Distances, Locations, Ages and Reproduction of Galaxies in Our Dynamic Universe
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Photometric Redshift Estimation of Distant Quasars
Photometric Redshift Estimation of Distant Quasars Joris van Vugt1 Department of Articial Intelligence Radboud University Nijmegen Supervisor: Dr. F. Gieseke2 Internal Supervisor: Dr. L.G. Vuurpijl3 July 6, 2016 Bachelor Thesis 1Student number: s4279859, correspondence: [email protected] 2Institute for Computing and Information Sciences, Radboud University Nijmegen 3Department of Articial Intelligence, Radboud University Nijmegen Abstract Light emitted by celestial objects is shifted towards higher wavelengths when it reaches Earth. This is called redshift. Photometric redshift estimation is necessary to process the large amount of data produced by contemporary and future telescopes. However, the lter bands recorded by the Sloan Digital Sky Survey are not sucient for accurate estimation of the redshift of high- redshift quasars. Filter bands that cover higher wavelengths, such as those in the WISE and UKIDSS catalogues provide more information. Taking these lter bands into account causes the problem of missing data, since they might not be available for every object. This thesis explores three ways of dealing with missing data: (1) discarding all objects with missing data, (2) training multiple models and (3) naively imputing the missing data. Contents 1 Introduction 3 1.1 Astroinformatics . .3 1.2 Photometric Redshift Estimation . .3 1.2.1 Classication Versus Regression . .4 1.2.2 Algorithms Used for the SDSS Catalogue . .5 1.3 Machine Learning . .5 1.4 Datasets . .5 1.4.1 SDSS . .5 1.4.2 Quasars from SDSS, WISE and UKIDSS . .6 2 Methods 8 2.1 Supervised learning . .8 2.1.1 k-Nearest Neighbours . .8 2.1.2 Random Forests . .9 2.2 Evaluation metrics . -
Expanding Space, Quasars and St. Augustine's Fireworks
Universe 2015, 1, 307-356; doi:10.3390/universe1030307 OPEN ACCESS universe ISSN 2218-1997 www.mdpi.com/journal/universe Article Expanding Space, Quasars and St. Augustine’s Fireworks Olga I. Chashchina 1;2 and Zurab K. Silagadze 2;3;* 1 École Polytechnique, 91128 Palaiseau, France; E-Mail: [email protected] 2 Department of physics, Novosibirsk State University, Novosibirsk 630 090, Russia 3 Budker Institute of Nuclear Physics SB RAS and Novosibirsk State University, Novosibirsk 630 090, Russia * Author to whom correspondence should be addressed; E-Mail: [email protected]. Academic Editors: Lorenzo Iorio and Elias C. Vagenas Received: 5 May 2015 / Accepted: 14 September 2015 / Published: 1 October 2015 Abstract: An attempt is made to explain time non-dilation allegedly observed in quasar light curves. The explanation is based on the assumption that quasar black holes are, in some sense, foreign for our Friedmann-Robertson-Walker universe and do not participate in the Hubble flow. Although at first sight such a weird explanation requires unreasonably fine-tuned Big Bang initial conditions, we find a natural justification for it using the Milne cosmological model as an inspiration. Keywords: quasar light curves; expanding space; Milne cosmological model; Hubble flow; St. Augustine’s objects PACS classifications: 98.80.-k, 98.54.-h You’d think capricious Hebe, feeding the eagle of Zeus, had raised a thunder-foaming goblet, unable to restrain her mirth, and tipped it on the earth. F.I.Tyutchev. A Spring Storm, 1828. Translated by F.Jude [1]. 1. Introduction “Quasar light curves do not show the effects of time dilation”—this result of the paper [2] seems incredible. -
2016-2017 Year Book Www
1 2016-2017 YEAR BOOK WWW. C A R N E G I E S C I E N C E . E D U Department of Embryology 3520 San Martin Dr. / Baltimore, MD 21218 410.246.3001 Geophysical Laboratory 5251 Broad Branch Rd., N.W. / Washington, DC 20015-1305 202.478.8900 Department of Global Ecology 260 Panama St. / Stanford, CA 94305-4101 650.462.1047 The Carnegie Observatories 813 Santa Barbara St. / Pasadena, CA 91101-1292 626.577.1122 Las Campanas Observatory Casilla 601 / La Serena, Chile Department of Plant Biology 260 Panama St. / Stanford, CA 94305-4101 650.325.1521 Department of Terrestrial Magnetism 5241 Broad Branch Rd., N.W. / Washington, DC 20015-1305 202.478.8820 Office of Administration 1530 P St., N.W. / Washington, DC 20005-1910 202.387.6400 2 0 1 6 - 2 0 1 7 Y E A R B O O K The President’s Report July 1, 2016 - June 30, 2017 C A R N E G I E I N S T I T U T I O N F O R S C I E N C E Former Presidents Daniel C. Gilman, 1902–1904 Robert S. Woodward, 1904–1920 John C. Merriam, 1921–1938 Vannevar Bush, 1939–1955 Caryl P. Haskins, 1956–1971 Philip H. Abelson, 1971–1978 James D. Ebert, 1978–1987 Edward E. David, Jr. (Acting President, 1987–1988) Maxine F. Singer, 1988–2002 Michael E. Gellert (Acting President, Jan.–April 2003) Richard A. Meserve, 2003–2014 Former Trustees Philip H. Abelson, 1978–2004 Patrick E. -
Cosmic Age Problem Revisited in the Holographic Dark Energy Model ∗ Jinglei Cui, Xin Zhang
中国科技论文在线 http://www.paper.edu.cn Physics Letters B 690 (2010) 233–238 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb Cosmic age problem revisited in the holographic dark energy model ∗ Jinglei Cui, Xin Zhang Department of Physics, College of Sciences, Northeastern University, Shenyang 110004, China article info abstract Article history: Because of an old quasar APM 08279 + 5255 at z = 3.91, some dark energy models face the challenge of Received 18 April 2010 the cosmic age problem. It has been shown by Wei and Zhang [H. Wei, S.N. Zhang, Phys. Rev. D 76 (2007) Received in revised form 18 May 2010 063003, arXiv:0707.2129 [astro-ph]] that the holographic dark energy model is also troubled with such a Accepted 20 May 2010 cosmic age problem. In order to accommodate this old quasar and solve the age problem, we propose in Available online 24 May 2010 this Letter to consider the interacting holographic dark energy in a non-flat universe. We show that the Editor: T. Yanagida cosmic age problem can be eliminated when the interaction and spatial curvature are both involved in Keywords: the holographic dark energy model. Holographic dark energy © 2010 Elsevier B.V. All rights reserved. Cosmic age problem 1. Introduction of quantum gravity could be taken into account. It is commonly believed that the holographic principle [16] is just a fundamental The fact that our universe is undergoing accelerated expansion principle of quantum gravity. Based on the effective quantum field has been confirmed by lots of astronomical observations such as theory, Cohen et al. -
Ira Sprague Bowen Papers, 1940-1973
http://oac.cdlib.org/findaid/ark:/13030/tf2p300278 No online items Inventory of the Ira Sprague Bowen Papers, 1940-1973 Processed by Ronald S. Brashear; machine-readable finding aid created by Gabriela A. Montoya Manuscripts Department The Huntington Library 1151 Oxford Road San Marino, California 91108 Phone: (626) 405-2203 Fax: (626) 449-5720 Email: [email protected] URL: http://www.huntington.org/huntingtonlibrary.aspx?id=554 © 1998 The Huntington Library. All rights reserved. Observatories of the Carnegie Institution of Washington Collection Inventory of the Ira Sprague 1 Bowen Papers, 1940-1973 Observatories of the Carnegie Institution of Washington Collection Inventory of the Ira Sprague Bowen Paper, 1940-1973 The Huntington Library San Marino, California Contact Information Manuscripts Department The Huntington Library 1151 Oxford Road San Marino, California 91108 Phone: (626) 405-2203 Fax: (626) 449-5720 Email: [email protected] URL: http://www.huntington.org/huntingtonlibrary.aspx?id=554 Processed by: Ronald S. Brashear Encoded by: Gabriela A. Montoya © 1998 The Huntington Library. All rights reserved. Descriptive Summary Title: Ira Sprague Bowen Papers, Date (inclusive): 1940-1973 Creator: Bowen, Ira Sprague Extent: Approximately 29,000 pieces in 88 boxes Repository: The Huntington Library San Marino, California 91108 Language: English. Provenance Placed on permanent deposit in the Huntington Library by the Observatories of the Carnegie Institution of Washington Collection. This was done in 1989 as part of a letter of agreement (dated November 5, 1987) between the Huntington and the Carnegie Observatories. The papers have yet to be officially accessioned. Cataloging of the papers was completed in 1989 prior to their transfer to the Huntington. -
Volume LX I, I 9
CALIFORNIA INSTITUTE Of TECHNOLOGY E N GI N E E Volume LX I, N II1llber 3, I 9 9 8 IN THIS ISSUE • Prosecuting Science Simulating Molecules Observing Anniversaries London Bridge? The Manhattan skyline? No, it's an oil refinery. figuring out how to squeeze more gasoline rrom a barrel or crude is just one project a group or theoretical chemists at Caltech have taken on in a series or academic industrial collaborations. for more on this partner sh ip, see the story on page 20. Photo courtesy or Chevron Corporation. \ California Inst i tute of Technology 2 Random Wa l k 10 Scie ntific Fraud and Misconduct in American Po litica l Cu lture : Reflections on the Baltimore Case - by Dan ie l J. Kevles Excessive zeal on the part of legislators and the media hyped public suspicion of scientists' behavior. 20 " H ave Method , Wi ll T rave l" - by Douglas L. Smi t h Computational chemistry ventures into the Real World as Cal tech theorists tackle industrial problems. 30 Tw o A s tronomical Anniv ers aries : Palomar at 50 Still going strong , the hale and hearty Hale Telescope hits the half century mark. 36 ... and OVRO at 40 Radio astronomers parry, too. On t he Cover: The six IO.4·meter antennas (one 42 Boo ks - The Earth in Tf{rmoil by Kerr y Si eh a n d S i mon LeVay is hidden behind the others here) of the Owe ns 43 Faculty Fil e Valley Radio Observat ory millimeter· wave array can receive signals from up t o Engineering & Science (ISSN 0013-7812) is published Warren G. -
The Large Scale Universe As a Quasi Quantum White Hole
International Astronomy and Astrophysics Research Journal 3(1): 22-42, 2021; Article no.IAARJ.66092 The Large Scale Universe as a Quasi Quantum White Hole U. V. S. Seshavatharam1*, Eugene Terry Tatum2 and S. Lakshminarayana3 1Honorary Faculty, I-SERVE, Survey no-42, Hitech city, Hyderabad-84,Telangana, India. 2760 Campbell Ln. Ste 106 #161, Bowling Green, KY, USA. 3Department of Nuclear Physics, Andhra University, Visakhapatnam-03, AP, India. Authors’ contributions This work was carried out in collaboration among all authors. Author UVSS designed the study, performed the statistical analysis, wrote the protocol, and wrote the first draft of the manuscript. Authors ETT and SL managed the analyses of the study. All authors read and approved the final manuscript. Article Information Editor(s): (1) Dr. David Garrison, University of Houston-Clear Lake, USA. (2) Professor. Hadia Hassan Selim, National Research Institute of Astronomy and Geophysics, Egypt. Reviewers: (1) Abhishek Kumar Singh, Magadh University, India. (2) Mohsen Lutephy, Azad Islamic university (IAU), Iran. (3) Sie Long Kek, Universiti Tun Hussein Onn Malaysia, Malaysia. (4) N.V.Krishna Prasad, GITAM University, India. (5) Maryam Roushan, University of Mazandaran, Iran. Complete Peer review History: http://www.sdiarticle4.com/review-history/66092 Received 17 January 2021 Original Research Article Accepted 23 March 2021 Published 01 April 2021 ABSTRACT We emphasize the point that, standard model of cosmology is basically a model of classical general relativity and it seems inevitable to have a revision with reference to quantum model of cosmology. Utmost important point to be noted is that, ‘Spin’ is a basic property of quantum mechanics and ‘rotation’ is a very common experience. -
Scientific Fraud ) !J." } .::; :"I~ I ::.T:U!O L.~ 4-F, J T.F;;
California Institute of Technology Engineering & Science Winter 1991 7 _ 4 In this i.sue I;', ~l. 1,150/" q-, >'h 11 1,3t J,~, ~ ~ 0 '., ';.. '".l.l b: -)1 f' I.f): ., 0.',)9 First Lights > 1-" I , - , ,,LJ~'7 Scientific Fraud ) !J." } .::; :"I~ I ::.t:u!o l.~ 4-f, j t.f;; . - '-I~ /2.- .o1l-/r, I) .... ,; "'. t'+t -. 'b~, 1.1 If • ~ ~ ;,, ~I loJ I( 1",_ Technology Lf~IOr 3f7U " i~ "" If l!f Transfer /1 11 " • , ;,).lJ h~ ,, ~ ~ "!> ~, "_ /.>, Is ~I ).. a.- I ~ 4; 7 Semiconductor I I >'f , ,, 1> "II , .... ., Quality Control 'Is i" ,, 0,./, 'i 'l{'1- , ~ ' '''1 i' r 'I $7(, '>'/11 "-1, > • ~'i 1,0:, ~ ~ .., ~I -: /' q, ' " c. t. , u- f'! ~~~ ":lk.i e ... ,- , 11J 3 0 'f l.- , . fo'l' '" ~. "f I ~. (,. I ~ - '>- , ? tl6 . o I,! .,.!- .. - 31.r~{, ) .' J S"7 J. ) , F., a The 10·meter Keck Telescope saw first light in November 1990. California Institute of Technology Winter 1991 Volume LlV, Number 2 2 First Lights The lO-rneter Keck Telescope, with one quarter of its mirror segments installed, produces its first image; its predecessors had different definitions of "first light," as well as different problems. 10 Scientific Fraud - by David Goodstein Caltech's vice provost offers an opinion of what it is and what it isn't, and defends a couple of famous physicists against false charges. 20 Deposit Insurance The layers that make up a computer chip are deposited inside a sealed chamber. A new way to see what's going on within the chamber can improve chip quality. -
Dancing to the Tempo of LEP
INTERNATIONAL JOURNAL OF HIGH-ENERGY PHYSICS CERN COURIER VOLUME 40 NUMBER 10 DECEMBER 2000 Dancing to the tempo of LEP SPIN SUPERSYMMETRY INTERNET Polarized protons accelerated Striking suggestions for How the Web was Born, a new in new RHIC ring p8 additional physics symmetry pl7 book p43 E RI Hew Gêner CES Creative Electronic Systems 70 route du Hunt-dun*! CH-1213 Petit-Uncy, Switzerland Internet: nttp://www.ces.cft I The Ultimate VME Machine CES Switzeriand The RI03 features a twin bus architecture, a Tel: ^41.22.879.51.00 ifque fnter-processor communication mechanism Fax: +4U2.792.57.4d Email; [email protected] for ultra-high-speed data acquisitions g and user-level load balance control CES.O Germany with dedicated hardware. Tel: +49.60.51.96.97.41 Fax; +49.60,51.96.97.33 Sheer Speed: Êttuiil: [email protected] # • VME - block transfers in 2eSST at CES MSâ 300 MBytes/s, single cycles at 20 MBytes/s Tel:+ 1.518.843.1445 Fax;+1.518.643.1447 * Memory - 400 MBytes/s average, Email: [email protected] 800 MBytes/s peak • Multi-Access - VME + PCM + PCI 2 + CPU without global degradation CPU Power: PowerPC 750 or 7400 at maximum available speed I Flexible: Two Independent 64-bit PCI with simultaneous access to the memory I Scalable: Up to four additional PMC's on a PMC carrier system MFCC 844x PMC PROCESSORS • 130 KGates user-FPGA • Continuous acquisition at 50 MBytes/s In 32 or 64~bit mode • Full 750 / 7400 computing core • Full network services on PCI * Complete multi-processing software with connection oriented high-speed data transfers SOFTWARE SUPPORT VxWorics®, Lynxob®, muecat® and LINUX® development software including support for hard real-time target machines. -
12 Strong Gravitational Lenses
12 Strong Gravitational Lenses Phil Marshall, MaruˇsaBradaˇc,George Chartas, Gregory Dobler, Ard´ısEl´ıasd´ottir,´ Emilio Falco, Chris Fassnacht, James Jee, Charles Keeton, Masamune Oguri, Anthony Tyson LSST will contain more strong gravitational lensing events than any other survey preceding it, and will monitor them all at a cadence of a few days to a few weeks. Concurrent space-based optical or perhaps ground-based surveys may provide higher resolution imaging: the biggest advances in strong lensing science made with LSST will be in those areas that benefit most from the large volume and the high accuracy, multi-filter time series. In this chapter we propose an array of science projects that fit this bill. We first provide a brief introduction to the basic physics of gravitational lensing, focusing on the formation of multiple images: the strong lensing regime. Further description of lensing phenomena will be provided as they arise throughout the chapter. We then make some predictions for the properties of samples of lenses of various kinds we can expect to discover with LSST: their numbers and distributions in redshift, image separation, and so on. This is important, since the principal step forward provided by LSST will be one of lens sample size, and the extent to which new lensing science projects will be enabled depends very much on the samples generated. From § 12.3 onwards we introduce the proposed LSST science projects. This is by no means an exhaustive list, but should serve as a good starting point for investigators looking to exploit the strong lensing phenomenon with LSST. -
Mapping Weak Gravitational Lensing Signals from Low-Redshift Galaxy Clusters to Compare Dark Matter and X-Ray Gas Substructures
MAPPING WEAK GRAVITATIONAL LENSING SIGNALS FROM LOW-REDSHIFT GALAXY CLUSTERS TO COMPARE DARK MATTER AND X-RAY GAS SUBSTRUCTURES. CLAIRE HAWKINS BROWN UNIVERSITY MAY 2020 1 Contents Acknowledgements: ...................................................................................................................................... 3 Abstract: ........................................................................................................................................................ 4 Introduction: .................................................................................................................................................. 5 Background: .................................................................................................................................................. 7 GR and Gravitational Lensing .................................................................................................................. 7 General Relativity ................................................................................................................................. 7 Gravitational Lensing ............................................................................................................................ 9 Galaxy Clusters ....................................................................................................................................... 11 Introduction to Galaxy Clusters ......................................................................................................... -
An Introduction to Our Universe
An Introduction to Our Universe Lyman Page Princeton, NJ [email protected] Draft, August 31, 2018 The full-sky heat map of the temperature differences in the remnant light from the birth of the universe. From the bluest to the reddest corresponds to a temperature difference of 400 millionths of a degree Celsius. The goal of this essay is to explain this image and what it tells us about the universe. 1 Contents 1 Preface 2 2 Introduction to Cosmology 3 3 How Big is the Universe? 4 4 The Universe is Expanding 10 5 The Age of the Universe is Finite 15 6 The Observable Universe 17 7 The Universe is Infinite ?! 17 8 Telescopes are Like Time Machines 18 9 The CMB 20 10 Dark Matter 23 11 The Accelerating Universe 25 12 Structure Formation and the Cosmic Timeline 26 13 The CMB Anisotropy 29 14 How Do We Measure the CMB? 36 15 The Geometry of the Universe 40 16 Quantum Mechanics and the Seeds of Cosmic Structure Formation. 43 17 Pulling it all Together with the Standard Model of Cosmology 45 18 Frontiers 48 19 Endnote 49 A Appendix A: The Electromagnetic Spectrum 51 B Appendix B: Expanding Space 52 C Appendix C: Significant Events in the Cosmic Timeline 53 D Appendix D: Size and Age of the Observable Universe 54 1 1 Preface These pages are a brief introduction to modern cosmology. They were written for family and friends who at various times have asked what I work on. The goal is to convey a geometrical picture of how to think about the universe on the grandest scales.