Dependencies of the Apparent Luminosity of Quasars on Their Redshift
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Aspects of Spatially Homogeneous and Isotropic Cosmology
Faculty of Technology and Science Department of Physics and Electrical Engineering Mikael Isaksson Aspects of Spatially Homogeneous and Isotropic Cosmology Degree Project of 15 credit points Physics Program Date/Term: 02-04-11 Supervisor: Prof. Claes Uggla Examiner: Prof. Jürgen Fuchs Karlstads universitet 651 88 Karlstad Tfn 054-700 10 00 Fax 054-700 14 60 [email protected] www.kau.se Abstract In this thesis, after a general introduction, we first review some differential geom- etry to provide the mathematical background needed to derive the key equations in cosmology. Then we consider the Robertson-Walker geometry and its relation- ship to cosmography, i.e., how one makes measurements in cosmology. We finally connect the Robertson-Walker geometry to Einstein's field equation to obtain so- called cosmological Friedmann-Lema^ıtre models. These models are subsequently studied by means of potential diagrams. 1 CONTENTS CONTENTS Contents 1 Introduction 3 2 Differential geometry prerequisites 8 3 Cosmography 13 3.1 Robertson-Walker geometry . 13 3.2 Concepts and measurements in cosmography . 18 4 Friedmann-Lema^ıtre dynamics 30 5 Bibliography 42 2 1 INTRODUCTION 1 Introduction Cosmology comes from the Greek word kosmos, `universe' and logia, `study', and is the study of the large-scale structure, origin, and evolution of the universe, that is, of the universe taken as a whole [1]. Even though the word cosmology is relatively recent (first used in 1730 in Christian Wolff's Cosmologia Generalis), the study of the universe has a long history involving science, philosophy, eso- tericism, and religion. Cosmologies in their earliest form were concerned with, what is now known as celestial mechanics (the study of the heavens). -
Methods of Measuring Astronomical Distances
LASER INTERFEROMETER GRAVITATIONAL WAVE OBSERVATORY - LIGO - =============================== LIGO SCIENTIFIC COLLABORATION Technical Note LIGO-T1200427{v1 2012/09/02 Methods of Measuring Astronomical Distances Sarah Gossan and Christian Ott California Institute of Technology Massachusetts Institute of Technology LIGO Project, MS 18-34 LIGO Project, Room NW22-295 Pasadena, CA 91125 Cambridge, MA 02139 Phone (626) 395-2129 Phone (617) 253-4824 Fax (626) 304-9834 Fax (617) 253-7014 E-mail: [email protected] E-mail: [email protected] LIGO Hanford Observatory LIGO Livingston Observatory Route 10, Mile Marker 2 19100 LIGO Lane Richland, WA 99352 Livingston, LA 70754 Phone (509) 372-8106 Phone (225) 686-3100 Fax (509) 372-8137 Fax (225) 686-7189 E-mail: [email protected] E-mail: [email protected] http://www.ligo.org/ LIGO-T1200427{v1 1 Introduction The determination of source distances, from solar system to cosmological scales, holds great importance for the purposes of all areas of astrophysics. Over all distance scales, there is not one method of measuring distances that works consistently, and as a result, distance scales must be built up step-by-step, using different methods that each work over limited ranges of the full distance required. Broadly, astronomical distance `calibrators' can be categorised as primary, secondary or tertiary, with secondary calibrated themselves by primary, and tertiary by secondary, thus compounding any uncertainties in the distances measured with each rung ascended on the cosmological `distance ladder'. Typically, primary calibrators can only be used for nearby stars and stellar clusters, whereas secondary and tertiary calibrators are employed for sources within and beyond the Virgo cluster respectively. -
Observational Cosmology - 30H Course 218.163.109.230 Et Al
Observational cosmology - 30h course 218.163.109.230 et al. (2004–2014) PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Thu, 31 Oct 2013 03:42:03 UTC Contents Articles Observational cosmology 1 Observations: expansion, nucleosynthesis, CMB 5 Redshift 5 Hubble's law 19 Metric expansion of space 29 Big Bang nucleosynthesis 41 Cosmic microwave background 47 Hot big bang model 58 Friedmann equations 58 Friedmann–Lemaître–Robertson–Walker metric 62 Distance measures (cosmology) 68 Observations: up to 10 Gpc/h 71 Observable universe 71 Structure formation 82 Galaxy formation and evolution 88 Quasar 93 Active galactic nucleus 99 Galaxy filament 106 Phenomenological model: LambdaCDM + MOND 111 Lambda-CDM model 111 Inflation (cosmology) 116 Modified Newtonian dynamics 129 Towards a physical model 137 Shape of the universe 137 Inhomogeneous cosmology 143 Back-reaction 144 References Article Sources and Contributors 145 Image Sources, Licenses and Contributors 148 Article Licenses License 150 Observational cosmology 1 Observational cosmology Observational cosmology is the study of the structure, the evolution and the origin of the universe through observation, using instruments such as telescopes and cosmic ray detectors. Early observations The science of physical cosmology as it is practiced today had its subject material defined in the years following the Shapley-Curtis debate when it was determined that the universe had a larger scale than the Milky Way galaxy. This was precipitated by observations that established the size and the dynamics of the cosmos that could be explained by Einstein's General Theory of Relativity. -
Cosmological Constraints from Low-Redshift Data
Noname manuscript No. (will be inserted by the editor) Cosmological constraints from low-redshift data Vladimir V. Lukovic´ · Balakrishna S. Haridasu · Nicola Vittorio the date of receipt and acceptance should be inserted later Contents as well as on inhomogeneous but isotropic models. We pro- vide a broad overlook into these cosmological scenarios and 1 Introduction . .1 several aspects of data analysis. In particular, we review a 2 Theoretical scenarios . .2 number of systematic issues of SN Ia analysis that include 2.1 Concordance model of cosmology and its extensions .3 2.2 Power-law cosmologies . .5 magnitude correction techniques, selection bias and their in- 2.3 Challenging the cosmological principle: LTB models .5 fluence on the inferred cosmological constraints. Further- 3 Type Ia supernovae . .6 more, we examine the isotropic and anisotropic components 3.1 From dozens to a thousand SN Ia . .6 of the BAO data and their individual relevance for cosmo- 3.2 Standardisation techniques . .7 logical model-fitting. We extend the discussion presented 3.3 Hubble residual . .8 3.4 Selection bias . .9 in earlier works regarding the inferred dynamics of cosmic 4 Baryon acoustic oscillations . 10 expansion and its present rate from the low-redshift data. 5 Cosmic expansion rate . 10 Specifically, we discuss the cosmological constraints on the 5.1 Direct measurements . 10 accelerated expansion and related model-selections. In addi- 5.2 H as a cosmological parameter . 12 0 tion, we extensively talk about the Hubble constant problem, 6 Constraints on cosmological models . 13 6.1 Results focusing on SN Ia data . 13 then focus on the low-redshift data constraint on H0 that is 6.2 Results focusing on BAO data . -
Observed Cosmological Redshifts Support Contracting Accelerating Universe
Observed Cosmological Redshifts Support Contracting Accelerating Universe Branislav Vlahovic∗ Department of Physics, North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707 USA. The main argument that Universe is currently expanding is observed redshift increase by distance. However, this conclusion may not be correct, because cosmological redshift depends only on the scaling factors, the change in the size of the universe during the time of light propagation and is not related to the speed of observer or speed of the object emitting the light. An observer in expanding universe will measure the same redshift as observer in contracting universe with the same scaling. This was not taken into account in analysing the SN Ia data related to the universe acceleration. Possibility that universe may contract, but that the observed light is cosmologically redshifted allows for completely different set of cosmological parameters ΩM ; ΩΛ, including the solution ΩM = 1; ΩΛ = 0. The contracting and in the same time accelerating universe explains observed deceleration and acceleration in SN Ia data, but also gives significantly larger value for the age of the universe, t0 = 24 Gyr. This allows to reconsider classical cosmological models with Λ = 0. The contracting stage also may explain the observed association of high redshifted quasars to low redshifted galaxies. COSMOLOGICAL REDSHIFT period t0 − te. Cosmological redshift is not related to the speed of the In co-moving Robertson-Walker coordinate system, re- object that emits the light nor the speed of observer. It is lation between the redshift z, in the frequencies of spec- also not related to the relative velocity between objects. -
CMB Tensions with Low-Redshift H0 and S8 Measurements: Impact of a Redshift-Dependent Type-Ia Supernovae Intrinsic Luminosity
S S symmetry Article CMB Tensions with Low-Redshift H0 and S8 Measurements: Impact of a Redshift-Dependent Type-Ia Supernovae Intrinsic Luminosity Matteo Martinelli 1,* and Isaac Tutusaus 2,3,4,* 1 Institute Lorentz, Leiden University, PO Box 9506, 2300 RA Leiden, The Netherlands 2 Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, 08193 Barcelona, Spain 3 Institut d’Estudis Espacials de Catalunya (IEEC), Carrer Gran Capità 2-4, 08193 Barcelona, Spain 4 CNRS, IRAP, UPS-OMP, Université de Toulouse, 14 Avenue Edouard Belin, F-31400 Toulouse, France * Correspondence: [email protected] (M.M.); [email protected] (I.T.) Received: 28 June 2019; Accepted: 24 July 2019; Published: 2 August 2019 Abstract: With the recent increase in precision of our cosmological datasets, measurements of LCDM model parameter provided by high- and low-redshift observations started to be in tension, i.e., the obtained values of such parameters were shown to be significantly different in a statistical sense. In this work we tackle the tension on the value of the Hubble parameter, H0, and the weighted amplitude of matter fluctuations, S8, obtained from local or low-redshift measurements and from cosmic microwave background (CMB) observations. We combine the main approaches previously used in the literature by extending the cosmological model and accounting for extra systematic uncertainties. With such analysis we aim at exploring non standard cosmological models, implying deviation from a cosmological constant driven acceleration of the Universe expansion, in the presence of additional uncertainties in measurements. In more detail, we reconstruct the Dark Energy equation of state as a function of redshift, while we study the impact of type-Ia supernovae (SNIa) redshift-dependent astrophysical systematic effects on these tensions. -
Distance Modulus
Astronomy from 4 Perspectives Bi-national Heraeus Sumer School Series for Teacher Students and Teachers I. Cosmology Prof. Dr. Andreas Just Zentrum für Astronomie Heidelberg University Cosmic Distances 22. Aug. 2013 Cosmic Distances - A. Just 1 Cosmic Distances Distance determinations: a fundamental, omnipresent problem in astronomy Local universe Distance ladder Methods/objects/calibration Hubble constant and galaxy distribution expanding curved space Distance and redshift Luminosity, surface brightness, sizes Cornerstone observations 22. Aug. 2013 Cosmic Distances - A. Just 2 Units Units Length: Time: Velocity: Mass: Gravitational constant: 22. Aug. 2013 Cosmic Distances - A. Just 3 Units the astronomical unit AU physical definition from light running time * Attention: semi-major axis of the orbit therefore rounded value: maximum diameter D (e=0.017, b=minor axis): 22. Aug. 2013 Cosmic Distances - A. Just 4 Basic principle Compare an absolute and an apparent property with known dependence on distance Trigonometric parallax . orbital motion of Earth - angular motion of star at sky Distance modulus . Absolute luminosity - apparent brightness . Classification of objects and calibration • Period-luminosity relation (variable stars) • Tully-Fisher relation (spiral galaxies) Kinematic distances . Binary stars: Radial velocities (+ Kepler laws) . Radial velocities – proper motion (+spherical expansion) . Radial velocities – Galactic rotation (+ rotation curve) Hubble flow . Hubble constant and redshift 22. Aug. 2013 -
000001 Proceedings New Directions in Modern Cosmology
000001 Proceedings New Directions in Modern Cosmology Proceedings New Directions in Modern Cosmology 000002 000003 Proceedings New Directions in Modern Cosmology 000004 Prediction for the neutrino mass in the KATRIN experiment from lensing by the galaxy cluster A1689 Theo M. Nieuwenhuizen Center for Cosmology and Particle Physics, New York University, New York, NY 10003 On leave of: Institute for Theoretical Physics, University of Amsterdam, Science Park 904, P.O. Box 94485, 1090 GL Amsterdam, The Netherlands Andrea Morandi Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel [email protected]; [email protected] Proceedings New Directions in Modern Cosmology ABSTRACT The KATRIN experiment in Karlsruhe Germany will monitor the decay of tritium, which produces an electron-antineutrino. While the present upper bound for its mass is 2 eV/c2, KATRIN will search down to 0.2 eV=c2. If the dark matter of the galaxy cluster Abell 1689 is modeled as degenerate isothermal fermions, the strong and weak lensing data may be explained by degenerate neutrinos with mass of 1.5 eV=c2. Strong lensing data beyond 275 kpc put tension on the standard cold dark matter interpretation. In the most natural scenario, the electron antineutrino will have a mass of 1.5 eV/c2, a value that will be tested in KATRIN. Subject headings: Introduction, NFW profile for cold dark matter, Isothermal neutrino mass models, Applications of the NFW and isothermal neutrino models, Fit to the most recent data sets, Conclusion 1. Introduction The neutrino sector of the Standard Model of elementary particles is one of today's most intense research fields (Kusenko, 2010; Altarelli and Feruglio 2010; Avignone et al. -
On the Jet Activity in 3C
On the Jet Activity in 3C 273 Lukasz Stawarz Obserwatorium Astronomiczne, Uniwersytet Jagiello´nski, ul. Orla 171, 30-244 Krak´ow, Poland [email protected] ABSTRACT In this paper we comment on the possibility for intermittent jet activity in quasar 3C 273 on different time-scales. We propose, that striking morphology of the large-scale radio jet in this source, as well as the apparent lack of its counterpart on the opposite side of the active center, may be explained in a framework of a restarting jet model. In particular, we propose that 3C 273 radio source is intrinsically two-sided, and represents an analogue of double-double radio galaxies, but only inclined at a small angle to the line of sight. In this case, the apparent one-sideness of the kiloparsec-scale radio structure may be due to combined Doppler and time-travel effects alone, if the 3C 273 large-scale jet itself is relativistic and matter-dominated. We also propose, that knotty morphology of the discussed jet, which is observed now additionally at optical and X-ray frequencies, indicates modulation in the jet kinetic power. This, together with the variability of the jet at small (parsec) scales, indicates that the jet activity in 3C 273, and possibly in other similar sources, is variable/modulated/intermittent over many different time-scales. arXiv:astro-ph/0403179v2 28 May 2004 Subject headings: galaxies: active—galaxies: jets—quasars: individual (3C 273) 1. Introduction 3C 273 is the well-known quasar at the redshift z =0.158, discovered together with its famous large-scale jet at the very beginning of quasar optical researches (see a review by Courvoisier 1998). -
Distance Measures in Cosmology
Distance measures in cosmology David W. Hogg Institute for Advanced Study, 1 Einstein Drive, Princeton NJ 08540 [email protected] 2000 December 1 Introduction In cosmology (or to be more specific, cosmography, the measurement of the Universe) there are many ways to specify the distance between two points, because in the expanding Universe, the distances between comoving objects are constantly changing, and Earth-bound observers look back in time as they look out in distance. The unifying aspect is that all distance measures somehow measure the separation between events on radial null trajectories, ie, trajectories of photons which terminate at the observer. In this note, formulae for many different cosmological distance measures are provided. I treat the concept of “distance measure” very liberally, so, for instance, the lookback time and comoving volume are both considered distance measures. The bibliography of source material can be consulted for many of the derivations; this is merely a “cheat sheet.” Minimal C routines (KR) which compute all of these distance measures are available from the author upon request. Comments and corrections are highly appreciated, as are acknowledgments or citation in research that makes use of this summary or the associated code. 2 Cosmographic parameters The Hubble constant H0 is the constant of proportionality between recession speed v and distance d in the expanding Universe; v = H0 d (1) arXiv:astro-ph/9905116v4 16 Dec 2000 The subscripted “0” refers to the present epoch because in general H changes with time. The dimensions of H0 are inverse time, but it is usually written 1 1 H0 = 100 h km s− Mpc− (2) where h is a dimensionless number parameterizing our ignorance. -
The Dark Energy Survey Collaboration , 2015) Using DES Data As Well As Combined Analyses Focusing on Smaller Scales (Park Et Al., 2015) Have Been Presented Elsewhere
ADVERTIMENT. Lʼaccés als continguts dʼaquesta tesi queda condicionat a lʼacceptació de les condicions dʼús establertes per la següent llicència Creative Commons: http://cat.creativecommons.org/?page_id=184 ADVERTENCIA. El acceso a los contenidos de esta tesis queda condicionado a la aceptación de las condiciones de uso establecidas por la siguiente licencia Creative Commons: http://es.creativecommons.org/blog/licencias/ WARNING. The access to the contents of this doctoral thesis it is limited to the acceptance of the use conditions set by the following Creative Commons license: https://creativecommons.org/licenses/?lang=en Dark Energy properties from the combination of large-scale structure and weak gravitational lensing in the Dark Energy Survey Author: Carles Sánchez Alonso Departament de Física Universitat Autònoma de Barcelona A thesis submitted for the degree of Philosophae Doctor (PhD) Day of defense: 28 September 2017 Director & Tutor: Dr. Ramon Miquel Pascual IFAE & ICREA Edifici Cn, UAB 08193 Bellaterra (Barcelona), Spain [email protected] CONTENTS Introduction 1 I Preliminars 3 1 Cosmological framework 5 1.1 The smooth universe ............................. 6 1.1.1 The field equations ......................... 6 1.1.2 The FLRW metric ........................... 7 1.1.3 The Friedmann equations ..................... 8 1.2 Fundamental observations ......................... 9 1.2.1 The expansion of the universe: Hubble’s law .......... 9 1.2.2 The Cosmic Microwave Background ............... 11 1.2.3 The abundance of primordial elements ............. 14 1.3 Distances in the universe .......................... 16 1.3.1 Comoving distance .......................... 16 1.3.2 Angular diameter distance ..................... 16 1.3.3 Luminosity distance ......................... 17 1.4 The accelerating universe .......................... 18 1.5 The Large-Scale Structure of the Universe ............... -
ASTRONOMY and ASTROPHYSICS Beaming and Precession in The
View metadata, citation and similar papers at core.ac.uk brought to you by CORE Astron. Astrophys. 360, 57–64 (2000) providedASTRONOMY by Servicio de Difusión de la Creación Intelectual AND ASTROPHYSICS Beaming and precession in the inner jet of 3C 273 II. The central engine G.E. Romero1,?, L. Chajet2, Z. Abraham3, and J.H. Fan4 1 Instituto Argentino de Radioastronom´ıa, C.C.5, (1894) Villa Elisa, Bs. As., Argentina 2 Facultad de Ciencias Astronomicas´ y Geof´ısicas, UNLP, Paseo del Bosque, 1900 La Plata, Argentina 3 Universidade de Sao˜ Paulo, Instituto Astronomicoˆ e Geof´ısico, Av. M. Stefano 4200, CEP 04301-904 Sao˜ Paulo, SP, Brazil 4 Guangzhou Normal University, Center for Astrophysics, Guangzhou 510400, P.R. China Received 29 December 1999 / Accepted 25 May 2000 Abstract. The quasar 3C 273 is a well-known superluminal Recently, Abraham & Romero (1999, hereafter Paper I) have source. More than 10 radio components have been detected used all available VLBI data of superluminal components in moving away from the nucleus with different superluminal 3C 273 to determine the kinematic evolution of the inner jet. speeds and position angles. The pattern of ejection suggests the They have shown that the different velocities and position angles existence of a precessing inner jet, whose kinematics has been at the ejection time of the various well-monitored components discussed by Abraham & Romero (1999). We now present a are consistent with the existence of a precessing inner jet in the binary black hole model for the central engine of 3C 273 where quasar. Fits of the VLBI data suggest a period of precession the rapid precession is tidally induced in the primary accretion of 16 years in the observer’s frame.