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Selected Topics in Extragalactic Astronomy Spring Quarter, 2007 Class: Wed., Fri
– 1 – Astronomy 31300: Selected Topics in Extragalactic Astronomy Spring Quarter, 2007 Class: Wed., Fri. 10:30 – 11:50 am Instructor: Josh Frieman ([email protected]), AAC 032 Tel: (773)702-7971 (campus); (630)840-2226 (Fermilab) http://astro.uchicago.edu/∼frieman/A313/ I. Galaxies Observed: • Challenges/Limitations to Extragalactic Astronomy: - Atmospheric absorption and emission: - Surface brightness and sky subtraction errors - Photometric calibration: filter, detector response/efficiencies - Milky Way dust absorption and emission - Observing in the Expanding Universe: K corrections, surface brightness dimming - Galaxy photometry: aperture vs model fit photometry • Overview of the Milky Way (probably skip): - Stellar populations; bulge; thin & thick disks; globular clusters - Gas in different phases - Dust, metals - Ionizing radiation - Dark Matter • Galaxy Types and Classification: - Morphological, color, and spectroscopic classification schemes - The Hubble sequence - Surface brightness profiles: de Vaucouleurs spheroids and exponential disks - Automatic morphology classification: neural networks - Morphological classification in SDSS - Classification caveats - Bimodal galaxy color distribution - Interpretation of galaxy spectra: stellar and ISM signatures; velocity dispersion; - Spectroscopic classification via Principal Component Analysis - Correlations between spectroscopic and photometric properties - Morphology-density relation - Oddballs: irregulars, starbursts, ULIRGs, CDs – 2 – • Galaxy Population Distributions: - Galaxy Luminosity Function: -
Galaxies: Structure, Formation and Evolution Lecture 11
Galaxies: Structure, formation and evolution Lecture 11 Yogesh Wadadekar Jan-Feb 2018 ncralogo IUCAA-NCRA Grad School 1 / 24 The winding problem Why do flat rotation curves lead to winding of spiral arms? ncralogo IUCAA-NCRA Grad School 2 / 24 Winding of spiral arms ncralogo Show winding video and Star Orbit Video IUCAA-NCRA Grad School 3 / 24 Another issue Spiral arms are defined mainly by blue light from hot massive stars, thus lifetime is << galactic rotation period. Should’nt spiral arms just fade away? ncralogo IUCAA-NCRA Grad School 4 / 24 A cryptic observation For galaxies where the galactic rotation has been measured, the spiral arms almost always trail the rotation of the underlying disc. Relative to the disk they seem to be rotating in a direction opposite to the disk. ncralogo IUCAA-NCRA Grad School 5 / 24 Spiral arms Long lived spiral arms are not material features in the disk they are a pattern, through which stars and gas move these might be the grand design spirals Short lived spiral arms can arise from temporary patches pulled out by differential rotation the patches might arise from local disk instabilities, leading to star formation these might be the flocculent spirals. ncralogo IUCAA-NCRA Grad School 6 / 24 Grand Design Spirals ncralogo IUCAA-NCRA Grad School 7 / 24 Flocculent Spiral ncralogo IUCAA-NCRA Grad School 8 / 24 Orbit winding ncralogo IUCAA-NCRA Grad School 9 / 24 Density wave theory by Lin and Shu Spiral arm patterns must be persistent. Why? Density wave theory provides an explanation: the arms are density waves propagating in differentially rotating disks. -
Strong Evidence for the Density-Wave Theory of Spiral Structure from a Multi-Wavelength Study of Disk Galaxies Hamed Pour-Imani University of Arkansas, Fayetteville
University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 8-2018 Strong Evidence for the Density-wave Theory of Spiral Structure from a Multi-wavelength Study of Disk Galaxies Hamed Pour-Imani University of Arkansas, Fayetteville Follow this and additional works at: http://scholarworks.uark.edu/etd Part of the Physical Processes Commons, and the Stars, Interstellar Medium and the Galaxy Commons Recommended Citation Pour-Imani, Hamed, "Strong Evidence for the Density-wave Theory of Spiral Structure from a Multi-wavelength Study of Disk Galaxies" (2018). Theses and Dissertations. 2864. http://scholarworks.uark.edu/etd/2864 This Dissertation is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ScholarWorks@UARK. For more information, please contact [email protected], [email protected]. Strong Evidence for the Density-wave Theory of Spiral Structure from a Multi-wavelength Study of Disk Galaxies A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physics by Hamed Pour-Imani University of Isfahan Bachelor of Science in Physics, 2004 University of Arkansas Master of Science in Physics, 2016 August 2018 University of Arkansas This dissertation is approved for recommendation to the Graduate Council. Daniel Kennefick, Ph.D. Dissertation Director Vincent Chevrier, Ph.D. Claud Lacy, Ph.D. Committee Member Committee Member Julia Kennefick, Ph.D. William Oliver, Ph.D. Committee Member Committee Member ABSTRACT The density-wave theory of spiral structure, though first proposed as long ago as the mid-1960s by C.C. -
Is the Spiral Galaxy a Cosmic Hurricane?
Draft version February 20, 2018 Preprint typeset using LATEX style AASTeX6 v. 1.0 IS THE SPIRAL GALAXY A COSMIC HURRICANE? CAO Zexin1 College of Science, Shenyang Aerospace University, Shenyang 110136, China LIU Ling, ZHENG Tingting College of Physics Science and Technology, Shenyang Normal University, ShenYang 110034, China [email protected] ABSTRACT It is discussed that the formation of the spiral galaxies is driven by the cosmic background rotation, not a result of an isolated evolution proposed by the density wave theory. To analyze the motions of the galaxies, a simple double particle galaxy model is considered and the Coriolis force formed by the rotational background is introduced. The numerical analysis shows that not only the trajectory of the particle is the spiral shape, but also the relationship between the velocity and the radius reveals both the existence of spiral arm and the change of the arm number. In addition, the results of the three-dimensional simulation also give the warped structure of the spiral galaxies, and shows that the disc surface of the warped galaxy, like a spinning coins on the table, exists a whole overturning movement. Through the analysis, it can be concluded that the background environment of the spiral galaxies have a large-scale rotation, and both the formation and evolution of hurricane-like spiral galaxies are driven by this background rotation. Keywords: Galaxy:background rotation — Galaxy:spiral galaxy — Galaxy:Coriolis force — Galaxy:warped structure— Galaxy:spiral arm 1. INTRODUCTION density would be maintained self-consistently. Accord- The beautiful and unusual spiral structure of spiral ing to the model of the density wave theory, the quasi- galaxy attracts people’s attention all the time. -
Galaxies: Structure, Dynamics, and Evolution
Galaxies: Structure, Dynamics, and Evolution Spiral Galaxies/Disk Galaxies (III): Spiral Structure Review: Collisionless Boltzmann Equation and Collisionless Dynamics Layout of the Course Feb 5: Review: Galaxies and Cosmology Feb 12: Review: Disk Galaxies and Galaxy Formation Basics Feb 19: Disk Galaxies (I) Feb 26: Disk Galaxies (II) Mar 5: Disk Galaxies (III) / Review: Vlasov Equations this lecture Mar 12: Elliptical Galaxies (I) Mar 19: Elliptical Galaxies (II) Mar 26: Elliptical Galaxies (III) Apr 2: (No Class) Apr 9: Dark Matter Halos Apr 16: Large Scale Structure Apr 23: (No Class) Apr 30: Analysis of Galaxy Stellar Populations May 7: Lessons from Large Galaxy Samples at z<0.2 May 14: (No Class) May 21: Evolution of Galaxies with Redshift May 28: Galaxy Evolution at z>1.5 / Review for Final Exam June 4: Final Exam You have a homework assignment that is due on Monday, Mar 9, before noon There will be a new homework assignment that will be due on Monday, Mar 16, before noon First, let’s review the important material from last week Multiple arm spiral Grand design spiral How doNGC 6946the arms in spiral galaxies evolve with time? 3-4-12see http://www.strw.leidenuniv.nl/˜ franx/college/galaxies12 12-c02-3 Most spiral3-4-12see arms http://www.strw.leidenuniv.nl/˜ are This could franx/college/galaxbe determinedies12 by 12-c02-4 looking at Flocculent spiral Most spiralfound arms toare trailingbe trailing. reddening in globular clusters / novae globular clusters seen around disk galaxy. amount of reddening indicated by whether circles are solid or open allows us to determine which way a spiral galaxy is 3-4-12see http://www.strw.leidenuniv.nl/˜ franx/college/galaxies12 12-c02-3 3-4-12see http://www.strw.leidenuniv.nl/˜tilted. -
The Relation Between Surface Star Formation Rate Density and Spiral Arms in NGC 5236 (M 83)
A&A 537, A145 (2012) Astronomy DOI: 10.1051/0004-6361/201117432 & c ESO 2012 Astrophysics The relation between surface star formation rate density and spiral arms in NGC 5236 (M 83) E. Silva-Villa and S. S. Larsen Astronomy Institute, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands e-mail: [e.silvavilla;s.s.larsen]@uu.nl Received 7 June 2011 / Accepted 20 October 2011 ABSTRACT Context. For a long time the consensus has been that star formation rates are higher in the interior of spiral arms in galaxies, compared to inter-arm regions. However, recent studies have found that the star formation inside the arms is not more efficient than elsewhere in the galaxy. Previous studies have based their conclusion mainly on integrated light. We use resolved stellar populations to investigate the star formation rates throughout the nearby spiral galaxy NGC 5236. Aims. We aim to investigate how the star formation rate varies in the spiral arms compared to the inter-arm regions, using optical space-based observations of NGC 5236. Methods. Using ground-based Hα images we traced regions of recent star formation, and reconstructed the arms of the galaxy. Using HST/ACS images we estimate star formation histories by means of the synthetic CMD method. Results. ArmsbasedonHα images showed to follow the regions where stellar crowding is higher. Star formation rates for individual arms over the fields covered were estimated between 10 to 100 Myr, where the stellar photometry is less affected by incompleteness. Comparison between arms and inter-arm surface star formation rate densities (ΣSFR) suggested higher values in the arms (∼0.6 dex). -
Extragalactic Astronomy
Astrophysics and Space Science Library 435 Mauro D’Onofrio Roberto Rampazzo Simone Zaggia Editors From the Realm of the Nebulae to Populations of Galaxies Dialogues on a Century of Research From the Realm of the Nebulae to Populations of Galaxies Astrophysics and Space Science Library EDITORIAL BOARD Chairman W. B. BURTON, National Radio Astronomy Observatory, Charlottesville, Virginia, U.S.A. ([email protected]); University of Leiden, The Netherlands ([email protected]) F. BERTOLA, University of Padua, Italy C. J. CESARSKY, Commission for Atomic Energy, Saclay, France P. EHRENFREUND, Leiden University, The Netherlands O. ENGVOLD, University of Oslo, Norway A. HECK, Strasbourg Astronomical Observatory, France E. P. J. VAN DEN HEUVEL, University of Amsterdam, The Netherlands V. M. KASPI, McGill University, Montreal, Canada J. M. E. KUIJPERS, University of Nijmegen, The Netherlands H. VAN DER LAAN, University of Utrecht, The Netherlands P. G. MURDIN, Institute of Astronomy, Cambridge, UK B. V. SO M OV, Astronomical Institute, Moscow State University, Russia R. A. SUNYAEV, Space Research Institute, Moscow, Russia More information about this series at http://www.springer.com/series/5664 Mauro D’Onofrio • Roberto Rampazzo • Simone Zaggia Editors From the Realm of the Nebulae to Populations of Galaxies Dialogues on a Century of Research 123 Editors Mauro D’Onofrio Roberto Rampazzo Department of Physics and Astronomy INAF–Osservatorio Astronomico University of Padova di Padova Italy Padova, Italy Simone Zaggia INAF–Osservatorio Astronomico di Padova Padova, Italy ISSN 0067-0057 ISSN 2214-7985 (electronic) Astrophysics and Space Science Library ISBN 978-3-319-31004-6 ISBN 978-3-319-31006-0 (eBook) DOI 10.1007/978-3-319-31006-0 Library of Congress Control Number: 2016946611 © Springer International Publishing Switzerland 2016 This work is subject to copyright. -
MASS DISTRIBUTIONS and STELLAR POPULATIONS in SPIRAL GALAXIES By
RICE UNIVERSITY MASS DISTRIBUTIONS AND STELLAR POPULATIONS IN SPIRAL GALAXIES by Joseph C. Davis, Jr. A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE THESIS DIRECTOR'S SIGNATURE: March 1977 MASS DISTRIBUTIONS AND STELLAR POPULATIONS IN SPIRAL GALAXIES by Joseph C. Davis, Jr. ABSTRACT The techniques of obtaining mass models for spiral galaxies from their observed rotation curves are reviewed. A fast method for fitting the Toomre type disk mass model together with a simple prescription for the distribution of central bulge material is developed based on observed rotation curves. Several well observed galaxies are then modeled in this fashion. These mass models of real galaxies are then used as in¬ put to an extension of an ongoing program of galactic evolu¬ tion modeling. Multizone galactic models are constructed assuming each radial zone evolves independently with a rate of star formation proportional to the frequency of spiral arm passage as derived from density wave theory. The pro¬ portionality factor, called the efficiency of star formation, is the only free parameter of the model. An initial era of star formation is assumed to deplete an amount of gas into stars equal to: the amount of bulge mass at each radius. A constant initial mass function equal to the Salpeter IMF is employed throughout. An evolutionary model of the near¬ by spiral galaxy M33 shows that a variable efficiency factor is required to reproduce both the observed integrated colors and luminosities. i It is also shown that this model for the star forma¬ tion rate coupled with the initial mass function determined from the stars in the local solar neighborhood will not produce model galaxies as blue as the bluest real galaxies. -
On Wave Dark Matter, Shells in Elliptical Galaxies, and the Axioms of General Relativity
On Wave Dark Matter, Shells in Elliptical Galaxies, and the Axioms of General Relativity Hubert L. Bray ∗ December 22, 2012 Abstract This paper is a sequel to the author’s paper entitled “On Dark Matter, Spiral Galaxies, and the Axioms of General Relativity” which explored a geometrically natural axiomatic definition for dark matter modeled by a scalar field satisfying the Einstein-Klein-Gordon wave equations which, after much calculation, was shown to be consistent with the observed spiral and barred spiral patterns in disk galaxies, as seen in Figures 3, 4, 5, 6. We give an update on where things stand on this “wave dark matter” model of dark matter (aka scalar field dark matter and boson stars), an interesting alternative to the WIMP model of dark matter, and discuss how it has the potential to help explain the long-observed interleaved shell patterns, also known as ripples, in the images of elliptical galaxies. In section 1, we begin with a discussion of dark matter and how the wave dark matter model com- pares with observations related to dark matter, particularly on the galactic scale. In section 2, we show explicitly how wave dark matter shells may occur in the wave dark matter model via approximate solu- tions to the Einstein-Klein-Gordon equations. How much these wave dark matter shells (as in Figure 2) might contribute to visible shells in elliptical galaxies (as in Figure 1) is an important open question. 1 Introduction What is dark matter? No one really knows exactly, in part because dark matter does not interact signif- icantly with light, making it invisible. -
A 'Catchers Tale' the 'Leviathan Lord'
The ‘Leviathan Lord’ of Birr Castle The ‘Leviathan Lord’ of Birr Castle William Parsons, 3rd Earl of Rosse A ‘Catchers Tale’ Featuring Featuringthe Forgotten the Forgotten LivesLives of theof Men the and Men Women and who FirstWomen who First PhotographedPhotographed the Heavens the Heavens Stefan Hughes Contents 1. The ‘Catchers Tales’ 1 1.1 Introduction 2 1.2 Birr Castle Today 4 1.3 The ‘Great Telescope Builder’ 5 2. The Life and Work of William Parsons 6 2.1 ‘Great Telescopes’ 7 2.2 Lord Oxmantown 8 2.3 Mary Field of Heaton Hall 10 2.4 Parsonstown 17 2.5 Mirror, Mirror on the Estate... 23 2.6 The ‘Leviathan’ 30 2.7 ‘The Problem of the Nebulae’ 36 2.8 ‘Spirals’ 44 2.9 Photography at Birr 50 2.10 Homage 54 2.11 After... 58 3. Appendices 64 A: William Parsons: Family Pedigree 65 B: Mary Field: Family Pedigree 69 C: Glossary of Terms & Personalities 73 4. End Piece 80 Notes & Bibliography 81 Acknowledgements 91 Index 92 The Author 97 i 1. The ‘Catchers Tales’ Catchers of the Light William Parsons 3rd Earl of Rosse The Forgotten Lives of the Men and Women who First Photographed the Heavens Their True Tales of Adventure, Adversity & Triumph Stefan Hughes1 1.1 Introduction The ‘Catchers Tales’, each feature a single life of one of the men and women who first photographed the heavens. Their lives are ones full of adventure, adversity and triumph - which would test the abilities of even the best author or screenwriter to recreate as a work of fiction. -
Prime Focus (04-08)
Highlights of the April Sky. -- -- -- 2nd -- -- -- The Moon below Neptune at dawn. PPrime Focuss -- -- -- 4th -- -- -- A Publication of the Kalamazoo Astronomical Society Venus near a very thin Moon, look east about 20 minutes before sunrise. April 2008 -- -- -- 5th -- -- -- New Moon 11:55 pm EDT ThisThis MonthsMonths KAS EventsEvents -- -- -- 8th -- -- -- The Moon occults the Pleiades, 10 pm. General Meeting: Friday, April 4 @ 7:00 pm -- -- -- 12thth -- -- -- Kalamazoo Math & Science Center - See Page 10 for Details The Moon less than 2º ofof Mars after midnight. Observing Session: Saturday, April 5 @ 8:00 pm First Quarter Moon Saturn & Orion Nebula - Kalamazoo Nature Center 2:32 pm EDT thth Astronomy Day: Saturday, April 19 @ 10:00 am -- -- -- 14 -- -- -- Moon is right of Saturn Kalamazoo Nature Center - See Page 3 for Details and Regulus after dusk. -- -- -- 19th -- -- -- Observing Session: Saturday, April 19 @ 8:00 pm The Moon is 4º oror 55º belowbelow Saturn & Full Moon - Kalamazoo Nature Center Spica at dusk. -- -- -- 20th -- -- -- Full Moon 6:25 am EDT Inside the Newsletter. Inside the Newsletter. -- -- -- 22nd -- -- -- Lyrid meteor shower peaks March Meeting Minutes.........................p. 2 (10--20 meteors per hour). Board Meeting Minutes......................... p. 3 -- -- -- 23rd -- -- -- Astronomy Day 2008............................ p. 3 The Moon south of Antares before dawn. KAS Online Redesign Underway........ p. 4 Turtles and the Speed of Light............ p. 4 -- -- -- 27th -- -- -- The Moon passes 4º southsouth Rhea Also May Have Rings................... p. 5 of Jupiter, 4 am. NASA Space Place.................................. p. 6 -- -- -- 28thth -- -- -- Membership of the KAS........................p. 7 Last Quarter Moon 10:12 am EDT April Night Sky........................................ p. 8 Mars passes 5º southsouth ofof KAS Officers & Announcements....... -
Rosse Papers Summary List: 17Th Century Correspondence
ROSSE PAPERS SUMMARY LIST: 17TH CENTURY CORRESPONDENCE A/ DATE DESCRIPTION 1-26 1595-1699: 17th-century letters and papers of the two branches of the 1871 Parsons family, the Parsonses of Bellamont, Co. Dublin, Viscounts Rosse, and the Parsonses of Parsonstown, alias Birr, King’s County. [N.B. The whole of this section is kept in the right-hand cupboard of the Muniment Room in Birr Castle. It has been microfilmed by the Carroll Institute, Carroll House, 2-6 Catherine Place, London SW1E 6HF. A copy of the microfilm is available in the Muniment Room at Birr Castle and in PRONI.] 1 1595-1699 Large folio volume containing c.125 very miscellaneous documents, amateurishly but sensibly attached to its pages, and referred to in other sub-sections of Section A as ‘MSS ii’. This volume is described in R. J. Hayes, Manuscript Sources for the History of Irish Civilisation, as ‘A volume of documents relating to the Parsons family of Birr, Earls of Rosse, and lands in Offaly and property in Birr, 1595-1699’, and has been microfilmed by the National Library of Ireland (n.526: p. 799). It includes letters of c.1640 from Rev. Richard Heaton, the early and important Irish botanist. 2 1595-1699 Late 19th-century, and not quite complete, table of contents to A/1 (‘MSS ii’) [in the handwriting of the 5th Earl of Rosse (d. 1918)], and including the following entries: ‘1. 1595. Elizabeth Regina, grant to Richard Hardinge (copia). ... 7. 1629. Agreement of sale from Samuel Smith of Birr to Lady Anne Parsons, relict of Sir Laurence Parsons, of cattle, “especially the cows of English breed”.