DOCSLIB.ORG

Constructing the Universe

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Constructing the Universe Constructing the universe Subir Sarkar None of us can understand why there is a Universe at all, why anything should exist; that’s the ultimate question. But while we cannot answer this question, we can at least make progress with the next simpler one of what the Universe as a whole is like. Dennis Sciama (1978) 15th Central European Seminar on Particle Physics & Quantum Field Theory, Vienna, 28-29 Nov 2019 This is a ‘popular’ talk but I will include discussion of a recent result that has fundamental implications for cosmology In the Ptolemic/Aristotlean standard cosmology (350 BC➛1600 AD) the universe was static and finite and centred on the Earth (1321) Alligheri The Divine Comedy, Dante Dante The Divine Comedy, This was a simple model and fitted all the observational data … but the underlying principle was unphysical Today we have a ‘standard LCDM model’ of the universe … dominated by dark energy and undergoing accelerated expansion It too is ‘simple’ (if we count L as just one parameter) and fits all the observational data … but lacks a physical foundation The universe appears complex & structured on many scales ... How can we possibly describe it by a simple mathematical model? Although the universe is lumpy, it seems to become smoother and smoother when averaged over larger and larger scales Tegmark Courtesy: Max Max Courtesy: “Data from the Planck satellite show the universe to be highly isotropic” (Wikipedia) We observe a statistically isotropic Gaussian random field of small temperature fluctuations (fully quantified by the 2-point correlations angular power spectrum) isotropy does … unless not there is necessarily isotropy imply around every homogeneity point in space But all we can ever learn about the universe is contained within our past light cone We cannot move over cosmological distances and check … so there are limits if the universe looks to what we can know the same from ‘over (‘cosmic variance’) there’ as it does from here … the Universe must appear to be the same to all observers wherever they are This ‘cosmological principle’ … Edward Arthur Milne (1896-1950) Rouse Ball Professor of Mathematics & Fellow of Wadham College, Oxford, 1928- Until about a hundred years ago all we saw in the sky was our Milky Way … and other stars like our Sun (whose distances could be measured by parallax) Diameter of the Earth’s orbit is ~1000 light-seconds. so if the ‘parallax’ of a star is 1’’, then its distance is 1 parsec ⇒ ~3.3 light-years First measured in 1838 by Wilhelm Bessel for 61 Cygni (0.3”) To measure distances in the universe we need ‘standard candles’ – astronomical sources whose absolute luminosity is known from its correlation with some other property E.g. pulsation period in the case of Cepheid variable stars … and thus we build up the ‘cosmic distance ladder’ to the furthest galaxies In 1923 Edwin Hubble used the 100” Mt Wilson telescope to determine the distance to the Andromeda Nebula He was searching for ‘novae’ … instead he found a ‘Cepheid variable’, which Henrietta Leavitt had shown (in 1912) to be a distance indicator Hubble discovered that Andromeda (M31) is not a cloud of stars and gas in our Milky Way, but a galaxy similar to our own at a very substantial distance … 2.5 million light years (⇒ 0.8 Mpc)! The Universe had suddenly became a lot bigger … and thus began modern cosmology The Hubble Space Telescope (1990-) can resolve Cepheids in galaxies much further away M100 is a galaxy in the Virgo cluster at a distance of 54 million light years (16.4 Mpc) Cepheids can be used to ‘calibrate’ other sources such as supernovae – exploding stars which are bright enough to be seen even further away … using supernovae we can now measure distances of billions of light-years Looking far away is the same as looking back into our past We see the We see the nearest star Sun as it was Proxima Centauri, 8 minutes ago as it was 4 years ago We see the Galactic We see our nearest centre as it was galaxy Andromeda as 30,000 years ago it was 2.5 million years ago We see the Virgo We see galaxies in cluster as it was the Hubble Ultra 54 million years ago Deep Field as they were - up to 12 billion years ago But there is something odd about the spectra of distant galaxies … they are shifted towards the red (longer wavelengths) as if they are travelling away from us - Doppler effect? The New Yorker “Every time I see Edwin Hubble, he is moving rapidly away from me!” The ‘expansion’ of the universe Hubble (1931) to De Sitter: “The interpretation, we feel, should be left to you and the very few others who are competent to discuss the matter with authority”. Hubble’s data (1929) (2002) The redshift of distant galaxies is not a Doppler effect … it occurs because the wavelength of light is apparently increased by the stretching of space-time (aka ‘expansion of the universe’) λobserved/λemitted =1 + z = robserved/remitted : Wayne Hu : Wayne Courtesey This picture also makes it clear that the expansion has no ‘centre’ The changing view, going back in back timegoing changingThe view, Theview back,now and later Robert Osserman, Poetry of the Universe: A Mathematical Exploration of the Cosmos,1996 The Gravity of matter should be slowing down the expansion rate … however it was claimed in1998 that distant SNIa appear fainter than expected for “standard candles” in a decelerating universe This was interpreted as Þ accelerated expansion below z ~ 0.5 The observations are made at one instant (the redshift is taken as a proxy for time) so this is not a direct measurement of acceleration, nevertheless it is presently more direct than all other such ‘evidence’ PHYS 652: Astrophysics 19 After straightforward yet tedious calculations (which I relegate to homework), we obtain the com- ponents of the Ricci tensor: 0 a¨ R0 =3, a Standard cosmological model 0 The universe is isotropic + homogeneous (when averaged on ‘large’ scales) Ri =0, ⇒ Maximally1 -symmetric2 space-time + ideal fluid energy-momentum tensor Ri = aa¨ +2˙a +2k δα. j 2 a2 µ ⌫ β ds g!µ⌫ dx dx " 1 ⌘ R(93)µ⌫ Rgµ⌫ + λgµ⌫ = a2(⌘) d⌘2 dx¯2 − 2 The t t component of the Einstein’s equation given in eq. (92) becomes − − Einstein =8⇡GNTµ⌫ 3¨a ⇥ 1 ⇤ =8πG (ρ + P )+ (ρ P ) , (94) a Robertson#− -Walker 2 − $ or 4πG a¨ = (ρ +3P ) a. (95) − 3 ⇢m k ⇤ ⌦m 2 , ⌦k 2 2 , ⌦⇤ 2 The i i component of the Einstein’s(3 equationH /8⇡GN) is (3H a ) (3H − <latexit sha1_base64="51ZpQU/7JoM1nBLtKyfzpNYhoVQ=">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</latexit>sha1_base64="AdU/Mra5g13ogMW+ETWlZL5ZXyo=">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</latexit>sha1_base64="RqT+kXNNr6jO9+ym5MT2++WvKAA=">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</latexit> ⌘ 0 ⌘ 0 0 ⌘ 0 1 2 1 aa¨ So+2˙ thea +2 Friedmannk =8πG-Lemaitre(ρ P equation) , ⇒ ‘cosmic sum rule’:(96) W + W + W = 1 a2 #2 − $ m k L ! " or We observe: 0.8Ωm - 0.6ΩL ≈ -0.2 (Supernovae), Ωk ≈ 0.0 (CMB), Wm ~ 0.3 (Clusters) 2 2 aa¨ +2˙a +2k =4πG(ρ P )a , (97) 2 infer universe is dominated− by dark energy: WΛ = 1 - Wm - Wk ~ 0.7 ⇒ Λ ~ 2H0 The eqs. (95)-(97) are the basic equations connecting the scale factor a to ρ and P .Toobtaina closed system of equations, we onlyTo need drive an accelerated equation ofexpansion state P = requiresP (ρ), which negative relates pressureP and (ρP.< -r/3) so this is 1/4 2 1/4 -12 -1/2 2 The system then reduces to two equationsinterpreted for as two vacuum unknownsenergy:a and (rL)ρ. = (H0 /8pGN) ~ 10 GeV << GF ~ 10 GeV It is, however, beneficial to furtherThis makes massage no physical these basic sense equ …ations exacerbates into a set the that (old) is Cosmological more easily Constant problem! solved. Solving the eq. (97) fora ¨,weobtain 2˙a2 2k a¨ =4πG(ρ P )a + , (98) − − a a which can be combined with eq. (95) to cancel out P dependence and yield 16πGρa 2k 2˙a2 =0, (99) 3 − a − a or 2 8πG 2 a˙ + k = ρa . (100) 3 When combined with the eq. (62) derived in the context of conservation of energy-momentum tensor, and the equation of state, we obtain a closed system of Friedmann
Load more

Recommended publications
  • FY08 Technical Papers by GSMTPO Staff
    AURA/NOAO ANNUAL REPORT FY 2008 Submitted to the National Science Foundation July 23, 2008 Revised as Complete and Submitted December 23, 2008 NGC 660, ~13 Mpc from the Earth, is a peculiar, polar ring galaxy that resulted from two galaxies colliding. It consists of a nearly edge-on disk and a strongly warped outer disk. Image Credit: T.A. Rector/University of Alaska, Anchorage NATIONAL OPTICAL ASTRONOMY OBSERVATORY NOAO ANNUAL REPORT FY 2008 Submitted to the National Science Foundation December 23, 2008 TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................................................. 1 1 SCIENTIFIC ACTIVITIES AND FINDINGS ..................................................................................... 2 1.1 Cerro Tololo Inter-American Observatory...................................................................................... 2 The Once and Future Supernova η Carinae...................................................................................................... 2 A Stellar Merger and a Missing White Dwarf.................................................................................................. 3 Imaging the COSMOS...................................................................................................................................... 3 The Hubble Constant from a Gravitational Lens.............................................................................................. 4 A New Dwarf Nova in the Period Gap............................................................................................................
    [Show full text]
  • Star Formation and Galaxy Evolution of the Local Universe Based on HIPASS
    Star formation and galaxy evolution of the Local Universe based on HIPASS Oiwei Ivy Wong Submitted in total fulfilment of the requirements of the Degree of Doctor of Philosophy School of Physics University of Melbourne December, 2007 Abstract This thesis investigates the star formation and galaxy evolution of the nearby Local Volume based on Neutral Hydrogen (HI) studies. A large portion of this thesis con- sists of work with the Northern extension of the HI Parkes All Sky Survey (HIPASS). HIPASS is an HI survey of the entire Southern sky up to a declination of +25.5 de- grees (including the Northern extension) using the Parkes 64-metre radio telescope. I have also produced a catalogue of the optical counterparts corresponding to the galaxies found in Northern HIPASS. From this optical catalogue, we also conclude that we did not find any isolated dark galaxies. The other half of my thesis consists of work with the SINGG and SUNGG projects. SINGG is the Survey for Ioniza- tion in Neutral Gas Galaxies and SUNGG is the Survey of Ultraviolet emission in Neutral Gas Galaxies. Both SINGG and SUNGG are selected from HIPASS and are star formation studies in the H-alpha and ultraviolet (UV), respectively. My work in the SINGG-SUNGG collaboration is mostly based on SUNGG. Using the results of SUNGG, I measured the local luminosity density and the cosmic star formation rate density (SFRD) of the Local Universe. Using far-infrared (FIR) observations from IRAS, the FIR luminosity density was also calculated. Combining the FUV luminosity density and the FIR luminosity density, the bolometric SFRD of the Lo- cal Universe was estimated.
    [Show full text]
  • Dynamics and Mass of the Shapley Supercluster, the Largest Bound Structure in the Local Universe A
    mega-telescopes and their IR instru- modern techniques such as radial ve- such systems with evolutionary models mentation it will be possible to in- locities, planetary occultations (transits) of our own solar system. vestigate the physical characteristics and micro-lensing. Once ALMA is avail- of these objects, particularly those in able we will be able to undertake mo- The present article could not have orbit around nearby stars which will al- lecular line observations of the atmos- been written without the contribution of low us to obtain their masses. ALMA pheres of planets and other bodies the FONDAP Centre of Excellence will be a perfect instrument for the fol- which will give new knowledge of plan- Director, Guido Garay, and of its P.I. low-up studies of brown dwarfs found in etary “weather”, the structure of atmos- Members. I thankfully acknowledge the these studies. pheric wind and the variations in chem- contribution from M.T. Ruiz, Director of • Extrasolar planets and proto-plane- ical constituents. Studies of proto-plan- the Astronomy Department at Universi- tary disks. – One of the great appeals etary disks will be carried out using the dad de Chile; L. Infante, Chairman of of astronomy is undoubtedly its poten- recently available IR facilities. ALMA, the Pontificia Universidad Católica de tial to help us understand the origin of with its sensitivity and resolving power, Chile Department of Astronomy and our planet. The Centre will foster the will be the ideal instrument to provide Astrophysics; W. Gieren, Head of the development of the area of planetary definite answers regarding the forma- Astronomy Group at the Universidad de science, currently non-existent in the tion and evolution of proto-planetary Concepción Physics Department; L.
    [Show full text]
  • Astrophysical Plasma Modeling of the Hot Universe
    Astrophysical plasma modeling of the hot Universe Advances and challenges in high-resolution X-ray spectroscopy Astrophysical plasma modeling of the hot Universe Advances and challenges in high-resolution X-ray spectroscopy Proefschrift ter verkrijging van de graad van Doctor aan de Universiteit Leiden, op gezag van de Rector Magnificus prof. mr. C. J. J. M. Stolker, volgens besluit van het College voor Promoties te verdedigen op donderdag 7 juni 2018 klokke 10:00 uur door Junjie Mao geboren te Ningbo, China in 1988 Promotiecommissie: Promotor: Prof. dr. J. S. Kaastra Co-promotor: Dr. J. de Plaa (SRON) Overige leden: Prof. dr. H. Röttgering Prof. dr. J. Schaye Prof. dr. W. R. Jaffe Prof. dr. G. Branduardi-Raymont (University College London) Prof. dr. F. B. S. Paerels (Columbia University) To Lilan our active family nucleus with her inflows and outflows © 2018 Junjie Mao Cover design by Junjie Mao Image credit: Adobe Spark Contents 1 Introduction 1 1.1 Hot astrophysical plasmas in X-rays . 2 1.2 Active Galactic Nuclei and circumnuclear media . 3 1.3 Intracluster media and chemical enrichment . 9 1.4 Plasma code and atomic data . 13 1.5 This thesis . 15 References. 18 2 Parameterization of the level-resolved radiative recombination rate coefficients for the SPEX code 21 2.1 Introduction . 22 2.2 Historical background . 22 2.3 RR rate coefficients for H-like ions . 25 2.3.1 Photoionization cross sections . 25 2.3.2 Radiative recombination data . 26 2.4 RR rate coefficients for He-like to Na-like ions. 26 2.5 Fitting strategy .
    [Show full text]
  • 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.
    [Show full text]
  • The 13Th HEAD Program Book
    13th Meeting of the High Energy Astrophysics Division Program Book Monterey CA 7-11 April 2013 13th Meeting of the American Astronomical Society’s High Energy Astrophysics Division (HEAD) 7-11 April 2013 Monterey, California Scientific sessions will be held at the: Portola Hotel and Spa 2 Portola Plaza ATTENDEE Monterey, CA 93940 SERVICES.......... 4 HEAD Paper Sorters SCHEDULE......... 6 Keith Arnaud Joshua Bloom MONDAY............ 12 Joel Bregman Paolo Coppi Rosanne Di Stefano POSTERS........... 17 Daryl Haggard Chryssa Kouveliotou TUESDAY........... 43 Henric Krawczynski Stephen Reynolds WEDNESDAY...... 48 Randall Smith Jan Vrtilek THURSDAY......... 52 Nicholas White AUTHOR INDEX.. 56 Session Numbering Key 100’s Monday and posters NASA PCOS X-RAY SAG 200’s Tuesday 300’s Wednesday HEAD DISSERTATIONS 400’s Thursday Please Note: All posters are displayed Monday-Thursday. Current HEAD Officers Current HEAD Committee Joel Bregman Chair Daryl Haggard 2013-2016 Nicholas White Vice-Chair Henric Krawczynski 2013-2016 Randall Smith Secretary Rosanne DiStefano 2011-2014 Keith Arnaud Treasurer Stephen Reynolds 2011-2014 Megan Watzke Press Officer Jan Vrtilek 2011-2014 Chryssa Kouveliotou Past Chair Joshua Bloom 2012-2015 Paolo Coppi 2012-2015 1 2 Peter B’s Entrance Cottonwood Plaza Jacks Restaurant Brew Pub s p o h S Cottonwood Bonsai III e Lower Atrium Bonsai II ung Restrooms o e nc cks L Ironwood Redwood Bonsai I a a J Entr Elevators Elevators a l o rt o P Restrooms s De Anza De Anza p Ballroom II-III Ballroom I o De Anza Sh Foyer Upper Atrium Entrance OOMS R Entrance BONZAI Entrance De ANZA BALLROOM FA ELEVATORS TO BONZAI ROOMS Y B OB L TEL O General eANZA D A H O Z T Session ANCE R OLA PLA T ENT R PO FA FA STORAGE A UP F ENTRANCE TO 3 De ANZA FOYER ATTENDEE SERVICES Registration De Anza Foyer Sunday: 1:00pm-7:00pm Monday-Wednesday: 7:30am-6:00pm Thursday: 8:00am-5:00pm Poster Viewing Monday-Wednesday: 7:30am-6:45pm Thursday: 7:30am-5:00pm Please do not leave personal items unattended.
    [Show full text]
  • 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
    [Show full text]
  • "#$%&'() + '', %-./0$%)%1 2 ()3 4&(5' 456')5'
    rs uvvwxyuzyws { yz|z|} rsz}~suzywsu}u~w vz~wsw 456789@A C 99D 7EFGH67A7I P @AQ R8@S9 RST9AS9 UVWUX `abcdUVVe fATg96GTHP7Eh96HE76QGiT69pf q rAS76876@HTAs tFR u Fv wxxy @AQ 4FR 4u Fv wxxy UVVe abbc d dbdc e f gc hi` ij ad bch dgcadabdddc c d ac k lgbc bcgb dmg agd g` kg bdcd dW dd k bg c ngddbaadgc gabmob nb boglWad g kdcoddog kedgcW pd gc bcogbpd kb obpcggc dd kfq` UVVe c iba ! " #$%& $' ())01023 Book of Abstracts – Table of Contents Welcome to the European Week of Astronomy & Space Science ...................................................... iii How space, and a few stars, came to Hatfield ............................................................................... v Plenary I: UK Solar Physics (UKSP) and Magnetosphere, Ionosphere and Solar Terrestrial (MIST) ....... 1 Plenary II: European Organisation for Astronomical Research in the Southern Hemisphere (ESO) ....... 2 Plenary III: European Space Agency (ESA) .................................................................................. 3 Plenary IV: Square Kilometre Array (SKA), High-Energy Astrophysics, Asteroseismology ................... 4 Symposia (1) The next era in radio astronomy: the pathway to SKA .............................................................. 5 (2) The standard cosmological models - successes and challenges .................................................. 17 (3) Understanding substellar populations and atmospheres: from brown dwarfs to exo-planets .......... 28 (4) The life cycle of dust ...........................................................................................................
    [Show full text]
  • VST in the Era of the Large Sky Surveys
    Astronomical News DOI: 10.18727/0722-6691/5100 Report on the ESO–INAF Workshop VST in the Era of the Large Sky Surveys held at INAF–Astronomical Observatory of Capodimonte, Naples, Italy, 5–8 June 2018 Pietro Schipani 1 encompasses a range of research areas groups and large-scale structure. Recent Magda Arnaboldi 2 across multiple wavelengths and using results were presented that demonstrated Enrica Iodice 1 different telescopes. The surveys have how cosmological constraints can be Bruno Leibundgut 2 demonstrated an increasingly high level derived from KiDS lensing measurements. of scientific productivity and, as with The high image quality and deep photo- large programmes, have generally had a metry of KiDS are ideal for galaxy evolu- 1 INAF–Astronomical Observatory of high impact. The operational aspects tion studies and for hunting peculiar Capodimonte, Naples, Italy underpinning these programmes were and rare objects, such as massive com- 2 ESO also discussed. The efforts of ESO’s pact galaxies and gravitational lenses. quality control group were presented, as Methods and techniques to find Quasi- well as the night and day operations at Stellar Objects (QSO) and arcs were This workshop focussed on science the telescope; these help to ensure sta- addressed, as were the first spectro- programmes carried out with the ble operation with negligible technical scopic follow-ups and specific science INAF–ESO VLT Survey Telescope (VST) downtime. There were also talks on the cases (for example, the Fornax dwarf several years into its operation. The aim publication of science data products via spheroidal galaxy). Synergies between of the conference was to review the the ESO Archive, in order to ensure that KiDS and other projects (both current latest results and ongoing programmes, they can be used for further scientific and future) were also discussed.
    [Show full text]
  • OUR SOLAR SYSTEM Realms of Fire and Ice We Start Your Tour of the Cosmos with Gas and Ice Giants, a Lot of Rocks, and the Only Known Abode for Life
    © 2016 Kalmbach Publishing Co. This material may not be reproduced in any form without permission from the publisher. www.Astronomy.com OUR SOLAR SYSTEM Realms of fire and ice We start your tour of the cosmos with gas and ice giants, a lot of rocks, and the only known abode for life. by Francis Reddy cosmic perspective is always a correctly describe our planetary system The cosmic distance scale little unnerving. For example, we as consisting of Jupiter plus debris. It’s hard to imagine just how big occupy the third large rock from The star that brightens our days, the our universe is. To give a sense of its a middle-aged dwarf star we Sun, is the solar system’s source of heat vast scale, we’ve devoted the bot- call the Sun, which resides in a and light as well as its central mass, a tom of this and the next four stories Aquiet backwater of a barred spiral galaxy gravitational anchor holding everything to a linear scale of the cosmos. The known as the Milky Way, itself one of bil- together as we travel around the galaxy. distance to each object represents the amount of space its light has lions of galaxies. Yet at the same time, we Its warmth naturally divides the planetary traversed to reach Earth. Because can take heart in knowing that our little system into two zones of disparate size: the universe is expanding, a distant tract of the universe remains exceptional one hot, bright, and compact, and the body will have moved farther away as the only place where we know life other cold, dark, and sprawling.
    [Show full text]
  • Arxiv:2011.10882V1 [Astro-Ph.GA] 21 Nov 2020 Variety of Astrophysical Objects and Environments
    MNRAS 000,1–22 (2020) Preprint 24 November 2020 Compiled using MNRAS LATEX style file v3.0 Polycyclic Aromatic Hydrocarbons in Seyfert and star-forming galaxies I. Garc´ıa-Bernete1?, D. Rigopoulou,1, A. Alonso-Herrero2, M. Pereira-Santaella3, P.F. Roche,1 and B. Kerkeni1 1Department of Physics, University of Oxford, Oxford OX1 3RH, UK 2Centro de Astrobiolog´ıa,CSIC-INTA, ESAC Campus, E-28692, Villanueva de la Ca˜nada,Madrid, Spain 3Centro de Astrobiolog´ıa,CSIC-INTA, Carretera de Torrej´ona Ajalvir, E-28880 Torrej´onde Ardoz, Madrid, Spain Accepted XXX. Received YYY; in original form ZZZ ABSTRACT Polycyclic Aromatic Hydrocarbons (PAHs) are carbon-based molecules resulting from the union of aromatic rings and related species, which are likely responsible for strong infrared emission features (3.3, 6.2, 7.7, 8.6, 11.3 and 12.7 µm). In this work, using a sample of Seyfert galaxies (DL <100 Mpc), we compare the circumnuclear (inner kpc) PAH emission of AGN and star-forming control samples, and we investigate the difference between the cen- tral and extended PAH properties. We employ newly developed PAH diagnostic model grids, derived from theoretical spectra, to compare the predicted and observed PAH ratios. We use Spitzer/InfraRed Spectrograph spectral data for a large sample of Seyfert galaxies and star- forming galaxies. In general we find that star-forming galaxies and powerful Seyfert galaxies are located in different regions of the PAH diagnostic diagram, which indicates that the size and charge of the PAH molecules but also the nature and hardness of the radiation field that excite them are different.
    [Show full text]
  • The Nuclear and Extended Mid-Infrared Emission of Seyfert Galaxies
    MNRAS 463, 3531–3555 (2016) doi:10.1093/mnras/stw2125 Advance Access publication 2016 August 24 The nuclear and extended mid-infrared emission of Seyfert galaxies I. Garc´ıa-Bernete,1,2‹ C. Ramos Almeida,1,2‹ J. A. Acosta-Pulido,1,2‹ A. Alonso-Herrero,3,4,5 O. Gonzalez-Mart´ ´ın,6 A. Hernan-Caballero,´ 7,8 M. Pereira-Santaella,9 N. A. Levenson,10 C. Packham,5,11 E. S. Perlman,12 K. Ichikawa,11 P. Esquej13 and T. D´ıaz-Santos14 1Instituto de Astrof´ısica de Canarias, Calle V´ıa Lactea,´ s/n, E-38205 La Laguna, Tenerife, Spain 2Departamento de Astrof´ısica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain Downloaded from https://academic.oup.com/mnras/article/463/4/3531/2646309 by guest on 27 September 2021 3Centro de Astrobiolog´ıa, CSIC-INTA, ESAC Campus, E-28692 Villanueva de la Canada,˜ Madrid, Spain 4Department of Physics, University of Oxford, Oxford OX1 3RH, UK 5Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA 6Centro de Radioastronom´ıa y Astrof´ısica (CRyA-UNAM), 3-72 (Xangari), 8701, Morelia, Mexico 7Instituto de F´ısica de Cantabria, CSIC-Universidad de Cantabria, E-39005 Santander, Spain 8Departamento de Astrof´ısica y CC. de la Atmosfera,´ Facultad de CC. F´ısicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain 9Centro de Astrobiolog´ıa, CSIC-INTA, Ctra de Torrejon´ a Ajalvir, km 4, E-28850 Torrejon´ de Ardoz, Madrid, Spain 10Gemini Observatory, Casilla 603, La Silla, Chile 11National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 12Department of Physics and Space Sciences, Florida Institute of Technology, 150 W.
    [Show full text]