Local Superclusters
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Flat Rotation Curves and Low Velocity Dispersions in KMOS Star-Forming Galaxies at Z ∼ 1? E
A&A 594, A77 (2016) Astronomy DOI: 10.1051/0004-6361/201628315 & c ESO 2016 Astrophysics Flat rotation curves and low velocity dispersions in KMOS star-forming galaxies at z ∼ 1? E. M. Di Teodoro1; 2, F. Fraternali1; 3, and S. H. Miller4 1 Department of Physics and Astronomy, University of Bologna, 6/2 Viale Berti Pichat, 40127 Bologna, Italy 2 Research School of Astronomy and Astrophysics – The Australian National University, Canberra, ACT, 2611, Australia e-mail: [email protected] 3 Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen, The Netherlands 4 University of California – Irvine, Irvine, CA 92697, USA Received 15 February 2016 / Accepted 18 July 2016 ABSTRACT The study of the evolution of star-forming galaxies requires the determination of accurate kinematics and scaling relations out to high redshift. In this paper we select a sample of 18 galaxies at z ∼ 1; observed in the Hα emission line with KMOS, to derive accurate kinematics using a novel 3D analysis technique. We use the new code 3DBarolo, which models the galaxy emission directly in 3D observational space, without the need to extract kinematic maps. This major advantage of this technique is that it is not affected by beam smearing and thus it enables the determination of rotation velocity and intrinsic velocity dispersion, even at low spatial resolution. We find that (1) the rotation curves of these z ∼ 1 galaxies rise very steeply within few kiloparsecs and remain flat out to the outermost radius and (2) the Hα velocity dispersions are low, ranging from 15 to 40 km s−1, which leads to V/σ = 3–10. -
Isolated Elliptical Galaxies in the Local Universe
A&A 588, A79 (2016) Astronomy DOI: 10.1051/0004-6361/201527844 & c ESO 2016 Astrophysics Isolated elliptical galaxies in the local Universe I. Lacerna1,2,3, H. M. Hernández-Toledo4 , V. Avila-Reese4, J. Abonza-Sane4, and A. del Olmo5 1 Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. V. Mackenna 4860, Santiago, Chile e-mail: [email protected] 2 Centro de Astro-Ingeniería, Pontificia Universidad Católica de Chile, Av. V. Mackenna 4860, Santiago, Chile 3 Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany 4 Instituto de Astronomía, Universidad Nacional Autónoma de México, A.P. 70-264, 04510 México D. F., Mexico 5 Instituto de Astrofísica de Andalucía IAA – CSIC, Glorieta de la Astronomía s/n, 18008 Granada, Spain Received 26 November 2015 / Accepted 6 January 2016 ABSTRACT Context. We have studied a sample of 89 very isolated, elliptical galaxies at z < 0.08 and compared their properties with elliptical galaxies located in a high-density environment such as the Coma supercluster. Aims. Our aim is to probe the role of environment on the morphological transformation and quenching of elliptical galaxies as a function of mass. In addition, we elucidate the nature of a particular set of blue and star-forming isolated ellipticals identified here. Methods. We studied physical properties of ellipticals, such as color, specific star formation rate, galaxy size, and stellar age, as a function of stellar mass and environment based on SDSS data. We analyzed the blue and star-forming isolated ellipticals in more detail, through photometric characterization using GALFIT, and infer their star formation history using STARLIGHT. -
Astronomical Evidence for an Alternative to Dark Matter?
Astronomical Evidence for an Alternative to Dark Matter? by Alphonsus J. Fagan St. John's NL, Canada Abstract Unexplained gravitational potentials in deep space have been generally attributed to dark matter. This paper explores an alternative that unites the concepts of dark matter and dark energy, and is rooted in the idea that space is a tangible ‘substance’ that is being created at different rates at different locations. The concept of congenital gravitational structure ('structural gravity') is introduced and the possibility that antimatter experiences anti-gravity is discussed. Among other things, the conjectures predict the phenomenon of 'inverse gravitational lensing' and possible examples are identified — in particular as associated with the peculiar galaxy known as Hoag's Object. The conjectures also offer possible explanations for a number of poorly understood phenomena, including: the antimatter cloud; dark matter halos; the vacuum catastrophe; counter-rotating galaxies; the Hubble radius; and, large scale cosmic features. Although the ideas are mainly discussed at a conceptual level, the proposed model also makes a number of testable predictions. Keywords: cosmology; modified gravity; time; dark energy; dark matter; antimatter; diffuse x-ray background; ring galaxies; Hoag's Object; vacuum catastrophe; cosmic horizon Author’s Note: The ideas presented herein are a condensed form of a larger model presented in a (2020) book “Mind Openers 2.0: A Conceptual Reinterpretation of Modern Physics”: currently available at Mind Openers 2.0 on Amazon 1. Introduction 1.1 Unexplained Gravity As first pointed out by Fritz Zwicky in the 1930s, and later confirmed by Vera Rubin and Kent Ford in the 1960s and 70s, the amount of ordinary matter in galaxies and intergalactic gas and dust, does not provide sufficient gravitational potential to account for galactic rotation curves, or the velocities of galaxies within clusters. -
Galactic-Scale Macro-Engineering: Looking for Signs of Other Intelligent Species, As an Exercise in Hope for Our Own
Galactic-scale macro-engineering: Looking for signs of other intelligent species, as an exercise in hope for our own * Joseph Voros Senior Lecturer in Strategic Foresight Faculty of Business & Law, Swinburne University of Technology, Melbourne, Australia Abstract If we consider Big History as simply ‘our’ example of the process of cosmic evolution playing out, then we can seek to broaden our view of our possible fate as a species by asking questions about what paths or trajectories other species’ own versions of Big History might take or have taken. This paper explores the broad outlines of possible scenarios for the evolution of long-lived intelligent engineering species—scenarios which might have been part of another species’ own Big History story, or which may yet lie ahead in our own distant future. A sufficiently long-lived engineering-oriented species may decide to undertake a program of macro-engineering projects that might eventually lead to a re-engineered galaxy so altered that its artificiality may be detectable from Earth. We consider activities that lead ultimately to a galactic structure consisting of a central inner core surrounded by a more distant ring of stars separated by a relatively sparser ‘gap’, where star systems and stellar materials may have been removed, ‘lifted’ or turned into Dyson Spheres. When one looks to the sky, one finds that such galaxies do indeed exist—including the beautiful ringed galaxy known as ‘Hoag’s Object’ (PGC 54559) in the constellation Serpens. This leads us to pose the question: Is Hoag’s Object an example of galaxy-scale macro-engineering? And this suggests a program of possible observational activities and theoretical explorations, several of which are presented here, that could be carried out in order to begin to investigate this beguiling question. -
Broad-Band Photometry and Long-Slit Spectroscopy of the Peculiar Ring Galaxy FM 287-14
A&A 559, A8 (2013) Astronomy DOI: 10.1051/0004-6361/201219721 & c ESO 2013 Astrophysics Broad-band photometry and long-slit spectroscopy of the peculiar ring galaxy FM 287-14 M. Faúndez-Abans1, P. C. da Rocha-Poppe2,3, V. A. Fernandes-Martin2,3, M. de Oliveira-Abans1,5, I. F. Fernandes2,3,E.Wenderoth4, and A. Rodríguez-Ardila1 1 MCTI/Laboratório Nacional de Astrofísica, Rua Estados Unidos 154, CEP 37504-364 Itajubá, MG, Brazil e-mail: [max;mabans;aardila]@lna.br 2 UEFS, Departamento de Física, Av. Transnordenstina, S/N, Novo Horizonte, CEP 44036-900 Feira de Santana, BA, Brazil 3 UEFS, Observatório Astronômico Antares, Rua da Barra, 925, Jardim Cruzeiro, CEP 44015-430 Feira de Santana, BA, Brazil e-mail: [paulopoppe;vmartin][email protected]; [email protected] 4 Gemini Observatory, Southern Operations Center, c/o AURA, 603 Casilla, La Serena, Chile e-mail: [email protected] 5 UNIFEI, Instituto de Engenharia de Produção e Gestão, Av. BPS, 1303, Pinheirinho, CEP 37500-903 Itajubá, MG, Brazil Received 30 May 2013 / Accepted 21 August 2013 ABSTRACT Aims. We report detailed morphological and kinematical insights into the disturbed galaxy FM 287-14, which is reported in the literature as a member of strongly interacting galaxies with a clear case of mergers. The main purpose of this paper is to provide a first observational study of this double-nuclei object based on photometry and spectroscopy. Methods. The study is based on BVR photometry with the 1.6-m telescope at OPD, and long-slit spectroscopy with Gemini South’s GMOS spectrograph, with two-gratings centered at 5 011 Å and 6 765 Å. -
Observational Evidence of AGN Feedback
Observational Evidence of AGN Feedback A.C Fabian Institute of Astronomy, Madingley Road Cambridge CB3 0HA, UK Abstract Radiation, winds and jets from the active nucleus of a massive galaxy can interact with its interstellar medium leading to ejection or heating of the gas. This can terminate star formation in the galaxy and stifle accretion onto the black hole. Such Active Galactic Nucleus (AGN) feedback can account for the observed proportionality between central black hole and host galaxy mass. Direct observational evidence for the radiative or quasar mode of feedback, which occurs when the AGN is very luminous, has been difficult to obtain but is accumulating from a few exceptional objects. Feedback from the kinetic or radio mode, which uses the mechanical energy of radio-emitting jets often seen when the AGN is operating at a lower level, is common in massive elliptical galaxies. This mode is well observed directly through X-ray observations of the central galaxies of cool core clusters in the form of bubbles in the hot surrounding medium. The energy flow, which is roughly continuous, heats the hot intracluster gas and reduces radiative cooling and subsequent star formation by an order of magnitude. Feedback appears to maintain a long-lived heating/cooling balance. Powerful, jetted radio outbursts may represent a further mode of energy feedback which affect the cores of groups and subclusters. New telescopes and instruments from the radio to X-ray bands will come into operation over the next few years and lead to a rapid expansion in observational data on all modes of AGN feedback. -
A Basic Requirement for Studying the Heavens Is Determining Where In
Abasic requirement for studying the heavens is determining where in the sky things are. To specify sky positions, astronomers have developed several coordinate systems. Each uses a coordinate grid projected on to the celestial sphere, in analogy to the geographic coordinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth's equator) . Each coordinate system is named for its choice of fundamental plane. The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the one most closely related to the geographic coordinate system, because they use the same fun damental plane and the same poles. The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles on to the celest ial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate systems: the geographic system is fixed to the Earth; it rotates as the Earth does . The equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but of course it's really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec for short) . It measures the angle of an object above or below the celestial equator. The longitud inal angle is called the right ascension (RA for short). -
A Deep Spectroscopic Study of the Filamentary Nebulosity in NGC 4696, the Brightest Cluster Galaxy in the Centaurus Cluster R
University of Kentucky UKnowledge Physics and Astronomy Faculty Publications Physics and Astronomy 2011 A Deep Spectroscopic Study of the Filamentary Nebulosity in NGC 4696, the Brightest Cluster Galaxy in the Centaurus Cluster R. E. A. Canning University of Cambridge, UK A. C. Fabian University of Cambridge, UK R. M. Johnstone University of Cambridge, UK J. S. Sanders University of Cambridge, UK C. S. Crawford University of Cambridge, UK See next page for additional authors Right click to open a feedback form in a new tab to let us know how this document benefits oy u. Follow this and additional works at: https://uknowledge.uky.edu/physastron_facpub Part of the Astrophysics and Astronomy Commons, and the Physics Commons Repository Citation Canning, R. E. A.; Fabian, A. C.; Johnstone, R. M.; Sanders, J. S.; Crawford, C. S.; Ferland, Gary J.; and Hatch, N. A., "A Deep Spectroscopic Study of the Filamentary Nebulosity in NGC 4696, the Brightest Cluster Galaxy in the Centaurus Cluster" (2011). Physics and Astronomy Faculty Publications. 36. https://uknowledge.uky.edu/physastron_facpub/36 This Article is brought to you for free and open access by the Physics and Astronomy at UKnowledge. It has been accepted for inclusion in Physics and Astronomy Faculty Publications by an authorized administrator of UKnowledge. For more information, please contact [email protected]. Authors R. E. A. Canning, A. C. Fabian, R. M. Johnstone, J. S. Sanders, C. S. Crawford, Gary J. Ferland, and N. A. Hatch A Deep Spectroscopic Study of the Filamentary Nebulosity in NGC 4696, the Brightest Cluster Galaxy in the Centaurus Cluster Notes/Citation Information Published in Monthly Notices of the Royal Astronomical Society, v. -
Detection of Co Emission in Hydra I Cluster Galaxies
DETECTION OF CO EMISSION IN HYDRA I CLUSTER GALAXIES W.K. Huehtmeier Max- Planek-Ins t it ut fur Radioastr onomie Auf dem Huge1 69 5300 Bonn 1 , W. Germany Abstract A survey of bright Hydra cluster spiral galaxies for the CO(1-0) transition at 115 GHa was performed with the 15m Swedish-ESO submillimeter telescope (SEST). Five out of 15 galaxies observed have been detected in the CO(1-0) line. The largest spiral galaxy in the cluster , NGC 3312, got more CO than any spiral of the Virgo cluster. This Sa-type galaxy is optically largely distorted and disrupted on one side. It is a good candidate for ram pressure stripping while passing through the cluster's central region. A comparison with global CO properties of Virgo cluster spirals shows a relatively good agreement with the detected Hydra cluster galaxies. 0 bservations Observations were performed with the 15m Swedish-ESO submillimeter telescope (SEST) at La Silla in January 1989 under favorable meteorological conditions. At a frequency of 115 GHz the half power beamwidth (HPBW) of this telescope is 43 arcsec. The cooled Schottky heterodyne receiver had a typical receiver temperature of 350 K; the system temperature was typically 650 to 900 K depending on elevation and humidity. An accousto-optic spectrometer (Zensen 1984) with a bandwidth of 500 MHz yielded a channel width of 0.69 MHz or about 1.8 km/s. In order to improve the signal-to-noise ratio of the integrated profiles usually 5 to 10 frequency channels were averaged resulting in a resolution of 9 to 18 km/s. -
Molecular Gas Content of Galaxies in the Hydra-Centaurus Supercluster
MOLECULAR GAS CONTENT OF GALAXIES IN THE HYDRA-CENTAURUS SUPERCLUSTER W.K. Huchtmeier ™ ** <$ '"" & ^ O Max-Planck-Institut fiir Radioastronomie Auf dem Hugel 69 , 5300 Bonn 1 , W. Germany • Abstract A survey of bright spiral galaxies in the Hydra-Centaurus supercluster for the CO(l-O) transition at 115 GHz was performed with the 15m Swedish-ESO submillimeter telescope (SEST). A total of 30 galaxies have been detected in the CO(l-O) transition out of 47 observed, which is a detection rate over 60%. Global physical parameters of these galaxies derived from optical, CO, HI, and IR measurements compare very well with properties of galaxies in the Virgo cluster. The Hydra I cluster (Abell 1060) is one of the nearest clusters and very similar to the Virgo cluster in many global parameters like type, population, size, and shape. Both clusters have comparable velocity dispersions (i.e. total mass) and are spiral rich. Hydra is well isolated in velocity space and appears more circular (Kwast 1966), and might be dynamically more relaxed, although the center may contain significant substructures (Fitchett and Meritt 1988) or projected foreground groups. Both clusters contain low luminosity central X-ray sources. We assume a distance of 68.4 Mpc for Hydra I in order to allow direct comparison with some (nearly) complete galaxy samples. The Centaurus cluster provides a valuable contrast to Virgo and Coma. It is intermediate in distance and in galaxy population type with a relatively well defined SO-dominated core and an extensive S-rich halo. Its richness class in the Abell scale is 1 or 2 which is richer than Virgo and poorer than Coma. -
From Messier to Abell: 200 Years of Science with Galaxy Clusters
Constructing the Universe with Clusters of Galaxies, IAP 2000 meeting, Paris (France) July 2000 Florence Durret & Daniel Gerbal eds. FROM MESSIER TO ABELL: 200 YEARS OF SCIENCE WITH GALAXY CLUSTERS Andrea BIVIANO Osservatorio Astronomico di Trieste via G.B. Tiepolo 11 – I-34131 Trieste, Italy [email protected] 1 Introduction The history of the scientific investigation of galaxy clusters starts with the XVIII century, when Charles Messier and F. Wilhelm Herschel independently produced the first catalogues of nebulæ, and noticed remarkable concentrations of nebulæ on the sky. Many astronomers of the XIX and early XX century investigated the distribution of nebulæ in order to understand their relation to the local “sidereal system”, the Milky Way. The question they were trying to answer was whether or not the nebulæ are external to our own galaxy. The answer came at the beginning of the XX century, mainly through the works of V.M. Slipher and E. Hubble (see, e.g., Smith424). The extragalactic nature of nebulæ being established, astronomers started to consider clus- ters of galaxies as physical systems. The issue of how clusters form attracted the attention of K. Lundmark287 as early as in 1927. Six years later, F. Zwicky512 first estimated the mass of a galaxy cluster, thus establishing the need for dark matter. The role of clusters as laboratories for studying the evolution of galaxies was also soon realized (notably with the collisional stripping theory of Spitzer & Baade430). In the 50’s the investigation of galaxy clusters started to cover all aspects, from the distri- bution and properties of galaxies in clusters, to the existence of sub- and super-clustering, from the origin and evolution of clusters, to their dynamical status, and the nature of dark matter (or “positive energy”, see e.g., Ambartsumian29). -
Australia Telescope National Facility Annual Report 2002
Australia Telescope National Facility Australia Telescope National Facility Annual Report 2002 Annual Report 2002 © Australia Telescope National CSIRO Australia Telescope National Facility Annual Report 2002 Facility ISSN 1038-9554 PO Box 76 Epping NSW 1710 This is the report of the Steering Australia Committee of the CSIRO Tel: +61 2 9372 4100 Australia Telescope National Facility for Fax: +61 2 9372 4310 the calendar year 2002. Parkes Observatory PO Box 276 Editor: Dr Jessica Chapman, Parkes NSW 2870 Australia Telescope National Facility Design and typesetting: Vicki Drazenovic, Australia Australia Telescope National Facility Tel: +61 2 6861 1700 Fax: +61 2 6861 1730 Printed and bound by Pirion Printers Pty Paul Wild Observatory Narrabri Cover image: Warm atomic hydrogen gas is a Locked Bag 194 major constituent of our Galaxy, but it is peppered Narrabri NSW 2390 with holes. This image, made with the Australia Australia Telescope Compact Array and the Parkes radio telescope, shows a structure called Tel: +61 2 6790 4000 GSH 277+00+36 that has a void in the atomic Fax: +61 2 6790 4090 hydrogen more than 2,000 light years across. It lies 21,000 light years from the Sun on the edge of the [email protected] Sagittarius-Carina spiral arm in the outer Milky Way. www.atnf.csiro.au The void was probably formed by winds and supernova explosions from about 300 massive stars over the course of several million years. It eventually grew so large that it broke out of the disk of the Galaxy, forming a “chimney”. GSH 277+00+36 is one of only a handful of chimneys known in the Milky Way and the only one known to have exploded out of both sides of the Galactic plane.