X-Ray Shapes of Elliptical Galaxies and Implications for Self-Interacting Dark Matter
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MOND Prediction of a New Giant Shell in the Elliptical Galaxy NGC 3923
A&A 566, A151 (2014) Astronomy DOI: 10.1051/0004-6361/201423935 & c ESO 2014 Astrophysics MOND prediction of a new giant shell in the elliptical galaxy NGC 3923 M. Bílek1,2,K.Bartošková1,3,I.Ebrová1,4, and B. Jungwiert1,2 1 Astronomical Institute, Academy of Sciences of the Czech Republic, Bocníˇ II 1401/1a, 141 00 Prague, Czech Republic e-mail: [email protected] 2 Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 121 16 Prague, Czech Republic 3 Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlárskᡠ2, 611 37 Brno, Czech Republic 4 Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 1999/2, 182 21 Prague, Czech Republic Received 2 April 2014 / Accepted 27 April 2014 ABSTRACT Context. Stellar shells, which form axially symmetric systems of arcs in some elliptical galaxies, are most likely remnants of radial minor mergers. They are observed up a radius of ∼100 kpc. The stars in them oscillate in radial orbits. The radius of a shell depends on the free-fall time at the position of the shell and on the time since the merger. We previously verified the consistency of shell radii in the elliptical galaxy NGC 3923 with its most probable MOND potential. Our results implied that an as yet undiscovered shell exists at the outskirts of the galaxy. Aims. We here extend our study by assuming more general models for the gravitational potential to verify the prediction of the new shell and to estimate its position. -
Particle Dark Matter an Introduction Into Evidence, Models, and Direct Searches
Particle Dark Matter An Introduction into Evidence, Models, and Direct Searches Lecture for ESIPAP 2016 European School of Instrumentation in Particle & Astroparticle Physics Archamps Technopole XENON1T January 25th, 2016 Uwe Oberlack Institute of Physics & PRISMA Cluster of Excellence Johannes Gutenberg University Mainz http://xenon.physik.uni-mainz.de Outline ● Evidence for Dark Matter: ▸ The Problem of Missing Mass ▸ In galaxies ▸ In galaxy clusters ▸ In the universe as a whole ● DM Candidates: ▸ The DM particle zoo ▸ WIMPs ● DM Direct Searches: ▸ Detection principle, physics inputs ▸ Example experiments & results ▸ Outlook Uwe Oberlack ESIPAP 2016 2 Types of Evidences for Dark Matter ● Kinematic studies use luminous astrophysical objects to probe the gravitational potential of a massive environment, e.g.: ▸ Stars or gas clouds probing the gravitational potential of galaxies ▸ Galaxies or intergalactic gas probing the gravitational potential of galaxy clusters ● Gravitational lensing is an independent way to measure the total mass (profle) of a foreground object using the light of background sources (galaxies, active galactic nuclei). ● Comparison of mass profles with observed luminosity profles lead to a problem of missing mass, usually interpreted as evidence for Dark Matter. ● Measuring the geometry (curvature) of the universe, indicates a ”fat” universe with close to critical density. Comparison with luminous mass: → a major accounting problem! Including observations of the expansion history lead to the Standard Model of Cosmology: accounting defcit solved by ~68% Dark Energy, ~27% Dark Matter and <5% “regular” (baryonic) matter. ● Other lines of evidence probe properties of matter under the infuence of gravity: ▸ the equation of state of oscillating matter as observed through fuctuations of the Cosmic Microwave Background (acoustic peaks). -
Guide Du Ciel Profond
Guide du ciel profond Olivier PETIT 8 mai 2004 2 Introduction hjjdfhgf ghjfghfd fg hdfjgdf gfdhfdk dfkgfd fghfkg fdkg fhdkg fkg kfghfhk Table des mati`eres I Objets par constellation 21 1 Androm`ede (And) Andromeda 23 1.1 Messier 31 (La grande Galaxie d'Androm`ede) . 25 1.2 Messier 32 . 27 1.3 Messier 110 . 29 1.4 NGC 404 . 31 1.5 NGC 752 . 33 1.6 NGC 891 . 35 1.7 NGC 7640 . 37 1.8 NGC 7662 (La boule de neige bleue) . 39 2 La Machine pneumatique (Ant) Antlia 41 2.1 NGC 2997 . 43 3 le Verseau (Aqr) Aquarius 45 3.1 Messier 2 . 47 3.2 Messier 72 . 49 3.3 Messier 73 . 51 3.4 NGC 7009 (La n¶ebuleuse Saturne) . 53 3.5 NGC 7293 (La n¶ebuleuse de l'h¶elice) . 56 3.6 NGC 7492 . 58 3.7 NGC 7606 . 60 3.8 Cederblad 211 (N¶ebuleuse de R Aquarii) . 62 4 l'Aigle (Aql) Aquila 63 4.1 NGC 6709 . 65 4.2 NGC 6741 . 67 4.3 NGC 6751 (La n¶ebuleuse de l’œil flou) . 69 4.4 NGC 6760 . 71 4.5 NGC 6781 (Le nid de l'Aigle ) . 73 TABLE DES MATIERES` 5 4.6 NGC 6790 . 75 4.7 NGC 6804 . 77 4.8 Barnard 142-143 (La tani`ere noire) . 79 5 le B¶elier (Ari) Aries 81 5.1 NGC 772 . 83 6 le Cocher (Aur) Auriga 85 6.1 Messier 36 . 87 6.2 Messier 37 . 89 6.3 Messier 38 . -
Scaling Mass Profiles Around Elliptical Galaxies Observed with Chandra
Scaling Mass Profiles around Elliptical Galaxies Observed with Chandra and XMM-Newton Y. Fukazawa1, J. G. Betoya-Nonesa1, J. Pu1, A. Ohto1, and N. Kawano1 Department of Physical Science, School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 [email protected] ABSTRACT We investigated the dynamical structure of 53 elliptical galaxies, based on the Chandra archival X-ray data. In X-ray luminous galaxies, a temperature increases with radius and a gas density is systematically higher at the optical outskirts, indicating a presence of a significant amount of the group-scale hot gas. In contrast, X-ray dim galaxies show a flat or declining temperature profile against radius and the gas density is relatively lower at the optical outskirts. Thus it is found that X-ray bright and faint elliptical galaxies are clearly distinguished by the temperature and gas density profile. The mass profile is well scaled by a virial radius r200 rather than an optical-half radius re, and is quite similar at (0.001 − 0.03)r200 between X-ray luminous and dim galaxies, and smoothly connects to those of clusters of galaxies. At the inner region of (0.001 − 0.01)r200 or (0.1 − 1)re, the mass profile well traces a stellar mass with a constant mass-to- light ratio of M/LB =3 − 10(M⊙/L⊙). M/LB ratio of X-ray bright galaxies rises up steeply beyond 0.01r200, and thus requires a presence of massive dark matter halo. From the deprojection analysis combined with the XMM-Newton data, we arXiv:astro-ph/0509521v1 18 Sep 2005 found that X-ray dim galaxies, NGC 3923, NGC 720, and IC 1459, also have a high M/LB ratio of 20–30 at 20 kpc, comparable to that of X-ray luminous galaxies. -
Exploring the Globular Cluster Systems of the Leo II Group and Their Global Relationships
MNRAS 458, 105–126 (2016) doi:10.1093/mnras/stw185 The SLUGGS survey∗: exploring the globular cluster systems of the Leo II group and their global relationships Sreeja S. Kartha,1‹ Duncan A. Forbes,1 Adebusola B. Alabi,1 Jean P. Brodie,2 Aaron J. Romanowsky,2,3 Jay Strader,4 Lee R. Spitler,5,6 Zachary G. Jennings2 and Joel C. Roediger7 1Centre for Astrophysics & Supercomputing, Swinburne University, Hawthorn VIC 3122, Australia 2University of California Observatories, 1156 High St., Santa Cruz, CA 95064, USA 3Department of Physics and Astronomy, San Jose´ State University, One Washington Square, San Jose, CA 95192, USA 4Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA 5Macquarie University, Macquarie Park, Sydney, NSW 2113, Australia 6Australian Astronomical Observatory, PO Box 915, North Ryde, NSW 1670, Australia 7NRC Herzberg Astronomy & Astrophysics, Victoria, BC V9E 2E7, Canada Accepted 2016 January 20. Received 2016 January 20; in original form 2015 July 23 ABSTRACT We present an investigation of the globular cluster (GC) systems of NGC 3607 and NGC 3608 as part of the ongoing SLUGGS (SAGES Legacy Unifying Globulars and GalaxieS) survey. We use wide-field imaging data from the Subaru telescope in the g, r and i filters to analyse the radial density, colour and azimuthal distributions of both GC systems. With the complementary kinematic data obtained from the Keck II telescope, we measure the radial velocities of a total of 81 GCs. Our results show that the GC systems of NGC 3607 and NGC 3608 have a detectable spatial extent of ∼15 and 13 galaxy effective radii, respectively. -
Arxiv:1705.02358V2 [Hep-Ph] 24 Nov 2017
Dark Matter Self-interactions and Small Scale Structure Sean Tulin1, ∗ and Hai-Bo Yu2, y 1Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada 2Department of Physics and Astronomy, University of California, Riverside, California 92521, USA (Dated: November 28, 2017) Abstract We review theories of dark matter (DM) beyond the collisionless paradigm, known as self-interacting dark matter (SIDM), and their observable implications for astrophysical structure in the Universe. Self- interactions are motivated, in part, due to the potential to explain long-standing (and more recent) small scale structure observations that are in tension with collisionless cold DM (CDM) predictions. Simple particle physics models for SIDM can provide a universal explanation for these observations across a wide range of mass scales spanning dwarf galaxies, low and high surface brightness spiral galaxies, and clusters of galaxies. At the same time, SIDM leaves intact the success of ΛCDM cosmology on large scales. This report covers the following topics: (1) small scale structure issues, including the core-cusp problem, the diversity problem for rotation curves, the missing satellites problem, and the too-big-to-fail problem, as well as recent progress in hydrodynamical simulations of galaxy formation; (2) N-body simulations for SIDM, including implications for density profiles, halo shapes, substructure, and the interplay between baryons and self- interactions; (3) semi-analytic Jeans-based methods that provide a complementary approach for connecting particle models with observations; (4) merging systems, such as cluster mergers (e.g., the Bullet Cluster) and minor infalls, along with recent simulation results for mergers; (5) particle physics models, including light mediator models and composite DM models; and (6) complementary probes for SIDM, including indirect and direct detection experiments, particle collider searches, and cosmological observations. -
Explosion of the Science Modification of Newtonian Dynamics Via Mach's
Physics International Original Research Paper Explosion of the Science Modification of Newtonian Dynamics Via Mach’s Inertia Principle and Generalization in Gravitational Quantum Bound Systems and Finite Range of the Gravity-Carriers, Consistent Merely On the Bosons and the Fermions Mohsen Lutephy Faculty of Science, Azad Islamic University (IAU), South Tehran branch, Iran Article history Abstract: Newtonian gravity is modified here via Mach's inertia principle Received: 29-04-2020 (inertia fully governed by universe) and it is generalized to gravitationally Revised: 11-05-2020 quantum bound systems, resulting scale invariant fully relational dynamics Accepted: 24-06-2020 (mere ordering upon actual objects), answering to rotation curves and velocity dispersions of the galaxies and clusters (large scale quantum bound Email: [email protected] systems), successful in all dimensions and scales from particle to the universe. Against the Milgrom’s theory, no fundamental acceleration to separate the physical systems to the low and large accelerations, on the contrary the Newtonian regime of HSB galaxies sourced by natural inertia constancy there. All phenomenological paradigms are argued here via Machian modified gravity generalized to quantum gravity, especially Milgrom empirical paradigms and even we have resolved the mystery of missing dark matter in newly discovered Ultra Diffuse Galaxies (UDGs) for potential hollow in host galaxy generated by sub quantum bound system of the globular clusters. Also we see that the strong nuclear force (Yukawa force) is in reality, the enhanced gravity for limitation of the gravitational potential because finite-range of the Compton wavelength of hadronic gravity-carriers in the nucleuses, reasoning to resolve ultimately, one of the biggest questions in the physics, that is, so called the fine structure constant and answering to mysterious saturation features of the nuclear forces and we have resolved also the mystery of the proton stability, reasonable as a quantum micro black hole and the exact calculation of the universe matter. -