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Stereoelectronic Effects in Ligand design: Enantioselective rhodium‐Catalyzed Hydrogenation of Aliphatic Cyclic Tetrasubstituted Enamides and Concise Synthesis of (r)‐Tofacitinib

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Angewandte Chemie 2019年第38期131卷

作者： Chengxi Li Feng Wan Yuan Chen Henian Peng Wenjun Tang Shu Yu J. Christopher McWilliams Jason Mustakis Lacey Samp robert J. Maguire State Key Laboratory of Bio-Organic and Natural Products Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences 345 Ling Ling Road Shanghai 200032 China Chemical Research and Development Pfizer Global R&D Eastern Point Road Groton CT 06340 USA Chemical Research and Applied Synthetic Technologies Pfizer Global R&D Eastern Point Road Groton CT 06340 USA

We herein report the development of a conformationally defined, electron‐rich, C 2 ‐symmetric, P‐chiral bisphosphorus ligand, ArcPhos, by taking advantage of stereoelectronic effects in ligand design. With the rh‐ArcPhos catalyst, excellent enantioselectivities and unprecedentedly high turnovers (TON up to 10 000) were achieved in the asymmetric hydrogenation of aliphatic carbocyclic and heterocyclic tetrasubstituted enamides, to generate a series of chiral cis ‐2‐alkyl‐substituted carbocyclic and heterocyclic amine derivatives in excellent enantiomeric ratios. This method also enabled an efficient and practical synthesis of the Janus kinase inhibitor ( r )‐tofacitinib.

关键词： Asymmetrische Hydrierung Enamide P-Liganden Stereoelektronische Effekte Tofacitinib

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A Study on the Calculation Method for the Coverage rate of Early Warning release

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IOP Conference Series: Earth and Environmental Science 2019年第5期233卷

作者： Zhiyu Cao Yuxing Feng Xiao Li National Early Warning Center Beijing 100081 010-58995628 *** Address: NO.46 South ZhongGuancun Street Haidian district Beijing National Key R&D Program of China 2018YFC0807000 School of Mathematics Shandong University Jinan Shandong 250100

The coverage rate of early warning release is an important indicator of early warning releasing capacity. How to calculate the coverage rate of early warning in a certain area objectively and reasonably plays an important role in evaluating the effectiveness of early warning releasing. This paper analyzes the principle and components of the coverage rate calculation for early warning releasing, and puts forward three combination calculation methods. They are inclusion-exclusion principle, method of weighting and maximum value method. This paper also analyzes the differences between the three methods in calculation feasibility, calculation accuracy and rationality of the results, so as to confirm that the relative best method for calculating the coverage rate of early warning is maximum value method. Finally, combined with the characteristics of China's early warning release system and administrative regionalization, the paper further proposes national, provincial and municipal three level calculation models of early warning releasing coverage rate, and provides a calculation example, and discusses the enlightenment to improve the early warning releasing capacity.

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Photocatalytic Cr(Ⅵ) reduction and organic-pollutant degradation in a stable 2d coordination polymer

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Chinese Journal of Catalysis 2017年第12期38卷 2141-2149页

作者： Fu‐Xue Wang Xiao‐Hong Yi Chong‐Chen Wang Ji‐Guang deng Beijing Key Laboratory of Functional Materials for Building Structure and Environment Remediation/Sino‐Dutch R&D Centre for Future Wastewater Treatment Technologies Beijing University of Civil Engineering and Architecture Beijing 100044 China Department of Chemistry and Chemical Engineering College of Environmental and Energy Engineering Beijing University of Technology Beijing 100022 China

A new coordination polymer,Zn(bpy)L(BUC‐21),(H2L=cis‐1,3‐dibenzyl‐2‐imidazolidone‐4,5‐dicarboxylic acid,bpy=4,4′‐bipyridine),has been synthesized under hydrothermal conditions,and characterized by single‐crystal X‐ray analysis,Fourier transform infrared spectroscopy,thermogravimetric analyses,CNH elemental analysis and UV‐Vis diffuse reflectance ***‐21exhibited an excellent performance for photocatalytic Cr(VI)reduction with a conversion efficiency of96%,better than that of commercial P25(39%),under UV light irradiation ***‐21could also be used to conduct photocatalytic degradation of organic dyes including methylene blue,rhodamine B,methyl orange and reactive red X‐***,the photocatalytic activity of BUC‐21remained high across a wide pH range *** is interesting to note,however,that BUC‐21was unable to achieve simultaneous reduction of Cr(VI)and degradation of an organic pollutant in a mixed matrix,which can be attributed to the competition between Cr(VI)and the organic dyes for access to the photo‐excited electrons.

关键词： Photocatalysis Cr(VI) reduction Organic dyes Coordination polymers degradation

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Stability of concentration-related self-interstitial atoms in fusion material tungsten

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Chinese Physics B 2016年第5期25卷 242-245页

作者：张红温述龙潘敏黄整赵勇刘翔谌继明 Key Laboratory of Advanced Technology of Materials Superconductivity and New Energy R&D CenterSouthwest Jiao Tong University Western Superconducting Technologies Company Limited Fusion Science of Southwestern Institute of Physics

Based on the density functional theory, we calculated the structures of the two main possible self-interstitial atoms（SIAs） as well as the migration energy of tungsten（W） atoms. It was found that the difference of the 110 and 111 formation energies is 0.05–0.3 e V. Further analysis indicated that the stability of SIAs is closely related to the concentration of the defect. When the concentration of the point defect is high, 110 SIAs are more likely to exist, 111 SIAs are the opposite. In addition, the vacancy migration probability and self-recovery zones for these SIAs were researched by making a detailed comparison. The calculation provided a new viewpoint about the stability of point defects for selfinterstitial configurations and would benefit the understanding of the control mechanism of defect behavior for this novel fusion material.

关键词： irradiation self-interstitial atoms fusion material tungsten

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The genome sequence of segmental allotetraploid peanut Arachis hypogaea

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NATUrE GENETICS 2019年第5期51卷 877-+页

作者： Bertioli, david J. Jenkins, Jerry Clevenger, Josh dudchenko, Olga Gao, dongying Seijo, Guillermo Leal-Bertioli, Soraya C. M. ren, Longhui Farmer, Andrew d. Pandey, Manish K. Samoluk, Sergio S. Abernathy, Brian Agarwal, Gaurav Ballen-Taborda, Carolina Cameron, Connor Campbell, Jacqueline Chavarro, Carolina Chitikineni, Annapurna Chu, Ye dash, Sudhansu El Baidouri, Moaine Guo, Baozhu Huang, Wei do Kim, Kyung Korani, Walid Lanciano, Sophie Lui, Christopher G. Mirouze, Marie Moretzsohn, Marcio C. Pham, Melanie Shin, Jin Hee Shirasawa, Kenta Sinharoy, Senjuti Sreedasyam, Avinash Weeks, Nathan T. Zhang, Xinyou Zheng, Zheng Sun, Ziqi Froenicke, Lutz Aiden, Erez L. Michelmore, richard Varshney, rajeev K. Holbrook, C. Corley Cannon, Ethalinda K. S. Scheffler, Brian E. Grimwood, Jane Ozias-Akins, Peggy Cannon, Steven B. Jackson, Scott A. Schmutz, Jeremy Univ Georgia Ctr Appl Genet Technol Athens GA 30602 USA Univ Georgia Inst Plant Breeding Genet & Genom Athens GA 30602 USA Univ Georgia Dept Crop & Soil Sci Athens GA 30602 USA HudsonAlpha Inst Biotechnol Huntsville AL 35806 USA Baylor Coll Med Ctr Genome Architecture Houston TX 77030 USA UNNE CONICET Inst Bot Nordeste Corrientes Argentina Univ Nacl Nordeste FACENA Corrientes Argentina Univ Georgia Dept Plant Pathol Tifton GA 31793 USA Iowa State Univ Interdept Genet Grad Program Ames IA USA Natl Ctr Genome Resources Santa Fe NM USA Int Crops Res Inst Semi Arid Trop Ctr Excellence Genom & Syst Biol Hyderabad Telangana India Iowa State Univ Dept Comp Sci Ames IA USA Univ Georgia Dept Hort Tifton GA USA CNRS UMR5096 Lab Genome & Dev Plantes Perpignan France Univ Perpignan UMR5096 Lab Genome & Dev Plantes Perpignan France ARS Crop Protect & Management Res Unit USDA Tifton GA USA LG Chem Corp R&D Seoul South Korea IRD UMR232 Diversite Adaptat & Dev Plantes Montpellier France Univ Montpellier UMR232 Diversite Adaptat & Dev Plantes Montpellier France Embrapa Genet Resources & Biotechnol Brasilia DF Brazil Kazusa DNA Res Inst Dept Frontier Res & Dev Kisarazu Japan Natl Inst Plant Genome Res New Delhi India ARS Corn Insects & Crop Genet Res Unit USDA Ames IA USA Henan Acad Agr Sci Ind Crops Res Inst Henan Prov Key Lab Genet Improvement Oil Crops Zhengzhou Henan Peoples R China Minist Agr & Rural Affairs Key Lab Oil Crops Huanghuaihai Plains Zhengzhou Henan Peoples R China Univ Calif Davis Genome Ctr Davis CA 95616 USA ARS Crop Genet & Breeding Res Unit USDA Tifton GA USA ARS Genom & Bioinformat Res Unit USDA Stoneville MS USA Joint Genome Inst Dept Energy Walnut Creek CA USA

Like many other crops, the cultivated peanut (Arachis hypogaea L.) is of hybrid origin and has a polyploid genome that contains essentially complete sets of chromosomes from two ancestral species. Here we report the genome sequence of peanut and show that after its polyploid origin, the genome has evolved through mobile-element activity, deletions and by the flow of genetic information between corresponding ancestral chromosomes (that is, homeologous recombination). Uniformity of patterns of homeologous recombination at the ends of chromosomes favors a single origin for cultivated peanut and its wild counterpart A. monticola. However, through much of the genome, homeologous recombination has created diversity. Using new polyploid hybrids made from the ancestral species, we show how this can generate phenotypic changes such as spontaneous changes in the color of the flowers. We suggest that diversity generated by these genetic mechanisms helped to favor the domestication of the polyploid A. hypogaea over other diploid Arachis species cultivated by humans.

关键词： Genomics Plant genetics

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Mid-range Science Objectives for the Event Horizon Telescope

arXiv

引用

arXiv 2024年

作者： Akiyama, Kazunori Albentosa-ruíz, Ezequiel Alberdi, Antxon Alef, Walter Algaba, Juan Carlos Anantua, richard Asada, Keiichi Azulay, rebecca Bach, Uwe Baczko, Anne-Kathrin Ball, david Balokovi, Mislav Bandyopadhyay, Bidisha Barrett, John Baubck, Michi Benson, Bradford A. Bintley, dan Blackburn, Lindy Blundell, raymond Bouman, Katherine L. Bower, Geoffrey C. Bremer, Michael Brissenden, roger Britzen, Silke Broderick, Avery E. Broguiere, dominique Bronzwaer, Thomas Bustamante, Sandra Carlstrom, John E. Chael, Andrew Chan, Chi-Kwan Chang, dominic O. Chatterjee, Koushik Chatterjee, Shami Chen, Ming-Tang Chen, Yongjun Cheng, Xiaopeng Cho, Ilje Christian, Pierre Conroy, Nicholas S. Conway, John E. Crawford, Thomas M. Crew, Geoffrey B. Cruz-Osorio, Alejandro Cui, Yuzhu Curd, Brandon dahale, rohan davelaar, Jordy de Laurentis, Mariafelicia deane, roger dempsey, Jessica desvignes, Gregory dexter, Jason dhruv, Vedant dihingia, Indu K. doeleman, Sheperd S. dzib, Sergio A. Eatough, ralph P. Emami, razieh Falcke, Heino Farah, Joseph Fish, Vincent L. Fomalont, Edward Ford, H. Alyson Foschi, Marianna Fraga-Encinas, raquel Freeman, William T. Friberg, Per Fromm, Christian M. Fuentes, Antonio Galison, Peter Gammie, Charles F. García, roberto Gentaz, Olivier Georgiev, Boris Goddi, Ciriaco Gold, roman Gómez-ruiz, Arturo I. Gómez, JoséL Gu, Minfeng Gurwell, Mark Hada, Kazuhiro Haggard, daryl Hesper, ronald Heumann, dirk Ho, Luis C. Ho, Paul Honma, Mareki Huang, Chih-Wei L. Huang, Lei Hughes, david H. Ikeda, Shiro Impellizzeri, C.M. Violette Inoue, Makoto Issaoun, Sara James, david J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton Jiang, Wu Jiménez-rosales, Alejandra Johnson, Michael d. Jorstad, Svetlana Jones, Adam C. Joshi, Abhishek V. Jung, Taehyun Karuppusamy, ramesh Kawashima, Tomohisa Keating, Garrett K. Kettenis, Mark Kim, dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kino, Motoki Koay, Jun Yi Kocherlakota, Prashant Kofuji, Yutaro Koch, Patrick M. Koyama, Shoko Kramer, Carsten Kramer, Joana A. Kramer, Michael Krichbaum, T Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road WestfordMA01886 United States National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Black Hole Initiative Harvard University 20 Garden Street CambridgeMA02138 United States Departament d’Astronomia i Astrofísica Universitat de València C. Dr. Moliner 50 Burjassot ValènciaE-46100 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n GranadaE-18008 Spain Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Department of Physics Faculty of Science Universiti Malaya Kuala Lumpur50603 Malaysia Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Department of Physics & Astronomy The University of Texas at San Antonio One UTSA Circle San AntonioTX78249 United States Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. 4 Roosevelt Rd. Taipei106216 Taiwan Observatori Astronòmic Universitat de València C. Catedrático JoséBeltrán 2 Paterna ValènciaE-46980 Spain Department of Space Earth and Environment Chalmers University of Technology Onsala Space Observatory OnsalaSE-43992 Sweden Steward Observatory Department of Astronomy University of Arizona 933 N. Cherry Ave. TucsonAZ85721 United States Yale Center for Astronomy & Astrophysics Yale University 52 Hillhouse Avenue New HavenCT06511 United States Astronomy Department Universidad de Concepción Casilla 160-C Concepción Chile Department of Physics University of Illinois 1110 West Green Street UrbanaIL61801 United States Fermi National Accelerator Laboratory MS209 P.O. Box 500 BataviaIL60510 United States Department of Astronomy and Astrophysics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States East Asian Observatory 660 N. A’ohoku Place HiloHI96720 United States 660 N. A’ohoku Place HiloHI

The first images of the black holes in Sgr A∗ and M87∗ have created a wide range of new scientific opportunities in gravitational physics, compact objects, and relativistic astrophysics. We discuss here the scientific opportunities that arise from the rich data sets that have already been obtained and the new data sets that will be obtained, exploiting a wide range of technical advances, including observational agility, receiver upgrades, and the addition of new stations. This document provides a 5-year framework for Event Horizon Telescope (EHT) science structured around four fundamental questions that are used to prioritize the analysis of existing data, guide technical upgrades, and determine the optimal use of future observational opportunities with EHT, ALMA, and multi-wavelength facilities. Through enhancements over this period, the EHT will create the first movie of M87∗ connecting black hole and jet physics, provide detailed studies of the structure and dynamics of Sgr A∗, characterize the magnetospheres of both systems through polarimetric imaging, and explore the spacetime properties of black holes with greater precision and range. © 2024, CC BY.

关键词： Astrophysics

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Synthesis and photoelectrical performance of nanoscale PbS and Bi2S3 co-sensitized on TiO2 nanotube arrays

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Journal of Modern Transportation 2017年第1期25卷 52-57页

作者： Fanggong Cai Min Pan Yong Feng Guo Yan Yong Zhang Yong Zhao Superconductivity and New Energy R&D Center Key Laboratory of Advanced Technology of Materials(Ministryof Education of China)Southwest Jiaotong UniversityMail Stop 165#Cheng du 610031People's Republic of China National Engineering Labortary for Superconducting Materials Western Superconducting Technologies Co.LtdXi'anPeople's Republic of China School of Physical Science and Technology Southwest Jiaotong UniversityChengdu 610031People's Republic of China

TiO2 films have been widely applied in photo- voltaic conversion techniques. TiO2 nanotube arrays （TiO2 NAs） can be grown directly on the surface of metal Ti by the anodic oxidation method. Bi2S3 and PbS nanoparticles （NPs） were firstly co-sensitized on TiOa NAs （denoted as PbS/Bi2S3（n）/TiO2 NAs） by a two-step process containing hydrothermal and sonication-assisted SILAr method. When the concentration of Bi3＋ is 5 mmol/L, the best photoelectrical performance was obtained under simulated solar irradiation. The short-circuit photocurrent （Jsc） and photoconversion efficiency （η） of PbS/Bi2S3（5）/TiO2 NAs electrode were 4.70 mA/cm and 1.13 %, respectively.

关键词： Solar cells TiO2 nanotube arrays Bi2S3 PbS Surface photovoltage

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Large-scale production of extracellular vesicles: report on the “massivEVs” ISEV workshop

Journal of Extracellular Biology

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Journal of Extracellular Biology 2022年第10期1卷 e63页

作者： Paolini, Lucia Monguió-Tortajada, Marta Costa, Marta Antenucci, Fabio Barilani, Mario Clos-Sansalvador, Marta Andrade, André Cronemberger driedonks, Tom A. P. Giancaterino, Sara Kronstadt, Stephanie M. Mizenko, rachel r. Nawaz, Muhammad Osteikoetxea, Xabier Pereira, Carla Shrivastava, Surya Boysen, Anders Toftegaard van de Wakker, Simonides Immanuel van Herwijnen, Martijn J. C. Wang, Xiaoqin Watson, dionysios C. Gimona, Mario Kaparakis-Liaskos, Maria Konstantinov, Konstantin Lim, Sai Kiang Meisner-Kober, Nicole Stork, Michiel Nejsum, Peter radeghieri, Annalisa rohde, Eva Touzet, Nicolas Wauben, Marca H. M. Witwer, Kenneth W. Bongiovanni, Antonella Bergese, Paolo Department of Molecular and Translational Medicine University of Brescia Brescia Italy Center for Colloid and Surface Science (CSGI) Department of Chemistry University of Florence Sesto Fiorentino (FI) Italy Department of Medical and Surgical Specialties Radiological Sciences and Public Health University of Brescia Brescia Italy CREC Research Program Health Science Research Institute Germans Trias i Pujol (IGTP) Badalona Spain Heart Institute (iCor) Cardiology Department Germans Trias i Pujol University Hospital Badalona Spain iBET Instituto de Biologia Experimental e Tecnológica Oeiras Portugal Instituto de Tecnologia Química e Biológica António Xavier Universidade Nova de Lisboa Oeiras Portugal Department of Veterinary and Animal Sciences University of Copenhagen Copenhagen Denmark Laboratory of Regenerative Medicine ‒ Cell Factory Department of Transfusion Medicine and Hematology Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano Italy REMAR-IGTP Group Germans Trias i Pujol Research Institute (IGTP) & Nephrology Department University Hospital Germans Trias i Pujol (HUGTiP) Catalonia Badalona (Barcelona) Spain Department of Cell Biology Physiology and Immunology Universitat Autònoma de Barcelona (UAB) Bellaterra Spain Experimental and Clinical Cell Therapy Institute (ExCT) Spinal Cord Injury and Tissue Regeneration Center Paracelsus Medical University Salzburg Austria CDL Research University Medical Center Utrecht Utrecht University Utrecht Netherlands Department of Molecular and Comparative Pathology Johns Hopkins School of Medicine Baltimore MD United States Department of Civil Chemical Environmental and Materials Engineering Alma Mater Studiorum University of Bologna Bologna Italy Fischell Department of Bioengineering University of Maryland College Park MD United States Department of Biomedical Engineering University of California Davis CA United States Department of Rheumatology and Inflammation Research Institute of Medicine

Extracellular vesicles (EVs) large-scale production is a crucial point for the translation of EVs from discovery to application of EV-based products. In October 2021, the International Society for Extracellular Vesicles (ISEV), along with support by the FET-OPEN projects, “The Extracellular Vesicle Foundry” (evFOUNdrY) and “Extracellular vesicles from a natural source for tailor-made nanomaterials” (VES4US), organized a workshop entitled “massivEVs” to discuss the potential challenges for translation of EV-based products. This report gives an overview of the topics discussed during “massivEVs”, the most important points raised, and the points of consensus reached after discussion among academia and industry representatives. Overall, the review of the existing EV manufacturing, upscaling challenges and directions for their resolution highlighted in the workshop painted an optimistic future for the expanding EV field. © 2022 The Authors. Journal of Extracellular Biology published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles.

关键词： EV-based products extracellular vesicles ISEV workshop large-scale production manufacturing processing regulatory issues

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Polybenzimidazole membranes with nanophase-separated structure induced by non-ionic hydrophilic side chains for vanadium flow batteries

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Journal of Materials Chemistry A 2017年第9期6卷 3895-3905页

作者： Sangshan Peng Xuemei Wu Xiaoming Yan Li Gao Yangzhi Zhu daishuang Zhang Jie Li Qian Wang Gaohong He State Key Laboratory of Fine Chemicals R&D Center of Membrane Science and Technology School of Chemical Engineering Dalian University of Technology Dalian China School of Petroleum and Chemical Engineering Dalian University of Technology Panjin China Department of Chemical and Environmental Engineering Materials Science Engineering Program Bourns College of Engineering University of California Riverside California 92521 USA

Polybenzimidazole (PBI) membranes with nanophase-separated structure induced by non-ionic hydrophilic side chain are designed and fabricated for vanadium flow batteries (VFBs). The designed PBI membranes are prepared by grafting non-ionic hydrophilic side chains via an N-substitution reaction. This molecular modification induces nanophase separation and formation of hydrophilic clusters, which act as effective proton transfer pathways, hence dramatically improving the proton conductivity. Meanwhile, the vanadium permeability is inappreciable due to the appropriate size of hydrophilic clusters and donnan exclusion of protonated grafted-PBI membranes (GPBI). Free from ion exchange groups, GPBI membranes maintain the good chemical stability of the pristine PBI membrane. As a result, the designed membrane exhibits an impressive performance, combining ultrahigh proton conductivity, ion selectivity and chemical stability. The GPBI-based VFB exhibits a coulombic efficiency of over 99% and an energy efficiency of 84% at 120 mA cm⁻², the highest reported for dense PBI membranes for VFB applications. The decent stability of GPBI membranes is demonstrated by the stable performance over 200 charge–discharge cycles and the ex situ immersion test. This work provides a new insight into the design of high-performance PBI membranes for VFB applications.

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First Sagittarius A* Event Horizon Telescope results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

arXiv

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arXiv 2023年

作者： Akiyama, Kazunori Alberdi, Antxon Alef, Walter Algaba, Juan Carlos Anantua, richard Asada, Keiichi Azulay, rebecca Bach, Uwe Baczko, Anne-Kathrin Ball, david Baloković, Mislav Barrett, John Bauböck, Michi Benson, Bradford A. Bintley, dan Blackburn, Lindy Blundell, raymond Bouman, Katherine L. Bower, Geoffrey C. Boyce, Hope Bremer, Michael Brinkerink, Christiaan d. Brissenden, roger Britzen, Silke Broderick, Avery E. Broguiere, dominique Bronzwaer, Thomas Bustamante, Sandra Byun, do-Young Carlstrom, John E. Ceccobello, Chiara Chael, Andrew Chan, Chi-Kwan Chatterjee, Koushik Chatterjee, Shami Chen, Ming-Tang Chen, Yongjun Cheng, Xiaopeng Cho, Ilje Christian, Pierre Conroy, Nicholas S. Conway, John E. Cordes, James M. Crawford, Thomas M. Crew, Geoffrey B. Cruz-Osorio, Alejandro Cui, Yuzhu davelaar, Jordy de Laurentis, Mariafelicia deane, roger dempsey, Jessica desvignes, Gregory dexter, Jason dhruv, Vedant doeleman, Sheperd S. dougal, Sean dzib, Sergio A. Eatough, ralph P. Emami, razieh Falcke, Heino Farah, Joseph Fish, Vincent L. Fomalont, Ed Ford, H. Alyson Fraga-Encinas, raquel Freeman, William T. Friberg, Per Fromm, Christian M. Fuentes, Antonio Galison, Peter Gammie, Charles F. García, roberto Gentaz, Olivier Georgiev, Boris Goddi, Ciriaco Gold, roman Gómez-ruiz, Arturo I. Gómez, José L. Gu, Minfeng Gurwell, Mark Hada, Kazuhiro Haggard, daryl Haworth, Kari Hecht, Michael H. Hesper, ronald Heumann, dirk Ho, Luis C. Ho, Paul Honma, Mareki Huang, Chih-Wei L. Huang, Lei Hughes, david H. Ikeda, Shiro Impellizzeri, C.M. Violette Inoue, Makoto Issaoun, Sara James, david J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton Jiang, Wu Jiménez-rosales, Alejandra Johnson, Michael d. Jorstad, Svetlana Joshi, Abhishek V. Jung, Taehyun Karami, Mansour Karuppusamy, ramesh Kawashima, Tomohisa Keating, Garrett K. Kettenis, Mark Kim, dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kino, Motoki Koay, Jun Yi Kocherlakota, Prashant Kofuji, Yutaro Koch, Patrick M. Koyama, Shoko Kramer, Carsten Kramer, Michael Krichbaum, Thomas P. Ku Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road WestfordMA01886 United States National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Black Hole Initiative Harvard University 20 Garden Street CambridgeMA02138 United States Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n GranadaE-18008 Spain Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Department of Physics Faculty of Science Universiti Malaya Kuala Lumpur50603 Malaysia Center for Astrophysics | Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Department of Physics & Astronomy The University of Texas at San Antonio One UTSA Circle San AntonioTX78249 United States Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan Departament d'Astronomia i Astrofísica Universitat de València C. Dr. Moliner 50 Burjassot ValènciaE-46100 Spain Observatori Astronòmic Universitat de València C. Catedrático José Beltrán 2 Paterna ValènciaE-46980 Spain Steward Observatory Department of Astronomy University of Arizona 933 N. Cherry Ave. TucsonAZ85721 United States Yale Center for Astronomy & Astrophysics Yale University 52 Hillhouse Avenue New HavenCT06511 United States Department of Physics University of Illinois 1110 West Green Street UrbanaIL61801 United States Fermi National Accelerator Laboratory MS209 P.O. Box 500 BataviaIL60510 United States Department of Astronomy and Astrophysics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States East Asian Observatory 660 N. A'ohoku Place HiloHI96720 United States 660 N. A'ohoku Place HiloHI96720 United States California Institute of Technology 1200 East California Boulevard PasadenaCA91125 United States Institute of Astronomy and Astrophysics Academia Sinica 645 N. A'ohoku Place HiloHI

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A∗), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength of λ = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of 51.8 ± 2.3 µas (68% credible interval). The ring has modest azimuthal brightness asymmetry and a comparatively dim interior. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A∗ are consistent with the expected appearance of a Kerr black hole with mass ∼4 × 106 M☉, which is inferred to exist at this location based on previous infrared observations of individual stellar orbits as well as maser proper motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50◦), as well as non-spinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way galaxy, and for the first time we connect the predictions from dynamical measurements of stellar orbits on scales of 103 − 105 gravitational radii to event horizon-scale images and variability. Furthermore, a comparison with the EHT results for the supermassive black hole M87∗ shows consistency with the predictions of general relativity spanning over three orders of magnitude in central mass. © 2023, CC BY.

关键词： Telescopes

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