Sne Ia Redshift in a Nonadiabatic Universe
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
The Hubble Constant H0 --- Describing How Fast the Universe Is Expanding A˙ (T) H(T) = , A(T) = the Cosmic Scale Factor A(T)
Determining H0 and q0 from Supernova Data LA-UR-11-03930 Mian Wang Henan Normal University, P.R. China Baolian Cheng Los Alamos National Laboratory PANIC11, 25 July, 2011,MIT, Cambridge, MA Abstract Since 1929 when Edwin Hubble showed that the Universe is expanding, extensive observations of redshifts and relative distances of galaxies have established the form of expansion law. Mapping the kinematics of the expanding universe requires sets of measurements of the relative size and age of the universe at different epochs of its history. There has been decades effort to get precise measurements of two parameters that provide a crucial test for cosmology models. The two key parameters are the rate of expansion, i.e., the Hubble constant (H0) and the deceleration in expansion (q0). These two parameters have been studied from the exceedingly distant clusters where redshift is large. It is indicated that the universe is made up by roughly 73% of dark energy, 23% of dark matter, and 4% of normal luminous matter; and the universe is currently accelerating. Recently, however, the unexpected faintness of the Type Ia supernovae (SNe) at low redshifts (z<1) provides unique information to the study of the expansion behavior of the universe and the determination of the Hubble constant. In this work, We present a method based upon the distance modulus redshift relation and use the recent supernova Ia data to determine the parameters H0 and q0 simultaneously. Preliminary results will be presented and some intriguing questions to current theories are also raised. Outline 1. Introduction 2. Model and data analysis 3. -
Download This Article in PDF Format
A&A 561, L12 (2014) Astronomy DOI: 10.1051/0004-6361/201323020 & c ESO 2014 Astrophysics Letter to the Editor Possible structure in the GRB sky distribution at redshift two István Horváth1, Jon Hakkila2, and Zsolt Bagoly1,3 1 National University of Public Service, 1093 Budapest, Hungary e-mail: [email protected] 2 College of Charleston, Charleston, SC, USA 3 Eötvös University, 1056 Budapest, Hungary Received 9 November 2013 / Accepted 24 December 2013 ABSTRACT Context. Research over the past three decades has revolutionized cosmology while supporting the standard cosmological model. However, the cosmological principle of Universal homogeneity and isotropy has always been in question, since structures as large as the survey size have always been found each time the survey size has increased. Until 2013, the largest known structure in our Universe was the Sloan Great Wall, which is more than 400 Mpc long located approximately one billion light years away. Aims. Gamma-ray bursts (GRBs) are the most energetic explosions in the Universe. As they are associated with the stellar endpoints of massive stars and are found in and near distant galaxies, they are viable indicators of the dense part of the Universe containing normal matter. The spatial distribution of GRBs can thus help expose the large scale structure of the Universe. Methods. As of July 2012, 283 GRB redshifts have been measured. Subdividing this sample into nine radial parts, each contain- ing 31 GRBs, indicates that the GRB sample having 1.6 < z < 2.1differs significantly from the others in that 14 of the 31 GRBs are concentrated in roughly 1/8 of the sky. -
The Reionization of Cosmic Hydrogen by the First Galaxies Abstract 1
David Goodstein’s Cosmology Book The Reionization of Cosmic Hydrogen by the First Galaxies Abraham Loeb Department of Astronomy, Harvard University, 60 Garden St., Cambridge MA, 02138 Abstract Cosmology is by now a mature experimental science. We are privileged to live at a time when the story of genesis (how the Universe started and developed) can be critically explored by direct observations. Looking deep into the Universe through powerful telescopes, we can see images of the Universe when it was younger because of the finite time it takes light to travel to us from distant sources. Existing data sets include an image of the Universe when it was 0.4 million years old (in the form of the cosmic microwave background), as well as images of individual galaxies when the Universe was older than a billion years. But there is a serious challenge: in between these two epochs was a period when the Universe was dark, stars had not yet formed, and the cosmic microwave background no longer traced the distribution of matter. And this is precisely the most interesting period, when the primordial soup evolved into the rich zoo of objects we now see. The observers are moving ahead along several fronts. The first involves the construction of large infrared telescopes on the ground and in space, that will provide us with new photos of the first galaxies. Current plans include ground-based telescopes which are 24-42 meter in diameter, and NASA’s successor to the Hubble Space Telescope, called the James Webb Space Telescope. In addition, several observational groups around the globe are constructing radio arrays that will be capable of mapping the three-dimensional distribution of cosmic hydrogen in the infant Universe. -
The High Redshift Universe: Galaxies and the Intergalactic Medium
The High Redshift Universe: Galaxies and the Intergalactic Medium Koki Kakiichi M¨unchen2016 The High Redshift Universe: Galaxies and the Intergalactic Medium Koki Kakiichi Dissertation an der Fakult¨atf¨urPhysik der Ludwig{Maximilians{Universit¨at M¨unchen vorgelegt von Koki Kakiichi aus Komono, Mie, Japan M¨unchen, den 15 Juni 2016 Erstgutachter: Prof. Dr. Simon White Zweitgutachter: Prof. Dr. Jochen Weller Tag der m¨undlichen Pr¨ufung:Juli 2016 Contents Summary xiii 1 Extragalactic Astrophysics and Cosmology 1 1.1 Prologue . 1 1.2 Briefly Story about Reionization . 3 1.3 Foundation of Observational Cosmology . 3 1.4 Hierarchical Structure Formation . 5 1.5 Cosmological probes . 8 1.5.1 H0 measurement and the extragalactic distance scale . 8 1.5.2 Cosmic Microwave Background (CMB) . 10 1.5.3 Large-Scale Structure: galaxy surveys and Lyα forests . 11 1.6 Astrophysics of Galaxies and the IGM . 13 1.6.1 Physical processes in galaxies . 14 1.6.2 Physical processes in the IGM . 17 1.6.3 Radiation Hydrodynamics of Galaxies and the IGM . 20 1.7 Bridging theory and observations . 23 1.8 Observations of the High-Redshift Universe . 23 1.8.1 General demographics of galaxies . 23 1.8.2 Lyman-break galaxies, Lyα emitters, Lyα emitting galaxies . 26 1.8.3 Luminosity functions of LBGs and LAEs . 26 1.8.4 Lyα emission and absorption in LBGs: the physical state of high-z star forming galaxies . 27 1.8.5 Clustering properties of LBGs and LAEs: host dark matter haloes and galaxy environment . 30 1.8.6 Circum-/intergalactic gas environment of LBGs and LAEs . -
Measuring Dark Energy and Primordial Non-Gaussianity: Things to (Or Not To?) Worry About!
Measuring Dark Energy and Primordial Non-Gaussianity: Things To (or Not To?) Worry About! Devdeep Sarkar Center for Cosmology, UC Irvine in collaboration with: Scott Sullivan (UCI/UCLA), Shahab Joudaki (UCI), Alexandre Amblard (UCI), Paolo Serra (UCI), Daniel Holz (Chicago/LANL), and Asantha Cooray (UCI) UC Berkeley-LBNL Cosmology Group Seminar September 16, 2008 Outline Outline Start With... Dark Energy Why Pursue Dark Energy? DE Equation of State (EOS) DE from SNe Ia ++ Beware of Systematics Two Population Model Gravitational Lensing Outline Start With... And Then... Dark Energy CMB Bispectrum Why Pursue Dark Energy? Why Non-Gaussianity? DE Equation of State (EOS) Why in CMB Bispectrum? DE from SNe Ia ++ The fNL Beware of Systematics WL of CMB Bispectrum Two Population Model Analytic Sketch Gravitational Lensing Numerical Results Outline Start With... And Then... Dark Energy CMB Bispectrum Why Pursue Dark Energy? Why Non-Gaussianity? DE Equation of State (EOS) Why in CMB Bispectrum? DE from SNe Ia ++ The fNL Beware of Systematics WL of CMB Bispectrum Two Population Model Analytical Sketch Gravitational Lensing Numerical Results Credit: NASA/WMAP Science Team Credit: NASA/WMAP Science Team Credit: NASA/WMAP Science Team THE ASTRONOMICAL JOURNAL, 116:1009È1038, 1998 September ( 1998. The American Astronomical Society. All rights reserved. Printed in U.S.A. OBSERVATIONAL EVIDENCE FROM SUPERNOVAE FOR AN ACCELERATING UNIVERSE AND A COSMOLOGICAL CONSTANT ADAM G. RIESS,1 ALEXEI V. FILIPPENKO,1 PETER CHALLIS,2 ALEJANDRO CLOCCHIATTI,3 ALAN DIERCKS,4 PETER M. GARNAVICH,2 RON L. GILLILAND,5 CRAIG J. HOGAN,4 SAURABH JHA,2 ROBERT P. KIRSHNER,2 B. LEIBUNDGUT,6 M. -
Is the Universe Really Expanding?
Is the Universe really expanding? J.G. Hartnett School of Physics, the University of Western Australia 35 Stirling Hwy, Crawley 6009 WA Australia; [email protected] (Dated: November 22, 2011) The Hubble law, determined from the distance modulii and redshifts of galaxies, for the past 80 years, has been used as strong evidence for an expanding universe. This claim is reviewed in light of the claimed lack of necessary evidence for time dilation in quasar and gamma-ray burst luminosity variations and other lines of evidence. It is concluded that the observations could be used to describe either a static universe (where the Hubble law results from some as-yet-unknown mechanism) or an expanding universe described by the standard Λ cold dark matter model. In the latter case, size evolution of galaxies is necessary for agreement with observations. Yet the simple non-expanding Euclidean universe fits most data with the least number of assumptions. From this review it is apparent that there are still many unanswered questions in cosmology and the title question of this paper is still far from being answered. Keywords: expanding universe, static universe, time dilation I. INTRODUCTION eral relativity, which has been successfully empirically tested in the solar system by numerous tests [74], and with pulsar/neutron star and pulsar/pulsar binary pairs Ever since the late 1920’s, when Edwin Hubble discov- [16, 45, 62] in the Galaxy, is a very strong point in its fa- ered a simple proportionality [40] between the redshifts vor, and strong evidence for an expanding universe [69]. -
Einstein's Role in the Creation of Relativistic Cosmology
EINSTEIN'S ROLE IN THE CREATION OF RELATIVISTIC COSMOLOGY CHRISTOPHER SMEENK 1. Introduction Einstein's paper, \Cosmological Considerations in the General Theory of Relativ- ity" (Einstein 1917b), is rightly regarded as the first step in modern theoretical cosmology. Perhaps the most striking novelty introduced by Einstein was the very idea of a cosmological model, an exact solution to his new gravitational field equations that gives a global description of the universe in its entirety. Einstein's paper inspired a small group of theorists to study cosmological models using his new gravitational theory, and the ideas developed during these early days have been a crucial part of cosmology ever since. We will see below that understanding the physical properties of these models and their possible connections to astro- nomical observations was the central problem facing relativistic cosmology in the 20s. By the early 30s, there was widespread consensus that a class of models de- scribing the expanding universe was in at least rough agreement with astronomical observations. But this achievement was certainly not what Einstein had in mind in introducing the first cosmological model. Einstein's seminal paper was not simply a straightforward application of his new theory to an area where one would ex- pect the greatest differences from Newtonian theory. Instead, Einstein's foray into cosmology was a final attempt to guarantee that a version of \Mach's principle" holds. The Machian idea that inertia is due only to matter shaped Einstein's work on a new theory of gravity, but he soon realized that this might not hold in his “final” theory of November 1915. -
Common Misconceptions of Cosmological Horizons and the Superluminal Expansion of the Universe
CSIRO PUBLISHING www.publish.csiro.au/journals/pasa Publications of the Astronomical Society of Australia, 2004, 21, 97–109 Expanding Confusion: Common Misconceptions of Cosmological Horizons and the Superluminal Expansion of the Universe Tamara M. Davis and Charles H. Lineweaver University of New South Wales, Sydney NSW 2052, Australia (e-mail: [email protected]; [email protected]) Received 2003 June 3, accepted 2003 October 10 Abstract: We use standard general relativity to illustrate and clarify several common misconceptions about the expansion of the universe. To show the abundance of these misconceptions we cite numerous misleading, or easily misinterpreted, statements in the literature. In the context of the new standard CDM cosmology we point out confusions regarding the particle horizon, the event horizon, the ‘observable universe’ and the Hubble sphere (distance at which recession velocity = c). We show that we can observe galaxies that have, and always have had, recession velocities greater than the speed of light. We explain why this does not violate special relativity and we link these concepts to observational tests. Attempts to restrict recession velocities to less than the speed of light require a special relativistic interpretation of cosmological redshifts. We analyze apparent magnitudes of supernovae and observationally rule out the special relativistic Doppler interpretation of cosmological redshifts at a confidence level of 23σ. Keywords: cosmology: observations — cosmology: theory 1 Introduction description of the expanding universe using spacetime The general relativistic (GR) interpretation of the redshifts diagrams and we provide a mathematical summary in of distant galaxies, as the expansion of the universe, is Appendix A. -
Arxiv:Astro-Ph/9805201V1 15 May 1998 Hitpe Stubbs Christopher .Phillips M
Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant To Appear in the Astronomical Journal Adam G. Riess1, Alexei V. Filippenko1, Peter Challis2, Alejandro Clocchiatti3, Alan Diercks4, Peter M. Garnavich2, Ron L. Gilliland5, Craig J. Hogan4,SaurabhJha2,RobertP.Kirshner2, B. Leibundgut6,M. M. Phillips7, David Reiss4, Brian P. Schmidt89, Robert A. Schommer7,R.ChrisSmith710, J. Spyromilio6, Christopher Stubbs4, Nicholas B. Suntzeff7, John Tonry11 ABSTRACT We present spectral and photometric observations of 10 type Ia supernovae (SNe Ia) in the redshift range 0.16 ≤ z ≤ 0.62. The luminosity distances of these objects are determined by methods that employ relations between SN Ia luminosity and light curve shape. Combined with previous data from our High-Z Supernova Search Team (Garnavich et al. 1998; Schmidt et al. 1998) and Riess et al. (1998a), this expanded set of 16 high-redshift supernovae and a set of 34 nearby supernovae are used to place constraints on the following cosmological parameters: the Hubble constant (H0), the mass density (ΩM ), the cosmological constant (i.e., the vacuum energy density, ΩΛ), the deceleration parameter (q0), and the dynamical age of the Universe (t0). The distances of the high-redshift SNe Ia are, on average, 10% to 15% farther than expected in a low mass density (ΩM =0.2) Universe without a cosmological constant. Different light curve fitting methods, SN Ia subsamples, and prior constraints unanimously favor eternally expanding models with positive cosmological constant -
Hubble's Diagram and Cosmic Expansion
Hubble’s diagram and cosmic expansion Robert P. Kirshner* Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 Contributed by Robert P. Kirshner, October 21, 2003 Edwin Hubble’s classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168–173]. The chief result, that a galaxy’s distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble’s Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble’s distances have a large systematic error, Hubble’s velocities come chiefly from Vesto Melvin Slipher, and the interpretation in terms of the de Sitter effect is out of the mainstream of modern cosmology, this article opened the way to investigation of the expanding, evolving, and accelerating universe that engages today’s burgeoning field of cosmology. he publication of Edwin Hub- ble’s 1929 article ‘‘A relation between distance and radial T velocity among extra-galactic nebulae’’ marked a turning point in un- derstanding the universe. In this brief report, Hubble laid out the evidence for one of the great discoveries in 20th cen- tury science: the expanding universe. Hubble showed that galaxies recede from us in all directions and more dis- tant ones recede more rapidly in pro- portion to their distance. His graph of velocity against distance (Fig. 1) is the original Hubble diagram; the equation that describes the linear fit, velocity ϭ ϫ Ho distance, is Hubble’s Law; the slope of that line is the Hubble con- ͞ stant, Ho; and 1 Ho is the Hubble time. -
III EO Lawrenc
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server OBSERVATION OF COSMOLOGICAL TIME DILATION USING TYPE IA SUPERNOVAE AS CLOCKS The Supernova Cosmology Project : III G.GOLDHABER1, S. DEUSTUA, S. GABI, D. GROOM, I. HOOK, A. KIM, M. KIM, J. LEE, R. PAIN2, C. PENNYPACKER, S. PERLMUTTER AND I. SMALL E. O. Lawrence Berkeley National Laboratory & Center for Particle Astrophysics, University of California, Berkeley A. GOOBAR University of Stockholm R. ELLIS AND R. MCMAHON Institute of Astronomy, Cambridge University B. BOYLE, P. BUNCLARK, D. CARTER, K. GLAZEBROOK3 AND M. IRWIN Royal Greenwich Observatory H. NEWBERG Fermi National Accelerator Laboratory A. V. FILIPPENKO AND T. MATHESON University of California, Berkeley M. DOPITA AND J. MOULD MSSSO, Australian National University AND W. COUCH University of New South Wales . Abstract. This work is based on the first results from a systematic search for high redshift Type Ia supernovae. Using filters in the R-band we dis- covered seven such SNe, with redshift z =0:3 0:5, before or at maximum light. Type Ia SNe are known to be a homogeneous− group of SNe, to first order, with very similar light curves, spectra and peak luminosities. In this 1Presented by G. Goldhaber, e-mail address:[email protected] 2Current address: CNRS-IN2P3, University of Paris 3Current address: Anglo-Australian Observatory 2 talk we report that the light curves we observe are all broadened (time dilated) as expected from the expanding universe hypothesis. Small vari- ations from the expected 1 + z broadening of the light curve widths can be attributed to a width-brightness correlation that has been observed for nearby SNe (z<0:1). -
19. Big-Bang Cosmology 1 19
19. Big-Bang cosmology 1 19. BIG-BANG COSMOLOGY Revised September 2009 by K.A. Olive (University of Minnesota) and J.A. Peacock (University of Edinburgh). 19.1. Introduction to Standard Big-Bang Model The observed expansion of the Universe [1,2,3] is a natural (almost inevitable) result of any homogeneous and isotropic cosmological model based on general relativity. However, by itself, the Hubble expansion does not provide sufficient evidence for what we generally refer to as the Big-Bang model of cosmology. While general relativity is in principle capable of describing the cosmology of any given distribution of matter, it is extremely fortunate that our Universe appears to be homogeneous and isotropic on large scales. Together, homogeneity and isotropy allow us to extend the Copernican Principle to the Cosmological Principle, stating that all spatial positions in the Universe are essentially equivalent. The formulation of the Big-Bang model began in the 1940s with the work of George Gamow and his collaborators, Alpher and Herman. In order to account for the possibility that the abundances of the elements had a cosmological origin, they proposed that the early Universe which was once very hot and dense (enough so as to allow for the nucleosynthetic processing of hydrogen), and has expanded and cooled to its present state [4,5]. In 1948, Alpher and Herman predicted that a direct consequence of this model is the presence of a relic background radiation with a temperature of order a few K [6,7]. Of course this radiation was observed 16 years later as the microwave background radiation [8].