful jets of substances, accompanied by radiation of electromagnetic waves in a wide frequency range.

    The discovered gamma burst is the so-called short gamma burst. Previously, scientists only predicted that short gamma bursts were generated when merging neutron stars, and now it is confirmed by observations. But, despite the fact that the source of the discovered short gamma burst was one of the closest to the ground, visible so far, the surge itself was unexpectedly weak for such a distance. Now scientists have to find an explanation for this fact.

    With the speed of light

    At the time of collision, the main part of the two neutron stars merged into one ultra-blank object emitting gamma rays. The first measurements of gamma radiation in combination with the detection of gravitational waves confirm the prediction of the general theory of the relativity of Einstein, namely, the gravitational waves propagate at the speed of light.

    "YouTube / Georgia Tech"

    "In all previous cases, the source of gravitational waves had merging black holes. Like paradoxically, black holes are very simple objects consisting exclusively from the curved space and therefore fully described by well-known laws of the general theory of relativity. At the same time, the structure of neutron stars and, in particular, the equation of the state of neutron matter is still unknown. Therefore, the study of signals from merging neutron stars will allow to obtain a huge number of new information also on the properties of super-proper matter in extreme conditions, "said Professor of the Physics Faculty of Moscow State University Farit Khalili, which so same enters the Mitrofanov group.

    Factory of heavy elements

    Theorists predicted that as a result of the merger, "Kilonovaya" is formed. This phenomenon at which the material remaining from the collision of neutron stars is brightly glow and thrown out of the collision area far into space. In this case, processes occur, as a result of which heavy elements are created, such as lead and gold. Observation After the burning of the merger of neutron stars allows you to receive additional information about the various stages of this merge, about the interaction of the object with the environment and processes that produce the most difficult elements in the universe.

    "In the process of merger, the formation of heavy elements has been recorded. Therefore, it can even be said about the galactic factory for the production of heavy elements, including gold - after all, this metal is most interested in earthlings. Scientists begin to offer models that would explain the observed parameters of this merger", - Noted Vyatchanin.

    About the collaboration of Ligo-LSC

    The scientific collaboration of LIGO-LSC (LIGO SCIENTFIC COLLABORATION) unites more than 1,200 scientists from 100 institutes of various countries. The LIGO Observatory is built and operated by California and Massachusetts technological institutions. LIGO partner is the Virgo collaboration, which employs 280 European scientists and engineers from 20 research groups. Virgo detector is close to Pisa (Italy).

    Two scientific teams from Russia are involved in Ligo Scientific Collaboration studies: a group of the physical faculty of Moscow State University named after M.V. Lomonosov and group of the Institute of Applied Physics RAS (Nizhny Novgorod). Studies are supported by the Russian Foundation for Fundamental Research and the Russian Scientific Foundation.

    LIGO detectors in 2015 were first recorded gravitational waves from the collision of black holes, and in February 2016, the opening was announced at a press conference. In 2017, American Physicists Rainer Weiss, Kip Thorn and Berry Barisch for a decisive contribution to the LIGO project, as well as "monitoring gravitational waves, became laureates of the Nobel Prize in Physics.

    mOB_INFO.