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The Atacama Cosmology Telescope: Detection of the pairwise kinematic Sunyaev-Zel’dovich effect with SDSS DR15 galaxies

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Physical Review D 2021年第4期104卷 043502-043502页

作者： V. Calafut P. A. Gallardo E. M. Vavagiakis S. Amodeo S. Aiola J. E. Austermann N. Battaglia E. S. Battistelli J. A. Beall R. Bean J. R. Bond E. Calabrese S. K. Choi N. F. Cothard M. J. Devlin C. J. Duell S. M. Duff A. J. Duivenvoorden J. Dunkley R. Dunner S. Ferraro Y. Guan J. C. Hill G. C. Hilton M. Hilton R. Hložek Z. B. Huber J. Hubmayr K. M. Huffenberger J. P. Hughes B. J. Koopman A. Kosowsky Y. Li M. Lokken M. Madhavacheril J. McMahon K. Moodley S. Naess F. Nati L. B. Newburgh M. D. Niemack L. A. Page B. Partridge E. Schaan A. Schillaci C. Sifón D. N. Spergel S. T. Staggs J. N. Ullom L. R. Vale A. Van Engelen J. Van Lanen E. J. Wollack Z. Xu Department of Astronomy Cornell University Ithaca New York 14853 USA Department of Physics Cornell University Ithaca New York 14853 USA Center for Computational Astrophysics Flatiron Institute New York New York 10010 USA NIST Quantum Devices Group 325 Broadway Mailcode 817.03 Boulder Colorado 80305 USA Physics Department Sapienza University of Rome Piazzale Aldo Moro 5 I-00185 Rome Italy Canadian Institute for Theoretical Astrophysics University of Toronto Toronto Ontario M5S 3H8 Canada School of Physics and Astronomy Cardiff University The Parade Cardiff CF24 3AA United Kingdom Department of Applied and Engineering Physics Cornell University Ithaca New York USA 14853 Department of Physics and Astronomy University of Pennsylvania 209 South 33rd Street Philadelphia Pennsylvania 19104 USA Joseph Henry Laboratories of Physics Jadwin Hall Princeton University Princeton New Jersey 08544 USA Department of Astrophysical Sciences Peyton Hall Princeton University Princeton New Jersey 08544 USA Instituto de Astrofísica and Centro de Astro-Ingeniería Facultad de Física Pontificia Universidad Católica de Chile Avenue Vicuña Mackenna 4860 7820436 Macul Santiago Chile Lawrence Berkeley National Laboratory One Cyclotron Road Berkeley California 94720 USA Berkeley Center for Cosmological Physics UC Berkeley Berkley California 94720 USA Department of Physics and Astronomy University of Pittsburgh Pittsburgh Pennsylvania 15260 USA Department of Physics Columbia University New York New York 10027 USA Astrophysics Research Centre University of KwaZulu-Natal Westville Campus Durban 4041 South Africa David A. Dunlap Department of Astronomy and Astrophysics University of Toronto 50 St. George Street Toronto Ontario M5S 3H4 Canada Dunlap Institute for Astronomy and Astrophysics University of Toronto 50 St. George Street Toronto Ontario M5S 3H4 Canada Department of Physics Florida State University Tallahassee Florida 32306 USA Department of Physics and

We present a 5.4σ detection of the pairwise kinematic Sunyaev-Zeldovich (kSZ) effect using Atacama Cosmology Telescope (ACT) and Planck CMB observations in combination with Luminous Red Galaxy samples from the Sloan Digital Sky Survey (SDSS) DR15 catalog. Results are obtained using three ACT CMB maps: co-added 150 and 98 GHz maps, combining observations from 2008–2018 (ACT DR5), which overlap with SDSS DR15 over 3,700 sq. deg., and a component-separated map using night-time only observations from 2014–2015 (ACT DR4), overlapping with SDSS DR15 over 2,089 sq. deg. Comparisons of the results from these three maps provide consistency checks in relation to potential frequency-dependent foreground contamination. A total of 343,647 galaxies are used as tracers to identify and locate galaxy groups and clusters from which the kSZ signal is extracted using aperture photometry. We consider the impact of various aperture photometry assumptions and covariance estimation methods on the signal extraction. Theoretical predictions of the pairwise velocities are used to obtain best-fit, mass-averaged, optical depth estimates for each of five luminosity-selected tracer samples. A comparison of the kSZ-derived optical depth measurements obtained here to those derived from the thermal SZ effect for the same sample is presented in a companion paper.

关键词： Cosmic microwave background Cosmological parameters Large scale structure of the Universe

Correction: CEPC Technical Design Report: Accelerator

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Radiation Detection Technology and Methods 2024年第1期9卷 184-192页

作者： Abdallah, Waleed de Freitas, Tiago CarlosAdorno Afanaciev, Konstantin Ahmad, Shakeel Ahmed, Ijaz Ai, Xiaocong Aleem, Abid Altmannshofer, Wolfgang Alves, Fabio An, Weiming An, Rui Anderle, Daniele Paolo Antusch, Stefan Arai, Yasuo Arbuzov, Andrej Arhrib, Abdesslam Ashry, Mustafa Bai, Sha Bai, Yu Bai, Yang Bairathi, Vipul Balazs, Csaba Bambade, Philip Ban, Yong Bandyopadhyay, Triparno Bao, Shou-Shan Barber, Desmond P. Bat, Ays¸e Batozskaya, Varvara Behera, Subash Chandra Belyaev, Alexander Bertucci, Michele Bi, Xiao-Jun Bi, Yuanjie Bian, Tianjian Bianchi, Fabrizio Bieko¨tter, Thomas Biglietti, Michela Bilanishvili, Shalva Binglin, Deng Bodrov, Denis Bogomyagkov, Anton Bondarenko, Serge Boogert, Stewart Boonekamp, Maarten Borri, Marcello Bosotti, Angelo Boudry, Vincent Boukidi, Mohammed Boyko, Igor Bozovic, Ivanka Bozzi, Giuseppe Brient, Jean-Claude Budzinskaya, Anastasiia Bukhari, Masroor Bytev, Vladimir Cacciapaglia, Giacomo Cai, Hua Cai, Wenyong Cai, Wujun Cai, Yijian Cai, Yizhou Cai, Yuchen Cai, Haiying Cai, Huacheng Calibbi, Lorenzo Cang, Junsong Cao, Guofu Cao, Jianshe Chance, Antoine Chang, Xuejun Chang, Yue Chang, Zhe Chang, Xinyuan Chao, Wei Chatrabhuti, Auttakit Che, Yimin Che, Yuzhi Chen, Bin Chen, Danping Chen, Fuqing Chen, Fusan Chen, Gang Chen, Guoming Chen, Hua-Xing Chen, Huirun Chen, Jinhui Chen, Ji-Yuan Chen, Kai Chen, Mali Chen, Mingjun Chen, Mingshui Chen, Ning Chen, Shanhong Chen, Shanzhen Chen, Shao-Long Chen, Shaomin Chen, Shiqiang Chen, Tianlu Chen, Wei Chen, Xiang Chen, Xiaoyu Chen, Xin Chen, Xun Chen, Xurong Chen, Ye Chen, Ying Chen, Yukai Chen, Zelin Chen, Zilin Chen, Boping Chen, Chunhui Cheng, Hok Chuen Cheng, Huajie Cheng, Shan Cheng, Tongguang Chi, Yunlong Chimenti, Pietro Chiu, Wen Han Cho, Guk Chu, Ming-Chung Chu, Xiaotong Chu, Ziliang Coloretti, Guglielmo Crivellin, Andreas Cui, Hanhua Cui, Xiaohao Cui, Zhaoyuan D’Anzi, Brunella Dai, Ling-Yun Dai, Xinchen Dai, Xuwen De Maria, Antonio De Filippis, Nicola De La Taille, Christophe De Mori, Francesca De Sio, Chiara Del Core, Elisa Deng, Cairo University Giza Egypt Xi’an Jiaotong-Liverpool University Suzhou China Institute of Power Engineering of National Academy of Sciences of Belarus Minsk Belarus Pakistan Institute of Nuclear Science and Technology (PINSTECH) Islamabad Pakistan Applied Physics Department Science and Technology Federal Urdu University of Arts Islamabad Pakistan Zhengzhou University Zhengzhou China Institute of High Energy Physics Chinese Academy of Sciences Beijing China University of California Santa Cruz Santa Cruz USA Nanjing University Nanjing China Beijing Normal University Beijing China Harvard University Cambridge USA South China Normal University Guangzhou China University of Basel Basel Switzerland High Energy Accelerator Research Organization (KEK) Tsukuba Japan Joint Institute for Nuclear Research Dubna Russia Faculty of Sciences and Techniques Université Abdelmalek Essaadi Tangier Morocco Southeast University Nanjing China Department of Physics University of Wisconsin–Madison Madison USA Instituto de Alta Investigación Universidad de Tarapacá Arica Chile Monash University Melbourne Australia Laboratoire de Physique des 2 infinis Irène Joliot-Curie – IJCLab Orsay France Peking University Beijing China Department of Physics and Nanotechnology SRM Institute of Science and Technology Kattankulathur India Shandong University Jinan China University of New Mexico Albuquerque USA Bandirma Onyedi Eylul University Bandırma Turkey National Centre for Nuclear Research Warsaw Poland Indian Institute of Technology Madras (IN) Chennai India University of Southampton Southampton UK INFN Milano - LASA Segrate Italy Sun Yat-Sen University Guangzhou China China Institute of Atomic Energy Beijing China INFN-University of Torino Turin Italy Karlsruhe Institute of Technology Institute for Theoretical Physics Karlsruhe Germany INFN-Sezione di Roma Tre Rome Italy Kutaisi International University Kutaisi Georgia Soochow University Suzhou China Budker Institute

The persistent shadow of the supermassive black hole of M 87: I. Observations, calibration, imaging, and analysis*

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Astronomy and Astrophysics 2024年 681卷

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 Bandyopadhyay, Bidisha Barrett, John Bauböck, Michi Benson, Bradford A. Bintley, Dan Blackburn, Lindy Blundell, Raymond Bouman, Katherine L. Bower, Geoffrey C. Boyce, Hope 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 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, José L. 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 Violette Impellizzeri, C.M. Inoue, Makoto Issaoun, Sara James, David J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton 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 Granada18008 Spain Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 Bonn53121 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 València Burjassot46100 Spain Observatori Astronòmic Universitat de València C. Catedrático José Beltrán 2 València Paterna46980 Spain Department of Space Earth and Environment Chalmers University of Technology Onsala Space Observatory Onsala43992 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 Concepción Chile Department of Physics University of Illinois 1110 West Green Street UrbanaIL61801 United States Fermi National Accelerator Laboratory MS209 PO 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 Uni

In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in the giant elliptical galaxy M 87. These images reveal a ring with a southerly brightness distribution and a diameter of ∼42 μas, consistent with the predicted size and shape of a shadow produced by the gravitationally lensed emission around a supermassive black hole. These results were obtained as part of the April 2017 EHT observation campaign, using a global very long baseline interferometric radio array operating at a wavelength of 1.3 mm. Here, we present results based on the second EHT observing campaign, taking place in April 2018 with an improved array, wider frequency coverage, and increased bandwidth. In particular, the additional baselines provided by the Greenland telescope improved the coverage of the array. Multiyear EHT observations provide independent snapshots of the horizon-scale emission, allowing us to confirm the persistence, size, and shape of the black hole shadow, and constrain the intrinsic structural variability of the accretion flow. We have confirmed the presence of an asymmetric ring structure, brighter in the southwest, with a median diameter of 43.3-3.1+1.5 μas. The diameter of the 2018 ring is remarkably consistent with the diameter obtained from the previous 2017 observations. On the other hand, the position angle of the brightness asymmetry in 2018 is shifted by about 30 relative to 2017. The perennial persistence of the ring and its diameter robustly support the interpretation that the ring is formed by lensed emission surrounding a Kerr black hole with a mass ∼6.5× 109M. The significant change in the ring brightness asymmetry implies a spin axis that is more consistent with the position angle of the large-scale jet. © 2023 The Author(s).

关键词： Gravitation

The APOGEE Value Added Catalogue of Galactic globular cluster stars

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arXiv 2023年

作者： Schiavon, Ricardo P. Phillips, Siân G. Myers, Natalie Horta, Danny Minniti, Dante Prieto, Carlos Allende Anguiano, Borja Beaton, Rachael L. Beers, Timothy C. Brownstein, Joel R. Cohen, Roger E. Fernández-Trincado, José G. Frinchaboy, Peter M. Jönsson, Henrik Kisku, Shobhit Lane, Richard R. Majewski, Steven R. Mason, Andrew C. Mészáros, Szabolcs Stringfellow, Guy S. Astrophysics Research Institute Liverpool John Moores University 146 Brownlow Hill LiverpoolL3 5RF United Kingdom Department of Physics & Astronomy Texas Christian University Fort WorthTX76129 United States Center for Computational Astrophysics Flatiron Institute 162 5th Ave. New YorkNY10010 United States Instituto de Astrofísica Facultad de Ciencias Exactas Universidad Andrés Bello Fernández Concha 700 Las Condes Santiago Chile Vatican Observatory Vatican City State V-00120 Italy Departamento de Física Universidade Federal de Santa Catarina Trindade Florianópolis88040-900 Brazil Instituto de Astrofísica de Canarias Vía Láctea S/N Tenerife La Laguna38205 Spain Universidad de La Laguna Departamento de Astrofísica Tenerife La Laguna38206 Spain Department of Physics and Astronomy University of Notre Dame 225 Nieuwland Science Hall Notre DameIN46556 United States Department of Astronomy University of Virginia CharlottesvilleVA22904 United States Department of Astrophysical Sciences Princeton University 4 Ivy Lane PrincetonNJ08544 United States The Observatories of the Carnegie Institution for Science 813 Santa Barbara St. PasadenaCA91101 United States Department of Physics and Astronomy JINA Center for the Evolution of the Elements University of Notre Dame Notre DameIN46556 United States Department of Physics and Astronomy University of Utah 115 S. 1400 E. Salt Lake CityUT84112 United States Rutgers the State University of New Jersey 136 Frelinghuysen Ave. PiscatawayNJ08854 United States Instituto de Astronomía Universidad Católica del Norte Av. Angamos 0610 Antofagasta Chile Materials Science and Applied Mathematics Malmö University MalmöSE-205 06 Sweden Centro de Investigación en Astronomía Universidad Bernardo O’Higgins Avenida Viel 1497 Santiago Chile ELTE Eötvös Loránd University Gothard Astrophysical Observatory Szent Imre H. st. 112 Szombathely9700 Hungary MTA-ELTE Lendület "Momentum" Milky Way Research Group Hung

We introduce the SDSS/APOGEE Value Added Catalogue of Galactic Globular Cluster (GC) Stars. The catalogue is the result of a critical search of the APOGEE data release 17 (DR17) catalogue for candidate members of all known Galactic GCs. Candidate members are assigned to various GCs on the basis of position on the sky, proper motion, and radial velocity. The catalogue contains a total of 7,737 entries for 6,422 unique stars associated with 72 Galactic GCs. Full APOGEE DR17 information is provided, including radial velocities and abundances for up to 20 elements. Membership probabilities estimated on the basis of precision radial velocities are made available. Comparisons with chemical compositions derived by the GALAH survey, as well as optical values from the literature, show good agreement. This catalogue represents a significant increase in the public database of GC star chemical compositions and kinematics, providing a massive homogeneous data set that will enable a variety of studies. The catalogue in fits format is available for public download from the SDSS-IV DR17 value added catalogue website. © 2023, CC BY.

关键词： Stars

Adaptive coupling of a deep neural network potential to a classical force field

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arXiv 2018年

作者： Zhang, Linfeng Wang, Han Weinan, E. Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Huayuan Road 6 Beijing100088 China Department of Mathematics and Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Center for Data Science and Beijing International Center for Mathematical Research Peking University China Beijing Institute of Big Data Research Beijing100871 China

An adaptive modeling method (AMM) that couples a deep neural network potential and a classical force field is introduced to address the accuracy-efficiency dilemma faced by the molecular simulation community. The AMM simulated system is decomposed into three types of regions. The first type captures the important phenomena in the system and requires high accuracy, for which we use the Deep Potential Molecular Dynamics (DeePMD) model in this work. The DeePMD model is trained to accurately reproduce the statistical properties of the ab initio molecular dynamics. The second type does not require high accuracy and a classical force field is used to describe it in an efficient way. The third type is used for a smooth transition between the first and the second types of regions. By using a force interpolation scheme and imposing a thermodynamics force in the transition region, we make the DeePMD region embedded in the AMM simulated system as if it were embedded in a system that is fully described by the accurate potential. A representative example of the liquid water system is used to show the feasibility and promise of this method. Copyright © 2018, The Authors. All rights reserved.

关键词： Deep neural networks

Optimal unidirectional amplification induced by optical gain in optomechanical systems

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Physical Review A 2019年第4期100卷 043835-043835页

作者： L. N. Song Qiang Zheng Xun-Wei Xu Cheng Jiang Yong Li Beijing Computational Science Research Center Beijing 100193 China School of Mathematics Guizhou Normal University Guiyang 550001 China Department of Applied Physics East China Jiaotong University Nanchang 330013 China School of Physics and Electronic Electrical Engineering Huaiyin Normal University Huai'an 223300 China Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China

We propose a three-mode optomechanical system to realize optical nonreciprocal transmission with unidirectional amplification, where the system consists of two coupled cavities and one mechanical resonator which interacts with only one of the cavities. Additionally, the optical gain is introduced into the optomechanical cavity. It is found that for a strong optical input, the optical transmission coefficient can be greatly amplified in a particular direction and suppressed in the opposite direction. The expressions of the optimal transmission coefficient and the corresponding isolation ratio are given analytically. Our results pave a way to design high-quality nonreciprocal devices based on optomechanical systems.

关键词： Optical bistability Optical parametric oscillators & amplifiers Optomechanics

Observation of Indirect Ionization of W7+in EBIT plasma

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arXiv 2019年

作者： Lu, Q. He, J. Tian, H. Li, M. Yang, Y. Yao, K. Chen, C. Xiao, J. Li, J.G. Tu, B. Zou, Y. Institute of Modern Physics Department of Nuclear Science and Technology Fudan University Shanghai200433 China Fudan University Shanghai200433 China Institute of Applied Physics and Computational Mathematics Beijing100088 China Max-Planck-Institute für Kernphysik Saupfercheckweg 1 Heidelberg69117 Germany

In this work, visible and EUV spectra of W7+have been measured using the high-temperature superconducting electron-beam ion trap at the Shanghai EBIT laboratory under extremely low-energy conditions (lower than the nominal electron beam energy of 130 eV). The relevant atomic structure has been calculated by using the flexible atomic code package based on the relativistic configuration interaction method. The GRASP2K code in the framework of the multi-configuration Dirac-Hartree-Fock method is employed as well when high-precision atomic parameters are required. The W7+spectra are observed 2 charge states in advance according to the ionization energy of W6+. A hypothesis for the charge-state evolution of W7+is proposed based on our experimental and theoretical results, that is, the occurrence of W7+ions results from indirect ionization caused by cascade excitation between some metastable states of lower-charge-state W ions, at the nominal electron beam energy of 59 eV. Copyright © 2019, The Authors. All rights reserved.

关键词： Electron beams

Cross-correlation of Dark Energy Survey Year 3 lensing data with ACT and Planck thermal Sunyaev-Zel’dovich effect observations. I. Measurements, systematics tests, and feedback model constraints

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Physical Review D 2022年第12期105卷 123525-123525页

作者： M. Gatti S. Pandey E. Baxter J. C. Hill E. Moser M. Raveri X. Fang J. DeRose G. Giannini C. Doux H. Huang N. Battaglia A. Alarcon A. Amon M. Becker A. Campos C. Chang R. Chen A. Choi K. Eckert J. Elvin-Poole S. Everett A. Ferte I. Harrison N. Maccrann J. Mccullough J. Myles A. Navarro Alsina J. Prat R. P. Rollins C. Sanchez T. Shin M. Troxel I. Tutusaus B. Yin T. Abbott M. Aguena S. Allam F. Andrade-Oliveira J. Annis G. Bernstein E. Bertin B. Bolliet J. R. Bond D. Brooks D. L. Burke E. Calabrese A. Carnero Rosell M. Carrasco Kind J. Carretero R. Cawthon M. Costanzi M. Crocce L. N. da Costa M. E. da Silva Pereira J. De Vicente S. Desai H. T. Diehl J. P. Dietrich P. Doel J. Dunkley A. E. Evrard S. Ferraro I. Ferrero B. Flaugher P. Fosalba J. Frieman J. García-Bellido E. Gaztanaga D. W. Gerdes T. Giannantonio D. Gruen R. A. Gruendl J. Gschwend G. Gutierrez K. Herner A. D. Hincks S. R. Hinton D. L. Hollowood K. Honscheid J. P. Hughes D. Huterer B. Jain D. J. James E. Krause K. Kuehn N. Kuropatkin O. Lahav C. Lidman M. Lima M. Lokken M. S. Madhavacheril M. A. G. Maia J. L. Marshall J. J. Mcmahon P. Melchior K. Moodley J. J. Mohr R. Morgan F. Nati M. D. Niemack L. Page A. Palmese F. Paz-Chinchón A. Pieres A. A. Plazas Malagón M. Rodriguez-Monroy A. K. Romer E. Sanchez V. Scarpine E. Schaan L. F. Secco S. Serrano E. Sheldon B. D. Sherwin C. Sifón M. Smith M. Soares-Santos D. Spergel E. Suchyta G. Tarle D. Thomas C. To D. L. Tucker T. N. Varga J. Weller R. D. Wilkinson E. J. Wollack Z. Xu Department of Physics and Astronomy University of Pennsylvania Philadelphia Pennsylvania 19104 USA Institute for Astronomy University of Hawai’i 2680 Woodlawn Drive Honolulu Hawai’i 96822 USA Department of Physics Columbia University New York New York 10027 USA Center for Computational Astrophysics Flatiron Institute New York New York 10010 USA Department of Astronomy Cornell University Ithaca New York 14853 USA Department of Astronomy/Steward Observatory University of Arizona 933 North Cherry Avenue Tucson Arizona 85721-0065 USA Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley California 94720 USA Institut de Física d’Altes Energies (IFAE) The Barcelona Institute of Science and Technology Campus UAB 08193 Bellaterra (Barcelona) Spain Department of Physics University of Arizona Tucson Arizona 85721 USA Argonne National Laboratory 9700 South Cass Avenue Lemont Illinois 60439 USA Kavli Institute for Particle Astrophysics and Cosmology P. O. Box 2450 Stanford University Stanford California 94305 USA Department of Physics Carnegie Mellon University Pittsburgh Pennsylvania 15312 USA Department of Astronomy and Astrophysics University of Chicago Chicago Illinois 60637 USA Kavli Institute for Cosmological Physics University of Chicago Chicago Illinois 60637 USA Department of Physics Duke University Durham North Carolina 27708 USA Center for Cosmology and Astro-Particle Physics The Ohio State University Columbus Ohio 43210 USA Department of Physics The Ohio State University Columbus Ohio 43210 USA Santa Cruz Institute for Particle Physics Santa Cruz California 95064 USA Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive Pasadena California 91109 USA Department of Physics University of Oxford Denys Wilkinson Building Keble Road Oxford OX1 3RH United Kingdom Jodrell Bank Center for Astrophysics School of Physics and Astronomy University of Manchester Oxford Road Manchester M13 9PL United Ki

We present a tomographic measurement of the cross-correlation between thermal Sunyaev-Zel’dovich (TSZ) maps from Planck and the Atacama Cosmology Telescope and weak galaxy lensing shears measured during the first three years of observations of the Dark Energy Survey. This correlation is sensitive to the thermal energy in baryons over a wide redshift range and is therefore a powerful probe of astrophysical feedback. We detect the correlation at a statistical significance of 21σ, the highest significance to date. We examine the TSZ maps for potential contaminants, including cosmic infrared background and radio sources, finding that cosmic infrared background has a substantial impact on our measurements and must be taken into account in our analysis. We use the cross-correlation measurements to test different feedback models. In particular, we model the TSZ using several different pressure profile models calibrated against hydrodynamical simulations. Our analysis marginalizes over redshift uncertainties, shear calibration biases, and intrinsic alignment effects. We also marginalize over Ωm and σ8 using Planck or DES priors. We find that the data prefer the model with a low amplitude of the pressure profile at small scales, compatible with a scenario with strong active galactic nuclei feedback and ejection of gas from the inner part of the halos. When using a more flexible model for the shear profile, constraints are weaker, and the data cannot discriminate between different baryonic prescriptions.

关键词： Cosmic microwave background Dark energy Dark matter Large scale structure of the Universe

Uniform-in-time weak error analysis for stochastic gradient descent algorithms via diffusion approximation

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arXiv 2019年

作者： Feng, Yuanyuan Gao, Tingran Li, Lei Liu, Jian-Guo Lu, Yulong Department of Mathematics Penn State University University ParkPA16802 United States Committee on Computational and Applied Mathematics Department of Statistics University of Chicago ChicagoIL60637 United States School of Mathematical Sciences Institute of Natural Sciences MOE-LSC Shanghai Jiao Tong University Shanghai200240 China Department of Mathematics Department of Physics Duke University DurhamNC27708 United States Department of Mathematics Duke University DurhamNC27708 United States

Diffusion approximation provides weak approximation for stochastic gradient descent algorithms in a finite time horizon. In this paper, we introduce new tools motivated by the backward error analysis of numerical stochastic differential equations into the theoretical framework of diffusion approximation, extending the validity of the weak approximation from finite to infinite time horizon. The new techniques developed in this paper enable us to characterize the asymptotic behavior of constant-step-size SGD algorithms near a local minimum around which the objective functions are locally strongly convex, a goal previously unreachable within the diffusion approximation framework. Our analysis builds upon a truncated formal power expansion of the solution of a Kolmogorov equation arising from diffusion approximation, where the main technical ingredient is uniform-in-time bounds controlling the long-term behavior of the expansion coefficient functions near the local minimum. We expect these new techniques to bring new understanding of the behaviors of SGD near local minimum and greatly expand the range of applicability of diffusion approximation to cover wider and deeper aspects of stochastic optimization algorithms in data science.60J20, 90C15 Copyright © 2019, The Authors. All rights reserved.

关键词： Differential equations