DOCSLIB.ORG

Cosmology Meets Condensed Matter

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cosmology Meets Condensed Matter Cosmology Meets Condensed Matter Mark N. Brook Thesis submitted to the University of Nottingham for the degree of Doctor of Philosophy. July 2010 The Feynman Problem-Solving Algorithm: 1. Write down the problem 2. Think very hard 3. Write down the answer – R. P. Feynman att. to M. Gell-Mann Supervisor: Prof. Peter Coles Examiners: Prof. Ed Copeland Prof. Ray Rivers Abstract This thesis is concerned with the interface of cosmology and condensed matter. Although at either end of the scale spectrum, the two disciplines have more in common than one might think. Condensed matter theorists and high-energy field theorists study, usually independently, phenomena embedded in the structure of a quantum field theory. It would appear at first glance that these phenomena are disjoint, and this has often led to the two fields developing their own procedures and strategies, and adopting their own nomenclature. We will look at some concepts that have helped bridge the gap between the two sub- jects, enabling progress in both, before incorporating condensed matter techniques to our own cosmological model. By considering ideas from cosmological high-energy field theory, we then critically examine other models of astrophysical condensed mat- ter phenomena. In Chapter 1, we introduce the current cosmological paradigm, and present a somewhat historical overview of the interplay between cosmology and condensed matter. Many concepts are introduced here that later chapters will follow up on, and we give some examples in which condensed matter physics has had a very real effect on informing cosmology. We also reflect on the most recent incarnations of the condensed matter / cosmology interplay, and the future of these developments. Chapter 2 presents the Einstein-Klein-Gordon system of equations and their non-relat- ivistic and nonlinear counterparts, the Schr¨odinger-Poisson, and nonlinear Schr¨odinger (Gross Pitaevskii)-Poisson systems. We give a more technical overview of the various applications of these systems of equations, as well as discussing the role and interpre- tation of condensates in the field of cosmology. Abstract iii In Chapter 3 we discuss more qualitatively the fluid-mechanical methods used in a wave-mechanical approach to structure formation, and in formulations of condensed matter models. Taking a lead from the condensed matter side, we look at some of the details of the Gross-Pitaevskii equation, particularly with regard to quantum vortices, and then put this quantum-mechanical system into a cosmological environment by coupling it to the Poisson equation, in an effort to pin down some of the parameters that may be consistent with the existence of vortices in a cosmological Bose-Einstein condensate. In Chapter 4 we turn to high-energy field theory and elucidate further some of the re- lationships with condensed matter physics that are present. We also critically examine a Bose-Einstein dark matter model in light of these considerations. Chapter 5 rounds off with a discussion and suggestions for further work based upon models we have discussed, as well as some ideas for models that have not yet been mentioned. An appendix discusses techniques for moving from the relativistic Einstein-Klein- Gordon equations to the Schr¨odinger-Poisson system. Acknowledgements Gratitude is extended to those who have conspired to keep my life interesting. Includ- ing, but not limited, to: David, Will, Edo, Jensen, Ryan, Sarah, Thea, Dan, Nic, Ben, Karen, Seb, Charlotte, Jon, Hari, Tony, Abigail, Ben, Dave, Matt, Bruce, Holger, Kiera, Martin, Bethan, Ed, Mike, Peter, Meghan, Kate, Kathleen, Omar, Paul, Nicky, Dan, Rob, Evelyn, Amanda, Beth, David, Lisa, Dolf, Emma, Steph, Dan, Mike, Ruth, Amanda, Ian, Malgorzata, Joe, Peter, Tom, Jesse, Amie, Jen, Shannon, Troy, Fred, Tiana, Charles, Justine, Joe, Richard, Andrew, Philip, Frazer, Anita, David, Ray, Sophie, BJ, Kyle, Carl, Chris, June, Simon, Sean, Gemma, Iris, David, Mike, Christine, Rowena, Janine, Emma, Gustavo, Emmaline, Dale, Jon, Katrina, David, Peter, Aman, Jonathan, Kate, Chris, Kev, Boris, Magda, Mark, Dave, Carly, Lizzy, Belinka, Elisa, Judith, Daniele, Jes´us, Dan, Maryam, Marco, Natasha, Giordano, Riccardo, Marion, Lynne, Jennie, Danny, Phillip, Harvey, Anne, Tim, Duncan, Mitsuo, Graeme, Marianne, Bec, Karima, Marco, Kate, Julie, Ben, Martyn, Clare, Michelle, Nara, Nat, Phil, Fiona, Caitlin, Alberto, Ned, Karen, Alessandra, Rachael, Alkistis, Becca, Tom, Claire, Gary, Martin, Arianna, Yara, Olivia, Philip. Contents Abstract ii Acknowledgements iv List of Figures and Tables viii 1 Cosmology and Condensed Matter 1 1.1 Cosmology ............................... 1 1.1.1 TheBirthofGeneralRelativity. 1 1.1.2 InflationandDarkEnergy . 13 1.1.3 The Traditional Approach to Structure Formation . ... 27 1.1.4 DarkMatter........................... 30 1.2 CosmologyMeetsCondensedMatter. 38 1.2.1 The‘Higgs-Anderson’mechanism . 39 1.2.2 Kibble-Zurek mechanism - Condensed Matter again informs Cosmology ........................... 41 1.3 TheFutureofMulti-DisciplinaryResearch . .... 45 1.4 Discussion................................ 48 2 Technical Background 49 2.1 BeyondColdDarkMatter. 50 2.2 A Wave-Mechanical Approach to Structure Formation . ..... 52 2.3 QuantumMechanicalDarkMatter . 55 2.3.1 DarkMatterasaBose-EinsteinCondensate . 56 2.4 ScalarFieldDarkMatter . 59 2.4.1 Scalar Fieldsand Bose-EinsteinCondensation . ... 63 2.5 ExoticObjects.............................. 66 2.5.1 BosonStars ........................... 66 2.5.2 Oscillatons ........................... 68 2.6 PenroseandtheQuantumStateReductionProblem . ... 69 CONTENTS vi 2.7 Discussion................................ 71 3 The nonlinear Schrodinger¨ Equation in Condensed Matter and Cosmol- ogy 73 3.1 TheBose-EinsteinCondensate . 74 3.2 TheGross-PitaevskiiEquation . 77 3.2.1 TheMadelungTransformation . 82 3.2.2 Vortices ............................. 83 3.2.3 ApproximationstotheDensityProfile . 86 3.3 The Wave-Mechanical Approach to Structure Formation . ..... 88 3.4 Gravitational Stability of Vortices in Bose-Einstein Condensate Dark Matter.................................. 90 3.4.1 Vortices in Gravitationally Coupled Bose-Einstein Condensates 92 3.4.2 Vortex Stability in Gravitationally Coupled Bose-Einstein Condensates........................... 93 3.4.3 BoundsonParameters . 95 3.4.4 Results ............................. 99 3.5 Discussion................................ 100 4 Relations to Field Theory 105 4.1 ComparisonofRelatedModels . 106 4.1.1 TheAbelian-HiggsModel . 106 4.1.2 TheGoldstoneModel. 110 4.1.3 TheLandau-GinzburgModel . 111 4.1.4 TheGross-PitaevskiiEquation . 113 4.2 The Relationship between Bose-Einstein Condensation and Sponta- neousSymmetryBreaking, and the Role of Temperature . 115 4.3 TheAxion................................ 120 4.4 The Domain Wall Problem in a Model of Bose-Einstein Condensate DarkMatter ............................... 123 4.4.1 TheModel ........................... 124 4.4.2 Existence of Domain Walls in the Silverman-Mallett Model. 125 4.4.3 Cosmological Constraints on the Existence of Domain Walls . 125 4.4.4 Mass and Symmetry-Breaking Parameters in the Silverman- MallettModel.......................... 127 4.4.5 FinalRemarks.......................... 129 4.5 Discussion................................ 130 CONTENTS vii 5 Conclusions and Further Work 133 A From Einstein-Klein-Gordon to Schrodinger-Poisson¨ 138 Bibliography 142 List of Figures 1.1 Hubble’s original data [23], compared with that of more recent surveys (see Kirshner [24] for image and data references). Note the difference inscale. ................................. 7 1.2 Comparison of Λ CDM models. From Choudhury and Padmanabhan [99]. Observational data points are obtained from the ‘Gold’ sample of Riess et al. [100] from the High-z Supernova Search. .. 24 1.3 Equation of state. From the Supernova Cosmology Project [89]. ... 25 1.4 Temperature anisotropies from WMAP 5 year data [101]. ..... 26 1.5 PowerspectrumfromWMAP5yeardata[102]. 27 3.1 Numeric solution to eqn. (3.59) (blue), the Pad`eapproximation, eqn. - (3.62) (red), and the scaled approximation used in this analysis, eqn. - (3.61)(green)............................... 87 3.2 Velocity Profiles for vG (green, dot dash) and vω (blue, dash). Density profile plotted schematically for comparison (red, solid). ....... 95 3.3 Allowedregionin(V0, m) parameter space, for a healing length of a0 = 1 1016 m ( 1parsec). ........................ 100 × ∼ 3.4 Allowed regions in (V0, m) parameter space, with n = 10. Healing lengthsaslabelled. .. .. .. .. .. .. .. .. 101 List of Tables 1.1 WMAP5YearParameters. 26 3.1 VortexEnergyperUnitLength.. 103 Chapter 1 Cosmology and Condensed Matter 1.1 Cosmology 1.1.1 The Birth of General Relativity The Einstein centenary in 2005 was a chance to celebrate the significant achievements made in cosmology in particular, and physics in general, during the hundred years since Einstein’s annus miribilis. This Latin phrase has also been linked to Newton’s own miracle year in 1666, three hundred and thirty nine years previously, and one might begin to wonder when another might be due. The history of progress in cosmology is interesting in its own right. A revolution in science is rarely as drastic or cataclysmic as the image invoked. The history of progress, as reported, does seem to come in fits and starts, but it is by more of an evolutionary process that the standard paradigms are formed. Often, many incorrect suggestions or interpretations are made, with a theory becoming established within
Load more

Recommended publications
  • Adrien Christian René THOB
    THE RELATIONSHIP BETWEEN THE MORPHOLOGY AND KINEMATICS OF GALAXIES AND ITS DEPENDENCE ON DARK MATTER HALO STRUCTURE IN SIMULATED GALAXIES Adrien Christian René THOB A thesis submitted in partial fulfilment of the requirements of Liverpool John Moores University for the degree of Doctor of Philosophy. 26 April 2019 To my grand-parents, René Roumeaux, Christian Thob, Yvette Roumeaux (née Bajaud) and Anne-Marie Thob (née Léglise). ii Abstract Galaxies are among nature’s most majestic and diverse structures. They can play host to as few as several thousands of stars, or as many as hundreds of billions. They exhibit a broad range of shapes, sizes, colours, and they can inhabit vastly differing cosmic environments. The physics of galaxy formation is highly non-linear and in- volves a variety of physical mechanisms, precluding the development of entirely an- alytic descriptions, thus requiring that theoretical ideas concerning the origin of this diversity are tested via the confrontation of numerical models (or “simulations”) with observational measurements. The EAGLE project (which stands for Evolution and Assembly of GaLaxies and their Environments) is a state-of-the-art suite of such cos- mological hydrodynamical simulations of the Universe. EAGLE is unique in that the ill-understood efficiencies of feedback mechanisms implemented in the model were calibrated to ensure that the observed stellar masses and sizes of present-day galaxies were reproduced. We investigate the connection between the morphology and internal 9:5 kinematics of the stellar component of central galaxies with mass M? > 10 M in the EAGLE simulations. We compare several kinematic diagnostics commonly used to describe simulated galaxies, and find good consistency between them.
    [Show full text]
  • Letter of Interest Cosmic Probes of Ultra-Light Axion Dark Matter
    Snowmass2021 - Letter of Interest Cosmic probes of ultra-light axion dark matter Thematic Areas: (check all that apply /) (CF1) Dark Matter: Particle Like (CF2) Dark Matter: Wavelike (CF3) Dark Matter: Cosmic Probes (CF4) Dark Energy and Cosmic Acceleration: The Modern Universe (CF5) Dark Energy and Cosmic Acceleration: Cosmic Dawn and Before (CF6) Dark Energy and Cosmic Acceleration: Complementarity of Probes and New Facilities (CF7) Cosmic Probes of Fundamental Physics (TF09) Astro-particle physics and cosmology Contact Information: Name (Institution) [email]: Keir K. Rogers (Oskar Klein Centre for Cosmoparticle Physics, Stockholm University; Dunlap Institute, University of Toronto) [ [email protected]] Authors: Simeon Bird (UC Riverside), Simon Birrer (Stanford University), Djuna Croon (TRIUMF), Alex Drlica-Wagner (Fermilab, University of Chicago), Jeff A. Dror (UC Berkeley, Lawrence Berkeley National Laboratory), Daniel Grin (Haverford College), David J. E. Marsh (Georg-August University Goettingen), Philip Mocz (Princeton), Ethan Nadler (Stanford), Chanda Prescod-Weinstein (University of New Hamp- shire), Keir K. Rogers (Oskar Klein Centre for Cosmoparticle Physics, Stockholm University; Dunlap Insti- tute, University of Toronto), Katelin Schutz (MIT), Neelima Sehgal (Stony Brook University), Yu-Dai Tsai (Fermilab), Tien-Tien Yu (University of Oregon), Yimin Zhong (University of Chicago). Abstract: Ultra-light axions are a compelling dark matter candidate, motivated by the string axiverse, the strong CP problem in QCD, and possible tensions in the CDM model. They are hard to probe experimentally, and so cosmological/astrophysical observations are very sensitive to the distinctive gravitational phenomena of ULA dark matter. There is the prospect of probing fifteen orders of magnitude in mass, often down to sub-percent contributions to the DM in the next ten to twenty years.
    [Show full text]
  • Dark Energy and Dark Matter
    Dark Energy and Dark Matter Jeevan Regmi Department of Physics, Prithvi Narayan Campus, Pokhara [email protected] Abstract: The new discoveries and evidences in the field of astrophysics have explored new area of discussion each day. It provides an inspiration for the search of new laws and symmetries in nature. One of the interesting issues of the decade is the accelerating universe. Though much is known about universe, still a lot of mysteries are present about it. The new concepts of dark energy and dark matter are being explained to answer the mysterious facts. However it unfolds the rays of hope for solving the various properties and dimensions of space. Keywords: dark energy, dark matter, accelerating universe, space-time curvature, cosmological constant, gravitational lensing. 1. INTRODUCTION observations. Precision measurements of the cosmic It was Albert Einstein first to realize that empty microwave background (CMB) have shown that the space is not 'nothing'. Space has amazing properties. total energy density of the universe is very near the Many of which are just beginning to be understood. critical density needed to make the universe flat The first property that Einstein discovered is that it is (i.e. the curvature of space-time, defined in General possible for more space to come into existence. And Relativity, goes to zero on large scales). Since energy his cosmological constant makes a prediction that is equivalent to mass (Special Relativity: E = mc2), empty space can possess its own energy. Theorists this is usually expressed in terms of a critical mass still don't have correct explanation for this but they density needed to make the universe flat.
    [Show full text]
  • Revisiting the Cooling Flow Problem in Galaxies, Groups, and Clusters of Galaxies
    Revisiting the Cooling Flow Problem in Galaxies, Groups, and Clusters of Galaxies The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation McDonald, Michael et. al., "Revisiting the Cooling Flow Problem in Galaxies, Groups, and Clusters of Galaxies." Astrophysical Journal 858, 1 (May 2018): no. 45 doi. 10.3847/1538-4357/AABACE ©2018 Authors As Published 10.3847/1538-4357/AABACE Publisher American Astronomical Society Version Final published version Citable link https://hdl.handle.net/1721.1/125311 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The Astrophysical Journal, 858:45 (15pp), 2018 May 1 https://doi.org/10.3847/1538-4357/aabace © 2018. The American Astronomical Society. All rights reserved. Revisiting the Cooling Flow Problem in Galaxies, Groups, and Clusters of Galaxies M. McDonald1 , M. Gaspari2,5 , B. R. McNamara3 , and G. R. Tremblay4 1 Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; [email protected] 2 Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544-1001, USA 3 Department of Physics & Astronomy, University of Waterloo, Canada 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA Received 2018 January 6; revised 2018 March 13; accepted 2018 March 27; published 2018 May 3 Abstract We present a study of 107 galaxies, groups, and clusters spanning ∼3 orders of magnitude in mass, ∼5 orders of magnitude in central galaxy star formation rate (SFR), ∼4 orders of magnitude in the classical cooling rate (MMrrt˙ coolº< gas() cool cool) of the intracluster medium (ICM), and ∼5 orders of magnitude in the central black hole accretion rate.
    [Show full text]
  • Ultra Light Axionic Dark Matter: Galactic Halos and Implications for Observations with Pulsar Timing Arrays
    galaxies Article Ultra Light Axionic Dark Matter: Galactic Halos and Implications for Observations with Pulsar Timing Arrays Ivan de Martino 1,* ID , Tom Broadhurst 1,2, S.-H. Henry Tye 3, Tzihong Chiueh 4, Hsi-Yu Schive 5 and Ruth Lazkoz 1 1 Department of Theoretical Physics, University of the Basque Country UPV/EHU, E-48080 Bilbao, Spain; [email protected] (T.B.); [email protected] (R.L.) 2 Ikerbasque, Basque Foundation for Science, E-48011 Bilbao, Spain 3 Institute for Advanced Study and Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China; [email protected] 4 National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan; [email protected] 5 National Center for Supercomputing Applications, Urbana, IL 61801, USA; [email protected] * Correspondence: [email protected] Received: 29 November 2017; Accepted: 8 January 2018; Published: 16 January 2018 Abstract: The cold dark matter (CDM) paradigm successfully explains the cosmic structure over an enormous span of redshifts. However, it fails when probing the innermost regions of dark matter halos and the properties of the Milky Way’s dwarf galaxy satellites. Moreover, the lack of experimental detection of Weakly Interacting Massive Particle (WIMP) favors alternative candidates such as light axionic dark matter that naturally arise in string theory. Cosmological N-body simulations have shown that axionic dark matter forms a solitonic core of size of '150 pc in the innermost region of the galactic halos. The oscillating scalar field associated to the axionic dark matter halo produces an oscillating gravitational potential that induces a time dilation of the pulse arrival time of −22 '400 ns/(mB/10 eV) for pulsar within such a solitonic core.
    [Show full text]
  • Arxiv:1306.3244V2 [Astro-Ph.CO] 4 Feb 2014
    The Scientific Reach of Multi-Ton Scale Dark Matter Direct Detection Experiments Jayden L. Newsteada, Thomas D. Jacquesa, Lawrence M. Kraussa;b, James B. Dentc, and Francesc Ferrerd a Department of Physics and School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA, b Research School of Astronomy and Astrophysics, Mt. Stromlo Observatory, Australian National University, Canberra 2614, Australia, c Department of Physics, University of Louisiana at Lafayette, Lafayette, LA 70504, USA, and d Physics Department and McDonnell Center for the Space Sciences, Washington University, St Louis, MO 63130, USA (Dated: November 6, 2018) Abstract The next generation of large scale WIMP direct detection experiments have the potential to go beyond the discovery phase and reveal detailed information about both the particle physics and astrophysics of dark matter. We report here on early results arising from the development of a detailed numerical code modeling the proposed DARWIN detector, involving both liquid argon and xenon targets. We incorporate realistic detector physics, particle physics and astrophysical uncertainties and demonstrate to what extent two targets with similar sensitivities can remove various degeneracies and allow a determination of dark matter cross sections and masses while also probing rough aspects of the dark matter phase space distribution. We find that, even assuming arXiv:1306.3244v2 [astro-ph.CO] 4 Feb 2014 dominance of spin-independent scattering, multi-ton scale experiments still have degeneracies that depend sensitively on the dark matter mass, and on the possibility of isospin violation and inelas- ticity in interactions. We find that these experiments are best able to discriminate dark matter properties for dark matter masses less than around 200 GeV.
    [Show full text]
  • The Boundary of Galaxy Clusters and Its Implications on SFR Quenching
    The splashback boundary of galaxy clusters in mass and light and its implications for galaxy evolution T.-H. Shin, Ph.D. candidate at UPenn Collaborators: S. Adhikari, E. J. Baxter, C. Chang, B. Jain, N. Battaglia et al. (DES collaboration) (SPT collaboration) (ACT collaboration) https://arxiv.org/abs/1811.06081 (accepted to MNRAS); 2019 paper in preparation Based on ~400 public cluster sample from ACT+SPT Ongoing analysis of 1000+ SZ-selected clusters from DES+ACT+SPT Background Mass and boundary of dark matter halos However, MΔ and RΔ are subject to pseudo-evolution due to the decrease in the ρ ρ reference density ( c or m) Haloes continuously accrete matter; there is no radius within which the matter is fully virialized ⇒ where is the physical boundary of the halos? Credit: Andrey Kravtsov Cosmology with galaxy clusters Galaxy clusters live in the high-mass tail of the halo mass function ⇒ very sensitive to the growth of the structure Ω σ ( m and 8) Thus, it is important to accurately define/measure Tinker et al. (2008) the mass of the cluster Preliminary work by Diemer et al. illuminates that the mass function becomes more universal against redshift when we use so-called “splashback radius” as the physical boundary of the dark matter halos Background ● Galaxies fall into the cluster potential, escaping from the Hubble flow ● They form a sharp “physical” boundary around their first apocenters after the infall, which we call “splashback radius” Background ● A simple spherical collapse model can predict the existence of the splashback feature (Gunn & Gott 1972, Fillmore & Goldreich 1984, Bertschinger 1985, Adhikari et al.
    [Show full text]
  • Dark Matter 18Th May 2021.Pdf
    Searches for Dark Matter Seminar presentation 18th May 2021 Iida Kostamo 1/20 Contents • Background and history - How did we end up with the dark matter hypothesis? • Hot and cold dark matter - Candidates for cold dark matter • The halo density profile • Simulations (Millennium and Bolshoi) • Summary Seminar presentation 18th May 2021 Iida Kostamo 2/20 Background • The total mass-energy density of the universe (approximately): 1. 5% ordinary baryonic matter 2. 25% dark matter 3. 70% dark energy • Originally dark matter was referred to as "the missing mass" - 1930's: Fritz Zwicky did research on galaxy clusters • ...The problem is the missing light, not the missing mass, hence "dark matter" Seminar presentation 18th May 2021 Iida Kostamo 3/20 The rotation curves of galaxies • The rotation curve describes how the rotation velocity of an object depends on the distance from the center of the galaxy • Assumption: Kepler's III law, i.e. the rotation velocities decrease with increasing distance • In the 1970's Vera Rubin and her colleagues did research on the rotation curves of various spiral galaxies Seminar presentation 18th May 2021 Iida Kostamo 4/20 The rotation curves of galaxies • H = Hubble constant • The rotation curves become flat when the radius is large enough • The same result for all galaxies: the rotation curves are not descending → There must be non-luminous mass in galaxies Seminar presentation 18th May 2021 Iida Kostamo 5/20 MACHOs (Massive Astrophysical Compact Halo Object) • Objects that emit extremely little or no light →
    [Show full text]
  • The Luminosity Function of the Milky Way Satellites
    Draft version June 3, 2018 A Preprint typeset using LTEX style emulateapj v. 02/07/07 THE LUMINOSITY FUNCTION OF THE MILKY WAY SATELLITES S. Koposov1,2, V. Belokurov2, N.W. Evans2, P.C. Hewett2, M.J. Irwin2, G. Gilmore2, D.B. Zucker2, H.-W. Rix1, M. Fellhauer2, E.F. Bell1, E.V. Glushkova3 Draft version June 3, 2018 ABSTRACT We quantify the detectability of stellar Milky Way satellites in the Sloan Digital Sky Survey (SDSS) Data Release 5. We show that the effective search volumes for the recently discovered SDSS–satellites depend strongly on their luminosity, with their maximum distance, Dmax, substantially smaller than the Milky Way halo’s virial radius. Calculating the maximum accessible volume, Vmax, for all faint detected satellites, allows the calculation of the luminosity function for Milky Way satellite galaxies, accounting quantitatively for their detectability. We find that the number density of satellite galaxies continues to rise towards low luminosities, but may flatten at MV 5; within the uncertainties, the ∼− 0.1(MV +5) luminosity function can be described by a single power law dN/dMV = 10 10 , spanning × luminosities from MV = 2 all the way to the luminosity of the Large Magellanic Cloud. Comparing these results to several semi-analytic− galaxy formation models, we find that their predictions differ significantly from the data: either the shape of the luminosity function, or the surface brightness distributions of the models, do not match. Subject headings: Galaxy: halo – Galaxy: structure – Galaxy: formation – Local Group 1. INTRODUCTION ing satellite” problem. First identified by Klypin et al. In Cold Dark Matter (CDM) models, large spiral (1999) and Moore et al.
    [Show full text]
  • Arxiv:1906.00969V2 [Hep-Ph] 2 Sep 2019
    FTUAM-19-11; IFT-UAM/CSIC-19-74 Very Light Asymmetric Dark Matter Gonzalo Alonso-Alvarez´ 1, Julia Gehrlein2;3, Joerg Jaeckel1 and Sebastian Schenk1 1Institut f¨urTheoretische Physik, Universit¨atHeidelberg, Philosophenweg 16, 69120 Heidelberg, Germany 2Instituto de F´ısica Te´orica UAM/CSIC, Calle Nicol´as Cabrera 13-15, Cantoblanco E-28049 Madrid, Spain 3Departamento de F´ısica Te´orica, Universidad Aut´onomade Madrid, Cantoblanco E-28049 Madrid, Spain Abstract Very light dark matter is usually taken to consist of uncharged bosons such as axion-like particles or dark photons. Here, we consider the prospect of very light, possibly even sub- eV dark matter carrying a net charge that is (approximately) conserved. By making use of the Affleck-Dine mechanism for its production, we show that a sizable fraction of the energy density can be stored in the asymmetric component. We furthermore argue that there exist regions of parameter space where the energy density contained in symmetric particle-antiparticle pairs without net charge can to some degree be depleted by considering couplings to additional fields. Finally, we make an initial foray into the phenomenology of this scenario by considering the possibility that dark matter is coupled to the visible sector via the Higgs portal. arXiv:1906.00969v2 [hep-ph] 2 Sep 2019 1 1 Introduction Very light bosons such as axion(-like) particles or dark photons are increasingly popular dark matter candidates (see, e.g., [1,2] for reviews). Currently, a significant and growing experimental community is set to hunt down these very weakly interacting particles [1,3{17].
    [Show full text]
  • And Ecclesiastical Cosmology
    GSJ: VOLUME 6, ISSUE 3, MARCH 2018 101 GSJ: Volume 6, Issue 3, March 2018, Online: ISSN 2320-9186 www.globalscientificjournal.com DEMOLITION HUBBLE'S LAW, BIG BANG THE BASIS OF "MODERN" AND ECCLESIASTICAL COSMOLOGY Author: Weitter Duckss (Slavko Sedic) Zadar Croatia Pусскй Croatian „If two objects are represented by ball bearings and space-time by the stretching of a rubber sheet, the Doppler effect is caused by the rolling of ball bearings over the rubber sheet in order to achieve a particular motion. A cosmological red shift occurs when ball bearings get stuck on the sheet, which is stretched.“ Wikipedia OK, let's check that on our local group of galaxies (the table from my article „Where did the blue spectral shift inside the universe come from?“) galaxies, local groups Redshift km/s Blueshift km/s Sextans B (4.44 ± 0.23 Mly) 300 ± 0 Sextans A 324 ± 2 NGC 3109 403 ± 1 Tucana Dwarf 130 ± ? Leo I 285 ± 2 NGC 6822 -57 ± 2 Andromeda Galaxy -301 ± 1 Leo II (about 690,000 ly) 79 ± 1 Phoenix Dwarf 60 ± 30 SagDIG -79 ± 1 Aquarius Dwarf -141 ± 2 Wolf–Lundmark–Melotte -122 ± 2 Pisces Dwarf -287 ± 0 Antlia Dwarf 362 ± 0 Leo A 0.000067 (z) Pegasus Dwarf Spheroidal -354 ± 3 IC 10 -348 ± 1 NGC 185 -202 ± 3 Canes Venatici I ~ 31 GSJ© 2018 www.globalscientificjournal.com GSJ: VOLUME 6, ISSUE 3, MARCH 2018 102 Andromeda III -351 ± 9 Andromeda II -188 ± 3 Triangulum Galaxy -179 ± 3 Messier 110 -241 ± 3 NGC 147 (2.53 ± 0.11 Mly) -193 ± 3 Small Magellanic Cloud 0.000527 Large Magellanic Cloud - - M32 -200 ± 6 NGC 205 -241 ± 3 IC 1613 -234 ± 1 Carina Dwarf 230 ± 60 Sextans Dwarf 224 ± 2 Ursa Minor Dwarf (200 ± 30 kly) -247 ± 1 Draco Dwarf -292 ± 21 Cassiopeia Dwarf -307 ± 2 Ursa Major II Dwarf - 116 Leo IV 130 Leo V ( 585 kly) 173 Leo T -60 Bootes II -120 Pegasus Dwarf -183 ± 0 Sculptor Dwarf 110 ± 1 Etc.
    [Show full text]
  • Radial Temperature Profiles for a Large Sample of Galaxy Clusters Observed with XMM-Newton
    A&A 486, 359–373 (2008) Astronomy DOI: 10.1051/0004-6361:200809538 & c ESO 2008 Astrophysics Radial temperature profiles for a large sample of galaxy clusters observed with XMM-Newton A. Leccardi1,2 and S. Molendi2 1 Università degli Studi di Milano, Dip. di Fisica, via Celoria 16, 20133 Milano, Italy 2 INAF-IASF Milano, via Bassini 15, 20133 Milano, Italy e-mail: [email protected] Received 8 February 2008 / Accepted 8 April 2008 ABSTRACT Aims. We measure radial temperature profiles as far out as possible for a sample of ≈50 hot, intermediate redshift galaxy clusters, selected from the XMM-Newton archive, keeping systematic errors under control. Methods. Our work is characterized by two major improvements. First, we used background modeling, rather than background subtraction, and the Cash statistic rather than the χ2. This method requires a careful characterization of all background components. Second, we assessed systematic effects in detail. We performed two groups of tests. Prior to the analysis, we made use of extensive simulations to quantify the impact of different spectral components on simulated spectra. After the analysis, we investigated how the measured temperature profile changes, when choosing different key parameters. Results. The mean temperature profile declines beyond 0.2 R180. For the first time, we provide an assessment of the source and the magnitude of systematic uncertainties. When comparing our profile with those obtained from hydrodynamic simulations, we find the slopes beyond ≈0.2 R180 to be similar. Our mean profile is similar but somewhat flatter with respect to those obtained by previous observational works, possibly as a consequence of a different level of characterizing systematic effects.
    [Show full text]