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Energy loss of an energetic Ga ion in hot Au plasmas

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Matter and Radiation at Extremes 2016年第5期1卷 257-263页

作者： Bin He Xujun Meng Jianguo Wang Data Center for High Energy Density Physics Research Institute of Applied Physics and Computational MathematicsBeijing 100088PR China

Self-consistent calculations of energy loss for a Ga ion moving in hot Au plasmas are made under the assumption of wide ranges of the projectile energy and the plasma temperature with all important mechanisms considered in *** relevant results are found to be quite different from those of an a particle or a *** important reason for this is the rapid increasing of the charge state of a Ga ion at plasma *** reason also leads to the inelastic stopping which does not always decrease with the increase of plasma temperature,unlike the case of an a *** nuclear stopping becomes very important at high enough plasma temperature due to the heavy reduced mass of a Ga and an Au ion and the above-mentioned *** well-known binary collision model[***.126(1962)1]and its revised one[***.A 29(1984)2145]are not working or unsatisfactory in this case.

关键词： Energy loss Hot Au plasma Ga ion

Machine learning clustering technique applied to powder X-ray diffraction patterns to distinguish alloy substitutions

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arXiv 2018年

作者： Utimula, Keishu Hunkao, Rutchapon Yano, Masao Kimoto, Hiroyuki Hongo, Kenta Kawaguchi, Shogo Suwanna, Sujin Maezono, Ryo School of Materials Science JAIST Asahidai 1-1 Nomi Ishikawa923-1292 Japan Optical and Quantum Physics Laboratory Department of Physics faculty of Science Mahidol University Bangkok10400 Thailand Advanced Material Engineering Div. Toyota Motor Corporation Toyota-cho 1 Toyota Aichi471-8572 Japan Research Center for Advanced Computing Infrastructure JAIST Asahidai 1-1 Nomi Ishikawa923-1292 Japan Center for Materials Research by Information Integration Research and Services Division of Materials Data and Integrated System National Institute for Materials Science Tsukuba305-0047 Japan PRESTO JST Kawaguchi Saitama332-0012 Japan Sayo-gun Hyogo679-5148 Japan Asahidai 1-1 Nomi Ishikawa923-1292 Japan Computational Engineering Applications Unit RIKEN 2-1 Hirosawa Wako Saitama351-0198 Japan

We applied the clustering technique using DTW (dynamic time wrapping) analysis to XRD (X-ray diffraction) spectrum patterns in order to identify the microscopic structures of substituents introduced in the main phase of magnetic alloys. The clustering is found to perform well to identify the concentrations of the substituents with successful rates (∼90%). The sufficient performance is attributed to the nature of DTW processing to filter out irrelevant informations such as the peak intensities (due to the incontrollability of diffraction conditions in polycrystalline samples) and the uniform shift of peak positions (due to the thermal expansions of lattices). The established framework is applicable not limited to the system treated in this work but widely to the systems to be tuned their properties by atomic substitutions within a phase. The framework has larger potential to predict wider properties from observed XRD patterns in a way that it can provide such properties evaluated from predicted microscopic local structure, such as magnetic moments, optical spectrum etc.). Copyright © 2018, The Authors. All rights reserved.

关键词： Cluster analysis

On one-parametric formula relating the frequencies of twin-peak quasi-periodic oscillations

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arXiv 2017年

作者： Török, Gabriel Goluchová, Kateřina Šrámková, Eva Horák, Jiří Bakala, Pavel Urbanec, Martin Institute of Physics and Research Centre for Computational Physics and Data Processing Faculty of Philosophy & Science Silesian University in Opava Bezručovo nám. 13 OpavaCZ-746 01 Czech Republic Astronomical Institute Boční II 1401/2a Praha 4 - SpořilovCZ-14131 Czech Republic

Twin-peak quasi-periodic oscillations (QPOs) are observed in several low-mass X-ray binary systems containing neutron stars (NSs). Timing analysis of X-ray fluxes of more than dozen of such systems reveals remarkable correlations between the frequencies of two characteristic peaks present in the power density spectra. The individual correlations clearly differ, but they roughly follow a common individual pattern. High values of measured QPO frequencies and strong modulation of the X-ray flux both suggest that the observed correlations are connected to orbital motion in the innermost part of an accretion disc. Several attempts to model these correlations with simple geodesic orbital models or phenomenological relations have failed in the past. We find and explore a surprisingly simple analytic relation that reproduces individual correlations for a group of several sources through a single parameter. When an additional free parameter is considered within our relation, it well reproduces the data of a large group of 14 sources. The very existence and form of this simple relation supports the hypothesis of the orbital origin of QPOs and provides the key for further development of QPO models. We discuss a possible physical interpretation of our relation’s parameters and their links to concrete QPO models. Copyright © 2017, The Authors. All rights reserved.

关键词： Stars

Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN

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Physical Review Letters 2019年第22期123卷 221802-221802页

作者： M. Aker K. Altenmüller M. Arenz M. Babutzka J. Barrett S. Bauer M. Beck A. Beglarian J. Behrens T. Bergmann U. Besserer K. Blaum F. Block S. Bobien K. Bokeloh J. Bonn B. Bornschein L. Bornschein H. Bouquet T. Brunst T. S. Caldwell L. La Cascio S. Chilingaryan W. Choi T. J. Corona K. Debowski M. Deffert M. Descher P. J. Doe O. Dragoun G. Drexlin J. A. Dunmore S. Dyba F. Edzards L. Eisenblätter K. Eitel E. Ellinger R. Engel S. Enomoto M. Erhard D. Eversheim M. Fedkevych A. Felden S. Fischer B. Flatt J. A. Formaggio F. M. Fränkle G. B. Franklin H. Frankrone F. Friedel D. Fuchs A. Fulst D. Furse K. Gauda H. Gemmeke W. Gil F. Glück S. Görhardt S. Groh S. Grohmann R. Grössle R. Gumbsheimer M. Ha Minh M. Hackenjos V. Hannen F. Harms J. Hartmann N. Haußmann F. Heizmann K. Helbing S. Hickford D. Hilk B. Hillen D. Hillesheimer D. Hinz T. Höhn B. Holzapfel S. Holzmann T. Houdy M. A. Howe A. Huber T. M. James A. Jansen A. Kaboth C. Karl O. Kazachenko J. Kellerer N. Kernert L. Kippenbrock M. Kleesiek M. Klein C. Köhler L. Köllenberger A. Kopmann M. Korzeczek A. Kosmider A. Kovalík B. Krasch M. Kraus H. Krause L. Kuckert B. Kuffner N. Kunka T. Lasserre T. L. Le O. Lebeda M. Leber B. Lehnert J. Letnev F. Leven S. Lichter V. M. Lobashev A. Lokhov M. Machatschek E. Malcherek K. Müller M. Mark A. Marsteller E. L. Martin C. Melzer A. Menshikov S. Mertens L. I. Minter S. Mirz B. Monreal P. I. Morales Guzmán U. Naumann W. Ndeke H. Neumann S. Niemes M. Noe N. S. Oblath H.-W. Ortjohann A. Osipowicz B. Ostrick E. Otten D. S. Parno D. G. Phillips, II P. Plischke A. Pollithy A. W. P. Poon J. Pouryamout M. Prall F. Priester M. Röllig C. Röttele P. C.-O. Ranitzsch O. Rest R. Rinderspacher R. G. H. Robertson C. Rodenbeck P. Rohr Ch. Roll S. Rupp M. Ryšavý R. Sack A. Saenz P. Schäfer L. Schimpf K. Schlösser M. Schlösser L. Schlüter H. Schön K. Schönung M. Schrank B. Schulz J. Schwarz H. Seitz-Moskaliuk W. Seller V. Sibille D. Siegmann A. Skasyrskaya M. Slezák A. Špalek F. Spanier M. Steidl N. Steinbrink M. Sturm M. Suesser M. Sun D. Tcherniak Institute for Nuclear Physics (IKP) Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany Institute for Technical Physics (ITEP) Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany Max-Planck-Institut für Physik Föhringer Ring 6 80805 München Germany Technische Universität München James-Franck-Straße 1 85748 Garching Germany IRFU (DPhP & APC) CEA Université Paris-Saclay 91191 Gif-sur-Yvette France Helmholtz-Institut für Strahlen- und Kernphysik Rheinische Friedrich-Wilhelms-Universität Bonn Nussallee 14-16 53115 Bonn Germany Institute of Experimental Particle Physics (ETP) Karlsruhe Institute of Technology (KIT) Wolfgang-Gaede-Straße 1 76131 Karlsruhe Germany Laboratory for Nuclear Science Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge Massachusetts 02139 USA Institut für Kernphysik Westfälische Wilhelms-Universität Münster Wilhelm-Klemm-Straße 9 48149 Münster Germany Institut für Physik Johannes-Gutenberg-Universität Mainz 55099 Mainz Germany Institute for Data Processing and Electronics (IPE) Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany Max-Planck-Institut für Kernphysik Saupfercheckweg 1 69117 Heidelberg Germany Department of Physics and Astronomy University of North Carolina Chapel Hill North Carolina 27599 USA Triangle Universities Nuclear Laboratory Durham North Carolina 27708 USA Department of Physics Faculty of Mathematics and Natural Sciences University of Wuppertal Gaußstraße 20 42119 Wuppertal Germany Center for Experimental Nuclear Physics and Astrophysics and Department of Physics University of Washington Seattle Washington 98195 USA Nuclear Physics Institute of the CAS v. v. i. CZ-250 68 Řež Czech Republic Department of Physics Carnegie Mellon University Pittsburgh Pennsylvania 15213 USA Institute for Nuclear Research of Russian Acade

We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57 keV gives an effective neutrino mass square value of (−1.0−1.1+0.9) eV2. From this, we derive an upper limit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a factor of 2 and provides model-independent input to cosmological studies of structure formation.

关键词： Neutrinos

Common Limitations of Image processing Metrics: A Picture Story

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arXiv 2021年

作者： Reinke, Annika Tizabi, Minu D. Sudre, Carole H. Eisenmann, Matthias Rädsch, Tim Baumgartner, Michael Acion, Laura Antonelli, Michela Arbel, Tal Bakas, Spyridon Bankhead, Peter Benis, Arriel Blaschko, Matthew Buettner, Florian Cardoso, M. Jorge Chen, Jianxu Cheplygina, Veronika Christodoulou, Evangelia Cimini, Beth A. Collins, Gary S. Engelhardt, Sandy Farahani, Keyvan Ferrer, Luciana Galdran, Adrian van Ginneken, Bram Glocker, Ben Godau, Patrick Haase, Robert Hamprecht, Fred Hashimoto, Daniel A. Heckmann-Nötzel, Doreen Hirsch, Peter Hoffman, Michael M. Huisman, Merel Isensee, Fabian Jannin, Pierre Kahn, Charles E. Kainmueller, Dagmar Kainz, Bernhard Karargyris, Alexandros Karthikesalingam, Alan Kavur, A. Emre Kenngott, Hannes Kleesiek, Jens Kleppe, Andreas Koehler, Sven Kofler, Florian Kopp-Schneider, Annette Kooi, Thijs Kozubek, Michal Kreshuk, Anna Kurc, Tahsin Landman, Bennett A. Litjens, Geert Madani, Amin Maier-Hein, Klaus Martel, Anne L. Mattson, Peter Meijering, Erik Menze, Bjoern Moher, David Moons, Karel G.M. Müller, Henning Nichyporuk, Brennan Nickel, Felix Noyan, M. Alican Petersen, Jens Polat, Gorkem Rafelski, Susanne M. Rajpoot, Nasir Reyes, Mauricio Rieke, Nicola Riegler, Michael A. Rivaz, Hassan Saez-Rodriguez, Julio Sánchez, Clara I. Schroeter, Julien Saha, Anindo Selver, M. Alper Sharan, Lalith Shetty, Shravya Smeden, Maarten V.A.N. Stieltjes, Bram Summers, Ronald M. Taha, Abdel A. Tiulpin, Aleksei Tsaftaris, Sotirios A. Calster, Ben V.A.N. Varoquaux, Gaël Wiesenfarth, Manuel Yaniv, Ziv R. Jäger, Paul Maier-Hein, Lena Division of Intelligent Medical Systems and HI Helmholtz Imaging Heidelberg Germany Faculty of Mathematics and Computer Science Heidelberg University Heidelberg Germany Division of Intelligent Medical Systems Heidelberg Germany NCT Heidelberg DKFZ University Medical Center Heidelberg Germany MRC Unit for Lifelong Health and Ageing UCL Centre for Medical Image Computing Department of Computer Science University College London London United Kingdom School of Biomedical Engineering and Imaging Science King’s College London London United Kingdom Division of Medical Image Computing Heidelberg Germany Instituto de Cálculo CONICET – Universidad de Buenos Aires Buenos Aires Argentina Centre for Medical Image Computing University College London London United Kingdom McGill University Montréal Canada Division of Computational Pathology Dept of Pathology & Laboratory Medicine Indiana University School of Medicine IU Health Information and Translational Sciences Building Indianapolis United States University of Pennsylvania Richards Medical Research Laboratories FL7 PhiladelphiaPA United States Institute of Genetics and Cancer University of Edinburgh Edinburgh United Kingdom Department of Digital Medical Technologies Holon Institute of Technology Holon Israel European Federation for Medical Informatics Le Mont-sur-Lausanne Switzerland Center for Processing Speech and Images Department of Electrical Engineering KU Leuven Kasteelpark Arenberg 10 - box 2441 Leuven3001 Belgium Frankfurt/Mainz DKFZ UCT Frankfurt-Marburg Germany Heidelberg Germany Goethe University Frankfurt Department of Medicine Germany Goethe University Frankfurt Department of Informatics Germany Frankfurt Cancer Insititute Germany Leibniz-Institut für Analytische Wissenschaften – ISAS – e.V. Dortmund Germany Department of Computer Science IT University of Copenhagen Copenhagen Denmark Imaging Platform Broad Institute of MIT and Harvard CambridgeMA United States Centre for St

While the importance of automatic image analysis is continuously increasing, recent meta-research revealed major flaws with respect to algorithm validation. Performance metrics are particularly key for meaningful, objective, and transparent performance assessment and validation of the used automatic algorithms, but relatively little attention has been given to the practical pitfalls when using specific metrics for a given image analysis task. These are typically related to (1) the disregard of inherent metric properties, such as the behaviour in the presence of class imbalance or small target structures, (2) the disregard of inherent data set properties, such as the non-independence of the test cases, and (3) the disregard of the actual biomedical domain interest that the metrics should reflect. This living dynamically document has the purpose to illustrate important limitations of performance metrics commonly applied in the field of image analysis. In this context, it focuses on biomedical image analysis problems that can be phrased as image-level classification, semantic segmentation, instance segmentation, or object detection task. The current version is based on a Delphi process on metrics conducted by an international consortium of image analysis experts from more than 60 institutions worldwide. © 2021, CC BY.

关键词： Medical imaging

Deep learning for multi-messenger astrophysics a gateway for discovery in the big data era

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arXiv 2019年

作者： Allen, Gabrielle Andreoni, Igor Bachelet, Etienne Bruce Berriman, G. Bianco, Federica B. Biswas, Rahul Kind, Matias Carrasco Chard, Kyle Cho, Minsik Cowperthwaite, Philip S. Etienne, Zachariah B. George, Daniel Gibbs, Tom Graham, Matthew Gropp, William Gupta, Anushri Haas, Roland Huerta, E.A. Jennings, Elise Katz, Daniel S. Khan, Asad Kindratenko, Volodymyr Kramer, William T.C. Liu, Xin Mahabal, Ashish McHenry, Kenton Miller, J.M. Neubauer, M.S. Oberlin, Steve Olivas, Alexander R. Rosofsky, Shawn Ruiz, Milton Saxton, Aaron Schutz, Bernard Schwing, Alex Seidel, Ed Shapiro, Stuart L. Shen, Hongyu Shen, Yue Sipocz, Brigitta M. Sun, Lunan Towns, John Tsokaros, Antonios Wei, Wei Wells, Jack Williams, Timothy J. Xiong, Jinjun Zhao, Zhizhen NCSA University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Astronomy University of Illinois at Urbana-Champaign UrbanaIL61801 United States California Institute of Technology 1200 E California Blvd PasadenaCA91125 United States Las Cumbres Observatory 6740 Cortona Drive Suite 102 GoletaCA93117 United States Caltech/IPAC-NExScI 1200 E California Blvd PasadenaCA91125 United States Department of Physics and Astronomy University of Delaware NewarkDE19716 United States Joseph R. Biden Jr . School of Public Policy and Administration University of Delaware NewarkDE19716 United States Data Science Institute University of Delaware NewarkDE19716 United States Center for Urban Science and Progress New York University 370 Jay St BrooklynNY11201 United States The Oskar Klein Centre for Cosmoparticle Physics Stockholm University AlbaNova StockholmSE-106 91 Sweden University of Chicago ChicagoIL60605 United States IBM Systems AustinTX78717 United States Observatories of the Carnegie Institution for Science 813 Santa Barbara St. PasadenaCA91101 United States Department of Mathematics West Virginia University MorgantownWV26506 United States Center for Gravitational Waves and Cosmology West Virginia University Chestnut Ridge Research Building MorgantownWV26505 United States NVIDIA 2788 San Tomas Expressway Santa ClaraCA95050 United States Center for Data Driven Discovery Caltech PasadenaCA91125 United States Department of Computer Science University of Illinois at Urbana-Champaign UrbanaIL61801 United States Argonne National Laboratory Leadership Computing Facility LemontIL60439 United States Department of Electrical & Computer Engineering University of Illinois at Urbana-Champaign UrbanaIL61801 United States School of Information Sciences University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Physics University of Illinois at Urbana-Champaign UrbanaIL61801 Unit

This report provides an overview of recent work that harnesses the Big data Revolution and Large Scale Computing to address grand computational challenges in Multi-Messenger Astrophysics, with a particular emphasis on real-time discovery campaigns. Acknowledging the transdisciplinary nature of Multi-Messenger Astrophysics, this document has been prepared by members of the physics, astronomy, computer science, data science, software and cyberinfrastructure communities who attended the NSF-, DOE- and NVIDIA-funded "Deep Learning for Multi-Messenger Astrophysics: Real-time Discovery at Scale" workshop, hosted at the National center for Supercomputing Applications, October 17-19, 2018. Highlights of this report include unanimous agreement that it is critical to accelerate the development and deployment of novel, signal-processing algorithms that use the synergy between artificial intelligence (AI) and high performance computing to maximize the potential for scientific discovery with Multi-Messenger Astrophysics. We discuss key aspects to realize this endeavor, namely (i) the design and exploitation of scalable and computationally efficient AI algorithms for Multi-Messenger Astrophysics;(ii) cyberinfrastructure requirements to numerically simulate astrophysical sources, and to process and interpret Multi-Messenger Astrophysics data;(iii) management of gravitational wave detections and triggers to enable electromagnetic and astro-particle follow-ups;(iv) a vision to harness future developments of machine and deep learning and cyberinfrastructure resources to cope with the scale of discovery in the Big data Era;(v) and the need to build a community that brings domain experts together with data scientists on equal footing to maximize and accelerate discovery in the nascent field of Multi-Messenger Astrophysics. Copyright © 2019, The Authors. All rights reserved.

关键词： Big data

Star Cluster Catalogs for the LEGUS Dwarf Galaxies

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arXiv 2019年

作者： Cook, D.O. Lee, J.C. Adamo, A. Kim, H. Chandar, R. Whitmore, B.C. Mok, A. Ryon, J.E. Dale, D.A. Calzetti, D. Andrews, J.E. Aloisi, A. Ashworth, G. Bright, S.N. Brown, T.M. Christian, C. Cignoni, M. Clayton, G.C. da Silva, R. de Mink, S.E. Dobbs, C.L. Elmegreen, B.G. Elmegreen, D.M. Evans, A.S. Fumagalli, M. Gallagher, J.S. Gouliermis, D.A. Grasha, K. Grebel, E.K. Herrero, A. Hunter, D.A. Jensen, E.I. Johnson, K.E. Kahre, L. Kennicutt, R.C. Krumholz, M.R. Lee, N.J. Lennon, D. Linden, S. Martin, C. Messa, M. Nair, P. Nota, A. Östlin, G. Parziale, R.C. Pellerin, A. Regan, M.W. Sabbi, E. Sacchi, E. Schaerer, D. Schiminovich, D. Shabani, F. Slane, F.A. Small, J. Smith, C.L. Smith, L.J. Taibi, S. Thilker, D.A. de la Torre, I.C. Tosi, M. Turner, J.A. Ubeda, L. van Dyk, S.D. Walterbos, R.A.M. Wofford, A. Department of Physics & Astronomy California Institute of Technology PasadenaCA91101 United States Infrared Processing and Analysis Center California Institute of Technology PasadenaCA United States Dept. of Astronomy Oskar Klein Centre Stockholm University Stockholm Sweden Gemini Observatory Casilla 603 La Serena Chile Dept. of Physics and Astronomy University of Toledo ToledoOH United States Space Telescope Science Institute BaltimoreMD United States Dept. of Physics and Astronomy University of Wyoming LaramieWY United States Department of Astronomy University of Massachusetts AmherstMA01003 United States Steward Observatory University of Arizona 933 North Cherry Avenue TucsonAZ85721 United States Institute for Computational Cosmology and Centre for Extragalactic Astronomy University of Durham Durham United Kingdom Department of Physics University of Pisa Largo B. Pontecorvo 3 Pisa56127 Italy Dept. of Physics and Astronomy Louisiana State University Baton RougeLA United States Dept. of Astronomy & Astrophysics University of California – Santa Cruz Santa CruzCA United States Astronomical Institute Anton Pannekoek University of Amsterdam Amsterdam Netherlands School of Physics and Astronomy University of Exeter Exeter United Kingdom IBM Research Division T.J. Watson Research Center Yorktown Hts.NY United States Dept. of Physics and Astronomy Vassar College PoughkeepsieNY United States Dept. of Astronomy University of Virginia CharlottesvilleVA United States National Radio Astronomy Observatory CharlottesvilleVA United States Institute for Computational Cosmology and Centre for Extragalactic Astronomy Durham University Durham United Kingdom Dept. of Astronomy University of Wisconsin–Madison MadisonWI United States Zentrum für Astronomie der Universität Heidelberg Institut für Theoretische Astrophysik Albert-Ueberle-Str. 2 Heidelberg69120 Germany Max Planck Institute for Astronomy Königstuhl17 Heidelberg69117 Germany Astronom

We present the star cluster catalogs for 17 dwarf and irregular galaxies in the HST Treasury Program "Legacy ExtraGalactic UV Survey" (LEGUS). Cluster identification and photometry in this subsample are similar to that of the entire LEGUS sample, but special methods were developed to provide robust catalogs with accurate fluxes due to low cluster statistics. The colors and ages are largely consistent for two widely used aperture corrections, but a significant fraction of the clusters are more compact than the average training cluster. However, the ensemble luminosity, mass, and age distributions are consistent suggesting that the systematics between the two methods are less than the random errors. When compared with the clusters from previous dwarf galaxy samples, we find that the LEGUS catalogs are more complete and provide more accurate total fluxes. Combining all clusters into a composite dwarf galaxy, we find that the luminosity and mass functions can be described by a power law with the canonical index of −2 independent of age and global SFR binning. The age distribution declines as a power law, with an index of ≈ −0.80±0.15, independent of cluster mass and global SFR binning. This decline of clusters is dominated by cluster disruption since the combined star formation histories and integrated-light SFRs are both approximately constant over the last few hundred Myr. Finally, we find little evidence for an upper-mass cutoff (4.5M* but cannot rule out the existence of a truncation at higher masses. Copyright © 2019, The Authors. All rights reserved.

关键词： Galaxies

Comparison of Polarized Radiative Transfer Codes Used by the EHT Collaboration

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The Astrophysical Journal 2023年第1期950卷 35-35页

作者： Ben S. Prather Jason Dexter Monika Moscibrodzka Hung-Yi Pu Thomas Bronzwaer Jordy Davelaar Ziri Younsi Charles F. Gammie Roman Gold George N. Wong Kazunori Akiyama Antxon Alberdi Walter Alef Juan Carlos Algaba Richard Anantua Keiichi Asada Rebecca Azulay Uwe Bach Anne-Kathrin Baczko David Ball Mislav Baloković John Barrett Michi Bauböck Bradford A. Benson Dan Bintley Lindy Blackburn Raymond Blundell Katherine L. Bouman Geoffrey C. Bower Hope Boyce Michael Bremer Christiaan D. Brinkerink Roger Brissenden Silke Britzen Avery E. Broderick Dominique Broguiere Sandra Bustamante Do-Young Byun John E. Carlstrom Chiara Ceccobello Andrew Chael Chi-kwan Chan Dominic O. Chang Koushik Chatterjee Shami Chatterjee Ming-Tang Chen Yongjun Chen Xiaopeng Cheng Ilje Cho Pierre Christian Nicholas S. Conroy John E. Conway James M. Cordes Thomas M. Crawford Geoffrey B. Crew Alejandro Cruz-Osorio Yuzhu Cui Mariafelicia De Laurentis Roger Deane Jessica Dempsey Gregory Desvignes Vedant Dhruv Sheperd S. Doeleman Sean Dougal Sergio A. Dzib Ralph P. Eatough Razieh Emami Heino Falcke Joseph Farah Vincent L. Fish Ed Fomalont H. Alyson Ford Raquel Fraga-Encinas William T. Freeman Per Friberg Christian M. Fromm Antonio Fuentes Peter Galison Roberto García Olivier Gentaz Boris Georgiev Ciriaco Goddi Arturo I. Gómez-Ruiz José L. Gómez Minfeng Gu Mark Gurwell Kazuhiro Hada Daryl Haggard Kari Haworth Michael H. Hecht Ronald Hesper Dirk Heumann Luis C. Ho Paul Ho Mareki Honma Chih-Wei L. Huang Lei Huang David H. Hughes Shiro Ikeda C. M. Violette Impellizzeri Makoto Inoue Sara Issaoun David J. James Buell T. Jannuzi Michael Janssen Britton Jeter Wu Jiang Alejandra Jiménez-Rosales Michael D. Johnson Svetlana Jorstad Abhishek V. Joshi Taehyun Jung Mansour Karami Ramesh Karuppusamy Tomohisa Kawashima Garrett K. Keating Mark Kettenis Dong-Jin Kim Jae-Young Kim Jongsoo Kim Junhan Kim Motoki Kino Jun Yi Koay Prashant Kocherlakota Yutaro Kofuji Shoko Koyama Carsten Kramer Michael Kramer Thomas P. Krichbaum Cheng-Yu Kuo Noemi La Bella Tod R. Lauer Daeyoung L CCS-2 Los Alamos National Laboratory P.O. Box 1663 Los Alamos NM 87545 USA bprather@lanl.gov JILA and Department of Astrophysical and Planetary Sciences University of Colorado Boulder CO 80309 USA Department of Astrophysics/IMAPP Radboud University P.O. Box 9010 6500 GL Nijmegen The Netherlands Department of Physics National Taiwan Normal University No. 88 Sec.4 Tingzhou Road Taipei 116 Taiwan R.O.C. Center of Astronomy and Gravitation National Taiwan Normal University No. 88 Sec. 4 Tingzhou Road Taipei 116 Taiwan R.O.C. Institute of Astronomy and Astrophysics Academia Sinica 11F of Astronomy-Mathematics Building AS/NTU No. 1 Sec. 4 Roosevelt Road Taipei 10617 Taiwan R.O.C. Department of Astronomy and Columbia Astrophysics Laboratory Columbia University 550 W. 120th Street New York NY 10027 USA Center for Computational Astrophysics Flatiron Institute 162 Fifth Avenue New York NY 10010 USA Department of Astrophysics Institute for Mathematics Astrophysics and Particle Physics (IMAPP) Radboud University P.O. Box 9010 6500 GL Nijmegen The Netherlands Mullard Space Science Laboratory University College London Holmbury St. Mary Dorking Surrey RH5 6NT UK Institut für Theoretische Physik Goethe-Universität Frankfurt Max-von-Laue-Straße 1 D-60438 Frankfurt am Main Germany Department of Physics University of Illinois 1110 West Green Street Urbana IL 61801 USA Department of Astronomy University of Illinois at Urbana-Champaign 1002 West Green Street Urbana IL 61801 USA NCSA University of Illinois 1205 W. Clark Street Urbana IL 61801 USA CP3-Origins University of Southern Denmark Campusvej 55 DK-5230 Odense M Denmark School of Natural Sciences Institute for Advanced Study 1 Einstein Drive Princeton NJ 08540 USA Princeton Gravity Initiative Princeton University Princeton NJ 08544 USA Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road Westford MA 01886 USA National Astronomical Observatory of Japan 2-21-1 Osaw

Interpretation of resolved polarized images of black holes by the Event Horizon Telescope (EHT) requires predictions of the polarized emission observable by an Earth-based instrument for a particular model of the black hole accretion system. Such predictions are generated by general relativistic radiative transfer (GRRT) codes, which integrate the equations of polarized radiative transfer in curved spacetime. A selection of ray-tracing GRRT codes used within the EHT Collaboration is evaluated for accuracy and consistency in producing a selection of test images, demonstrating that the various methods and implementations of radiative transfer calculations are highly consistent. When imaging an analytic accretion model, we find that all codes produce images similar within a pixel-wise normalized mean squared error (NMSE) of 0.012 in the worst case. When imaging a snapshot from a cell-based magnetohydrodynamic simulation, we find all test images to be similar within NMSEs of 0.02, 0.04, 0.04, and 0.12 in Stokes I, Q, U, and V, respectively. We additionally find the values of several image metrics relevant to published EHT results to be in agreement to much better precision than measurement uncertainties.

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Charge transfer of He^(2+)with H in a strong magnetic field

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Chinese physics B 2015年第9期24卷 192-197页

作者：刘春雷邹士阳何斌王建国 Data Center for High Energy Density Physics Research Institute of Applied Physics and Computational Mathematics

By solving a time-dependent Schrodinger equation（TDSE）, we studied the electron capture process in the He^2＋＋ H collision system under a strong magnetic field in a wide projectile energy range. The strong enhancement of the total charge transfer cross section is observed for the projectile energy below 2.0 ke V/u. With the projectile energy increasing, the cross sections will reduce a little and then increase again, compared with those in the field-free case. The cross sections to the states with different magnetic quantum numbers are presented and analyzed where the influence due to Zeeman splitting is obviously found, especially in the low projectile energy region. The comparison with other models is made and the tendency of the cross section varying with the projectile energy is found closer to that from other close coupling models.

关键词： time-dependent Schrdinger equation strong magnetic field charge transfer