Pub Date : 2024-04-19DOI: 10.1146/annurev-astro-052722-104109
Deidre A. Hunter, Bruce G. Elmegreen, Suzanne C. Madden
Dwarf irregular (dIrrs) galaxies are among the most common type of galaxy in the Universe. They typically have gas-rich, low surface-brightness, metal-poor, and relatively thick disks. Here, we summarize the current state of our knowledge of the interstellar medium (ISM), including atomic, molecular, and ionized gas, along with their dust properties and metals. We also discuss star-formation feedback, gas accretion, and mergers with other dwarfs that connect the ISM to the circumgalactic and intergalactic media. We highlight one of the most persistent mysteries: the nature of pervasive gas that is yet undetected as either molecular or cold hydrogen, the “dark gas.” Some highlights include the following: ▪ Significant quantities of Hi are in far-outer gas disks. ▪ Cold Hi in dIrrs would be molecular in the Milky Way, making the chemical properties of star-forming clouds significantly different. ▪ Stellar feedback has a much larger impact in dIrrs than in spiral galaxies. ▪ The escape fraction of ionizing photons is significant, making dIrrs a plausible source for reionization in the early Universe. ▪ Observations suggest a significantly higher abundance of hydrogen (H2 or cold Hi) associated with CO in star-forming regions than that traced by the CO alone.
矮不规则（dIrrs）星系是宇宙中最常见的星系类型之一。它们通常具有富含气体、低表面亮度、贫金属和相对较厚的星盘。在这里，我们总结了我们目前对星际介质（ISM）的了解，包括原子、分子和电离气体，以及它们的尘埃特性和金属。我们还讨论了恒星形成反馈、气体吸积以及与其他矮星的合并等问题，这些问题将星际介质与环银河系和星际介质联系在一起。我们将重点讨论最持久的谜团之一：尚未被探测到的分子气体或冷氢气--"暗气体"--的性质。其中一些亮点如下： 大量 Hi 存在于更远的气体盘中。 暗气体盘中的冷氢在银河系中是分子氢，这使得恒星形成云的化学性质大为不同。 恒星反馈对二轨道星系的影响比对螺旋星系的影响大得多。 电离光子的逃逸率很高，这使得 dIrrs 成为早期宇宙再电离的一个可信来源。 观测结果表明，在恒星形成区，与 CO 相关联的氢（H2 或冷 Hi）的丰度明显高于 CO 单独追踪到的丰度。
{"title":"The Interstellar Medium in Dwarf Irregular Galaxies","authors":"Deidre A. Hunter, Bruce G. Elmegreen, Suzanne C. Madden","doi":"10.1146/annurev-astro-052722-104109","DOIUrl":"https://doi.org/10.1146/annurev-astro-052722-104109","url":null,"abstract":"Dwarf irregular (dIrrs) galaxies are among the most common type of galaxy in the Universe. They typically have gas-rich, low surface-brightness, metal-poor, and relatively thick disks. Here, we summarize the current state of our knowledge of the interstellar medium (ISM), including atomic, molecular, and ionized gas, along with their dust properties and metals. We also discuss star-formation feedback, gas accretion, and mergers with other dwarfs that connect the ISM to the circumgalactic and intergalactic media. We highlight one of the most persistent mysteries: the nature of pervasive gas that is yet undetected as either molecular or cold hydrogen, the “dark gas.” Some highlights include the following: <jats:list list-type=\"symbol\"> <jats:list-item> <jats:label>▪</jats:label> Significant quantities of H<jats:sc>i</jats:sc> are in far-outer gas disks. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Cold H<jats:sc>i</jats:sc> in dIrrs would be molecular in the Milky Way, making the chemical properties of star-forming clouds significantly different. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Stellar feedback has a much larger impact in dIrrs than in spiral galaxies. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The escape fraction of ionizing photons is significant, making dIrrs a plausible source for reionization in the early Universe. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Observations suggest a significantly higher abundance of hydrogen (H<jats:sub>2</jats:sub> or cold H<jats:sc>i</jats:sc>) associated with CO in star-forming regions than that traced by the CO alone. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"20 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-19DOI: 10.1146/annurev-astro-071422-101131
Michel Mayor
Human interest in the possibility of other worlds in the Universe has existed for over two millennia. In recent centuries, this question has been translated into the following terms: Are there planetary systems linked to stars other than the Sun? Developments in astronomical instrumentation have transformed this philosophical dream into a new, vibrant chapter in astronomy. This article describes my journey that started over 40 years ago with the exploration of the dynamics of our Galaxy, that brought astonishing scientific progress to which my collaborators and I have contributed, and eventually led to the amazing discovery of the plurality of worlds.
{"title":"Plurality of Worlds","authors":"Michel Mayor","doi":"10.1146/annurev-astro-071422-101131","DOIUrl":"https://doi.org/10.1146/annurev-astro-071422-101131","url":null,"abstract":"Human interest in the possibility of other worlds in the Universe has existed for over two millennia. In recent centuries, this question has been translated into the following terms: Are there planetary systems linked to stars other than the Sun? Developments in astronomical instrumentation have transformed this philosophical dream into a new, vibrant chapter in astronomy. This article describes my journey that started over 40 years ago with the exploration of the dynamics of our Galaxy, that brought astonishing scientific progress to which my collaborators and I have contributed, and eventually led to the amazing discovery of the plurality of worlds.","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"16 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-19DOI: 10.1146/annurev-astro-052722-105936
Pablo Marchant, Julia Bodensteiner
Massive stars play a major role in the evolution of their host galaxies and serve as important probes of the distant Universe. It has been established that the majority of massive stars reside in close binaries and interact with their companion stars during their lifetimes. Such interactions drastically alter their life cycles and complicate our understanding of their evolution, but are also responsible for the production of interesting and exotic interaction products. ▪ Extensive observation campaigns with well-understood detection sensitivities have enabled the conversion of observed properties into intrinsic characteristics, facilitating a direct comparison to theory. ▪ Studies of large samples of massive stars in our Galaxy and the Magellanic Clouds have unveiled new types of interaction products, providing critical constraints on the mass transfer phase and the formation of compact objects. ▪ The direct detection of gravitational waves has revolutionized the study of stellar mass compact objects, providing a new window to study massive star evolution. Their formation processes are, however, still unclear. The known sample of compact object mergers will increase by orders of magnitude in the coming decade, which is vastly outgrowing the number of stellar-mass compact objects detected through electromagnetic radiation.
{"title":"The Evolution of Massive Binary Stars","authors":"Pablo Marchant, Julia Bodensteiner","doi":"10.1146/annurev-astro-052722-105936","DOIUrl":"https://doi.org/10.1146/annurev-astro-052722-105936","url":null,"abstract":"Massive stars play a major role in the evolution of their host galaxies and serve as important probes of the distant Universe. It has been established that the majority of massive stars reside in close binaries and interact with their companion stars during their lifetimes. Such interactions drastically alter their life cycles and complicate our understanding of their evolution, but are also responsible for the production of interesting and exotic interaction products. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Extensive observation campaigns with well-understood detection sensitivities have enabled the conversion of observed properties into intrinsic characteristics, facilitating a direct comparison to theory. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Studies of large samples of massive stars in our Galaxy and the Magellanic Clouds have unveiled new types of interaction products, providing critical constraints on the mass transfer phase and the formation of compact objects. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The direct detection of gravitational waves has revolutionized the study of stellar mass compact objects, providing a new window to study massive star evolution. Their formation processes are, however, still unclear. The known sample of compact object mergers will increase by orders of magnitude in the coming decade, which is vastly outgrowing the number of stellar-mass compact objects detected through electromagnetic radiation. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"4 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-18DOI: 10.1146/annurev-aa-61-070323-100001
R. Kennicutt, E. V. van Dishoeck
{"title":"Introduction","authors":"R. Kennicutt, E. V. van Dishoeck","doi":"10.1146/annurev-aa-61-070323-100001","DOIUrl":"https://doi.org/10.1146/annurev-aa-61-070323-100001","url":null,"abstract":"","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":" ","pages":""},"PeriodicalIF":33.3,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43223895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-20DOI: 10.1146/annurev-astro-041923-043618
R. Crain, F. Voort
We review the progress in modeling the galaxy population in hydrodynamical simulations of the ΛCDM cosmogony. State-of-the-art simulations now broadly reproduce the observed spatial clustering of galaxies; the distributions of key characteristics, such as mass, size, and SFR; and scaling relations connecting diverse properties to mass. Such improvements engender confidence in the insight drawn from simulations. Many important outcomes, however, particularly the properties of circumgalactic gas, are sensitive to the details of the subgrid models used to approximate the macroscopic effects of unresolved physics, such as feedback processes. We compare the outcomes of leading simulation suites with observations, and with each other, to identify the enduring successes they have cultivated and the outstanding challenges to be tackled with the next generation of models. Our key conclusions include the following: ▪ Realistic galaxies can be reproduced by calibrating the ill-constrained parameters of subgrid feedback models. Feedback is dominated by stars and black holes in low-mass and high mass galaxies, respectively. ▪ Adjusting or disabling the processes implemented in simulations can elucidate their impact on observables, but outcomes can be degenerate. ▪ Similar galaxy populations can emerge in simulations with dissimilar feedback implementations. However, these models generally predict markedly different gas flow rates into, and out of, galaxies and their halos. CGM observations are thus a promising means of breaking this degeneracy and guiding the development of new feedback models. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Hydrodynamical Simulations of the Galaxy Population: Enduring Successes and Outstanding Challenges","authors":"R. Crain, F. Voort","doi":"10.1146/annurev-astro-041923-043618","DOIUrl":"https://doi.org/10.1146/annurev-astro-041923-043618","url":null,"abstract":"We review the progress in modeling the galaxy population in hydrodynamical simulations of the ΛCDM cosmogony. State-of-the-art simulations now broadly reproduce the observed spatial clustering of galaxies; the distributions of key characteristics, such as mass, size, and SFR; and scaling relations connecting diverse properties to mass. Such improvements engender confidence in the insight drawn from simulations. Many important outcomes, however, particularly the properties of circumgalactic gas, are sensitive to the details of the subgrid models used to approximate the macroscopic effects of unresolved physics, such as feedback processes. We compare the outcomes of leading simulation suites with observations, and with each other, to identify the enduring successes they have cultivated and the outstanding challenges to be tackled with the next generation of models. Our key conclusions include the following: ▪ Realistic galaxies can be reproduced by calibrating the ill-constrained parameters of subgrid feedback models. Feedback is dominated by stars and black holes in low-mass and high mass galaxies, respectively. ▪ Adjusting or disabling the processes implemented in simulations can elucidate their impact on observables, but outcomes can be degenerate. ▪ Similar galaxy populations can emerge in simulations with dissimilar feedback implementations. However, these models generally predict markedly different gas flow rates into, and out of, galaxies and their halos. CGM observations are thus a promising means of breaking this degeneracy and guiding the development of new feedback models. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":" ","pages":""},"PeriodicalIF":33.3,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47355078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-12DOI: 10.1146/annurev-astro-071221-052744
D. Gary
Newly available high-resolution imaging of solar radio emission at many closely spaced frequencies and times provides new physical insight into the processes, structure, and dynamics of the solar atmosphere. The observational advances have spurred renewed interest in topics dating from the early days of solar radio astronomy and have led to considerable advances in our knowledge. Highlights of recent advances include the following: ▪ Quantitatively measuring the dynamic magnetic field strength, particle acceleration, and hot thermal plasma at the heart of solar flares and hinting at the processes that relate them. ▪ Resolving in space and time the energization and transport of electrons in a wide range of contexts. ▪ Mapping the magnetized thermal plasma structure of the solar chromosphere and corona over a substantial range of heights in active and quiet regions of the Sun. This review explains why solar radio imaging spectroscopy is so powerful, describes the body of recent results, and outlines the future work needed to fully realize its potential. The application of radio imaging spectroscopy to stars and planets is also briefly reviewed. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"New Insights from Imaging Spectroscopy of Solar Radio Emission","authors":"D. Gary","doi":"10.1146/annurev-astro-071221-052744","DOIUrl":"https://doi.org/10.1146/annurev-astro-071221-052744","url":null,"abstract":"Newly available high-resolution imaging of solar radio emission at many closely spaced frequencies and times provides new physical insight into the processes, structure, and dynamics of the solar atmosphere. The observational advances have spurred renewed interest in topics dating from the early days of solar radio astronomy and have led to considerable advances in our knowledge. Highlights of recent advances include the following: ▪ Quantitatively measuring the dynamic magnetic field strength, particle acceleration, and hot thermal plasma at the heart of solar flares and hinting at the processes that relate them. ▪ Resolving in space and time the energization and transport of electrons in a wide range of contexts. ▪ Mapping the magnetized thermal plasma structure of the solar chromosphere and corona over a substantial range of heights in active and quiet regions of the Sun. This review explains why solar radio imaging spectroscopy is so powerful, describes the body of recent results, and outlines the future work needed to fully realize its potential. The application of radio imaging spectroscopy to stars and planets is also briefly reviewed. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":" ","pages":""},"PeriodicalIF":33.3,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48801813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-07DOI: 10.1146/annurev-astro-022823-040820
K. Oberg, S. Facchini, D. Anderson
Planets form in disks of gas and dust around young stars. The disk molecular reservoirs and their chemical evolution affect all aspects of planet formation, from the coagulation of dust grains into pebbles to the elemental and molecular compositions of the mature planet. Disk chemistry also enables unique probes of disk structures and dynamics, including those directly linked to ongoing planet formation. We review the protoplanetary disk chemistry of the volatile elements H, O, C, N, S, and P; the associated observational and theoretical methods; and the links between disk and planet chemical compositions. Three takeaways from this review are: ▪ The disk chemical composition, including the organic reservoirs, is set by both inheritance and in situ chemistry. ▪ Disk gas and solid O/C/N/H elemental ratios often deviate from stellar values due to a combination of condensation of molecular carriers, chemistry, and dynamics. ▪ Chemical, physical, and dynamical processes in disks are closely linked, which complicates disk chemistry modeling, but they also present an opportunity to develop chemical probes of different aspects of disk evolution and planet formation. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Protoplanetary Disk Chemistry","authors":"K. Oberg, S. Facchini, D. Anderson","doi":"10.1146/annurev-astro-022823-040820","DOIUrl":"https://doi.org/10.1146/annurev-astro-022823-040820","url":null,"abstract":"Planets form in disks of gas and dust around young stars. The disk molecular reservoirs and their chemical evolution affect all aspects of planet formation, from the coagulation of dust grains into pebbles to the elemental and molecular compositions of the mature planet. Disk chemistry also enables unique probes of disk structures and dynamics, including those directly linked to ongoing planet formation. We review the protoplanetary disk chemistry of the volatile elements H, O, C, N, S, and P; the associated observational and theoretical methods; and the links between disk and planet chemical compositions. Three takeaways from this review are: ▪ The disk chemical composition, including the organic reservoirs, is set by both inheritance and in situ chemistry. ▪ Disk gas and solid O/C/N/H elemental ratios often deviate from stellar values due to a combination of condensation of molecular carriers, chemistry, and dynamics. ▪ Chemical, physical, and dynamical processes in disks are closely linked, which complicates disk chemistry modeling, but they also present an opportunity to develop chemical probes of different aspects of disk evolution and planet formation. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":" ","pages":""},"PeriodicalIF":33.3,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44169727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-30DOI: 10.1146/annurev-astro-052920-104851
N. McClure-Griffiths, S. Stanimirović, D. Rybarczyk
Atomic hydrogen (Hi) is a critical stepping stone in the gas evolution cycle of the interstellar medium (ISM) of the Milky Way. Hi traces both the cold, premolecular state before star formation and the warm, diffuse ISM before and after star formation. This review describes new, sensitive Hi absorption and emission surveys, which, together with high angular and spectral resolution Hi emission data, have revealed the physical properties of Hi, its structure, and its association with magnetic fields. We give an overview of the Hi phases and discuss how Hi properties depend on the environment and what its structure can tell us about feedback in the ISM. Key findings include the following: ▪ The mass fraction of the cold neutral medium is [Formula: see text]40% on average, increasing with AV due to the increase of mean gas density. ▪ The cold disk extends to at least R ∼ 25 kpc. ▪ Approximately 40% of the Hi is warm, with structural characteristics that derive from feedback events. ▪ Cold Hi is highly filamentary, whereas warm Hi is more smoothly distributed. We summarize future observational and simulation opportunities that can be used to unravel the 3D structure of the atomic ISM and the effects of heating and cooling on Hi properties. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"Atomic Hydrogen in the Milky Way: A Stepping Stone in the Evolution of Galaxies","authors":"N. McClure-Griffiths, S. Stanimirović, D. Rybarczyk","doi":"10.1146/annurev-astro-052920-104851","DOIUrl":"https://doi.org/10.1146/annurev-astro-052920-104851","url":null,"abstract":"Atomic hydrogen (Hi) is a critical stepping stone in the gas evolution cycle of the interstellar medium (ISM) of the Milky Way. Hi traces both the cold, premolecular state before star formation and the warm, diffuse ISM before and after star formation. This review describes new, sensitive Hi absorption and emission surveys, which, together with high angular and spectral resolution Hi emission data, have revealed the physical properties of Hi, its structure, and its association with magnetic fields. We give an overview of the Hi phases and discuss how Hi properties depend on the environment and what its structure can tell us about feedback in the ISM. Key findings include the following: ▪ The mass fraction of the cold neutral medium is [Formula: see text]40% on average, increasing with AV due to the increase of mean gas density. ▪ The cold disk extends to at least R ∼ 25 kpc. ▪ Approximately 40% of the Hi is warm, with structural characteristics that derive from feedback events. ▪ Cold Hi is highly filamentary, whereas warm Hi is more smoothly distributed. We summarize future observational and simulation opportunities that can be used to unravel the 3D structure of the atomic ISM and the effects of heating and cooling on Hi properties. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":" ","pages":""},"PeriodicalIF":33.3,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47695938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.1146/annurev-astro-121222-033350
S. Ye
This article depicts my life and career over the past decades, beginning with my birth in 1927 and ending in my two dreams yet to be realized. This article focuses on my school years during wartime and my work with Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences (CAS) from 1951 on—serving as Director of SHAO during 1981–1993 and a Member of CAS since 1980—and shares some social activities I've been involved in for the benefits of women and children. Special focus is given to the endeavors of building one of the world's most precise Universal Time systems in the 1960s, a very long baseline interferometry network, a satellite laser ranging research station during the 1970s–1990s, and the 65-m Radio Telescope in the early twenty-first century; developing astrogeodynamics in China and advancing the Asia-Pacific Space Geodynamics Program in the late twentieth century; and leading SHAO in international cooperation while serving as Chair of the International Astronomical Union Finance Committee during 1985–1988, the IAU Vice-President during 1988–1994, and a foreign fellow of the Royal Astronomical Society of Britain in 1985. This autobiographical account should, hopefully, serve its purpose of offering a glimpse of me and my lifelong interaction with time and space. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
{"title":"A Walk in Time and Space: My Journey as a Strategic Scientist","authors":"S. Ye","doi":"10.1146/annurev-astro-121222-033350","DOIUrl":"https://doi.org/10.1146/annurev-astro-121222-033350","url":null,"abstract":"This article depicts my life and career over the past decades, beginning with my birth in 1927 and ending in my two dreams yet to be realized. This article focuses on my school years during wartime and my work with Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences (CAS) from 1951 on—serving as Director of SHAO during 1981–1993 and a Member of CAS since 1980—and shares some social activities I've been involved in for the benefits of women and children. Special focus is given to the endeavors of building one of the world's most precise Universal Time systems in the 1960s, a very long baseline interferometry network, a satellite laser ranging research station during the 1970s–1990s, and the 65-m Radio Telescope in the early twenty-first century; developing astrogeodynamics in China and advancing the Asia-Pacific Space Geodynamics Program in the late twentieth century; and leading SHAO in international cooperation while serving as Chair of the International Astronomical Union Finance Committee during 1985–1988, the IAU Vice-President during 1988–1994, and a foreign fellow of the Royal Astronomical Society of Britain in 1985. This autobiographical account should, hopefully, serve its purpose of offering a glimpse of me and my lifelong interaction with time and space. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42492728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-22DOI: 10.1146/annurev-astro-071221-053453
R. Klessen, S. Glover
The first generation of stars, often called Population III (or Pop III), form from metal-free primordial gas at redshifts z ∼ 30 and below. They dominate the cosmic star-formation history until z ∼ 15–20, at which point the formation of metal-enriched Population II stars takes over. We review current theoretical models for the formation, properties, and impact of Pop III stars and discuss existing and future observational constraints. Key takeaways from this review include the following: ▪ Primordial gas is highly susceptible to fragmentation and Pop III stars form as members of small clusters with a logarithmically flat mass function. ▪ Feedback from massive Pop III stars plays a central role in regulating subsequent star formation, but major uncertainties remain regarding its immediate impact. ▪ In extreme conditions, supermassive Pop III stars can form, reaching masses of several 105 M⊙. Their remnants may be the seeds of the supermassive black holes observed in high-redshift quasars. ▪ Direct observations of Pop III stars in the early Universe remain extremely challenging. Indirect constraints from the global 21-cm signal or gravitational waves are more promising. ▪ Stellar archeological surveys allow us to constrain both the low-mass and the high-mass ends of the Pop III mass distribution. Observations suggest that most massive Pop III stars end their lives as core-collapse supernovae rather than as pair-instability supernovae. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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