Cosmic Homogeneity As Standard Ruler Pierros Ntelis
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An Overview of Nonstandard Signals in Cosmological Data †
Proceeding Paper An Overview of Nonstandard Signals in Cosmological Data † George Alestas ‡,* , George V. Kraniotis ‡ and Leandros Perivolaropoulos ‡ Division of Theoretical Physics, University of Ioannina, 45110 Ioannina, Greece; [email protected] (G.V.K.); [email protected] (L.P.) * Correspondence: [email protected] † Presented at the 1st Electronic Conference on Universe, 22–28 February 2021; Available online: https://ecu2021.sciforum.net/. ‡ Current address: Department of Physics, University of Ioannina, 45110 Ioannina, Greece. Abstract: We discuss in a unified manner many existing signals in cosmological and astrophysical data that appear to be in some tension (2s or larger) with the standard LCDM as defined by the Planck18 parameter values. The well known tensions of LCDM include the H0 tension the S8 tension and the lensing (Alens) CMB anomaly. There is however, a wide range of other, less standard signals towards new physics. Such signals include, hints for a closed universe in the CMB, the cold spot anomaly indicating non-Gaussian fluctuations in the CMB, the hemispherical temperature variance assymetry and other CMB anomalies, cosmic dipoles challenging the cosmological principle, the Lyman-a forest Baryon Accoustic Oscillation anomaly, the cosmic birefringence in the CMB, the Lithium problem, oscillating force signals in short range gravity experiments etc. In this contribution present the current status of many such signals emphasizing their level of significance and referring to recent resources where more details can be found for each signal. We also briefly mention some possible generic theoretical approaches that can collectively explain the non-standard nature of these signals. In many cases, the signals presented are controversial and there is currently debate in the literature on the possible systematic origin of some of these signals. -
Finite Cosmology and a CMB Cold Spot
SLAC-PUB-11778 gr-qc/0602102 Finite cosmology and a CMB cold spot Ronald J. Adler,∗ James D. Bjorken† and James M. Overduin∗ ∗Gravity Probe B, Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, U.S.A. †Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94309, U.S.A. The standard cosmological model posits a spatially flat universe of infinite extent. However, no observation, even in principle, could verify that the matter extends to infinity. In this work we model the universe as a finite spherical ball of dust and dark energy, and obtain a lower limit estimate of its mass and present size: the mass 23 is at least 5 10 M⊙ and the present radius is at least 50 Gly. If we are not too far × from the dust-ball edge we might expect to see a cold spot in the cosmic microwave background, and there might be suppression of the low multipoles in the angular power spectrum. Thus the model may be testable, at least in principle. We also obtain and discuss the geometry exterior to the dust ball; it is Schwarzschild-de Sitter with a naked singularity, and provides an interesting picture of cosmogenesis. Finally we briefly sketch how radiation and inflation eras may be incorporated into the model. 1 Introduction The standard or “concordance” model of the present universe has been very successful in that it is consistent with a wide and diverse array of cosmological data. The model posits a spatially flat (k = 0) Friedmann-Robertson-Walker (FRW) universe of infinite extent, filled with dark energy, well described by a cosmological constant, and pressureless cold dark matter or “dust.” Despite the phenomenological success of the model, our present ignorance of the physical nature of both the dark energy and dark matter should prevent us from being complacent. -
On the Evolution of Large-Scale Structure in a Cosmic Void
On the Evolution of Large-Scale Structure in a Cosmic Void Town Sean Philip February Cape of Thesis Presented for the Degree of UniversityDoctor of Philosophy in the Department of Mathematics and Applied Mathematics University of Cape Town February 2014 Supervised by Assoc. Prof. Chris A. Clarkson & Prof. George F. R. Ellis The copyright of this thesis vests in the author. No quotation from it or information derived from it is to be published without full acknowledgementTown of the source. The thesis is to be used for private study or non- commercial research purposes only. Cape Published by the University ofof Cape Town (UCT) in terms of the non-exclusive license granted to UCT by the author. University ii Contents Declaration vii Abstract ix Acknowledgements xi Conventions and Acronyms xiii 1 The Standard Model of Cosmology 1 1.1 Introduction 1 1.1.1 Historical Overview 1 1.1.2 The Copernican Principle 5 1.2 Theoretical Foundations 10 1.2.1 General Relativity 10 1.2.2 Background Dynamics 10 1.2.3 Redshift, Cosmic Age and distances 13 1.2.4 Growth of Large-Scale Structure 16 1.3 Observational Constraints 23 1.3.1 Overview 23 1.3.2 A Closer Look at the BAO 27 iii 1.4 Challenges, and Steps Beyond 31 2 Lemaˆıtre-Tolman-Bondi Cosmology 35 2.1 Motivation and Review 35 2.2 Background Dynamics 37 2.2.1 Metric and field equations 37 2.2.2 Determining the solution 40 2.2.3 Connecting to observables 41 2.3 Linear Perturbation Theory in LTB 46 2.3.1 Introduction 46 2.3.2 Defining the perturbations 47 2.3.3 Einstein equations 57 2.3.4 The homogeneous -
The Cosmic Microwave Background Radiation at Large Scales and the Peak Theory
UNIVERSIDAD DE CANTABRIA La radiaci´ondel fondo c´osmicode microondas a gran escala y la teor´ıade picos por Airam Marcos Caballero Memoria presentada para optar al t´ıtulode Doctor en Ciencias F´ısicas en el Instituto de F´ısicade Cantabria Abril 2017 Declaraci´onde Autor´ıa Enrique Mart´ınezGonz´alez, doctor en ciencias f´ısicasy profesor de investigaci´ondel Consejo Superior de Investigaciones Cient´ıficas, y Patricio Vielva Mart´ınez, doctor en ciencias f´ısicasy profesor contratado doctor de la Universidad de Cantabria, CERTIFICAN que la presente memoria, La radiaci´ondel fondo c´osmicode microondas a gran scala y la teor´ıade picos ha sido realizada por Airam Marcos Caballero bajo nuestra direcci´onen el Instituto de F´ısicade Cantabr´ıa,para optar al t´ıtulode Doctor por la Universidad de Cantabria. Consideramos que esta memoria contiene aportaciones cient´ıficassuficientes para cons- tituir la Tesis Doctoral del interesado. En Santander, a 7 de abril de 2017, Enrique Mart´ınezGonz´alez Patricio Vielva Mart´ınez iii Agradecimientos Ciertamente, esta tesis no podr´ıahaber sido posible sin la ayuda, apoyo, trabajo y con- sejos de mis dos directores, Enrique y Patricio. Gracias a ellos he podido adentrarme en el mundo de la cosmolog´ıa,incluso en regiones que van mucho m´asall´ade lo presentado en esta tesis. Muchas gracias por todo este tiempo en el que no he dejado de aprender. No ser´ıajusto empezar estos agradecimientos sin mencionar tambi´ena los organismos que me han dado cobijo y apoyo econ´omico: el Instituto de F´ısica de Cantabria, la Universidad de Cantabria, el Consejo Superior de Investigaciones Cient´ıficasy el Minis- terio de Econom´ıay Competitividad. -
Orders of Magnitude (Length) - Wikipedia
03/08/2018 Orders of magnitude (length) - Wikipedia Orders of magnitude (length) The following are examples of orders of magnitude for different lengths. Contents Overview Detailed list Subatomic Atomic to cellular Cellular to human scale Human to astronomical scale Astronomical less than 10 yoctometres 10 yoctometres 100 yoctometres 1 zeptometre 10 zeptometres 100 zeptometres 1 attometre 10 attometres 100 attometres 1 femtometre 10 femtometres 100 femtometres 1 picometre 10 picometres 100 picometres 1 nanometre 10 nanometres 100 nanometres 1 micrometre 10 micrometres 100 micrometres 1 millimetre 1 centimetre 1 decimetre Conversions Wavelengths Human-defined scales and structures Nature Astronomical 1 metre Conversions https://en.wikipedia.org/wiki/Orders_of_magnitude_(length) 1/44 03/08/2018 Orders of magnitude (length) - Wikipedia Human-defined scales and structures Sports Nature Astronomical 1 decametre Conversions Human-defined scales and structures Sports Nature Astronomical 1 hectometre Conversions Human-defined scales and structures Sports Nature Astronomical 1 kilometre Conversions Human-defined scales and structures Geographical Astronomical 10 kilometres Conversions Sports Human-defined scales and structures Geographical Astronomical 100 kilometres Conversions Human-defined scales and structures Geographical Astronomical 1 megametre Conversions Human-defined scales and structures Sports Geographical Astronomical 10 megametres Conversions Human-defined scales and structures Geographical Astronomical 100 megametres 1 gigametre -
Arxiv:2007.04414V1 [Astro-Ph.CO] 8 Jul 2020 Bution of Matter on Large Scales Is Inferred from Tion)
Key words: large scale structure of universe | galaxies: distances and redshifts Draft version July 10, 2020 Typeset using LATEX preprint2 style in AASTeX62 Cosmicflows-3: The South Pole Wall Daniel Pomarede,` 1 R. Brent Tully,2 Romain Graziani,3 Hel´ ene` M. Courtois,4 Yehuda Hoffman,5 and Jer´ emy´ Lezmy4 1Institut de Recherche sur les Lois Fondamentales de l'Univers, CEA Universit´eParis-Saclay, 91191 Gif-sur-Yvette, France 2Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA 3Laboratoire de Physique de Clermont, Universit Clermont Auvergne, Aubire, France 4University of Lyon, UCB Lyon 1, CNRS/IN2P3, IUF, IP2I Lyon, France 5Racah Institute of Physics, Hebrew University, Jerusalem, 91904 Israel ABSTRACT Velocity and density field reconstructions of the volume of the universe within 0:05c derived from the Cosmicflows-3 catalog of galaxy distances has revealed the presence of a filamentary structure extending across ∼ 0:11c. The structure, at a characteristic redshift of 12,000 km s−1, has a density peak coincident with the celestial South Pole. This structure, the largest contiguous feature in the local volume and comparable to the Sloan Great Wall at half the distance, is given the name the South Pole Wall. 1. INTRODUCTION ble of measurements: to a first approximation The South Pole Wall rivals the Sloan Great Vpec = Vobs − H0d. Although uncertainties with Wall in extent, at a distance a factor two individual galaxies are large, the analysis bene- closer. The iconic structures that have trans- fits from the long range correlated nature of the formed our understanding of large scale struc- cosmic flow, allowing the reconstruction of the ture have come from the observed distribution 3D velocity field from noisy, finite and incom- of galaxies assembled from redshift surveys: the plete data (Zaroubi et al. -