The Structure of Supervoids { I: Void Hierarchy in the Northern Local
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SDSS DR7 Superclusters Morphology
A&A 532, A5 (2011) Astronomy DOI: 10.1051/0004-6361/201116564 & c ESO 2011 Astrophysics SDSS DR7 superclusters Morphology M. Einasto1,L.J.Liivamägi1,2,E.Tago1,E.Saar1,E.Tempel1,2,J.Einasto1, V. J. Martínez3, and P. Heinämäki4 1 Tartu Observatory, 61602 Tõravere, Estonia e-mail: [email protected] 2 Institute of Physics, Tartu University, Tähe 4, 51010 Tartu, Estonia 3 Observatori Astronòmic, Universitat de València, Apartat de Correus 22085, 46071 València, Spain 4 Tuorla Observatory, University of Turku, Väisäläntie 20, Piikkiö, Finland Received 24 January 2011 / Accepted 2 May 2011 ABSTRACT Aims. We study the morphology of a set of superclusters drawn from the SDSS DR7. Methods. We calculate the luminosity density field to determine superclusters from a flux-limited sample of galaxies from SDSS DR7 and select superclusters with 300 and more galaxies for our study. We characterise the morphology of superclusters using the fourth Minkowski functional V3, the morphological signature (the curve in the shapefinder’s K1-K2 plane) and the shape parameter (the ratio of the shapefinders K1/K2). We investigate the supercluster sample using multidimensional normal mixture modelling. We use Abell clusters to identify our superclusters with known superclusters and to study the large-scale distribution of superclusters. Results. The superclusters in our sample form three chains of superclusters; one of them is the Sloan Great Wall. Most superclusters have filament-like overall shapes. Superclusters can be divided into two sets; more elongated superclusters are more luminous, richer, have larger diameters and a more complex fine structure than less elongated superclusters. The fine structure of superclusters can be divided into four main morphological types: spiders, multispiders, filaments, and multibranching filaments. -
The Large–Scale Distribution of Galaxies in the Shapley Concentration
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server The large{scale distribution of galaxies in the Shapley Concentration S. Bardelli Osservatorio Astronomico di Trieste, via Tiepolo 11, I{34131 Trieste, Italy E. Zucca, G. Zamorani Osservatorio Astronomico di Bologna, via Zamboni 33, I{40126 Bologna, Italy Abstract. We present the results of a galaxy redshift survey in the central region of the Shapley Concentration. Our total sample contains 2000 radial velocities of galaxies both in the clusters and in the inter- cluster∼ field. We reconstruct the density profile of this supercluster, cal- culate its overdensity and total mass. Moreover we detect a massive structure behind the Shapley Concentration, at 30000 km/s. ∼ 1. Introduction The Shapley Concentration stands out as the richest system of Abell clusters in the list of Zucca et al. (1993), at every density excess. In particular, at a density contrast of 2, it has 25 members (at mean velocity 14000 km/s), while at the same density∼ contrast the Great Attractor, which is∼ the largest mass 1 condensation within 80 h− Mpc, has only 6 members and the Corona Borealis and Hercules superclusters are formed by 10 and 8 clusters, respectively. While the cluster distribution in the Shapley Concentration has been well studied, little is known about the distribution of the galaxies. Determining the properties of these galaxies is very important in order to assess the physical reality and extension of the structure and to determine if galaxies and clusters trace the matter distribution in the same way. -
Arxiv:1305.7264V2 [Astro-Ph.EP] 21 Apr 2014 Spain
Draft version September 18, 2018 Preprint typeset using LATEX style emulateapj v. 08/22/09 THE MOVING GROUP TARGETS OF THE SEEDS HIGH-CONTRAST IMAGING SURVEY OF EXOPLANETS AND DISKS: RESULTS AND OBSERVATIONS FROM THE FIRST THREE YEARS Timothy D. Brandt1, Masayuki Kuzuhara2, Michael W. McElwain3, Joshua E. Schlieder4, John P. Wisniewski5, Edwin L. Turner1,6, J. Carson7,4, T. Matsuo8, B. Biller4, M. Bonnefoy4, C. Dressing9, M. Janson1, G. R. Knapp1, A. Moro-Mart´ın10, C. Thalmann11, T. Kudo12, N. Kusakabe13, J. Hashimoto13,5, L. Abe14, W. Brandner4, T. Currie15, S. Egner12, M. Feldt4, T. Golota12, M. Goto16, C. A. Grady3,17, O. Guyon12, Y. Hayano12, M. Hayashi18, S. Hayashi12, T. Henning4, K. W. Hodapp19, M. Ishii12, M. Iye13, R. Kandori13, J. Kwon13,22, K. Mede18, S. Miyama20, J.-I. Morino13, T. Nishimura12, T.-S. Pyo12, E. Serabyn21, T. Suenaga22, H. Suto13, R. Suzuki13, M. Takami23, Y. Takahashi18, N. Takato12, H. Terada12, D. Tomono12, M. Watanabe24, T. Yamada25, H. Takami12, T. Usuda12, M. Tamura13,18 Draft version September 18, 2018 ABSTRACT We present results from the first three years of observations of moving group targets in the SEEDS high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of ∼105 at 100 and ∼106 beyond 200 around 63 proposed members of nearby kinematic moving groups. We review each of the kinematic associations to which our targets belong, concluding that five, β Pictoris (∼20 Myr), AB Doradus (∼100 Myr), Columba (∼30 Myr), Tucana-Horogium (∼30 Myr), and TW Hydrae (∼10 Myr), are sufficiently well-defined to constrain the ages of individual targets. -
An Outline of Stellar Astrophysics with Problems and Solutions
An Outline of Stellar Astrophysics with Problems and Solutions Using Maple R and Mathematica R Robert Roseberry 2016 1 Contents 1 Introduction 5 2 Electromagnetic Radiation 7 2.1 Specific intensity, luminosity and flux density ............7 Problem 1: luminous flux (**) . .8 Problem 2: galaxy fluxes (*) . .8 Problem 3: radiative pressure (**) . .9 2.2 Magnitude ...................................9 Problem 4: magnitude (**) . 10 2.3 Colour ..................................... 11 Problem 5: Planck{Stefan-Boltzmann{Wien{colour (***) . 13 Problem 6: Planck graph (**) . 13 Problem 7: radio and visual luminosity and brightness (***) . 14 Problem 8: Sirius (*) . 15 2.4 Emission Mechanisms: Continuum Emission ............. 15 Problem 9: Orion (***) . 17 Problem 10: synchrotron (***) . 18 Problem 11: Crab (**) . 18 2.5 Emission Mechanisms: Line Emission ................. 19 Problem 12: line spectrum (*) . 20 2.6 Interference: Line Broadening, Scattering, and Zeeman splitting 21 Problem 13: natural broadening (**) . 21 Problem 14: Doppler broadening (*) . 22 Problem 15: Thomson Cross Section (**) . 23 Problem 16: Inverse Compton scattering (***) . 24 Problem 17: normal Zeeman splitting (**) . 25 3 Measuring Distance 26 3.1 Parallax .................................... 27 Problem 18: parallax (*) . 27 3.2 Doppler shifting ............................... 27 Problem 19: supernova distance (***) . 28 3.3 Spectroscopic parallax and Main Sequence fitting .......... 28 Problem 20: Main Sequence fitting (**) . 29 3.4 Standard candles ............................... 30 Video: supernova light curve . 30 Problem 21: Cepheid distance (*) . 30 3.5 Tully-Fisher relation ............................ 31 3.6 Lyman-break galaxies and the Hubble flow .............. 33 4 Transparent Gas: Interstellar Gas Clouds and the Atmospheres and Photospheres of Stars 35 2 4.1 Transfer equation and optical depth .................. 36 Problem 22: optical depth (**) . 37 4.2 Plane-parallel atmosphere, Eddington's approximation, and limb darkening .................................. -
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. -
Astronomy 422
Astronomy 422 Lecture 15: Expansion and Large Scale Structure of the Universe Key concepts: Hubble Flow Clusters and Large scale structure Gravitational Lensing Sunyaev-Zeldovich Effect Expansion and age of the Universe • Slipher (1914) found that most 'spiral nebulae' were redshifted. • Hubble (1929): "Spiral nebulae" are • other galaxies. – Measured distances with Cepheids – Found V=H0d (Hubble's Law) • V is called recessional velocity, but redshift due to stretching of photons as Universe expands. • V=H0D is natural result of uniform expansion of the universe, and also provides a powerful distance determination method. • However, total observed redshift is due to expansion of the universe plus a galaxy's motion through space (peculiar motion). – For example, the Milky Way and M31 approaching each other at 119 km/s. • Hubble Flow : apparent motion of galaxies due to expansion of space. v ~ cz • Cosmological redshift: stretching of photon wavelength due to expansion of space. Recall relativistic Doppler shift: Thus, as long as H0 constant For z<<1 (OK within z ~ 0.1) What is H0? Main uncertainty is distance, though also galaxy peculiar motions play a role. Measurements now indicate H0 = 70.4 ± 1.4 (km/sec)/Mpc. Sometimes you will see For example, v=15,000 km/s => D=210 Mpc = 150 h-1 Mpc. Hubble time The Hubble time, th, is the time since Big Bang assuming a constant H0. How long ago was all of space at a single point? Consider a galaxy now at distance d from us, with recessional velocity v. At time th ago it was at our location For H0 = 71 km/s/Mpc Large scale structure of the universe • Density fluctuations evolve into structures we observe (galaxies, clusters etc.) • On scales > galaxies we talk about Large Scale Structure (LSS): – groups, clusters, filaments, walls, voids, superclusters • To map and quantify the LSS (and to compare with theoretical predictions), we use redshift surveys. -
Monthly Newsletter of the Durban Centre - March 2018
Page 1 Monthly Newsletter of the Durban Centre - March 2018 Page 2 Table of Contents Chairman’s Chatter …...…………………….……….………..….…… 3 Andrew Gray …………………………………………...………………. 5 The Hyades Star Cluster …...………………………….…….……….. 6 At the Eye Piece …………………………………………….….…….... 9 The Cover Image - Antennae Nebula …….……………………….. 11 Galaxy - Part 2 ….………………………………..………………….... 13 Self-Taught Astronomer …………………………………..………… 21 The Month Ahead …..…………………...….…….……………..…… 24 Minutes of the Previous Meeting …………………………….……. 25 Public Viewing Roster …………………………….……….…..……. 26 Pre-loved Telescope Equipment …………………………...……… 28 ASSA Symposium 2018 ………………………...……….…......…… 29 Member Submissions Disclaimer: The views expressed in ‘nDaba are solely those of the writer and are not necessarily the views of the Durban Centre, nor the Editor. All images and content is the work of the respective copyright owner Page 3 Chairman’s Chatter By Mike Hadlow Dear Members, The third month of the year is upon us and already the viewing conditions have been more favourable over the last few nights. Let’s hope it continues and we have clear skies and good viewing for the next five or six months. Our February meeting was well attended, with our main speaker being Dr Matt Hilton from the Astrophysics and Cosmology Research Unit at UKZN who gave us an excellent presentation on gravity waves. We really have to be thankful to Dr Hilton from ACRU UKZN for giving us his time to give us presentations and hope that we can maintain our relationship with ACRU and that we can draw other speakers from his colleagues and other research students! Thanks must also go to Debbie Abel and Piet Strauss for their monthly presentations on NASA and the sky for the following month, respectively. -
195 9Apj. . .130. .629B the HERCULES CLUSTER OF
.629B THE HERCULES CLUSTER OF NEBULAE* .130. G. R. Burbidge and E. Margaret Burbidge 9ApJ. Yerkes and McDonald Observatories Received March 26, 1959 195 ABSTRACT The northern of two clusters of nebulae in Hercules, first listed by Shapley in 1933, is an irregular group of about 75 bright nebulae and a larger number of faint ones, distributed over an area about Io X 40'. A set of plates of parts of this cluster, taken by Dr. Walter Baade with the 200-inch Hale reflector, is shown and described. More than three-quarters of the bright nebulae have been classified, and, of these, 69 per cent are spirals or irregulars and 31 per cent elliptical or SO. Radial velocities for 7 nebulae were obtained by Humason, and 10 have been obtained by us with the 82-inch reflector. The mean red shift is 10775 km/sec. From this sample, the total kinetic energy of the nebulae has been esti- mated. By measuring the distances between all pairs on a 48-inch Schmidt enlargement, the total poten- tial energy has been estimated. From these results it is concluded that, if the cluster is to be in a stationary state, the average galactic mass must be ^1012Mo. Three possibilities are discussed: that the masses are indeed as large as this, that there is a large amount of intergalactic matter, and that the cluster is expanding. The data for the Coma and Virgo clusters are also reviewed. It is concluded that both the Hercules and the Virgo clusters are probably expanding, but the situation is uncertain in the case of the Coma cluster. -
The Nanograv 11 Yr Data Set: Limits on Supermassive Black Hole Binaries in Galaxies Within 500 Mpc
The Astrophysical Journal, 914:121 (15pp), 2021 June 20 https://doi.org/10.3847/1538-4357/abfcd3 © 2021. The American Astronomical Society. All rights reserved. The NANOGrav 11 yr Data Set: Limits on Supermassive Black Hole Binaries in Galaxies within 500 Mpc Zaven Arzoumanian1, Paul T. Baker2 , Adam Brazier3, Paul R. Brook4,5 , Sarah Burke-Spolaor4,5 , Bence Becsy6 , Maria Charisi7,8,38 , Shami Chatterjee3 , James M. Cordes3 , Neil J. Cornish6 , Fronefield Crawford9 , H. Thankful Cromartie10 , Megan E. DeCesar11 , Paul B. Demorest12 , Timothy Dolch13,14 , Rodney D. Elliott15 , Justin A. Ellis16, Elizabeth C. Ferrara17 , Emmanuel Fonseca18 , Nathan Garver-Daniels4,5 , Peter A. Gentile4,5 , Deborah C. Good19 , Jeffrey S. Hazboun20 , Kristina Islo21, Ross J. Jennings3 , Megan L. Jones21 , Andrew R. Kaiser4,5 , David L. Kaplan21 , Luke Zoltan Kelley22 , Joey Shapiro Key20 , Michael T. Lam23,24 , T. Joseph W. Lazio7,25, Jing Luo26 , Ryan S. Lynch27 , Chung-Pei Ma28 , Dustin R. Madison4,5,39 , Maura A. McLaughlin4,5 , Chiara M. F. Mingarelli29,30 , Cherry Ng31 , David J. Nice11 , Timothy T. Pennucci32,33,40 , Nihan S. Pol4,5,8 , Scott M. Ransom32 , Paul S. Ray34 , Brent J. Shapiro-Albert4,5 , Xavier Siemens21,35 , Joseph Simon7,25 , Renée Spiewak36 , Ingrid H. Stairs19 , Daniel R. Stinebring37 , Kevin Stovall12 , Joseph K. Swiggum11,41 , Stephen R. Taylor8 , Michele Vallisneri7,25 , Sarah J. Vigeland21 , and Caitlin A. Witt4,5 The NANOGrav Collaboration 1 X-Ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771, USA 2 Department of Physics and Astronomy, Widener University, One University Place, Chester, PA 19013, USA 3 Cornell Center for Astrophysics and Planetary Science and Department of Astronomy, Cornell University, Ithaca, NY 14853, USA 4 Department of Physics and Astronomy, West Virginia University, P.O. -
FY13 High-Level Deliverables
National Optical Astronomy Observatory Fiscal Year Annual Report for FY 2013 (1 October 2012 – 30 September 2013) Submitted to the National Science Foundation Pursuant to Cooperative Support Agreement No. AST-0950945 13 December 2013 Revised 18 September 2014 Contents NOAO MISSION PROFILE .................................................................................................... 1 1 EXECUTIVE SUMMARY ................................................................................................ 2 2 NOAO ACCOMPLISHMENTS ....................................................................................... 4 2.1 Achievements ..................................................................................................... 4 2.2 Status of Vision and Goals ................................................................................. 5 2.2.1 Status of FY13 High-Level Deliverables ............................................ 5 2.2.2 FY13 Planned vs. Actual Spending and Revenues .............................. 8 2.3 Challenges and Their Impacts ............................................................................ 9 3 SCIENTIFIC ACTIVITIES AND FINDINGS .............................................................. 11 3.1 Cerro Tololo Inter-American Observatory ....................................................... 11 3.2 Kitt Peak National Observatory ....................................................................... 14 3.3 Gemini Observatory ........................................................................................ -
Clusters of Galaxy Hierarchical Structure the Universe Shows Range of Patterns of Structures on Decidedly Different Scales
Astronomy 218 Clusters of Galaxy Hierarchical Structure The Universe shows range of patterns of structures on decidedly different scales. Stars (typical diameter of d ~ 106 km) are found in gravitationally bound systems called star clusters (≲ 106 stars) and galaxies (106 ‒ 1012 stars). Galaxies (d ~ 10 kpc), composed of stars, star clusters, gas, dust and dark matter, are found in gravitationally bound systems called groups (< 50 galaxies) and clusters (50 ‒ 104 galaxies). Clusters (d ~ 1 Mpc), composed of galaxies, gas, and dark matter, are found in currently collapsing systems called superclusters. Superclusters (d ≲ 100 Mpc) are the largest known structures. The Local Group Three large spirals, the Milky Way Galaxy, Andromeda Galaxy(M31), and Triangulum Galaxy (M33) and their satellites make up the Local Group of galaxies. At least 45 galaxies are members of the Local Group, all within about 1 Mpc of the Milky Way. The mass of the Local Group is dominated by 11 11 10 M31 (7 × 10 M☉), MW (6 × 10 M☉), M33 (5 × 10 M☉) Virgo Cluster The nearest large cluster to the Local Group is the Virgo Cluster at a distance of 16 Mpc, has a width of ~2 Mpc though it is far from spherical. It covers 7° of the sky in the Constellations Virgo and Coma Berenices. Even these The 4 brightest very bright galaxies are giant galaxies are elliptical galaxies invisible to (M49, M60, M86 & the unaided M87). eye, mV ~ 9. Virgo Census The Virgo Cluster is loosely concentrated and irregularly shaped, making it fairly M88 M99 representative of the most M100 common class of clusters. -
Hercules a Monthly Sky Guide for the Beginning to Intermediate Amateur Astronomer Tom Trusock - 7/09
Small Wonders: Hercules A monthly sky guide for the beginning to intermediate amateur astronomer Tom Trusock - 7/09 Dragging forth the summer Milky Way, legendary strongman Hercules is yet another boundary constellation for the summer season. His toes are dipped in the stream of our galaxy, his head is firm in the depths of space. Hercules is populated by a dizzying array of targets, many extra-galactic in nature. Galaxy clusters abound and there are three Hickson objects for the aficionado. There are a smattering of nice galaxies, some planetary nebulae and of course a few very nice globular clusters. 2/19 Small Wonders: Hercules Widefield Finder Chart - Looking high and south, early July. Tom Trusock June-2009 3/19 Small Wonders: Hercules For those inclined to the straightforward list approach, here's ours for the evening: Globular Clusters M13 M92 NGC 6229 Planetary Nebulae IC 4593 NGC 6210 Vy 1-2 Galaxies NGC 6207 NGC 6482 NGC 6181 Galaxy Groups / Clusters AGC 2151 (Hercules Cluster) Tom Trusock June-2009 4/19 Small Wonders: Hercules Northern Hercules Finder Chart Tom Trusock June-2009 5/19 Small Wonders: Hercules M13 and NGC 6207 contributed by Emanuele Colognato Let's start off with the masterpiece and work our way out from there. Ask any longtime amateur the first thing they think of when one mentions the constellation Hercules, and I'd lay dollars to donuts, you'll be answered with the globular cluster Messier 13. M13 is one of the easiest objects in the constellation to locate. M13 lying about 1/3 of the way from eta to zeta, the two stars that define the westernmost side of the keystone.