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arXiv 2024年

作者： Abe, K. Abe, S. Abhishek, A. Acero, F. Aguasca-Cabot, A. Agudo, I. Alispach, C. Alvarez Crespo, N. Ambrosino, D. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Arcaro, C. Asano, K. Aubert, P. Baktash, A. Balbo, M. Bamba, A. Baquero Larriva, A. Barres de Almeida, U. Barrio, J.A. Barrios Jiménez, L. Batkovic, I. Baxter, J. Becerra González, J. Bernardini, E. Bernete Medrano, J. Berti, A. Bezshyiko, I. Bhattacharjee, P. Bigongiari, C. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Borkowski, G. Brunelli, G. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Cardillo, M. Caroff, S. Carosi, A. Carrasco, M.S. Cassol, F. Castrejón, N. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chon, G. Chytka, L. Cicciari, G.M. Cifuentes, A. Contreras, J.L. Cortina, J. Costantini, H. Da Vela, P. Dalchenko, M. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. de Menezes, R. Del Burgo, R. Del Peral, L. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Di Piano, A. Di Pierro, F. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Ferrarotto, F. Fiasson, A. Foffano, L. Freixas Coromina, L. Fröse, S. Fukazawa, Y. Garcia López, R. Gasbarra, C. Gasparrini, D. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Gliwny, P. Godinovic, N. Grau, R. Green, D. Green, J. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Hassan, T. Hayashi, K. Heckmann, L. Heller, M. Herrera Llorente, J. Hirotani, K. Hoffmann, D. Horns, D. Houles, J. Hrabovsky, M. Hrupec, D. Hui, D. Iarlori, M. Imazawa, R. Inada, T. Inome, Y. Inoue, S. Ioka, K. Iori, M. Iuliano, A. Jimenez Martinez, I. Jimenez Quiles, J. Jurysek, J. Kagaya, M. Kalashev, O. Karas, V. Katagiri, H. Kataoka, J. Kerszberg, D. Kobayashi, Y. Kohri, K. Kong, A. Kubo, H. Kushida, J. Lainez, M. Lamanna, G. Lamastra, A. Lemoigne, L. Linhoff, M. Department of Physics Tokai University 4-1-1 Kita-Kaname Kanagawa Hiratsuka259-1292 Japan Institute for Cosmic Ray Research University of Tokyo 5-1-5 Kashiwa-no-ha Chiba Kashiwa277-8582 Japan Sezione di Fisica Via Roma 56 Siena53100 Italy Université Paris-Saclay Université Paris Cité CEA CNRS AIM Gif-sur-YvetteF-91191 Cedex France FSLAC IRL 2009 CNRS/IAC Tenerife La Laguna Spain Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Martí i Franquès 1 Barcelona08028 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain Department of Astronomy University of Geneva Chemin d’Ecogia 16 VersoixCH-1290 Switzerland IPARCOS-UCM Instituto de Física de Partículas y del Cosmos EMFTEL Department Universidad Complutense de Madrid Plaza de Ciencias 1. Ciudad Universitaria Madrid28040 Spain INFN Sezione di Napoli Via Cintia ed. G Napoli80126 Italy INAF Osservatorio Astronomico di Roma Via di Frascati 33 Monteporzio Catone00040 Italy Max-Planck-Institut für Physik Föhringer Ring 6 München80805 Germany INFN Sezione di Padova Università degli Studi di Padova Via Marzolo 8 Padova35131 Italy Univ. Savoie Mont Blanc CNRS Laboratoire d’Annecy de Physique des Particules IN2P3 Annecy74000 France Universität Hamburg Institut für Experimentalphysik Luruper Chaussee 149 Hamburg22761 Germany Graduate School of Science University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan Faculty of Science and Technology Universidad del Azuay Cuenca Ecuador Centro Brasileiro de Pesquisas Físicas Rua Xavier Sigaud 150 RJ Rio de Janeiro22290-180 Brazil Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna C. Vía Láctea s/n Santa Cruz de Tenerife La Laguna38205 Spain CIEMAT Avda. Complutense 40 Madrid28040 Spain University of Geneva Département de Physique Nucléaire et Corpusculaire 24 Quai Ernest Ansernet

Context. Imaging atmospheric Cherenkov telescopes (IACTs) are used to observe very high-energy photons from the ground. Gamma rays are indirectly detected through the Cherenkov light emitted by the air showers they induce. The new generation of experiments, in particular the Cherenkov Telescope Array Observatory (CTAO), sets ambitious goals for discoveries of new gamma-ray sources and precise measurements of the already discovered ones. To achieve these goals, both hardware and data analysis must employ cutting-edge techniques. This also applies to the LST-1, the first IACT built for the CTAO, which is currently taking data on the Canary island of La Palma. Aims. This paper introduces a new event reconstruction technique for IACT data, aiming to improve the image reconstruction quality and the discrimination between the signal and the background from misidentified hadrons and electrons. Methods. The technique models the development of the extensive air shower signal, recorded as a waveform per pixel, seen by CTAO telescopes’ cameras. Model parameters are subsequently passed to random forest regressors and classifiers to extract information on the primary particle. Results. The new reconstruction was applied to simulated data and to data from observations of the Crab Nebula performed by the LST-1. The event reconstruction method presented here shows promising performance improvements. The angular and energy resolution, and the sensitivity, are improved by 10 to 20% over most of the energy range. At low energy, improvements reach up to 22%, 47%, and 50%, respectively. A future extension of the method to stereoscopic analysis for telescope arrays will be the next important step. Copyright © 2024, The Authors. All rights reserved.

关键词： Stereo image processing

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Characterization of TOF-PET detectors for a second generation radiofrequency-penetrable PET insert for simultaneous PET/MRI

Characterization of TOF-PET detectors for a second generatio...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Qian Dong Brian J. Lee Chen-Ming Chang Ilaria Sacco Ronald D. Watkins Peter Fischer Emily Anaya Craig S. Levin Departments of Electrical Engineering and Radiology Stanford University Stanford CA USA Departments of Mechanical Engineering and Radiology Stanford University Stanford CA USA Departments of Applied Physics and Radiology Stanford University Stanford CA USA Department of Radiology Stanford University Stanford CA USA Department of Computer Science Heidelberg University Mannheim Germany Departments of Radiology Electrical Engineering Bioengineering and Physics Stanford University and Molecular Imaging Program at Stanford (MIPS) Stanford CA USA

ISBN: (数字)9781728141640

ISBN: (纸本)9781728141657

Simultaneous PET/MRI combines two powerful and complementary modalities, providing multiparametric information to assess the anatomic as well as biochemical basis of disease. However, the high cost of the current commercial integrated PET/MRI systems limit the long-term potential, accessibility, and availability of PET/MRI. A portable PET insert provides a cost- effective alternative to achieve simultaneous PET/MRI for the sites that are already equipped with MR systems. Therefore, we are developing a radiofrequency (RF)-penetrable MR-compatible time-of-flight (TOF)-PET insert that can acquire simultaneous PET/MR data using the MR systems built-in body coil for RF transmission. In this study, we characterized performance of two detector modules in the MR bore under four different MRI conditions: B 0 only, echo planar imaging (EPI), gradient echo (GRE), and fast spin echo (FSE), each running for 15 minutes. The one-hour study results for coincidence timing resolution, energy resolution, coincidence count rate and ASIC chip temperature of two detector modules demonstrate the PET performance stability as well as the MR compatibility of the PET detectors under different MRI sequences. The global coincidence timing and energy resolution achieved was 264.21 ± 4.82 ps FWHM and 13.66 ± 0.08 % FWHM, respectively.

关键词： Detectors Clocks Energy resolution Magnetic resonance imaging Timing Positron emission tomography Radio frequency

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Hard convex lens-shaped particles: Characterization of dense disordered packings

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Physical Review E 2019年第6期100卷 062902-062902页

作者： Giorgio Cinacchi Salvatore Torquato Departamento de Física Teórica de la Materia Condensada Instituto de Física de la Materia Condensada (IFIMAC) Instituto de Ciencias de Materiales “Nicolás Cabrera” Universidad Autónoma de Madrid Ciudad Universitaria de Cantoblanco E-28049 Madrid Spain Department of Chemistry and Department of Physics Institute for the Science and Technology of Materials Program for Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Among the family of hard convex lens-shaped particles (lenses), the one with aspect ratio equal to 2/3 is “optimal” in the sense that the maximally random jammed (MRJ) packings of such lenses achieve the highest packing fraction ϕMRJ≃0.73 [G. Cinacchi and S. Torquato, Soft Matter 14, 8205 (2018)]. This value is only a few percent lower than ϕDKP=0.76210⋯, the packing fraction of the corresponding densest-known crystalline (degenerate) packings [G. Cinacchi and S. Torquato, J. Chem. Phys. 143, 224506 (2015)]. By exploiting the appreciably reduced propensity that a system of such optimal lenses has to positionally and orientationally order, disordered packings of them are progressively generated by a Monte Carlo method–based procedure from the dilute equilibrium isotropic fluid phase to the dense nonequilibrium MRJ state. This allows us to closely monitor how the (micro)structure of these packings changes in the process of formation of the MRJ state. The gradual changes undergone by the many structural descriptors calculated here can coherently and consistently be traced back to the gradual increase in contacts between the hard particles until the isostatic mean value of ten contact neighbors per lens is reached at the effectively hyperuniform MRJ state. Compared to the MRJ state of hard spheres, the MRJ state of such optimal lenses is denser (less porous), more disordered, and rattler-free. This set of characteristics makes them good glass formers. It is possible that this conclusion may also hold for other hard convex uniaxial particles with a correspondingly similar aspect ratio, be they oblate or prolate, and that, by using suitable biaxial variants of them, that set of characteristics might further improve.

关键词： Granular packing Jamming Colloids Disordered systems Granular materials Lyotropic liquid crystals Monte Carlo methods

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Measurement of inclusive jet cross section and substructure in p+p collisions at s=200 GeV

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Physical Review D 2025年第11期111卷 112008-112008页

作者： N. J. Abdulameer U. Acharya C. Aidala N. N. Ajitanand Y. Akiba R. Akimoto J. Alexander M. Alfred V. Andrieux S. Antsupov K. Aoki N. Apadula H. Asano E. T. Atomssa T. C. Awes B. Azmoun V. Babintsev M. Bai X. Bai N. S. Bandara B. Bannier E. Bannikov K. N. Barish S. Bathe V. Baublis C. Baumann S. Baumgart A. Bazilevsky M. Beaumier R. Belmont A. Berdnikov Y. Berdnikov L. Bichon D. Black B. Blankenship D. S. Blau J. S. Bok V. Borisov K. Boyle M. L. Brooks J. Bryslawskyj H. Buesching V. Bumazhnov S. Butsyk S. Campbell R. Cervantes C.-H. Chen D. Chen M. Chiu C. Y. Chi I. J. Choi J. B. Choi S. Choi P. Christiansen T. Chujo V. Cianciolo Z. Citron B. A. Cole M. Connors R. Corliss N. Cronin N. Crossette M. Csanád T. Csörgő L. D’Orazio T. W. Danley A. Datta M. S. Daugherity G. David K. DeBlasio K. Dehmelt A. Denisov A. Deshpande E. J. Desmond L. Ding A. Dion D. Dixit V. Doomra J. H. Do O. Drapier A. Drees K. A. Drees J. M. Durham A. Durum H. En’yo T. Engelmore A. Enokizono R. Esha K. O. Eyser B. Fadem W. Fan N. Feege D. E. Fields M. Finger, Jr. M. Finger D. Firak D. Fitzgerald F. Fleuret S. L. Fokin J. E. Frantz A. Franz A. D. Frawley Y. Fukao Y. Fukuda T. Fusayasu K. Gainey P. Gallus C. Gal P. Garg A. Garishvili I. Garishvili H. Ge F. Giordano A. Glenn X. Gong M. Gonin Y. Goto R. Granier de Cassagnac N. Grau S. V. Greene M. Grosse Perdekamp T. Gunji T. Guo H. Guragain Y. Gu T. Hachiya J. S. Haggerty K. I. Hahn H. Hamagaki H. F. Hamilton J. Hanks S. Y. Han S. Hasegawa T. O. S. Haseler K. Hashimoto R. Hayano T. K. Hemmick T. Hester X. He J. C. Hill K. Hill A. Hodges R. S. Hollis K. Homma B. Hong T. Hoshino N. Hotvedt J. Huang T. Ichihara Y. Ikeda K. Imai Y. Imazu M. Inaba A. Iordanova D. Isenhower A. Isinhue D. Ivanishchev S. J. Jeon M. Jezghani X. Jiang Z. Ji B. M. Johnson K. S. Joo D. Jouan D. S. Jumper J. Kamin S. Kanda B. H. Kang J. H. Kang J. S. Kang D. Kapukchyan J. Kapustinsky S. Karthas D. Kawall A. V. Kazantsev J. A. Key V. Khachatryan P. K. Khandai A. Khanzadeev K. M. Kijima C. Kim D. J. Kim E.-J. Kim M. Kim Y.-J. K Debrecen University H-4010 Debrecen Egyetem tér 1 Hungary HUN-REN ATOMKI H-4026 Debrecen Bem tér 18/c Hungary Georgia State University Atlanta Georgia 30303 USA Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Department of Physics University of Michigan Ann Arbor Michigan 48109-1040 USA Chemistry Department Stony Brook University SUNY Stony Brook New York 11794-3400 USA Deceased. RIKEN Nishina Center for Accelerator-Based Science Wako Saitama 351-0198 Japan RIKEN BNL Research Center Brookhaven National Laboratory Upton New York 11973-5000 USA Center for Nuclear Study Graduate School of Science University of Tokyo 7-3-1 Hongo Bunkyo Tokyo 113-0033 Japan Department of Physics and Astronomy Howard University Washington DC 20059 USA Saint Petersburg State Polytechnic University St. Petersburg 195251 Russia KEK High Energy Accelerator Research Organization Tsukuba Ibaraki 305-0801 Japan Iowa State University Ames Iowa 50011 USA Department of Physics and Astronomy Stony Brook University SUNY Stony Brook New York 11794-3800 USA Kyoto University Kyoto 606-8502 Japan Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Physics Department Brookhaven National Laboratory Upton New York 11973-5000 USA IHEP Protvino State Research Center of Russian Federation Institute for High Energy Physics Protvino 142281 Russia Collider-Accelerator Department Brookhaven National Laboratory Upton New York 11973-5000 USA Science and Technology on Nuclear Data Laboratory China Institute of Atomic Energy Beijing 102413 People’s Republic of China Department of Physics University of Massachusetts Amherst Massachusetts 01003-9337 USA University of California-Riverside Riverside California 92521 USA Baruch College City University of New York New York New York 10010 USA PNPI Petersburg Nuclear Physics Institute Gatchina Leningrad region 188300 Russia University of Colorado Boulder Colorado 80309 USA Physics and Astronomy Department Uni

The jet cross section and jet-substructure observables in p+p collisions at s=200 GeV were measured by the PHENIX Collaboration at the Relativistic Heavy Ion Collider (RHIC). Jets are reconstructed from charged-particle tracks and electromagnetic-calorimeter clusters using the anti-kt algorithm with a jet radius of R=0.3 for jets with transverse momentum within 8.0

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A detailed study of the very-high-energy Crab pulsar emission with the LST-1

arXiv

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arXiv 2024年

作者： Abe, K. Abe, S. Abhishek, A. Acero, F. Aguasca-Cabot, A. Agudo, I. Alvarez Crespo, N. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Arcaro, C. Artero, M. Asano, K. Aubert, P. Baktash, A. Bamba, A. Baquero Larriva, A. Baroncelli, L. Barres de Almeida, U. Barrio, J.A. Batkovic, I. Baxter, J. Becerra González, J. Bernardini, E. Bernete Medrano, J. Berti, A. Bhattacharjee, P. Bigongiari, C. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Brunelli, G. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Cardillo, M. Caroff, S. Carosi, A. Carrasco, M.S. Cassol, F. Castrejón, N. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chon, G. Chytka, L. Cicciari, G.M. Cifuentes, A. Contreras, J.L. Cortina, J. Costantini, H. Da Vela, P. Dalchenko, M. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. de Menezes, R. Del Peral, L. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Di Piano, A. Di Pierro, F. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Ferrarotto, F. Fiasson, A. Foffano, L. Freixas Coromina, L. Fröse, S. Fukazawa, Y. Garcia López, R. Gasbarra, C. Gasparrini, D. Gavira, L. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Gliwny, P. Godinovic, N. Grau, R. Green, D. Green, J. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Hassan, T. Hayashi, K. Heckmann, L. Heller, M. Herrera Llorente, J. Hirotani, K. Hoffmann, D. Horns, D. Houles, J. Hrabovsky, M. Hrupec, D. Hui, D. Iarlori, M. Imazawa, R. Inada, T. Inome, Y. Ioka, K. Iori, M. Jimenez Martinez, I. Jiménez Quiles, J. Jurysek, J. Kagaya, M. Karas, V. Katagiri, H. Kataoka, J. Kerszberg, D. Kobayashi, Y. Kohri, K. Kong, A. Kubo, H. Kushida, J. Lainez, M. Lamanna, G. Lamastra, A. Lemoigne, L. Linhoff, M. Longo, F. López-Coto, R. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. Lozano Bahilo, J. Luque-Escamilla, P.L. Department of Physics Tokai University 4-1-1 Kita-Kaname Hi-ratsuka Kanagawa259-1292 Japan Institute for Cosmic Ray Research University of Tokyo 5-1-5 Kashiwa-no-ha Chiba Kashiwa277-8582 Japan Sezione di Fisica Via Roma 56 Siena53100 Italy Université Paris-Saclay Université Paris Cité CEA CNRS AIM Gif-sur-YvetteF-91191 Cedex France FSLAC IRL 2009 CNRS IAC Tenerife La Laguna Spain Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Martí i Franquès 1 Barcelona08028 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la As-tronomía s/n Granada18008 Spain IPARCOS-UCM Instituto de Física de Partículas y del Cosmos EMFTEL Department Universidad Complutense de Madrid Ciudad Universitaria Plaza de Ciencias 1 Madrid28040 Spain INAF - Osservatorio Astronomico di Roma Via di Frascati 33 Monteporzio Catone00040 Italy INFN Sezione di Napoli Via Cintia ed. G Napoli80126 Italy Max-Planck-Institut für Physik Föhringer Ring 6 München80805 Germany INFN Sezione di Padova Università degli Studi di Padova Via Marzolo 8 Padova35131 Italy The Barcelona Institute of Science and Technology Campus UAB Bellaterra Barcelona08193 Spain Univ. Savoie Mont Blanc CNRS Laboratoire d'Annecy de Physique des Particules - IN2P3 Annecy74000 France Universität Hamburg Institut für Experimentalphysik Luruper Chaussee 149 Hamburg22761 Germany Graduate School of Science University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan Faculty of Science and Technology Universidad del Azuay Cuenca Ecuador INAF - Osservatorio di Astrofisica e Scienza dello spazio di Bologna Via Piero Gobetti 93/3 Bologna40129 Italy Centro Brasileiro de Pesquisas Físicas Rua Xavier Sigaud 150 RJ Rio de Janeiro22290-180 Brazil Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna C. Vía Láctea s/n Santa Cruz de Tenerife La Laguna38205 Spain CIEMAT Avda. Complutense

Context. There are currently three pulsars firmly detected by imaging atmospheric Cherenkov telescopes (IACTs), two of them reaching the TeV energy range, challenging models of very-high-energy (VHE) emission in pulsars. More precise observations are needed to better characterize pulsar emission at these energies. The LST-1 is the prototype of the Large-Sized Telescope, that will be part of the Cherenkov Telescope Array Observatory (CTAO). Its improved performance over previous IACTs makes it well suited for studying pulsars. Aims. In this work we aim to study the Crab pulsar emission with the LST-1, improving and complementing the results from other telescopes. Crab pulsar observations can also be used to characterize the potential of the LST-1 to study other pulsars and detect new ones. Methods. We analyzed a total of ∼103 hours of gamma-ray observations of the Crab pulsar conducted with the LST-1 in the period from September 2020 to January 2023. The observations were carried out at zenith angles less than 50 degrees. To characterize the Crab pulsar emission over a broader energy range, a new analysis of the Fermi-LAT data was also performed, including ∼14 years of observations. Results. The Crab pulsar phaseogram, long-term light-curve, and phase-resolved spectra is reconstructed with the LST-1 from 20 GeV to 450 GeV for P1 and up to 700 GeV for P2. The pulsed emission is detected with a significance level of 15.2σ. The two characteristic emission peaks of the Crab pulsar are clearly detected (>10σ), as well as the so-called bridge emission between them (5.7σ). We find that both peaks are well described by power laws, with spectral indices of ∼3.44 and ∼3.03 respectively. The joint analysis of Fermi-LAT and LST-1 data shows a good agreement between both instruments in the overlapping energy range. The detailed results obtained in the first observations of the Crab pulsar with LST-1 show the potential that CTAO will have to study this type of sources. © 2024, CC

关键词： Gamma rays

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First Sagittarius A∗ Event Horizon Telescope Results. IV. Variability, morphology, and black hole mass

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 Alyson Ford, H. 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 Violette Impellizzeri, C.M. 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 HiloHI96

In this paper we quantify the temporal variability and image morphology of the horizon-scale emission from Sgr A∗, as observed by the EHT in 2017 April at a wavelength of 1.3 mm. We find that the Sgr A∗ data exhibit variability that exceeds what can be explained by the uncertainties in the data or by the effects of interstellar scattering. The magnitude of this variability can be a substantial fraction of the correlated flux density, reaching ∼100% on some baselines. Through an exploration of simple geometric source models, we demonstrate that ring-like morphologies provide better fits to the Sgr A∗ data than do other morphologies with comparable complexity. We develop two strategies for fitting static geometric ring models to the time-variable Sgr A∗ data;one strategy fits models to short segments of data over which the source is static and averages these independent fits, while the other fits models to the full dataset using a parametric model for the structural variability power spectrum around the average source structure. Both geometric modeling and image-domain feature extraction techniques determine the ring diameter to be 51.8 ± 2.3 µas (68% credible intervals), with the ring thickness constrained to have an FWHM between ∼30% and 50% of the ring diameter. To bring the diameter measurements to a common physical scale, we calibrate them using synthetic data generated from GRMHD simulations. This calibration constrains the angular size of the gravitational radius to be 4.8+1−047 µas, which we combine with an independent distance measurement from maser parallaxes to determine the mass of Sgr A∗ to be 4.0+1−016 × 106 M. © 2023, CC BY.

关键词： Morphology

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Local Structure Analysis of Lead Zinc Niobate-Barium Titanate Ceramic by X-Ray Absorption Spectroscopy and Density Functional Calculation

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Chinese physics Letters 2017年第8期34卷 113-116页

作者： Kanokwan Kanchiang Phakkhananan Pakawanit Rattikorn Yimnirun Program in Applied Physics Faculty of Science Maejo University Chiang Mai 50290 Thailand Synchrotron Light Research Institute Ratchasima 30000 Thailand School of Physics Institute of Science and NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials Suranaree University of Technology Nakhon Ratchasima 30000 Thailand

The local structure of an alternative Pb（Zn1/3Nb2/3）O3-based perovskite ceramic is investigated. The 0.07BaTiO33-0.93Pb（Zn1/3Nb2/3）O3 ceramic is synthesized using a combination of Zn3Nb2O8 B-site precursor and BaTiO33 perovskite phase stabilizer. Then, x-ray absorption spectroscopy and density functional theory are employed to calculate the local structure configuration and formation energy of the prepared samples. Ba2＋ is found to replace Pb2＋ in AA-site with Zn2＋ occupying BB-site in Pb（Zn1/3Nb2/3）O3, while in the neighboring structure, Ti4＋4＋ replaces Nb5＋5＋ in BB-site with Pb2＋2＋ occupying AA-site. With the substitution of BaTiO33 in Pb（Zn1/3Nb2/3）O3, the bond length between Zn2＋ and Pb2＋ is longer than that of the typical perovskite phase of Pb（Zn1/3Nb2/3）O3. This indicates the key role of BaTiO33 in decreasing the steric hindrance of Pb2＋ lone pair, and the mutual interactions between Pb2＋ lone pair and Zn2＋ and the formation energy is seen to decrease. This finding of the formation energy and local structure configuration relationship can further extend a fundamental understanding of the role of BaTiO33 in stabilizing the perovskite phase in PbZn13Nb23O3-based materials, which in turn will lead to an improved preparation technique for desired electrical properties.

关键词： Pb Local Structure Analysis of Lead Zinc Niobate-Barium Titanate Ceramic by X-Ray Absorption Spectroscopy and Density Functional Calculation EXAFS Ba XANES Zn

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First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole

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. K 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 HiloHI96

In this paper, we provide a first physical interpretation for the Event Horizon Telescope (EHT)’s 2017 observations of Sgr A∗. Our main approach is to compare resolved EHT data at 230 GHz and unresolved non-EHT observations from radio to X-ray wavelengths to predictions from a library of models based on time-dependent general relativistic magnetohydrodynamics (GRMHD) simulations, including aligned, tilted, and stellar wind-fed simulations;radiative transfer is performed assuming both thermal and non-thermal electron distribution functions. We test the models against 11 constraints drawn from EHT 230 GHz data and observations at 86 GHz, 2.2 µm, and in the X-ray. All models fail at least one constraint. Light curve variability provides a particularly severe constraint, failing nearly all strongly magnetized (MAD) models and a large fraction of weakly magnetized (SANE) models. A number of models fail only the variability constraints. We identify a promising cluster of these models, which are MAD and have inclination i ≤ 30°. They have accretion rate (5.2–9.5) × 10−9M☉ yr−1, bolometric luminosity (6.8–9.2) × 1035 erg s−1, and outflow power (1.3–4.8) × 1038 erg s−1. We also find that: all models with i ≥ 70° fail at least two constraints, as do all models with equal ion and electron temperature;exploratory, non-thermal model sets tend to have higher 2.2 µm flux density;the population of cold electrons is limited by X-ray constraints due to the risk of bremsstrahlung overproduction. Finally we discuss physical and numerical limitations of the models, highlighting the possible importance of kinetic effects and duration of the simulations. © 2023, CC BY.

关键词： Galaxies

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The Hyper-Kamiokande experiment - snowmass LOI

arXiv

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arXiv 2020年

作者： Abe, K. Adrich, P. Aihara, H. Akutsu, R. Alekseev, I. Ali, A. Ameli, F. Anthony, L.H.V. Araya, A. Asaoka, Y. Aushev, V. Bandac, I. Barbi, M. Barr, G. Batkiewicz-Kwasniak, M. Bellato, M. Berardi, V. Bernard, L. Bernardini, E. Berns, L. Bhadra, S. Bian, J. Blanchet, A. Blondel, A. Boiano, A. Bolognesi, S. Bonavera, L. Borjabad, S. Boschi, T. Bose, D. Boyd, S.B. Bozza, C. Bravar, A. Bronner, C. Bubak, A. Buchowicz, A. Avanzini, M. Buizza Cafagna, F.S. Calabria, N.F. Calvo-Mozota, J.M. Cao, S. Catanesi, M.G. Chakraborty, S. Choi, J.H. Choubey, S. Cicerchia, M. Coleman, J. Collazuol, G. Cuen-Rochin, S. Danilov, M. Fuente, E. De la de Perio, P. de Rosa, G. Dealtry, T. Densham, C.J. Dergacheva, A. Deshmukh, N. Devi, M.M. Di Lodovico, F. Di Meo, P. Di Palma, I. Doyle, T.A. Drakopoulou, E. Drapier, O. Dumarchez, J. Eklund, L. El Hedri, S. Ellis, J. Emery, S. Esmaili, A. Fedotov, S. Feng, J. Fernández-Martinez, E. Ferrario, P. Ferrazzi, B. Finch, A. Finley, C. Fiorillo, G. Fitton, M. Friend, M. Fujii, Y. Fukuda, Y. Galinski, G. Gao, J. Garde, C. Garfagnini, A. Garode, S. Gialanella, L. Giganti, C. Gomez-Cadenas, J.J. Gonin, M. González-Nuevo, J. Gorin, A. Gornea, R. Gramegna, F. Grassi, M. Grella, G. Guigue, M. Hadley, D.R. Harada, M. Hartz, M. Hassani, S. Hastings, N.C. Hayato, Y. Hiraide, K. Hoshina, K. Hultqvist, K. Iacob, F. Ichikawa, A.K. Ibnsalih, W. Idrissi Ikeda, M. Inomoto, M. Ioannisian, A. Ishida, T. Ishidoshiro, K. Ishino, H. Ishitsuka, M. Ito, H. Ito, S. Itow, Y. Iwamoto, K. Izumi, N. Izumiyama, S. Jakkapu, M. Jamieson, B. Jang, J.S. Jo, H.S. Jonsson, P. Joo, K.K. Kajita, T. Kakuno, H. Kameda, J. Kano, Y. Karlen, D. Kataoka, Y. Kato, A. Katori, T. Kazarian, N. Khabibullin, M. Khotjantsev, A. Kikawa, T. Kim, J.Y. Kim, S.B. King, S. Kinoshita, T. Kisiel, J. Klekotko, A. Kobayashi, T. Koerich, L. Kolev, N. Konaka, A. Kormos, L.L. Koshio, Y. Kotsar, Y. Kouzakov, K.A. Kowalik, K.L. AGH University of Science and Technology Faculty of Computer Science Electronics and Telecommunications Krakow Poland British Columbia Institute of Technology Physics Department BurnabyBC Canada Università della Campania"L. Vanvitelli" INFN Sezione di Napoli Napoli Italy Carleton University Department of Physics OttawaON Canada University of California Irvine Department of Physics and Astronomy IrvineCA United States Charles University IPNP FMF Prague Czech Republic Chonnam National University Department of Physics Gwangju Korea Republic of Dongshin University Laboratory for High Energy Physics Naju Korea Republic of Donostia International Physics Center Ikerbasque Foundation Basque Country Spain Ecole Polytechnique IN2P3-CNRS Laboratoire Leprince-Ringuet Palaiseau France University of Edinburgh School of Physics and Astronomy Edinburgh United Kingdom ETH Zurich Institute for Particle and Astroparticle Physics Zurich Switzerland University of Geneva Section de Physique DPNC Geneva Switzerland GIST College Gwangju Institute of Science and Technology Gwangju Korea Republic of University of Glasgow School of Physics and Astronomy Glasgow United Kingdom Universidad de Guadalajara CUCEA IT.Ph.D. program GuadalajaraJal Mexico Universidad de Guadalajara CUCEI Departamento de Fisica GuadalajaraJal Mexico H. Niewodniczá nski Institute of Nuclear Physics PAN Cracow Poland Imperial College London Department of Physics London United Kingdom Indian Institute of Technology Guwahati Guwahati India Indian Institute of Technology Jodhpur Department of Physics Karwar Rajasthan India Indian Institute of Technology Kharagpur Department of Physics Kharagpur India INFN Gruppo Collegato di Salerno Fisciano Italy INFN Laboratori Nazionali di Legnaro LegnaroPD Italy INFN Sezione di Bari Università e Politecnico di Bari Bari Italy INFN Sezione di Napoli Università Federico II di Napoli Dipartimento di Fisica Napoli Italy INFN Sezione di Napoli Nap

Hyper-Kamiokande is the next generation underground water Cherenkov detector that builds on the highly successful Super-Kamiokande experiment. The detector which has an 8.4 times larger effective volume than its predecessor will be located along the T2K neutrino beamline and utilize an upgraded J-PARC beam with 2.6 times beam power. Hyper-K’s low energy threshold combined with the very large fiducial volume make the detector unique, that is expected to acquire an unprecedented exposure of 3.8 Mton·year over a period of 20 years of operation. Hyper-Kamiokande combines an extremely diverse science program including nucleon decays, long-baseline neutrino oscillations, atmospheric neutrinos, and neutrinos from astrophysical origins. The scientific scope of this program is highly complementary to liquid-argon detectors for example in sensitivity to nucleon decay channels or supernova detection modes. Hyper-Kamiokande construction has started in early 2020 and the experiment is expected to start operations in 2027. The Hyper-Kamiokande collaboration is presently being formed amongst groups from 19 countries including the United States, whose community has a long history of making significant contributions to the neutrino physics program in Japan. US physicists have played leading roles in the Kamiokande, Super-Kamiokande, EGADS, K2K, and T2K programs. Copyright © 2020, The Authors. All rights reserved.

关键词： Atomic physics

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Exciton Localization of High-Quality ZnO/Mg_xZn_1-xO Multiple Quantum Wells on Si (111) with a Y₂O₃ Buffer Layer (vol 1, pg 3829, 2018)

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ACS applied NANO MATERIALS 2018年第10期1卷 5958-5958页

作者： Liu, Wei-Rein Huang, Wei-Lun Wu, Yung-Chi Lai, Liang-Hsun Hsu, Chia-Hung Hsieh, Wen-Feng Chiang, Tsung-Hung Wan, H. W. Hong, M. Kao, J. National Synchrotron Radiation Research Center Hsinchu 30076 Taiwan Program for Science and Technology of Accelerator Light Source National Chiao Tung University Hsinchu 30010 Taiwan Department of Photonics College of Electrical and Computer Engineering National Chiao Tung University Hsinchu 30010 Taiwan Department of Photonics College of Electrical and Computer Engineering National Chiao Tung University Hsinchu 30010 Taiwan Department of Materials Science & Engineering National Tsing Hua University Hsinchu 30013 Taiwan Graduate Institute of Applied Physics and Department of Physics National Taiwan University Taipei 10617 Taiwan Department of Physics National Tsing Hua University Hsinchu 30013 Taiwan

We report the structural and optical properties of ten-period ZnO/MgxZn1–xO multiple quantum wells (MQWs) prepared on the most widely used semiconductor material, Si. The introduction of a nanometer thick high-k Y2O3transition layer between Si (111) substrate and a ZnO buffer layer significantly improves the structural perfection of the MQWs grown on top of it. The high structural quality of the ZnO/MgxZn1–xO MQWs is evidenced by the appearance of pronounced high order satellite peaks in X-ray crystal truncation rods; high resolution cross-sectional transmission electron microscopy images also confirmed the regularly arranged well and barrier layers. When the well width is less than ∼2.7 nm, the quantum-confined Stark effect in MQWs can be negligible. Not only the increasing exciton-binding energy but also reducing exciton–phonon coupling determined in temperature-dependent photoluminescence spectra indicate quantum-size effect. Our results demonstrate that ZnO/MgxZn1–xO MQWs integrated on Si have great potential in UV optoelectronic device applications.

关键词： Excitons Phonons Oxides Binding energy Layers

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