Long road to the top "Zeldovich"

On March 8, 2014, it turned 100 since the birth of an outstanding scientist of the twentieth century, academician Yakov Borisovich Zeldovich . The circle of his scientific interests was unusually wide: from chemical physics, theory of shock waves and detonations to physics of elementary particles, astrophysics and cosmology. He was one of the creators of the nuclear-nuclear shield of his country, for which three times (in 1949, 1955, 1956) he was awarded the title of Hero of Socialist Labor. A professor, a doct, tells about his teacher and co -response. physical. sciences, head. department of relativistic astrophysics of the Gaish of Moscow State University named after M.V. Lomonosova Nikolai Ivanovich Shakura . The full version of his article.

My first acquaintance is not with the academician himself, but with one of his books was as follows. After final exams in the secondary school of the urban village of Parichi, that in the Gomel region, for some matters, I went to the city of Bobruisk and went to the bookstore and saw there the book “Higher Mathematics for Beginners”, the author of which was Ya.B. Zeldovich. Naturally, the author’s name did not tell me anything, but the content of the book interested me for the following reason.

In those, now far for the author, times, secondary education in mathematics ended in taking the limits. The limits were preceded by elementary functions, one of which was (of course, there is now) Parabola. It was necessary to find the position of the minimum (parabola with “horns” up) or maximum (parabola “horns” down). Explaining how this is done according to the then methods using the Vietta formula, the school teacher of mathematics (as well as physics and astronomy) Alfred Viktorovich Baranovsky sentenced the following: “But the methods of higher mathematics are calculated much faster and more beautiful.” He was a vocation teacher - in the spring of 2004 Alfred Viktorovich was gone.

Of course, a little familiar with the highest mathematics will say: “Take a derivative of the function and equate it zero. For parabola, an equation is a linear relative to the “X”. ” Yes, very simple, but I repeat once again that secondary education ended in taking the limits, not derivatives. Alfred did not conduct special classes with the leading process leaders. But with his permission, we had admission to the physical office of the school. Yes, at that time what was not there!

I received my individual development in mathematics, getting acquainted with the contents of the postal items, which I wrote out of the country's chief university, Moscow Ut-T. M.V. Lomonosov.

After buying a book, I went into a small cozy square on Bakharev Street in Bobruisk and began to flip it out. On the first pages, school things were presented: graphs, functions, what is the way, speed, acceleration ... I was prevented by a pleasant gypsy to reach the chapters with higher mathematics. She guessed me, I handed her two coins of 15 kopecks and we parted. Yes, a young reader, then there were coins of such dignity, nicknamed the "spots", and what coins! And the first time, and many times after I got to Moscow from Bobruisk and back home by bus, since there is no direct railway path between these cities. If you recount the cost of purchased tickets along this route per unit of traveled path, then in those days this value was approximately 2 kopecks/km.

More in the book Ya.B. I did not look Zeldovich, since it was necessary to go to Moscow to take entrance exams at the astronomical department of the Faculty of Physics of Moscow State University. My first “fees” in Moscow was deposited in my memory. My school comrade Volodya Bukhalov, seeing the suitcase with whom I was going to go, for some reason “rejected” him and offered to go to our classmate Volodya Khoroneko and take his suitcase for a while, which was done. Later, when Mom Volodya Zhoronko found out that her new personal suitcase was in Moscow without her knowledge, she said that she no longer needed such a suitcase, and my mother had to buy this suitcase a little more than tickets to Moscow at one end.

The first three years of study at Moscow State University passed without Ya.B. Zeldovich. Moreover, I forgot about the book purchased in Bobruisk - it was not among the standard university textbooks. And not because she was bad. It was intended for those who comprehended the highest mathematics through self -education. The academician addressed it to novice engineers and technicians.

My scientific work began in the 3rd year in the sunny department of the GASH of Moscow State University, where I studied the mechanisms of borrowing the wings of the absorption lines in the spectrum of the Sun. With the help of a pencil and the ruler, I processed long paper rolls from the recorders. This work took place under the guidance of two employees from the Sunny Department of the GAISH. One of them was Olga Nikolaevna Metropolskaya (wife of Professor Solomon Borisovich Pikelner), the second - Anna Ivanovna Kiryukhina.

The work was unusually interesting for me, as for a student. However, this work ended for me sadly. They have a long-spectrograph pipe there, in which you can study different details on the surface of the sun, thanks to a small device constructed by a very talented department of the department, Igor Fedorovich Nikulin. The spectacle is very enchanted. So, once I sat at this pipe with the head of the Solar Department, Professor Sitnik Grigory Fedorovich. We simultaneously clung to the eyepiece of this device, and I knocked out the glasses of Grigory Fedorovich with my “head”. I was very scared: to bring down glasses to the professor is something unthinkable and incredible. I ran away and did not come to the sunny department anymore.

My first personal contact with the academician took place in 1966, when he began to give his lectures for 4th year students of the Astronomical Department of the Physics Faculty of Moscow State University named after M.V. Lomonosov. In the fall of that year, we found in the class schedule a new special course “Structure and evolution of stars”, which was supposed to read Ya.B. Zeldovich. Lectures were given on Fridays, and on Thursdays under the guidance of Yabs at the State Astronomical Institute. PC. Sternberg (GAISH of Moscow State University) held a combined astrophysical seminar (OSA).

Both already established scientists and youth, who received higher education, participated in the work of this seminar. Students ran to this seminar as far as possible, since it was not listed in the schedule of training sessions. After his first lecture, the Yab asked to linger who wanted to and get a topic for the course work. Several students, including me, remained in the audience. When the line reached me, he asked if I was at an OAS meeting yesterday.

I answered in the affirmative. To the second question: whether I listened to a report on (mysterious then) sources of space X -ray radiation, the answer was also affirmative. Then he said: “Try to calculate the structure and spectrum of radiation of a powerful shock wave, which occurs as a result of the fall of gas on a neutron star near its surface.”

The topic of work was due to the following circumstances. In 1962, the first sources of cosmic X -ray radiation were discovered by a group of American scientists, headed by Professor Ricardo Giacon. By the beginning of the 1960s, one extraterrestrial source of X-ray radiation was already known-the crown of our Sun. It turned out that the coronal gas was heated by some mechanisms to a temperature of several million degrees, and the luminosity of the solar crown in this range is approximately one millional from the optical luminosity of the Sun (4*1033 ERG/s). It was natural to assume that there were hot crowns around other stars. A simple calculation showed that the detectors of those times even the crown of the nearest stars could not fix with a distance of several parsecks.

Nevertheless, scientists hoped for the opening of X -ray radiation from the moon! Of course, the moon does not have an atmosphere. However, a possible mechanism consisted in the fluorescent glow of the lunar soil, irradiated by X -rays, coming from the sunny crown. And exactly at midnight from June 18 to 19, 1962, when the full moon shone in the sky, the Aerobi missile was launched. The rocket reached a height of 225 km, the flight lasted 350 s.

The launch was very successful-of the three Geiger meters with a large area and good sensitivity in the energy range of 1.5-6 KEV, two constantly functioned. In this range, the earthly atmosphere is completely opaque. And instead of x -ray radiation from the moon, a bright, previously unknown source was found, which is far beyond the solar system in the direction of the constellation Scorpio. The object was called SCO X-1.

Subsequently, new X -ray sources began to open as a result of new missile launches. Gradually, a map of the X -ray sky was created with sources of different nature. While there were few of them, they received a name in accordance with the direction of which constellation they were (CYG X-1, CYG X-2, HER X-1, CEN X-3, etc.). As it turned out later, their X -ray luminosity of thousands, or even tens of thousands of times higher than the optical luminosity of the sun. Thus began the era of X -ray astronomy, the era of extraordinary discoveries in the universe.

Simple estimates made by the Yab independently showed that mainly in the X -ray range of energies should be radiated by a shock wave, which is formed near the neutron star when the surrounding gas falls on its surface. Accordingly, he instructed me to calculate the “details” of this process. The complexity of the task of calculating the structure of the shock wave near the surface of the neutron star was that the length of the run of falling particles before their complete stop is ten times higher than the characteristic scale of the interaction of radiation with the substance.

When solving many problems, there is no need to consider the structure of the shock wave, only to set a jump in density, pressure, temperature and other physical values ​​depending on the rate of the fall and the adiabata indicator of the substance. In the task, the density, temperature, and other values ​​changed in the inhibition zone with energy release. Moreover, in this zone the occurrence of collective plasma processes with the release of calculation at a more complex level of physical kinetics instead of conventional hydrodynamics is not excluded. In the end, it was possible to show that the spectra of radiation of shock waves from accreting neutron stars explained the data obtained as a result of missile launches.

In the 1960s, the first identifications of cosmic X-ray sources in the optical range appeared, which made it possible to estimate the distance to them and their luminosity. It became clear to me and Yab that if it is accusing neutron stars, then their greater luminosity can only be provided in close double star systems, where the substance flows from one component to another and one of the components is a neutron star.

As a student, I listened to a course of lectures on the general astrophysicist of the director of Gaish Dmitry Yakovlevich Martynov. A special place in this course was occupied by close double star systems, which had a flow of substance from the surface of one component to another, through the inner point of the lagrange. Due to the relative movement in their orbits, in the process of such a flow around another component, a discable shell is formed.

It seemed to me natural as a second component in a double system to put a neutron star or even a black hole! In this case, a new type of accretion is realized, namely, discs, when the substance falling on the gravitational center has a relatively the latter with a significant angular moment of the amount of movement, which prevents the direct drop in the substance into the gravitational center.

In a first approximation, the substance in the disk rotates through almost keupler circular orbits. Only with an effective mechanism (turbulence and/or magnetic fields) of the moment of exchange between neighboring layers of a differently rotating disk and discs begins - a slow radial movement of the substance towards the gravitating center with the release of gravitational energy.

The article with the calculations of the structure of the shock wave was handed over to the Astronomical Journal in mid -1968 and went out of the press in the fall of 1969. She became my course and then the diploma work. I graduated from the university at the beginning of 1969 and in April of the same year I entered the yab into graduate school of the Faculty of Physics of Moscow State University.

For me, under the leadership of the Yab, a completely new era began - the era of calculating the structure and observation manifestations of accretions around relativistic stars, which are black holes and neutron stars.

A little earlier, in 1967, one of the greatest discoveries of our time occurred - a group of scientists under the leadership of the English astronomer Anthony Huguis discovered radio pulsars. As in the case of sources of cosmic X -ray radiation discovered by the Aerobi missile outside the plan, the history of this discovery is instructive. Scientists designed a relatively small radio telescope, with the help of which they hoped to study the flickering of radio emission from distant sources on the heterogeneities of the solar wind. And so, along with this relatively simple task, radio bulbs were opened.

The leading role in this opening was played by graduate student Jocelyn Bell, who, in the records of long rolls of paper from self -writings, was the first to see strictly periodic impulses following from the same area of ​​the sky. Pretty soon the world scientific community realized that radio pulsars are very luggage, rapidly rotating neutron stars. Unlike accreting neutron stars, the observant manifestations of which should be caused by the release of gravitational energy in the process of accretion, the source of the observed activity of neutron-radiopulsars is their rotational energy. The radio bulbs were so unusual that interest in the space sources of X -ray radiation was temporarily disappeared. Moreover, there was an opinion that neutron stars and, possibly, black holes, most likely, are single objects.

Our Earth also has a magnetic field, the tension of which near its surface is about 1 GS, while at the surface of a typical pulsar this value reaches a thousand billion Gaussians. A magnetic field is, first of all, a clot of energy. If, according to the well-known formula of A. Einstein (E = MC2), count the density of the magnetic energy of such a neutron star, then it turns out about 40 g/cm3 somewhere!
Recall that the average density of the usual substance of the Earth is 5.5 g/cm3.

The first radio pulsar in the double star system was opened by J. Taylor and R. Hals in 1975. But a few years earlier there was another event in practical astronomy. The Cosmic X -ray observatory "Uhuru" (USA) found that a number of sources were accreting neutron stars and black holes in close double star systems. Let us dwell on this event in more detail.

After the first missile launches, it became clear that the research of the sky in x -rays require the installation of telescopes on specialized satellites. On September 25, 1963, Herbert Gursky and Ricardo Giacconi submitted a well -founded document in NASA, which contained a detailed program of X -ray studies using orbital observatories. And on December 12, 1970, the first such observatory, Uhuru, started. The sensitivity of its detector is thousands of times higher than the device installed on the Aerobi missile. And the most important advantage of observations from a satellite is the possibility of prolonged monitoring of individual sources.

In a number of previously open X -ray sources, periodic shutdown of the flow with a period equal to the period of circulation of the source in the double star system was observed. The second component that the source closed for a while was an ordinary star. Separate sources turned out to be X-ray pulsars, due to the effect of the additional pulse, the impulses from these pulsars were also modulated with the orbital period. Thus, acclaiming relativistic stars in double star systems were discovered.

The Uhuru Observatory worked for three years, its results were stunning. Many new X -ray sources were opened, in the first first catalog there were 339.

Now space X -ray sources of various nature (not necessarily accreting relativistic stars in double systems!) Hundreds of thousands. With the development of complex modern technology for the manufacture of X -ray telescopes with a slanting drop mirrors, a new era began in X -ray astronomy. The first such telescope was installed at the Einstein space observatory, launched in 1979. В начале 1990 годов с помощью рентгеновского телескопа с зеркалами косого падения на обсерватории РОСАТ был открыт рентгеновский свет и от Луны.

За прошедшее время утвердилось то, что сейчас называют стандартной моделью дисковой аккреции, и ее суть заключается в следующем. Представим себе двойную звездную систему, состоящую из обычной звезды и черной дыры. Размеры обычной звезды в такой системе ограничены критической полостью Роша. В процессе звездной эволюции размеры обычной звезды могут увеличиваться, и после заполнения полости Роша начинается перетекание вещества с ее поверхности в зону гравитационного влияния черной дыры.

В двойной системе из-за относительного орбитального движения компонентов вещество не падает прямо на черную дыру, а формирует вокруг нее дифференциально вращающуюся дискообразную оболочку. Скопившееся в таком диске вещество из-за трения между соседними слоями сильно разогревается и начинает светиться. Вещество в диске, быстро вращаясь, медленно приближается (аккрецирует) в радиальном направлении к черной дыре по мере отдачи момента количества движения. Свечение диска обусловлено выделением гравитационной энергии в процессе аккреции. Наиболее близкие к черной дыре внутренние части такого диска разогреваются столь сильно, что начинают излучать энергию в рентгеновском диапазоне электромагнитного спектра.

Образование аккреционного диска возможно и в более сложном случае, когда оптический компаньон, не заполняя свою полость Роша, истекает во все стороны звездным ветром. В этом случае естественно ожидать формирования головной ударной волны в зоне гравитационного влияния черной дыры на течение звездного ветра. После прохождения ударной волны в области «гравитационного» захвата черной дыры вещество начинает падать на нее, однако не строго радиально! Из-за орбитального вращения падающее вещество наделено удельным моментом количества движения, который несколько больше, чем орбитальный удельный момент количества движения черной дыры. При падении с сохранением момента вещество опережает орбитальное движение черной дыры, а затем на некотором расстоянии закручивается вокруг нее, формируя диск. А далее — опять аккреция в дисковом режиме!

Если в двойной системе на месте черной дыры находится сильно замагниченная нейтронная звезда, то ее магнитное поле разрушает аккреционный диск на расстоянии порядка 100 радиусов нейтронной звезды. Далее аккрецирующее вещество стремительно падает вдоль магнитных силовых линий, встречаясь с поверхностью нейтронной звезды вблизи магнитных полюсов. В рентгеновском спектре ударной волны появляется характерная циклотронная линия, ее положение позволяет измерить величину магнитного поля. Благодаря ему выходящее наружу излучение поляризовано. Обычно магнитные полюса не находятся вблизи их географических полюсов, в результате вращения нейтронной звезды она будет наблюдаться как аккреционный пульсар.

Создание стандартной модели дисковой аккреции было выполнено совместно с Р.А.Сюняевым. Работа была представлена на симпозиум № 55 Международного Астрономического Союза, который состоялся в Мадриде в мае 1972 года. Именно на этом симпозиуме докладывались не только результаты работы спутника «Ухуру», но и первые теоретические разработки по моделированию открытых этим аппаратом компактных рентгеновских источников в двойных звездных системах, то бишь аккрецирующих черных дыр и нейтронных звезд.

Нашу совместную с Рашидом работу докладывал Джим Прингл из Великобритании. И я, и Рашид были «невыездными» на тот момент времени. Тот доклад представлял собой введение в большую статью, которая вышла из печати в солидном европейском журнале Astronomy and Astrophysics в 1973 году. На основании этой работы российский ученый Игорь Новиков и Кип Торн из Калифорнийского Технологического института (США) аккуратно вычислили релятивистские поправки, обусловленные эффектами Общей теории относительности вблизи черных дыр.

В настоящее время цитируемость является одним из способов оценки работы в ученом сообществе. Число ссылок на нашу, совместную с Рашидом, пионерскую работу на середину апреля 2014 года, т. е. спустя более 40 лет после публикации, превысило 6540. На рис. 3 приведено распределение числа ссылок на эту работу по годам. [1]

Пока мы были молодыми, контроль со стороны ЯБ за нашей работой был необыкновенно сильным. Со временем научные интересы ЯБ сосредоточились на космологии. В копилку мировой космологической науки вошли «блины» Зельдовича, эффект Сюняева — Зельдовича, спектр Зельдовича — Харрисона и другие результаты его изысканий. Как профессор Московского университета он читал для студентов и аспирантов два годовых курса лекций — один год по строению и эволюции звезд, а второй год по космологии.

К лекциям он готовился необыкновенно тщательно с записыванием содержания лекций в тонкие школьные тетрадки. Каждый год это были новые тетради. На мне висела обязанность оповещения (как сейчас говорят, рекламы) о его курсах путем развешивания объявлений. Я присутствовал на многих его лекциях. Мы с Сергеем Блинниковым законспектировали его лекции, в результате этой деятельности появилось учебное пособие «Физичекие основы строения и эволюции звезд», написанное тремя авторами (Зельдович, Блинников и Шакура) и изданное издательством МГУ. В этом же издательстве появилось на свет и другое пособие: «Космология ранней Вселенной» — авторы: Долгов, Зельдович, Сажин.

В начале 1980-х годов Якову Борисовичу предоставили возможность организовать в ГАИШ МГУ теоретический отдел, который он назвал Отделом релятивистской астрофизики, подчеркивая тем самым важность и необходимость первоочередного развития фундаментальных исследований и в области релятивистских звезд (нейтронные звезды и черные дыры), и в области современной космологии.

ЯБ пользовался необычайно огромным авторитетом в научном сообществе. Кроме звания трижды Героя Социалистического Труда он был награжден многими орденами и медалями Советского Союза. Его избрали иностранным членом многих зарубежных академий и почетным членом ряда физических обществ и университетов, он был удостоен многими почетными научными медалями.

Яков Борисович Зельдович скончался 2 декабря 1987 года в Москве и похоронен на Новодевичьем кладбище. Его именем названа малая планета 11438. 11 февраля 2014 года Президиум РАН принял решение учредить Золотую медаль его имени, а также установить мемориальные доски в честь ЯБ на зданиях Института прикладной математики им. M.V. Келдыша РАН, Института космических исследований РАН и Института химической физики им. N.N. Семенова РАН. Его именем будет названа одна из улиц в районе МГУ.

1. О самой цитируемой статье (Black Holes in Binary Systems. Observational appearance Shakura, NI, Sunyaev, RA // Astron. Astrophys. 1973. Vol 24. P. 337-355) см. также интервью С. Попова с Н.И. Шакурой «Крутятся диски» в ТрВ-Наука, № 1, 1 апреля 2008 года. www.scientific.ru/trv/2008/001/shakura.html