Interview with Rashid Sunyaev Interviewer: Naoki Yoshida

How to Become an astronomical survey, Subaru Independent Scientist Hyper Suprime-Cam survey. Sunyaev: This institute is Sunyaev: Are you participating great. in it? Yoshida: Thank you. Yoshida: Yes, and we will get Sunyaev: It was very real data and real results very interesting to see it. soon. Yoshida: Everything is Sunyaev: Very good. I going well, including a large remember that you were working at the Max Planck Institute for Astrophysics. Yoshida: As a student. Sunyaev: You are now working at the Hongo campus. Are you working in the Department of Physics, Rashid Sunyaev is a Chief Scientist not in this institute? of the Space Research Institute, the Russian Academy of Sciences (since Yoshida: I spend 60% of my 1992) and a Director of the Max time at the Department, and Planck Institute for Astrophysics (since 1996). He received Candidate 40% here. of Sciences (equivalent of Ph.D.) Sunyaev: It’s good sharing, in 1968 and Doctor of Sciences (astrophysics) in 1973 (this degree okay. is required in Russia to become Yoshida: Yes. I can conduct full professor), both from Moscow University. He also received a title of researches here at the Kavli Professor of Astrophysics from the IPMU. Okay, let me ask Superior Attestation Commission of the USSR Council of Ministers you about some questions in 1987. He became a Professor at today. The rst question is Moscow Institute for Physics and Technology in 1975. He was Head about“ independence.” One of the Laboratory of Theoretical particular thing I wanted to Astrophysics in 1974 – 1982, and Head of High Energy Astrophysics ask you is how to become an Department in 1982 – 2002, both independent scientist. At what at the Academy of Sciences’ Space Research Institute. He became a occasion did you rst realize corresponding member of the or become con dent enough USSR Academy of Sciences in 1984, and has been a full member of the that you would be a good Russian Academy of Sciences since scientist? 1992. He received the Crafoord Prize in Astronomy in 2008, Kyoto Prize Sunyaev: It’s a very dif cult in 2011, Benjamin Franklin Medal question. I have never in Physics in 2012, and many other distinguished awards. thought about it, but it’s my

10 Kavli IPMU News No. 29 March 2015 impression that there was a very well those narrow elds. moment when I recognized And then I recognized that that I wished to become I can be strong in some a scientist. It was a very elds even on the level of important moment, because those who were already full when you’re a student, you professors at that time, by don’t know what you are just interacting with people interested in, but there is a to whom Zeldovich sent great difference between the me to discuss things which interest and the belief that we were doing, and trying you really should do this. to get their advice on the Yoshida: Yes. concrete very narrow subject. Sunyaev: The second moment This was important. Then I is when you’re really starting started to work with some to be con dent that you’re of these people, for example, able to do this ― Is this what these experimentalists. you ask? Experimentalists are great. I Yoshida: Yes, something like admire them because their life it. is much more dif cult than Sunyaev: I was working with life of theoreticians. Anyway, Yakov Zeldovich in his group at some moment, you have at the Institute of Applied a pleasure recognizing that Mathematics, USSR Academy you might be extremely useful of Sciences. He was an for these experimentalists. extremely strong and bright You come to them and tell scientist, very well recognized that it’s possible to use their and very broad in his interests. data for this and that, and try He was sending me to to interpret their data in the different people to discuss best way. Then you see that science, recommending me you can nd your own niche Interview to work with them also. Very rapidly I recognized that Naoki Yoshida is a Professor at the there are different grades of School of Science and Kavli IPMU, strong scientists. Zeldovich is the University of Tokyo. After having graduated from the University of a very high-grade scientist. Tokyo in 1996, he completed his doctoral course in the Max Planck There are people who are Institute for Astrophysics in 2001 working in very narrow elds and received a Doctorate in Natural Science from München University in of science and who know 2002.

11 and that in this niche, you’re strong, you’re also learning so strong and so well known. and then the second person strong. a lot from them. They’re not This also showed you that made a rst correction to Yoshida: You found the value so busy and they learn much you are not absolutely the last his theory and so on. Finally, of yourself as… more rapidly than you. At person in the world. This was it became the“ seventh Sunyaev: It’s not only the some moment, they’re starting good. approximation.” From one value. I also understood the to be competitive. I think Yoshida: Okay, I think your side, people were able to go niche in which I was able to it’s very useful to work with story is very encouraging to very deep. From another side, compete with many people young people. You should young people and that’s why people were slow in progress, rather successfully. I was really do this. I wanted to ask this question because they were unable very happy and Zeldovich Yoshida: I see. Was that to you. to become broad ― the also recognized this. Written roughly when you were 30 conditions to become broader together with Zeldovich, years old? Relation between a were much more dif cult. some of our papers became Sunyaev: I think it was close Supervisor and a Student Yoshida: That’s very so successful. Sometimes, to the age of 25-27. Sunyaev: It’s important. But, interesting, because many I am thinking why, and Yoshida: Okay. Then, did you you know, life is changing. younger people struggle my impression is that one become so self-con dent? The behavior of people is with becoming independent of the reasons was the Sunyaev: I think I did. I also changing and the relation at some point. As a student, following. At a very early tell you this. At the beginning between a supervisor and a there is some learning without stage I recognized that I'm when I started to work with student is now very different much thinking. But, eventually, interested in how to make the Zeldovich, he was rather from that in the time when they want to become very result of a theory observable. tough when I was not doing I started. Also, the American independent and this happens Many theoreticians around something very rapidly way of interactions or Anglo in a variety of ways depending me were working only in because of dif culties. Saxon way of interactions on the person. theory, for theory, for further He was showing that he has between professors and Sunyaev: Yes, it depends on development of theory. I also no time to speak with me students is very different from personality and character. I found my niche to nd what and sometimes he was not that which was accepted in completely agree with you. is possible to observe. recognizing me. For me, it was Russia and Soviet Union when A lot depends also on the Yoshida: Interesting. really very, very bad feeling. I was young. interests. Zeldovich had the Sunyaev: This made my life Yoshida: I understand. Yoshida: In Russia and Soviet feeling of what is interesting much more interesting. I Sunyaev: But, when you Union, I suppose it was more for a person. When I rst also recognized that it was were getting new results and like a mixture, more like a came to him, he asked“ What possible to work not only coming to tell him“, I have family style and also like in are you interested in?” At with Zeldovich; I can be rather new results,” he immediately a more hierarchical, logical that time, I was rather good independent. This was also got ecstatic, telling“ Okay, let’s style. in mathematics, but I told him very useful. He was pleased discuss.” Then, I understood Sunyaev: In Soviet Union, it that I liked physical processes. when I was also working with that maybe his behavior was was strongly hierarchical. It It was interesting for me other people, young people just a way to demonstrate his was the same in Germany. to learn physical processes like a friend of mine Nikolay intention to make me work Usually people were staying in working in, for example, gas Shakura ― we were working more hard. the same group if they were chambers and other detectors on the accretion onto the Yoshida: To prompt or successful, practically whole of elementary particles. Then black holes. I had many motivate you. their scienti c life. This was he was trying to direct me strong students. I’m very Sunyaev: Yes, motivating, but completely different from the to where it was necessary grateful to them, not only this was a rather tough way of Anglo Saxon way. In America, to investigate elementary because students are useful, motivating. At some moment, it’s important to move from physical processes. This was but also because working I also recognized that he was place to place, and to learn interesting for me and this with strong students is a also happy to work with me. more. But in Russia, in many became very useful part of my pleasure. Students contribute This was a great feeling. He groups, their chief was doing work. a lot, but if students are was interested in you; he was something like a top advisor,

12 Kavli IPMU News No. 29 March 2015 Russian System of Finding wanted to know. I lived in the dormitory of Petersburg and so on. They’re Excellent Young Talent Sunyaev: We heard that if Moscow University and I was not only from Moscow, but Yoshida: Okay, interesting. you wish to do, for example, very impressed: according to from all over… Now, the second question is science or to learn most my level of understanding, it Sunyaev: Soviet Union. somewhat related. I'm always modern things, it’s better to was a great palace. It was an Yoshida: That is impressive. impressed by the Russian go to Moscow. We knew that enormously big building and or former Soviet Union’s there is continuous ow of very nice. They had theaters Best Students Come systems in many ways, and the strongest people there. inside. I was going to theaters. and Learn in the Best Universities one thing I want to know For example, if a professor They had very good canteens, is the following. There must in Tashkent was really very restaurants for students. Sunyaev: You know be some nationwide search good, at some moment he Everything was excellent. A lot when Soviet Union was process for excellent young was invited to go to Moscow. of young people. For me, this destroyed and we got a talent. You’re from Tashkent, If you had a really good was very impressive. lot of independent states, but somehow you went to ballet star at your theater, I was living in the room then there were attempts to Moscow. There must be some then Moscow was inviting with a mathematician make best schools of Russia centralization system, too. this ballet star. Therefore, student. This student told closed for people coming How do they work in Russia? people were going up. For me that there was another from different republics Sunyaev: I can tell you that me, extremely important was school (Moscow Institute of which were former part of system of Soviet Union. It an additional episode. When I Physics and Technology). It Soviet Union. At that time, was very strongly centralized, was 17, one day I was invited was not so attractive a place, I had conversation with my but there are many countries to participate ― just without but students there were friends in Russian Academy, with great centralization. any preparation ― in the even better. In that school, and we agreed to write a For example, in France every Olympiad. Do you know what entrance exams were held letter to the top people in the young person understands it is? 1 month earlier. Therefore, I country and to the Ministry of that for his career, it’s Yoshida: Yes. decided to go to that school Education. It said that if they important to go to Paris at Sunyaev: I was invited to take my exams. We had will consider the members some stage. to participate in the competition of 11.5 people of the Russian Academy of Yoshida: But, in Soviet Union, Mathematical Olympiad per place. I don’t know how, Sciences, they will discover I think even at the high school of Central Asia and but I passed. I was accepted. that these people are not only level, it seems to have been Kazakhstan. These were Life was not very simple. After people from Moscow. They working…. ve Soviet Republics ― I entered Moscow Institute are coming from the whole Sunyaev: Tashkent had now, independent states of Physics and Technology, country, because talents are universities, but everybody ― Uzbekistan, Tajikistan, ve people including me lived distributed uniformly. These knew that the level of these Kyrgyzstan, Turkmenistan, in one room and everything talents came to Moscow and universities was lower than and Kazakhstan. Altogether, was different. And there was learned in Moscow in some the universities in Moscow there were maybe 50 million a very pressing system that way, and they came to belong or Leningrad at that time ̶ people at that time. People you should learn, learn, and to the academy, and they but high schools were rather from different, best schools learn there, and very tough became best professors of good. in these republics were sent exams. But it was okay. I'm Moscow University and so on. Yoshida: High school teachers to Tashkent, and several very grateful to that school, If we do not permit people Interview were also very good? high school students from because professors were from half of the country, now Sunyaev: High school teachers Tashkent were also invited to really brilliant. People who outside of Russia, to study in were good. Schools were participate in this competition were teaching us were very Moscow, then we just lose good. But the best students, in mathematics. I don’t know good. them. It’s better for Russia if I don’t know how, knew that how, but I won, and then Yoshida: I guess it was also these people will be accepted it’s good to go to Moscow. I was sent to Moscow to similar for your friends, and will get this ability to Yoshida: Oh, you don’t know participate in the Olympiad perhaps, one maybe from learn. I don’t know how it how. That’s something I of the whole Soviet Union. Vladivostok, the other from St. worked, but many schools

13 now are permitted to accept young people were trying to Yoshida: Exactly. really computers are a great best students from whole enter schools of this sort. I Sunyaev: These instruments addition, because I wrote territory of former Soviet think maybe the same was will give enormous amount majority of my papers using Union without payment. true in Japan. of information, and it will slide rules. Then, I saw how Yoshida: Without payment? Yoshida: Similarly, yes. We still be necessary to have strong computers were becoming Sunyaev: They’re not paying have popularity or interest people to process the data more and more useful part of tuition, because people in the of high school students in and to interpret them to do our life. majority of these republics physics or basic science, but great science. Yoshida: It is. are poor because they do obviously, the overall interest Yoshida: Yes, exactly. I really Sunyaev: Numerical not have oil deposits. For is now decreasing. Well, there think astronomy would astrophysics and example, Tashkent was a very are lots of other interesting produce a lot of young talent. cosmology uses the biggest rich city in the times of Soviet stuffs. Sunyaev: Yes, but I think supercomputers, and is one Union, but now it’s poor in Sunyaev: But a lot of people life sciences certainly will be of the fastest developing comparison with Moscow. understand, for example, doing very well also. branches of our science. Yoshida: I see. that biology or life sciences Yoshida: There are many However, I wish to start with Sunyaev: Everything is simple. have great future, and young things to work in life sciences, the statement that life today Best students can come and people are going there. but I still like astronomy. without computers is really learn in the best universities, Yoshida: Yes. Sunyaev: Astronomy is very impossible. The rst thing is but obviously, they should Sunyaev: There was a good. I agree with you, but that they made our life much compete for their entrance. conference in Tallinn astronomy is still much smaller simpler. When I was young If they get excellent results, devoted to 100th birthday of than physics, and physics in Russia, for example, we then it’s not necessary for Zeldovich, and I was attending now is much smaller than life had, I do not know the exact them to pay tuition. This is it. There were several well- sciences. Do you agree? number, but something like very important. But, there known people there. They a million of secretaries who are quotas. I don’t know were asked what they were typing whole day. Computers in Basic Science exactly, but every year rules thought about the education Yoshida: I see. are changing. For example, system, and somebody asked Yoshida: Okay, that is true. Sunyaev: Now, it’s a very if you wish to enter schools “Would you recommend your That’s very interesting. Now, rare case for a secretary to of economy and the like, you children to go to astronomy?” the third topic I want to talk type. Everybody is typing on should pay, but if you wish to Everybody told what with you is about computers, computers himself or herself enter schools of science such profession their children had. especially using computers ― very fast and easy work. as physics, it’s possible not to Nobody of children of these in basic science. Here, I This is just an example of the pay as far as you are excellent. well-known astronomers was still have a sort of mixed changes that an enormous Yoshida: I see. Actually, is doing astronomy. One or two feelings. I appreciate the number of people were physics or basic science still a were doing physics, but the powerfulness or usefulness replaced by computers. top choice or popular among majority of them were doing of the computers, whereas Second, it was rather dif cult young students in Russia? life sciences and economics. still I’m not very sure whether at that time to make the Sunyaev: No. Unfortunately, it Yoshida: Okay. I usually tell or not computers can play computations, and we had has completely changed. my students that astronomy an important role to reach to spend a lot of time to Yoshida: Really? will be probably very good at a true or fundamental solve even simple problems Sunyaev: Many young people least for the next 20 years. understanding. As you know using approximate methods wish to be in the positions Sunyaev: I have no doubt I use computer simulation or using tables and special where it’s easier to get higher that for the next 25 years as my primary research tool, functions. Computers did this salaries and so on. But it’s astronomy will be blooming, and I’m always asking if this really very easily. Programs the same as the trend in the because we expect not only kind of activity or research like Mathematica or many whole world. But in my time, great ideas, but also great can really reach a very others just made use of physics or basic science was instruments which leading fundamental thing. simple mathematics much enormously popular and most countries are building. Sunyaev: I myself think that easier. It’s not necessary to sit

14 Kavli IPMU News No. 29 March 2015 whole day to compute with complicated problems where ask, I think. Do you have any also give us many suggestions a slide rule. But I understand we understand a lot, but we questions or suggestions? in the future. We will really that this is one side which cannot estimate numerically Sunyaev: No, I’m just appreciate it. is very useful and very all consequences. And here grateful, because I'm rst Sunyaev: Thank you and it’s a important, and computers obviously, computers are time at this institute, and it pleasure. will become more and more just unavoidable, and they is a great pleasure to see a Yoshida: Thank you very useful. At some stage, it will will give us a lot. Progress really international institute much. be possible to dictate a paper. without simulations, without here in Japan, where I had Computers can publish and these huge, computational conversation with several edit it, and so on. Computers resources will be really much young people from Germany, can do a lot, and this will slower. Therefore, I think that from Australia, from America, help enormously. But, then, it is great that they are there. and from Russia. Everybody there is a question. Can But, again, analytical solutions looks happy and everybody computers learn absolutely are extremely useful, because is saying that your top fundamental things? There if you have the exact solution people have created here the are two possibilities. The rst for something, you can always atmosphere where people possibility is to make very check if everything is correct. are happy to work, where it deep mathematics. I think for This is also a very important is interesting for them, and that we still need people. I and useful thing. But, I think it’s great. And you have these don’t know for how long. that it’s already impossible visitor programs. It seems that Yoshida: I just remembered, to return to science without they are very good, because many of these great Russian great computational facilities. you are inviting really the best or Soviet scientists, like you, Yoshida: I always ask this young people. It’s a mistake Aleksandr Kompaneets, and question to myself and to to invite only old people. It’s Leonid Sedov. students so that we keep a important to invite people Sunyaev: Academician Sedov sort of balance between… who are actively working and Prof. Kompaneets found Sunyaev: Yes, we should now, and it seems that this is great analytical solutions and keep balance, but I think that the case here. derived now well-known computers have changed Yoshida: Thank you very equations. These solutions our life. Just for normal life, much. I appreciate your and equations are always already calculators were compliments. useful and often necessary. useful. But with what we Sunyaev: No, it’s not Yoshida: I think you know have now, we can solve a lot compliment. It seems that that was actually… of simple problems. What is it’s true and I think that this Sunyaev: In this eld, I simple? Now you can solve institute should have a great don’t think that computers any differential equation future. In Russia, we are till will replace people in this which was enormously now unable to create similar direction very soon. People are dif cult 200 years ago. It’s not atmosphere; I’m very unhappy still very good in such things great science today. It’s just for that. There have been and also a lot depends on the useful. attempts, but in fundamental Interview intuition. It is one case where Yoshida: It is. science, there are practically I think our brains possibly will Sunyaev: I think it’s important no places, internationally, compete rather long with the not to forget this part of similarly open for discussions, most powerful computers, but classical mathematics, which except, possibly, the Euler there is a chance. is useful. International Mathematical Yoshida: Maybe, yes. Yoshida: Quite an interesting Institute in Saint Petersburg. Sunyaev: Then, there viewpoint. I actually asked Yoshida: I hope you keep your are simulations in the everything that I wanted to attention to our institute, and

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