Saas-Fee Advanced Course – serie

The 34th Saas-Fee advanced course of the Swiss Society of Astronomy and Astrophysics (SSAA) took place from March 15 to 20, 2004, in Davos, on the subject of The Sun, Solar Analogs and the Climate. PresentlytheSwissmountainresortofDavosisprobablymostwellknown for hosting an event on globalization. However, it is because Davos also happens to be the seat of the Physikalisch-Meteorologisches Observatorium Davos and World Radiation Center, that this course on a “global” subject was hosted here. Exceptionally, the topic of this course was not purely astrophysical, but themembersoftheSSAAdecidedtosupportitallthesameduetothetimely topic of global warming and its possible link to solar variations. In these times of concern about global warming, it is important to und- stand solar variability and its interaction with the atmosphere. Only in this way can we distinguish between the solar and anthropogenic contributions to the rising temperatures. Therefore, this course addressed the observed va- ability of the Sun and the present understanding of the variability’s origin and its impact on the Earth’s climate. Comparing the solar variability with that of solar analog stars leads to a better understanding of the solar activity cycle and magnetic activity in general, and helps us to estimate how large the solar variations could be on longer time scales. Inspiteofthefantasticweatherandsnowconditionswhichreignedduring this week, the participants assiduously took part in the lectures. This is proof ofthehighqualityofthelecturesthatthethreespeakers,JoannaHaigh,Mike Lockwood and David Soderblom, delivered. We deeply thank them for their contributions and e?orts and hope that the readers will enjoy the book as much as we enjoyed their lectures.

Research on extrasolar planets is one of the most exciting fields of activity in astrophysics. In a decade only, a huge step forward has been made from the early speculations on the existence of planets orbiting "other stars" to the first discoveries and to the characterization of extrasolar planets. This breakthrough is the result of a growing interest of a large community of researchers as well as the development of a wide range of new observational techniques and facilities.Based on their lectures given at the 31st Saas-Fee Advanced Course, Andreas Quirrenbach, Tristan Guillot and Pat Cassen have written up up-to-date comprehensive lecture notes on the "Detection and Characterization of Extrasolar Planets", "Physics of Substellar Objects Interiors, Atmospheres, Evolution" and "Protostellar Disks and Planet Formation". This book will serve graduate students, lecturers and scientists entering the field of extrasolar planets as detailed and comprehensive introduction.

The observation, in 1919 by A.S. Eddington and collaborators, of the gra- tational de?ection of light by the Sun proved one of the many predictions of Einstein’s Theory of General Relativity: The Sun was the ?rst example of a gravitational lens. In 1936, Albert Einstein published an article in which he suggested - ing stars as gravitational lenses. A year later, Fritz Zwicky pointed out that galaxies would act as lenses much more likely than stars, and also gave a list of possible applications, as a means to determine the dark matter content of galaxies and clusters of galaxies. It was only in 1979 that the ?rst example of an extragalactic gravitational lens was provided by the observation of the distant quasar QSO 0957+0561, by D. Walsh, R.F. Carswell, and R.J. Weymann. A few years later, the ?rst lens showing images in the form of arcs was detected. The theory, observations, and applications of gravitational lensing cons- tute one of the most rapidly growing branches of astrophysics. The gravi- tional de?ection of light generated by mass concentrations along a light path producesmagni?cation,multiplicity,anddistortionofimages,anddelaysp- ton propagation from one line of sight relative to another. The huge amount of scienti?c work produced over the last decade on gravitational lensing has clearly revealed its already substantial and wide impact, and its potential for future astrophysical applications.

After three decades of intense research in X-ray and gamma-ray astronomy, the time was ripe to summarize basic knowledge on X-ray and gamma-ray spectroscopy for interested students and researchers ready to become involved in new high-energy missions. This volume exposes both the scientific basics and modern methods of high-energy spectroscopic astrophysics. The emphasis is on physical principles and observing methods rather than a discussion of particular classes of high-energy objects, but many examples and new results are included in the three chapters as well.

Modern astronomy has stretched its domains of exploration tremendously. Not only objects at very large distances and very old states of the Universe can be examined, but also all kinds of radiations and phenomena are now accessible. Astronomers constantly move from considerations about very - luted to very dense systems. Hot and energetic systems, being the easiest to observe, have attracted a lot of attention. However the cold and low energetic states have been so- what neglected, either because being harder to observe they appear unexc- ing, or because being less well known they tend to be ignored. However the Universe background radiation has now been determined as the most perfect known case of a black-body spectrum, a substantial fraction of matter spends some time close to the temperature of this universal thermal bath, before - ingtransformedintostarsorplanets. Someobjects,suchasrapidlyexpanding gas shells in planetary nebulae, may even succeed in reaching a temperature well below the background radiation temperature through the mere action of adiabatic expansion. In view of the highly dynamical and turbulent state of the interstellar medium, hot and cold temperature ?uctuations must be expected, while the clear observational bias is to observe the hot rather than the cold ?uctuations. Fortunately with the accessibility of far-infrared and sub-millimetric instruments such as SCUBA, WMAP, Planck or ALMA, we can expect in the coming years continuous advances in our understanding of these harder to observe cold stages of matter.

The book begins with a historical introduction, "Star Formation: The Early History", that presents new material of interest for students and historians of science. This is followed by two long articles on "Pre-Main-Sequence Evolution of Stars and Young Clusters" and "Observations of Young Stellar Objects". These articles on the fascinating problem of star formation from interstellar matter give a thorough overview of present-day theories and observations. The articles contain material so far unpublished in the astronomical literature. The book addresses graduate students and can be used as a textbook for advanced courses in stellar astrophysics.

The Swiss Society for Astrophysics and Astronomy organizes each year in the late winter or early spring an advanced course. The format of the school is always iden­ tical: three leading lecturers are invited to cover the subject in nine or ten lectures each and to deliver a written version of their lecture notes. Lectures are held in the morning and late afternoon, thus leaving ample time for discussion and skiing. These arrangements prove very convivial and lead to an excellent atmosphere in which to learn exciting new subjects and establish contacts with colleagues. A wide variety of people attend the school, including many young students, mostly from Europe, and some experienced researchers. The 20th Advanced Course of the Swiss Society for Astrophysics and Astronomy took place in Les Diablerets from 1 to 6 April 1990. It was devoted to observational and theoretical aspects of active galactic nuclei. The previous advanced courses of the Swiss Society for Astrophysics and Astronomy have regularly taken place in Saas-Fee, a small resort in the Swiss Alps, hence the name "Saas-Fee" used to de­ scribe the courses and lecture notes. In the last three years, however, the course was organized in Leysin and in Les Diablerets, both also situated in the Swiss Alps.

The previous Saas-Fee Advanced Course dedicated to the interstellar medium took place in 1972. The tremendous scientific advances that have occurred in this field since then, in particular owing to the availabihty of receivers working at completely unexplored wavelength bands, fuUy justified a new set of lectures. As a consequence, the members of the Swiss Society for Astrophysics and As­ tronomy voted that "The Galactic Interstellar Medium" should be the subject of the 1991 course. The 21st Saas Fee Advanced Course took place in Les Diablerets from 18 to 23 March 1991, gathering together about 80 participants from all over the world, but mostly from Europe. According to a rule that has proved to lead to success, but also to chal­ lenge the lecturers' energy, the format of a Saas-Fee Advanced Course consists traditionally of 28 lectures of 45 minutes which take place in the morning and late afternoon, leaving ample time for discussions, self-study, hiking or skiing. Despite the inordinate work load imposed, this year's lecturers felt that the subject was sufficiently dense to increase the lecture time by 1/3! This proved judicious and left more time for questions and discussions during the lectures.

Observational and Theoretical Issues of Interacting Binaries was the topic of the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. It was the first time that binary systems were the center of attention of our course. The established concept and organisation of the Advanced Course has been retained: three scientists, all acknowledged experts in their respective fields, were each invited to give nine one-hour lectures within the period of a week. The Advanced Course took place from April 6 to 11, 1992, at Les Diablerets, a charming resort in the Swiss alps. The high level of the lectures, the international background of the 65 participants, including many young students, and the beauty of the surroundings all contributed to the success of the course. The lecture notes of this course, the 22nd in our series, are also the third to be published by Springer-Verlag. Well over half of all stars seem to exist in binary systems. The study of binary evolution is therefore essential for our understanding of stellar evolution in general. The evolution of interacting binaries contains in itself many of the problems met in other fields of modern astrophysics. This is very apparent in these lecture notes.

This volume presents the lecture notes of the 24th Advanced Course of the Swiss Society for Astrophysics and Astronomy in March 1994 at Les Diablerets. In three lectures on magnetohydrodynamics, on kinetic plasma physics and on particle acceleration leading experts describe the physical basis of their subjects and extend the discussion to several applications in modern problems of astrophysics. In style and presentation the texts are well-suited for graduate work in plasma astrophysics, one of the very important tools of modern astronomy. The themes developed in this book will be helpful in understanding many processes in the universe from the solar corona to active galaxies.

Cosmology has not been the subject matter of a Saas-Fee Advanced Course since 1978. That occasion was the memorable course entitled Observational Cosmologyy with lecturers J.E. Gunn, M.S. Longair, and M.J. Rees. A new course on cosmology seemed overdue, and we subsequently planned and or­ ganized, with the endorsement of the Swiss Society of Astrophysics and As­ tronomy, the present, 23"^^ Saas-Fee Advanced Course. Probing (drilling) the Universe to greatest depths, in terms of diffuse radiation and discrete objects, with all consequences for our understanding of cosmic evolution, was meant to be the unifying aspect of this course. Hence the title The Deep Universe. We are very happy to have won such competent and brilliant scientists as lecturers. Malcolm Longair - Saas-Fee lecturer for the second time! - lectured on cosmological background radiation ("The Physics of Background Radia­ tion"); Richard Kron on observations of extremely distant galaxies ("Evo­ lution in the Galaxy Population"); while the Grand Master of Cosmology, Allan Sandage, provided the fundaments of it all, also in a historical sense ("Practical Cosmology: Inventing the Past"). The course took place from 29 March to 3 April, 1993, in Les Diablerets, with around 90 participants. The format was as usual, every lecturer giving 9 or 10 lectures of 45 minutes.

Three eminent scientists, each well known for the clarity of their writing, present for students and researchers what is known about the internal structure, origin and evolution of White Dwarfs, Neutron Stars and Black Holes, all objects at the final stage of stellar evolution. They cover fascinating topics such as pulsation of white dwarfs, millisecond pulsars or the dynamics around black holes. The book is written for graduate students in astrophysics, but is also of interest to professional astronomers and physicists.

This volume contains the written version of the lectures given at the 26th course of the Saas-Fee series. The book represents a comprehensive review of the field of galaxy interaction. Galaxies are no longer seen as immutable objects - they evolve, interact, merge, blaze and reshape. Dynamic forces can induce powerful stellar activity able to transform the matter composition and morphology of galaxies. The lectures included in the book aim to further our understanding of the phenomena, giving a historical perspective and examining topics such as induced star formation. They are intended for graduate students and those studying astrophysics.

This book leads directly to the most modern numerical techniques for compressible fluid flow, with special consideration given to astrophysical applications. Emphasis is put on high-resolution shock-capturing finite-volume schemes based on Riemann solvers. The applications of such schemes, in particular the PPM method, are given and include large-scale simulations of supernova explosions by core collapse and thermonuclear burning and astrophysical jets. Parts two and three treat radiation hydrodynamics. The power of adaptive (moving) grids is demonstrated with a number of stellar-physical simulations showing very crispy shock-front structures.

Star clusters are at the heart of astronomy, being key objects for our understanding of stellar evolution and galactic structure. Observations with the Hubble Space Telescope and other modern equipment have revealed fascinating new facts about these galactic building blocks. This book provides two comprehensive and up-to-date, pedagogically designed reviews on star clusters by two well-known experts in the field. Bruce Carney presents our current knowledge of the relative and absolute ages of globular clusters and the chemical history of our Galaxy. Bill Harris addresses globular clusters in external galaxies and their use as tracers of galaxy formation and cosmic distance indicators. The book is written for graduate students as well as professionals in astronomy and astrophysics.

The study of the Solar system, particularly of its newly discovered outer parts, is one of the hottest topics in modern astrophysics with great potential for revealing fundamental clues about the origin of planets and even the emergence of life.The three lecturers of the 35th Saas-Fee Advanced Course cover the field from observational, theoretical and numerical perspectives. Highly sensitive, wide-field electronic detectors have enabled the discovery and the exploration of the Kuiper Belt, while fast computers allow for numerical simulations to be made with a degree of sophistication previously unimaginable. Additionally, the perception of the Solar system in the bigger context of the galactic disk is changing, particularly as planets encircling other stars are detected. This volume, reviewing what is known about the Solar system, is therefore extremely timely, and the style it is written in conveys the excitement this field of research holds.

The exploration of the first billion years of the history of the Universe represents one of the great challenges of contemporary astrophysics. This book contains the worked out lectures given at the 36th Saas-Fee Advanced Course "First Light in the Universe" by three eminent scientists in the field: Abraham Loeb, Andrea Ferrara, and Richard Ellis. The formation of the first stars and black holes, the initial mass function, feedback effects, early dust formation, the cosmic star formation history, distant galaxies, cosmic reionisation and the cosmic infrared background are the main topics treated. This book contains an accessible and up-to-date review of the field and will be useful to graduate students of astronomy, cosmologists, physicists and researchers. The topic of this book is particularly timely, as many new important observational facilities are being built, for which "first light in the universe" is one of the main science drivers.

The 34th Saas-Fee advanced course of the Swiss Society of Astronomy and Astrophysics (SSAA) took place from March 15 to 20, 2004, in Davos, on the subject of The Sun, Solar Analogs and the Climate. PresentlytheSwissmountainresortofDavosisprobablymostwellknown for hosting an event on globalization. However, it is because Davos also happens to be the seat of the Physikalisch-Meteorologisches Observatorium Davos and World Radiation Center, that this course on a “global” subject was hosted here. Exceptionally, the topic of this course was not purely astrophysical, but themembersoftheSSAAdecidedtosupportitallthesameduetothetimely topic of global warming and its possible link to solar variations. In these times of concern about global warming, it is important to und- stand solar variability and its interaction with the atmosphere. Only in this way can we distinguish between the solar and anthropogenic contributions to the rising temperatures. Therefore, this course addressed the observed va- ability of the Sun and the present understanding of the variability’s origin and its impact on the Earth’s climate. Comparing the solar variability with that of solar analog stars leads to a better understanding of the solar activity cycle and magnetic activity in general, and helps us to estimate how large the solar variations could be on longer time scales. Inspiteofthefantasticweatherandsnowconditionswhichreignedduring this week, the participants assiduously took part in the lectures. This is proof ofthehighqualityofthelecturesthatthethreespeakers,JoannaHaigh,Mike Lockwood and David Soderblom, delivered. We deeply thank them for their contributions and e?orts and hope that the readers will enjoy the book as much as we enjoyed their lectures.

Research on extrasolar planets is one of the most exciting fields of activity in astrophysics. In a decade only, a huge step forward has been made from the early speculations on the existence of planets orbiting "other stars" to the first discoveries and to the characterization of extrasolar planets. This breakthrough is the result of a growing interest of a large community of researchers as well as the development of a wide range of new observational techniques and facilities.Based on their lectures given at the 31st Saas-Fee Advanced Course, Andreas Quirrenbach, Tristan Guillot and Pat Cassen have written up up-to-date comprehensive lecture notes on the "Detection and Characterization of Extrasolar Planets", "Physics of Substellar Objects Interiors, Atmospheres, Evolution" and "Protostellar Disks and Planet Formation". This book will serve graduate students, lecturers and scientists entering the field of extrasolar planets as detailed and comprehensive introduction.

The observation, in 1919 by A.S. Eddington and collaborators, of the gra- tational de?ection of light by the Sun proved one of the many predictions of Einstein’s Theory of General Relativity: The Sun was the ?rst example of a gravitational lens. In 1936, Albert Einstein published an article in which he suggested - ing stars as gravitational lenses. A year later, Fritz Zwicky pointed out that galaxies would act as lenses much more likely than stars, and also gave a list of possible applications, as a means to determine the dark matter content of galaxies and clusters of galaxies. It was only in 1979 that the ?rst example of an extragalactic gravitational lens was provided by the observation of the distant quasar QSO 0957+0561, by D. Walsh, R.F. Carswell, and R.J. Weymann. A few years later, the ?rst lens showing images in the form of arcs was detected. The theory, observations, and applications of gravitational lensing cons- tute one of the most rapidly growing branches of astrophysics. The gravi- tional de?ection of light generated by mass concentrations along a light path producesmagni?cation,multiplicity,anddistortionofimages,anddelaysp- ton propagation from one line of sight relative to another. The huge amount of scienti?c work produced over the last decade on gravitational lensing has clearly revealed its already substantial and wide impact, and its potential for future astrophysical applications.

After three decades of intense research in X-ray and gamma-ray astronomy, the time was ripe to summarize basic knowledge on X-ray and gamma-ray spectroscopy for interested students and researchers ready to become involved in new high-energy missions. This volume exposes both the scientific basics and modern methods of high-energy spectroscopic astrophysics. The emphasis is on physical principles and observing methods rather than a discussion of particular classes of high-energy objects, but many examples and new results are included in the three chapters as well.

Modern astronomy has stretched its domains of exploration tremendously. Not only objects at very large distances and very old states of the Universe can be examined, but also all kinds of radiations and phenomena are now accessible. Astronomers constantly move from considerations about very - luted to very dense systems. Hot and energetic systems, being the easiest to observe, have attracted a lot of attention. However the cold and low energetic states have been so- what neglected, either because being harder to observe they appear unexc- ing, or because being less well known they tend to be ignored. However the Universe background radiation has now been determined as the most perfect known case of a black-body spectrum, a substantial fraction of matter spends some time close to the temperature of this universal thermal bath, before - ingtransformedintostarsorplanets. Someobjects,suchasrapidlyexpanding gas shells in planetary nebulae, may even succeed in reaching a temperature well below the background radiation temperature through the mere action of adiabatic expansion. In view of the highly dynamical and turbulent state of the interstellar medium, hot and cold temperature ?uctuations must be expected, while the clear observational bias is to observe the hot rather than the cold ?uctuations. Fortunately with the accessibility of far-infrared and sub-millimetric instruments such as SCUBA, WMAP, Planck or ALMA, we can expect in the coming years continuous advances in our understanding of these harder to observe cold stages of matter.

The book begins with a historical introduction, "Star Formation: The Early History", that presents new material of interest for students and historians of science. This is followed by two long articles on "Pre-Main-Sequence Evolution of Stars and Young Clusters" and "Observations of Young Stellar Objects". These articles on the fascinating problem of star formation from interstellar matter give a thorough overview of present-day theories and observations. The articles contain material so far unpublished in the astronomical literature. The book addresses graduate students and can be used as a textbook for advanced courses in stellar astrophysics.

The Swiss Society for Astrophysics and Astronomy organizes each year in the late winter or early spring an advanced course. The format of the school is always iden­ tical: three leading lecturers are invited to cover the subject in nine or ten lectures each and to deliver a written version of their lecture notes. Lectures are held in the morning and late afternoon, thus leaving ample time for discussion and skiing. These arrangements prove very convivial and lead to an excellent atmosphere in which to learn exciting new subjects and establish contacts with colleagues. A wide variety of people attend the school, including many young students, mostly from Europe, and some experienced researchers. The 20th Advanced Course of the Swiss Society for Astrophysics and Astronomy took place in Les Diablerets from 1 to 6 April 1990. It was devoted to observational and theoretical aspects of active galactic nuclei. The previous advanced courses of the Swiss Society for Astrophysics and Astronomy have regularly taken place in Saas-Fee, a small resort in the Swiss Alps, hence the name "Saas-Fee" used to de­ scribe the courses and lecture notes. In the last three years, however, the course was organized in Leysin and in Les Diablerets, both also situated in the Swiss Alps.

The previous Saas-Fee Advanced Course dedicated to the interstellar medium took place in 1972. The tremendous scientific advances that have occurred in this field since then, in particular owing to the availabihty of receivers working at completely unexplored wavelength bands, fuUy justified a new set of lectures. As a consequence, the members of the Swiss Society for Astrophysics and As­ tronomy voted that "The Galactic Interstellar Medium" should be the subject of the 1991 course. The 21st Saas Fee Advanced Course took place in Les Diablerets from 18 to 23 March 1991, gathering together about 80 participants from all over the world, but mostly from Europe. According to a rule that has proved to lead to success, but also to chal­ lenge the lecturers' energy, the format of a Saas-Fee Advanced Course consists traditionally of 28 lectures of 45 minutes which take place in the morning and late afternoon, leaving ample time for discussions, self-study, hiking or skiing. Despite the inordinate work load imposed, this year's lecturers felt that the subject was sufficiently dense to increase the lecture time by 1/3! This proved judicious and left more time for questions and discussions during the lectures.

Observational and Theoretical Issues of Interacting Binaries was the topic of the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. It was the first time that binary systems were the center of attention of our course. The established concept and organisation of the Advanced Course has been retained: three scientists, all acknowledged experts in their respective fields, were each invited to give nine one-hour lectures within the period of a week. The Advanced Course took place from April 6 to 11, 1992, at Les Diablerets, a charming resort in the Swiss alps. The high level of the lectures, the international background of the 65 participants, including many young students, and the beauty of the surroundings all contributed to the success of the course. The lecture notes of this course, the 22nd in our series, are also the third to be published by Springer-Verlag. Well over half of all stars seem to exist in binary systems. The study of binary evolution is therefore essential for our understanding of stellar evolution in general. The evolution of interacting binaries contains in itself many of the problems met in other fields of modern astrophysics. This is very apparent in these lecture notes.

This volume presents the lecture notes of the 24th Advanced Course of the Swiss Society for Astrophysics and Astronomy in March 1994 at Les Diablerets. In three lectures on magnetohydrodynamics, on kinetic plasma physics and on particle acceleration leading experts describe the physical basis of their subjects and extend the discussion to several applications in modern problems of astrophysics. In style and presentation the texts are well-suited for graduate work in plasma astrophysics, one of the very important tools of modern astronomy. The themes developed in this book will be helpful in understanding many processes in the universe from the solar corona to active galaxies.

Cosmology has not been the subject matter of a Saas-Fee Advanced Course since 1978. That occasion was the memorable course entitled Observational Cosmologyy with lecturers J.E. Gunn, M.S. Longair, and M.J. Rees. A new course on cosmology seemed overdue, and we subsequently planned and or­ ganized, with the endorsement of the Swiss Society of Astrophysics and As­ tronomy, the present, 23"^^ Saas-Fee Advanced Course. Probing (drilling) the Universe to greatest depths, in terms of diffuse radiation and discrete objects, with all consequences for our understanding of cosmic evolution, was meant to be the unifying aspect of this course. Hence the title The Deep Universe. We are very happy to have won such competent and brilliant scientists as lecturers. Malcolm Longair - Saas-Fee lecturer for the second time! - lectured on cosmological background radiation ("The Physics of Background Radia­ tion"); Richard Kron on observations of extremely distant galaxies ("Evo­ lution in the Galaxy Population"); while the Grand Master of Cosmology, Allan Sandage, provided the fundaments of it all, also in a historical sense ("Practical Cosmology: Inventing the Past"). The course took place from 29 March to 3 April, 1993, in Les Diablerets, with around 90 participants. The format was as usual, every lecturer giving 9 or 10 lectures of 45 minutes.

Three eminent scientists, each well known for the clarity of their writing, present for students and researchers what is known about the internal structure, origin and evolution of White Dwarfs, Neutron Stars and Black Holes, all objects at the final stage of stellar evolution. They cover fascinating topics such as pulsation of white dwarfs, millisecond pulsars or the dynamics around black holes. The book is written for graduate students in astrophysics, but is also of interest to professional astronomers and physicists.