New Mass Measurement for Galaxy Clusters
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Galaxy Clusters: Waking Perseus
PUBLISHED: 2 JUNE 2017 | VOLUME: 1 | ARTICLE NUMBER: 164 news & views GALAXY CLUSTERS Waking Perseus The Perseus cluster contains over 1,000 a Kelvin–Helmholtz instability, which galaxies packed into a region ~3,500 kpc propagates in the wave direction and in extent. It is inevitable that such close- causes the dark area indicated in the packed galaxies will interact, and the image. This dark ‘bay-like’ feature is Chandra X-ray Observatory has observed approximately the size of the Milky Way, the beautiful result of that interaction and may be the result of a cold front in (pictured). This is no snapshot — the cluster gas: an interface where the Chandra observed the galaxy cluster temperature drops dramatically on scales for over 16 days in order to capture this much smaller than the mean free path. image. Stephen Walker and colleagues An advantage of this comparison of have retrieved the archival data and observations and simulations is that processed it to enhance the edges of (unmeasurable) physical quantities the surface brightness distribution. This can be estimated. In this case, the bay analysis, reported last year (Sanders et al., 50 kpc feature only appears in this form when Mon. Not. R. Astron. Soc. 460, 1898–1911; the ratio of the thermal pressure to the ROYAL ASTRONOMICAL SOCIETY ASTRONOMICAL ROYAL 2016), highlighted two features in the magnetic pressure is ~200, and this X-ray emission that are discussed by determination in turn allows the authors Walker et al. (Mon. Not. R. Astron. Soc. pattern seen in the image could have been to obtain an order-of-magnitude estimate 468, 2506–2516; 2017): the swirling wave generated by a passing galaxy cluster about of the magnetic field. -
The Dynamical State of the Coma Cluster with XMM-Newton?
A&A 400, 811–821 (2003) Astronomy DOI: 10.1051/0004-6361:20021911 & c ESO 2003 Astrophysics The dynamical state of the Coma cluster with XMM-Newton? D. M. Neumann1,D.H.Lumb2,G.W.Pratt1, and U. G. Briel3 1 CEA/DSM/DAPNIA Saclay, Service d’Astrophysique, L’Orme des Merisiers, Bˆat. 709, 91191 Gif-sur-Yvette, France 2 Science Payloads Technology Division, Research and Science Support Dept., ESTEC, Postbus 299 Keplerlaan 1, 2200AG Noordwijk, The Netherlands 3 Max-Planck Institut f¨ur extraterrestrische Physik, Giessenbachstr., 85740 Garching, Germany Received 19 June 2002 / Accepted 13 December 2002 Abstract. We present in this paper a substructure and spectroimaging study of the Coma cluster of galaxies based on XMM- Newton data. XMM-Newton performed a mosaic of observations of Coma to ensure a large coverage of the cluster. We add the different pointings together and fit elliptical beta-models to the data. We subtract the cluster models from the data and look for residuals, which can be interpreted as substructure. We find several significant structures: the well-known subgroup connected to NGC 4839 in the South-West of the cluster, and another substructure located between NGC 4839 and the centre of the Coma cluster. Constructing a hardness ratio image, which can be used as a temperature map, we see that in front of this new structure the temperature is significantly increased (higher or equal 10 keV). We interpret this temperature enhancement as the result of heating as this structure falls onto the Coma cluster. We furthermore reconfirm the filament-like structure South-East of the cluster centre. -
Galaxies with Rows A
Astronomy Reports, Vol. 45, No. 11, 2001, pp. 841–853. Translated from Astronomicheski˘ı Zhurnal, Vol. 78, No. 11, 2001, pp. 963–976. Original Russian Text Copyright c 2001 by Chernin, Kravtsova, Zasov, Arkhipova. Galaxies with Rows A. D. Chernin, A. S. Kravtsova, A. V. Zasov, and V. P. Arkhipova Sternberg Astronomical Institute, Universitetskii˘ pr. 13, Moscow, 119899 Russia Received March 16, 2001 Abstract—The results of a search for galaxies with straight structural elements, usually spiral-arm rows (“rows” in the terminology of Vorontsov-Vel’yaminov), are reported. The list of galaxies that possess (or probably possess) such rows includes about 200 objects, of which about 70% are brighter than 14m.On the whole, galaxies with rows make up 6–8% of all spiral galaxies with well-developed spiral patterns. Most galaxies with rows are gas-rich Sbc–Scd spirals. The fraction of interacting galaxies among them is appreciably higher than among galaxies without rows. Earlier conclusions that, as a rule, the lengths of rows are similar to their galactocentric distances and that the angles between adjacent rows are concentrated near 120◦ are confirmed. It is concluded that the rows must be transient hydrodynamic structures that develop in normal galaxies. c 2001 MAIK “Nauka/Interperiodica”. 1. INTRODUCTION images were reproduced by Vorontsov-Vel’yaminov and analyze the general properties of these objects. The long, straight features found in some galaxies, which usually appear as straight spiral-arm rows and persist in spite of differential rotation of the galaxy 2. THE SAMPLE OF GALAXIES disks, pose an intriguing problem. These features, WITH STRAIGHT ROWS first described by Vorontsov-Vel’yaminov (to whom we owe the term “rows”) have long escaped the To identify galaxies with rows, we inspected about attention of researchers. -
Size and Scale Attendance Quiz II
Size and Scale Attendance Quiz II Are you here today? Here! (a) yes (b) no (c) are we still here? Today’s Topics • “How do we know?” exercise • Size and Scale • What is the Universe made of? • How big are these things? • How do they compare to each other? • How can we organize objects to make sense of them? What is the Universe made of? Stars • Stars make up the vast majority of the visible mass of the Universe • A star is a large, glowing ball of gas that generates heat and light through nuclear fusion • Our Sun is a star Planets • According to the IAU, a planet is an object that 1. orbits a star 2. has sufficient self-gravity to make it round 3. has a mass below the minimum mass to trigger nuclear fusion 4. has cleared the neighborhood around its orbit • A dwarf planet (such as Pluto) fulfills all these definitions except 4 • Planets shine by reflected light • Planets may be rocky, icy, or gaseous in composition. Moons, Asteroids, and Comets • Moons (or satellites) are objects that orbit a planet • An asteroid is a relatively small and rocky object that orbits a star • A comet is a relatively small and icy object that orbits a star Solar (Star) System • A solar (star) system consists of a star and all the material that orbits it, including its planets and their moons Star Clusters • Most stars are found in clusters; there are two main types • Open clusters consist of a few thousand stars and are young (1-10 million years old) • Globular clusters are denser collections of 10s-100s of thousand stars, and are older (10-14 billion years -
Constraining Cosmic Rays and Magnetic Fields in the Perseus
A&A 541, A99 (2012) Astronomy DOI: 10.1051/0004-6361/201118502 & c ESO 2012 Astrophysics Constraining cosmic rays and magnetic fields in the Perseus galaxy cluster with TeV observations by the MAGIC telescopes J. Aleksic´1,E.A.Alvarez2, L. A. Antonelli3, P. Antoranz4, M. Asensio2, M. Backes5, U. Barres de Almeida6, J. A. Barrio2, D. Bastieri7, J. Becerra González8,9, W. Bednarek10, A. Berdyugin11,K.Berger8,9,E.Bernardini12, A. Biland13,O.Blanch1,R.K.Bock6, A. Boller13, G. Bonnoli3, D. Borla Tridon6,I.Braun13, T. Bretz14,26, A. Cañellas15,E.Carmona6,28,A.Carosi3,P.Colin6,, E. Colombo8, J. L. Contreras2, J. Cortina1, L. Cossio16, S. Covino3, F. Dazzi16,27,A.DeAngelis16,G.DeCaneva12, E. De Cea del Pozo17,B.DeLotto16, C. Delgado Mendez8,28, A. Diago Ortega8,9,M.Doert5, A. Domínguez18, D. Dominis Prester19,D.Dorner13, M. Doro20, D. Eisenacher14, D. Elsaesser14,D.Ferenc19, M. V. Fonseca2, L. Font20,C.Fruck6,R.J.GarcíaLópez8,9, M. Garczarczyk8, D. Garrido20, G. Giavitto1, N. Godinovic´19,S.R.Gozzini12, D. Hadasch17,D.Häfner6, A. Herrero8,9, D. Hildebrand13, D. Höhne-Mönch14,J.Hose6, D. Hrupec19,T.Jogler6, H. Kellermann6,S.Klepser1, T. Krähenbühl13,J.Krause6, J. Kushida6,A.LaBarbera3,D.Lelas19,E.Leonardo4, N. Lewandowska14, E. Lindfors11, S. Lombardi7,, M. López2, R. López1, A. López-Oramas1,E.Lorenz13,6, M. Makariev21,G.Maneva21, N. Mankuzhiyil16, K. Mannheim14, L. Maraschi3, M. Mariotti7, M. Martínez1,D.Mazin1,6, M. Meucci4, J. M. Miranda4,R.Mirzoyan6, J. Moldón15,A.Moralejo1,P.Munar-Adrover15,A.Niedzwiecki10, D. Nieto2, K. Nilsson11,29,N.Nowak6, R. -
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. -
Astronomy Magazine 2011 Index Subject Index
Astronomy Magazine 2011 Index Subject Index A AAVSO (American Association of Variable Star Observers), 6:18, 44–47, 7:58, 10:11 Abell 35 (Sharpless 2-313) (planetary nebula), 10:70 Abell 85 (supernova remnant), 8:70 Abell 1656 (Coma galaxy cluster), 11:56 Abell 1689 (galaxy cluster), 3:23 Abell 2218 (galaxy cluster), 11:68 Abell 2744 (Pandora's Cluster) (galaxy cluster), 10:20 Abell catalog planetary nebulae, 6:50–53 Acheron Fossae (feature on Mars), 11:36 Adirondack Astronomy Retreat, 5:16 Adobe Photoshop software, 6:64 AKATSUKI orbiter, 4:19 AL (Astronomical League), 7:17, 8:50–51 albedo, 8:12 Alexhelios (moon of 216 Kleopatra), 6:18 Altair (star), 9:15 amateur astronomy change in construction of portable telescopes, 1:70–73 discovery of asteroids, 12:56–60 ten tips for, 1:68–69 American Association of Variable Star Observers (AAVSO), 6:18, 44–47, 7:58, 10:11 American Astronomical Society decadal survey recommendations, 7:16 Lancelot M. Berkeley-New York Community Trust Prize for Meritorious Work in Astronomy, 3:19 Andromeda Galaxy (M31) image of, 11:26 stellar disks, 6:19 Antarctica, astronomical research in, 10:44–48 Antennae galaxies (NGC 4038 and NGC 4039), 11:32, 56 antimatter, 8:24–29 Antu Telescope, 11:37 APM 08279+5255 (quasar), 11:18 arcminutes, 10:51 arcseconds, 10:51 Arp 147 (galaxy pair), 6:19 Arp 188 (Tadpole Galaxy), 11:30 Arp 273 (galaxy pair), 11:65 Arp 299 (NGC 3690) (galaxy pair), 10:55–57 ARTEMIS spacecraft, 11:17 asteroid belt, origin of, 8:55 asteroids See also names of specific asteroids amateur discovery of, 12:62–63 -
Making a Sky Atlas
Appendix A Making a Sky Atlas Although a number of very advanced sky atlases are now available in print, none is likely to be ideal for any given task. Published atlases will probably have too few or too many guide stars, too few or too many deep-sky objects plotted in them, wrong- size charts, etc. I found that with MegaStar I could design and make, specifically for my survey, a “just right” personalized atlas. My atlas consists of 108 charts, each about twenty square degrees in size, with guide stars down to magnitude 8.9. I used only the northernmost 78 charts, since I observed the sky only down to –35°. On the charts I plotted only the objects I wanted to observe. In addition I made enlargements of small, overcrowded areas (“quad charts”) as well as separate large-scale charts for the Virgo Galaxy Cluster, the latter with guide stars down to magnitude 11.4. I put the charts in plastic sheet protectors in a three-ring binder, taking them out and plac- ing them on my telescope mount’s clipboard as needed. To find an object I would use the 35 mm finder (except in the Virgo Cluster, where I used the 60 mm as the finder) to point the ensemble of telescopes at the indicated spot among the guide stars. If the object was not seen in the 35 mm, as it usually was not, I would then look in the larger telescopes. If the object was not immediately visible even in the primary telescope – a not uncommon occur- rence due to inexact initial pointing – I would then scan around for it. -
Morphology and Large-Scale Structure Within the Horologium-Reticulum Supercluster of Galaxies
Morphology and Large-Scale Structure within the Horologium-Reticulum Supercluster of Galaxies Matthew Clay Fleenor A dissertation submitted to the faculty of the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics & Astronomy. Chapel Hill 2006 Approved by Advisor: James A. Rose Reader: Gerald Cecil Reader: Wayne A. Christiansen Reader: Dan Reichart Reader: Paul Tiesinga c 2006 Matthew Clay Fleenor ii ABSTRACT Matthew Clay Fleenor: Morphology and Large-Scale Structure within the Horologium-Reticulum Supercluster of Galaxies (Under the Direction of James A. Rose) We have undertaken a comprehensive spectroscopic survey of the Horologium-Reticulum supercluster (HRS) of galaxies. With a concentration on the intercluster regions, our goal is to resolve the “cosmic web” of filaments, voids, and sheets within the HRS and to examine the interrelationship between them. What are the constituents of the HRS? What can be understood about the formation of such a behemoth from these current constituents? More locally, are there small-scale imprints of the larger, surrounding environment, and can we relate the two with any confidence? What is the relationship between the HRS and the other superclusters in the nearby universe? These are the questions driving our inquiry. To answer them, we have obtained over 2500 galaxy redshifts in the direction of the intercluster regions in the HRS. Specifically, we have developed a sample of galaxies with a limiting brightness of bJ < 17.5, which samples the galaxy luminosity function down to one magnitude below M⋆ at the mean redshift of the HRS,z ¯ ≈ 0.06. -
Coma Cluster of Galaxies
Coma Cluster of Galaxies In 2006, Hubble Space Telescope aimed at a nearby collection of NAT I O N A L SC I E N C E ED U C AT I O N STA N D A R D S galaxies called the Coma Cluster. Using the HST images, astronomers • Content Standard in 9-12 Science as gained fascinating insights into the evolution of galaxies in dense Inquiry (Abilities necessary to do sci- galactic neighborhoods. In this activity, students will first learn the entific inquiry, Understanding about basics of galaxy classification and grouping, then use HST images to scientific inquiry) discover the “morphology-density effect” and make hypotheses about • Content Standard in 9-12 Earth and its causes. Space Science (Origin and evolution of the universe) MAT E R I A L S & PR E PA R AT I O N • Each student needs a copy of the next 7 pages (not this page). You may InvIsIble Clu s t e r copy the pages out of this guide, but it is recommended that you go to If you aim a big telescope at the Coma mcdonaldobservatory.org/teachers/classroom and download the student Cluster, you’ll see galaxies galore worksheets. The galaxy images in the online worksheets are “negatives” — thousands of galaxies of all sizes of the real images, which provides better detail when printing. Supple and shapes, from little puffballs to mental materials for this activity are also available on the website. big, fuzzy footballs. Even so, you won’t • Each student or student team will need a calculator and a magnifying see most of the cluster because it’s invis glass (a linen tester works well). -
Evolution of Proto-Galaxy-Clusters to Their Present Form: Theory and Observations
Journal of Cosmology, 2010, 6, 1365-1384 Evolution of proto-galaxy-clusters … Gibson & Schild 1365 Evolution of proto-galaxy-clusters to their present form: theory and observations Carl H. Gibson 1,2 1 University of California San Diego, La Jolla, CA 92093-0411, USA [email protected], http://sdcc3.ucsd.edu/~ir118 and Rudolph E. Schild3,4 3 Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 4 [email protected] ABSTRACT From hydro-gravitational-dynamics theory HGD, gravitational structure formation begins 30,000 years (1012 s) after the turbulent big bang by viscous-gravitational fragmentation into super-cluster-voids and 1046 kg proto-galaxy-super-clusters. Linear and spiral gas- proto-galaxies GPGs are the smallest fragments to emerge from the plasma epoch at de- 13 1/2 coupling at 10 s with Nomura turbulence morphology and length scale LN ~ (/G) ~1020 m, determined by rate-of-strain , photon viscosity , and density of the plasma fossilized at 1012 s. GPGs fragment into 1036 kg proto-globular-star-cluster PGC clumps of 1024 kg primordial-fog-particle PFP dark matter planets. All stars form from planet mergers, with ~97% unmerged as galaxy baryonic-dark-matter BDM. The non-baryonic- dark-matter NBDM is so weakly collisional it diffuses to form galaxy cluster halos. It does not guide galaxy formation, contrary to conventional cold-dark-matter hierarchical clustering CDMHC theory (=0). NBDM has ~97% of the mass of the universe. It binds rotating clusters of galaxies by gravitational forces. The galaxy rotational spin axis matches that for low wavenumber spherical harmonic components of CMB temperature anomalies and extends to 4.5x1025 m (1.5 Gpc) in quasar polarization vectors, requiring a big bang turbulence origin. -
MACHINE LEARNING in GALAXY GROUPS DETECTION By
MACHINE LEARNING IN GALAXY GROUPS DETECTION by RAFEE TARIQ IBRAHEM A thesis submitted to The University of Birmingham for the degree of DOCTOR OF PHILOSOPHY School of Computer Science College of Engineering and Physical Sciences The University of Birmingham May 2017 University of Birmingham Research Archive e-theses repository This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. Abstract The detection of galaxy groups and clusters is of great importance in the field of astrophysics. In particular astrophysicists are interested in the evolution and formation of these systems, as well as the interactions that occur within galaxy groups and clusters. In this thesis, we developed a probabilistic model capa- ble of detecting galaxy groups and clusters based on the Hough transform. We called this approach probabilistic Hough transform based on adaptive local ker- nel (PHTALK). PHTALK was tested on a 3D realistic galaxy and mass assembly (GAMA) mock data catalogue (at close redshift z < 0:1)(mock data: contains information related to galaxies’ position, redshift and other properties). We com- pared the performance of our PHTALK method with the performance of two ver- sions of the standard friends-of-friends (FoF) method.