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14 results on '"Department of Astronomy [Madison]"'

1. Heliosheath Processes and the Structure of the Heliopause: Modeling Energetic Particles, Cosmic Rays, and Magnetic Fields

Author

E. C. Stone, Horst Fichtner, A. Czechowski, K. Scherer, Ming Zhang, Peter Wurz, J. A. le Roux, R. D. Strauss, T. Wiengarten, Marius S. Potgieter, Gary P. Zank, Bertrand Lembège, Nikolai V. Pogorelov, A. Lazarian, University of Alabama in Huntsville (UAH), Institut für Theoretische Physik IV [Bochum] (ITP4), Ruhr-Universität Bochum [Bochum], Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [Madison], University of Wisconsin-Madison, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), North-West University [South Aftrica] (NWU), California Institute of Technology (CALTECH), Universität Bern [Bern], Department of Physics and Space Sciences [FIT], Florida Institute of Technology [Melbourne], and Universität Bern [Bern] (UNIBE)

Subjects
010504 meteorology & atmospheric sciences, FOS: Physical sciences, Context (language use), Cosmic ray, Astrophysics, 01 natural sciences, Physics - Space Physics, 0103 physical sciences, Heliopause, Diffusion (business), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astronomy and Astrophysics, Magnetic reconnection, Plasma, 620 Engineering, Space Physics (physics.space-ph), Magnetic field, Solar cycle, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, Solar Astrophysics, Heliosphere
Abstract

This paper summarizes the results obtained by the team "Heliosheath Processes and the Structure of the Heliopause: Modeling Energetic Particles, Cosmic Rays, and Magnetic Fields" supported by the International Space Science Institute in Bern, Switzerland. We focus on the physical processes occurring in the outer heliosphere, especially at its boundary called the heliopause (HP), and in the LISM. The importance of magnetic field, charge exchange between atoms and ions, and solar cycle on the heliopause topology and observed heliocentric distances to different heliospheric discontinuities are discussed. It is shown that time-dependent boundary conditions are necessary to describe the heliospheric asymmetries detected by the Voyager spacecraft. We also discuss the structure of the HP, especially due to its instability and magnetic reconnection. It is demonstrated that the Rayleigh-Taylor instability of the nose of the HP creates consecutive layers of the interstellar and heliospheric plasma which are magnetically connected to different sources. This may be a possible explanation of abrupt changes in the galactic and anomalous cosmic ray fluxes observed by Voyager 1 when it was crossing the HP structure for a period of about one month in the summer of 2012. This paper also discusses the plausibility of fitting simulation results to a number of observational data sets obtained by in situ and remote measurements. The distribution of magnetic field in the vicinity of the HP is discussed in the context of Voyager measurements. We discuss the transport of energetic particles in the inner and outer heliosheath, concentrating on the anisotropic spatial diffusion diffusion tensor and the pitch-angle dependence of perpendicular diffusion and demonstrate that the latter can explain the observed pitch-angle anisotropies of both the anomalous and galactic cosmic rays in the outer heliosheath., Publication resulting from an International ISSI Team of the same name. Submitted to Space Science Reviews

Published
2017
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2. A study of a coronal hole associated with a large filament eruption

Author

Zadig Mouradian, Lela Taliashvili Enacolopas, A. Lazarian, Heidy Gutiérrez Garro, Department of Astronomy [Madison], University of Wisconsin-Madison, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, corona [Sun], oscillations [Sun], Coronal hole, Astronomy and Astrophysics, chromosphere [Sun], Astrophysics, 01 natural sciences, Solar prominence, coronal mass ejections (CMEs) [Sun], Protein filament, Space and Planetary Science, 0103 physical sciences, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, filaments, prominences [Sun], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

We report the results of a detailed study of an equatorial coronal hole and a dimming region related to the eruptions of a nearby large filament and subsequent coronal mass ejections (CMEs). The dynamic eruptions of the filament and the associated CMEs are probably related to the magnetic reconnection involving the magnetic field lines at the filament footpoints. During the starting processes of the filament eruption, we observed several newly emerged small magnetic flux concentrations close to the filament footpoints. Disturbance increase in the prominence body was observed during the pre-eruption processes. After the filament eruption, we observed evacuated filament material from the filament channel towards the coronal hole. Thus, all the region is perturbed and EUV loops and bright points are observed before and after the eruptions. Additionally, after the CME, we observed the disappearance of the dimming region and the coronal hole, followed by photospheric magnetic diffusion. We discussed a possible magnetic reconnection scenario and MHD waves involved during these processes. National Science Foundation/[1212096]/NSF/Estados Unidos National Aeronautics and Space Administration/[NNX14AJ53G]/NASA/Estados Unidos UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Espaciales (CINESPA)

Published
2017
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3. Herschel Detects a Massive Dust Reservoir in Supernova 1987A

Author

Charles W. Engelbracht, Takaya Nozawa, Karl D. Gordon, M. Lakićević, Peter Lundqvist, Julia Roman-Duval, Mikako Matsuura, Eli Dwek, Masaaki Otsuka, Brian Babler, E. Montiel, P. Panuzzo, Karl Misselt, M. J. Barlow, K. Okumura, Knox S. Long, J. Th. van Loon, George Sonneborn, Geoffrey C. Clayton, Marc Sauvage, Karin Sandstrom, Margaret Meixner, Sacha Hony, Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Mullard Space Science Laboratory (MSSL), NASA Goddard Space Flight Center (GSFC), Space Telescope Science Institute (STSci), Department of Astronomy [Madison], University of Wisconsin-Madison, Steward Observatory, University of Arizona, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Lennard-Jones Laboratories, European Southern Observatory (ESO), Louisiana State University (LSU), Stockholm University, Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo (UTokyo), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, We acknowledge the contributions and support of the European Space Agency (ESA), the PACS and SPIRE teams, the Herschel Science Centre, the NASA Herschel Science Centre and the PACS and SPIRE instrument control centres, University College of London [London] ( UCL ), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée ( DAPNIA ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), and The Oskar Klein Centre for Cosmoparticle Physics and Department of Physics, Stockholm University

Subjects
010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Large Magellanic Cloud, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Cosmic dust, Physics, Multidisciplinary, Astronomy, Intergalactic dust, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Near-Earth supernova, Dust lane, Galaxy, Supernova, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Circumstellar dust, Astrophysics::Earth and Planetary Astrophysics
Abstract

We report far-infrared and submillimeter observations of Supernova 1987A, the star that exploded on February 23, 1987 in the Large Magellanic Cloud, a galaxy located 160,000 lightyears away. The observations reveal the presence of a population of cold dust grains radiating with a temperature of ~17-23 K at a rate of about 220 solar luminosity. The intensity and spectral energy distribution of the emission suggests a dust mass of ~0.4-0.7 solar mass. The radiation must originate from the SN ejecta and requires the efficient precipitation of all refractory material into dust. Our observations imply that supernovae can produce the large dust masses detected in young galaxies at very high redshifts., Comment: This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. To appear in Science; available in Science Express on 7th July, DOI:10.1126/science.1205983 at http://www.sciencemag.org/lookup/doi/10.1126/science.1205983 ; 14 pages, 2 figures, 4 tables. High resolution images are available from the authors

Published
2011
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4. Interplanetary dust

Author

Jérémie Lasue, Alexander Lazarian, Anny Chantal Levasseur-Regourd, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [Madison], University of Wisconsin-Madison, L. Kolokolova, J. Hough, A.C. Levasseur-Regourd (eds), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Zodiacal light, 010504 meteorology & atmospheric sciences, Gegenschein, Polarimetry, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy, Astrophysics, Planetary system, 01 natural sciences, Stars, Interplanetary dust cloud, 13. Climate action, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Interplanetary spaceflight, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Cosmic dust
Abstract

International audience; This chapter reviews how the polarization of light scattered by interplanetary dust has been used to determine some physical properties of the dust population in the interplanetary medium. Though optically thin, the interplanetary dust cloud is visible due to the faint glow (the zodiacal light) it produces at visible wavelengths through the scattering of light from the Sun by interplanetary dust particles (IDPs). The light, scattered by an optically thin medium is linearly polarized, with the E-vector predominantly oscillating perpendicular or parallel to the scattering plane, leading to negative values of the degree of linear polarization, PQ, in the backscattering region. The zodiacal light also has an IR component, due to the thermal emission from the dust particles, whose characteristics are consistent with the conclusions from the polarimetry. While some results from intensity observations are used for discussion in this chapter, complete reviews of the zodiacal light intensity studies can be found in Leinert et al. (1998) and Levasseur-Regourd et al. (2001).Sections 24.1 and 24.2 summarize the zodiacal light photopolarimetric observations, going from the whole line-of-sight integrated values to the local values retrieved by inversion. Sections 24.3 and 24.4 explain how numerical simulations and laboratory experiments have been carried out to constrain the interplanetary dust properties at different locations in the cloud based on their polarimetric signatures.

Published
2015
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5. Convection and Differential Rotation in F-Type Stars

Author

Mark S. Miesch, Allan Sacha Brun, Kyle C. Augustson, Benjamin P. Brown, Juri Toomre, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Department of Astronomy [Madison], University of Wisconsin-Madison, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and STARS2

Subjects
Physics, Spherical harmonics, Astronomy and Astrophysics, stars: solar-type, Astrophysics, Type (model theory), stars: interiors, Rotation, Coupling (probability), [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Radiation zone, 010305 fluids & plasmas, Computational physics, Convection zone, Space and Planetary Science, stars: rotation, 0103 physical sciences, hydrodynamics, Differential rotation, 010303 astronomy & astrophysics, Main sequence, convection
Abstract

International audience; Differential rotation is a common feature of main-sequence spectral F-type stars. In seeking to make contact with observations and to provide a self-consistent picture of how differential rotation is achieved in the interiors of these stars, we use the three-dimensional anelastic spherical harmonic (ASH) code to simulate global-scale turbulent flows in 1.2 and 1.3 $M_\odot$ F-type stars at varying rotation rates. The simulations are carried out in spherical shells that encompass most of the convection zone and a portion of the stably stratified radiative zone below it, allowing us to explore the effects of overshooting convection. We examine the scaling of the mean flows and thermal state with rotation rate and mass and link these scalings to fundamental parameters of the simulations. Indeed, we find that the differential rotation becomes much stronger with more rapid rotation and larger mass, scaling as $\Delta\Omega$ $\alpha$ $M^{3.9}$$\Omega_0^{0.6}$. Accompanying the growing differential rotation is a significant latitudinal temperature contrast, with amplitudes of 1000 K or higher in the most rapidly rotating cases. This contrast in turn scales with mass and rotation rate as $\Delta$$T$ $\alpha$ $M^{6.4}$$\Omega_0^{1.6}$. On the other hand, the meridional circulations become much weaker with more rapid rotation and with higher mass, with their kinetic energy decreasing as KE$_{MC}$ $\alpha$ $M^{-1.2}$$\Omega_0^{-0.8}$. Additionally, three of our simulations exhibit a global-scale shear instability within their stable regions that persists for the duration of the simulations. The flow structures associated with the instabilities have a direct coupling to and impact on the flows within the convection zone.

Published
2013
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6. The Spitzer Extragalactic Representative Volume Survey (SERVS): Survey Definition and Goals

Author

E. A. Gonzalez-Solares, Roy R. Gal, Ray P. Norris, Luca Bizzocchi, Jamie Stevens, Huub Röttgering, S. A. Stanford, Marguerite Pierre, Giovanni Covone, Anna Sajina, Scott Chapman, A. M. J. Mortier, E. Dyke, D. Rigopoulou, Janine Pforr, Hugo Messias, S. Foucaud, A. Rettura, G. Parish, Steve Rawlings, S. J. Oliver, James Dunlop, H. C. Ferguson, Jose Afonso, N. Castro, Russell H. Taylor, Chris Simpson, Ian Smail, Bruno M. B. Henriques, Ross J. McLure, Nick Seymour, S. E. Ridgway, Lori M. Lubin, Tanya Urrutia, Jason Surace, Ismael Perez-Fournon, Antonio Cava, D. M. Nielsen, N. Dubois, M. Trichas, C. J. Lonsdale, Aprajita Verma, Gordon T. Richards, J. T. Falder, Minh Huynh, Philip Best, N. Christopher, James E. Geach, Jacqueline Hodge, R. H. Becker, David M. Alexander, E. van Kampen, Duncan Farrah, David L. Clements, Gordon K. Squires, Marco Grossi, A. Martinez-Sansigre, Alberto Franceschini, Alastair C. Edge, Mattia Vaccari, M. D. Lehnert, J. K. Grant, Peter A. Thomas, Masami Ouchi, Evanthia Hatziminaoglou, J.-S. Huang, Claudia Maraston, Gillian Wilson, Anthony C. S. Readhead, O. LeFevre, Mark Lacy, C. K. Xu, M. Kim, Gregory R. Zeimann, Samantha Hickey, A. K. Romer, Lucia Marchetti, Michael Rowan-Robinson, I. G. Rosebloom, Matt J. Jarvis, David Bonfield, Andreea Petric, J. C. Mauduit, Rob Ivison, Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), Department of Physics and Astronomy [Brighton] (DPA), University of Sussex, Centre for Astrophysics Research [Hatfield], University of Hertfordshire [Hatfield] (UH), Institute of Cosmology and Gravitation [Portsmouth] (ICG), University of Portsmouth, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), University of the Western Cape (UWC), Visual servoing in robotics, computer vision, and augmented reality (Lagadic), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-SIGNAUX ET IMAGES NUMÉRIQUES, ROBOTIQUE (IRISA-D5), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Univ California Davis] (Physics - UC Davis), University of California [Davis] (UC Davis), University of California (UC)-University of California (UC), Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), National Optical Astronomy Observatory (NOAO), Observatório Astronómico de Lisboa, Centro de Astronomia e Astrofísica da Universidade de Lisboa (CAAUL), Universidade de Lisboa = University of Lisbon (ULISBOA), Department of Physics and Astronomy [Riverside], University of California [Riverside] (UC Riverside), Department of Physics [Montréal], McGill University = Université McGill [Montréal, Canada], International Centre for Radio Astronomy Research (ICRAR), The University of Western Australia (UWA)-Government of Western Australia-Curtin University [Perth], Planning and Transport Research Centre (PATREC)-Planning and Transport Research Centre (PATREC), CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Department of Physics - Drexel University, Drexel University, Lawrence Livermore National Laboratory (LLNL), Department of Physics [Durham University], Durham University, Royal Observatory Edinburgh (ROE), University of Edinburgh, Instituto de Astrofisica de Canarias (IAC), Department of Physics [Oxford], University of Oxford, Astrophysics Group, Blackett Laboratory, Imperial College London-Imperial College London, Dipartimento di Scienze Fisiche [Naples], University of Naples Federico II = Università degli studi di Napoli Federico II, Institute for Computational Cosmology (ICC), Space Telescope Science Institute (STSci), National Taiwan Normal University (NTNU), University of Hawai'i [Honolulu] (UH), Department of Physics and Astronomy [Calgary], University of Calgary, European Southern Observatory (ESO), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [Madison], University of Wisconsin-Madison, Carnegie Institution for Science, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Caltech Department of Astronomy [Pasadena], Cerro Tololo Inter-American Observatory, Leiden Observatory [Leiden], Universiteit Leiden, Haverford College, Astrophysics Research Institute [Liverpool] (ARI), Liverpool John Moores University (LJMU), Leibniz Institute for Astrophysics Potsdam (AIP), Mauduit, J. C., Lacy, M., Farrah, D., Surace, J. A., Jarvis, M., Oliver, S., Maraston, C., Vaccari, M., Marchetti, L., Zeimann, G., Gonzalez Solares, E. A., Pforr, J., Petric, A. O., Henriques, B., Thomas, P. A., Afonso, J., Rettura, A., Wilson, G., Falder, J. T., Geach, J. E., Huynh, M., Norris, R. P., Seymour, N., Richards, G. T., Stanford, S. A., Alexander, D. M., Becker, R. H., Best, P. N., Bizzocchi, L., Bonfield, D., Castro, N., Cava, A., Chapman, S., Christopher, N., Clements, D. L., Covone, Giovanni, Dubois, N., Dunlop, J. S., Dyke, E., Edge, A., Ferguson, H. C., Foucaud, S., Franceschini, A., Gal, R. R., Grant, J. K., Grossi, M., Hatziminaoglou, E., Hickey, S., Hodge, J. A., Huang, J. S., Ivison, R. J., Kim, M., Lefevre, O., Lehnert, M., Lonsdale, C. J., Lubin, L. M., Mclure, R. J., Messias, H., Martinez Sansigre, A., Mortier, A. M. J., Nielsen, D. M., Ouchi, M., Parish, G., Perez Fournon, I., Pierre, M., Rawlings, S., Readhead, A., Ridgway, S. E., Rigopoulou, D., Romer, A. K., Rosebloom, I. G., Rottgering, H. J. A., Rowan Robinson, M., Sajina, A., Simpson, C. J., Smail, I., Squires, G. K., Stevens, J. A., Taylor, R., Trichas, M., Urrutia, T., van Kampen, E., Verma, A., Xu, C. K., Universita degli Studi di Padova, University of the Western Cape, CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Department of Physics [Davis], University of California-University of California, Universidade de Lisboa (ULISBOA), University of California [Riverside] (UCR), University of Oxford [Oxford], Università degli studi di Napoli Federico II, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Carnegie Institution for Science [Washington], and Universiteit Leiden [Leiden]

Subjects
Physics, evoluzione delle galassie, Cosmology and Nongalactic Astrophysics (astro-ph.CO), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Volume (computing), FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Quasar, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, Spitzer Space Telescope, Space and Planetary Science, 0103 physical sciences, Galaxy formation and evolution, Chandra Deep Field South, survey astronomica, 010303 astronomy & astrophysics, Galaxy cluster, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present the Spitzer Extragalactic Representative Volume Survey (SERVS), an 18 square degrees medium-deep survey at 3.6 and 4.5 microns with the post-cryogenic Spitzer Space Telescope to ~2 microJy (AB=23.1) depth of five highly observed astronomical fields (ELAIS-N1, ELAIS-S1, Lockman Hole, Chandra Deep Field South and XMM-LSS). SERVS is designed to enable the study of galaxy evolution as a function of environment from z~5 to the present day, and is the first extragalactic survey both large enough and deep enough to put rare objects such as luminous quasars and galaxy clusters at z>1 into their cosmological context. SERVS is designed to overlap with several key surveys at optical, near- through far-infrared, submillimeter and radio wavelengths to provide an unprecedented view of the formation and evolution of massive galaxies. In this paper, we discuss the SERVS survey design, the data processing flow from image reduction and mosaicing to catalogs, as well as coverage of ancillary data from other surveys in the SERVS fields. We also highlight a variety of early science results from the survey., 21 pages, 23 figures, published in PASP. This version differs slightly from PASP, mainly due to formatting issues. Figure 2 was also corrected from the previous version

Published
2012
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7. Magnetic Wreaths and Cycles in Convective Dynamos

Author

Mark S. Miesch, Benjamin P. Brown, Allan Sacha Brun, Nicholas J. Nelson, Juri Toomre, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Department of Astronomy [Madison], University of Wisconsin-Madison, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Convection, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, 01 natural sciences, Geomagnetic reversal, Physics::Fluid Dynamics, symbols.namesake, 0103 physical sciences, Differential rotation, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Reynolds number, Astronomy and Astrophysics, Mechanics, Computational Physics (physics.comp-ph), Magnetic flux, Magnetic field, Electromagnetic induction, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, symbols, Physics - Computational Physics, Dynamo
Abstract

Solar-type stars exhibit a rich variety of magnetic activity. Seeking to explore the convective origins of this activity, we have carried out a series of global 3D magnetohydrodynamic (MHD) simulations with the anelastic spherical harmonic (ASH) code. Here we report on the dynamo mechanisms achieved as the effects of artificial diffusion are systematically decreased. The simulations are carried out at a nominal rotation rate of three times the solar value (3$\Omega_\odot$), but similar dynamics may also apply to the Sun. Our previous simulations demonstrated that convective dynamos can build persistent toroidal flux structures (magnetic wreaths) in the midst of a turbulent convection zone and that high rotation rates promote the cyclic reversal of these wreaths. Here we demonstrate that magnetic cycles can also be achieved by reducing the diffusion, thus increasing the Reynolds and magnetic Reynolds numbers. In these more turbulent models, diffusive processes no longer play a significant role in the key dynamical balances that establish and maintain the differential rotation and magnetic wreaths. Magnetic reversals are attributed to an imbalance in the poloidal magnetic induction by convective motions that is stabilized at higher diffusion levels. Additionally, the enhanced levels of turbulence lead to greater intermittency in the toroidal magnetic wreaths, promoting the generation of buoyant magnetic loops that rise from the deep interior to the upper regions of our simulated domain. The implications of such turbulence-induced magnetic buoyancy for solar and stellar flux emergence are also discussed., Comment: 21 pages, 16 figures, accepted for publication in ApJ

Published
2012
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8. Magnetic Cycles in a Convective Dynamo Simulation of a Young Solar-type Star

Author

Mark S. Miesch, Matthew K. Browning, Benjamin P. Brown, Allan Sacha Brun, Juri Toomre, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Department of Astronomy [Madison], University of Wisconsin-Madison, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Convection, Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Magnetic field, Physics::Fluid Dynamics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Physics::Space Physics, Differential rotation, Polar, Solar rotation, Astrophysics::Solar and Stellar Astrophysics, Magnetohydrodynamics, Solar dynamo, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Dynamo
Abstract

Young solar-type stars rotate rapidly and many are magnetically active; some undergo magnetic cycles similar to the 22-year solar activity cycle. We conduct simulations of dynamo action in rapidly rotating suns with the 3D MHD anelastic spherical harmonic (ASH) code to explore dynamo action achieved in the convective envelope of a solar-type star rotating at 5 times the current solar rotation rate. Striking global-scale magnetic wreaths appear in the midst of the turbulent convection zone and show rich time-dependence. The dynamo exhibits cyclic activity and undergoes quasi-periodic polarity reversals where both the global-scale poloidal and toroidal fields change in sense on a roughly 1500 day time scale. These magnetic activity patterns emerge spontaneously from the turbulent flow and are more organized temporally and spatially than those realized in our previous simulations of the solar dynamo. We assess in detail the competing processes of magnetic field creation and destruction within our simulations that contribute to the global-scale reversals. We find that the mean toroidal fields are built primarily through an $\Omega$-effect, while the mean poloidal fields are built by turbulent correlations which are not necessarily well represented by a simple $\alpha$-effect. During a reversal the magnetic wreaths propagate towards the polar regions, and this appears to arise from a poleward propagating dynamo wave. The primary response in the convective flows involves the axisymmetric differential rotation which shows variations associated with the poleward propagating magnetic wreaths. In the Sun, similar patterns are observed in the poleward branch of the torsional oscillations, and these may represent poleward propagating magnetic fields deep below the solar surface. [abridged], Comment: 20 pages, 14 figures, emulateapj format; accepted for publication in ApJ. Expanded and published version of sections 5-6 from http://arxiv.org/abs/0906.2407

Published
2011
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9. Buoyant Magnetic Loops in a Global Dynamo Simulation of a Young Sun

Author

Nicholas J. Nelson, Mark S. Miesch, Juri Toomre, Benjamin P. Brown, Allan Sacha Brun, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Department of Astronomy [Madison], University of Wisconsin-Madison, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Convection, FOS: Physical sciences, 01 natural sciences, Physics::Fluid Dynamics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, magnetic field -Sun, Photosphere, Sunspot, activity, Starspot, Stellar atmosphere, Astronomy and Astrophysics, Mechanics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Physics - Plasma Physics, Plasma Physics (physics.plasm-ph), convection -magnetohydrodynamics (MHD) -stars, Convection zone, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, interiors -stars, Magnetohydrodynamics, Dynamo
Abstract

The current dynamo paradigm for the Sun and sun-like stars places the generation site for strong toroidal magnetic structures deep in the solar interior. Sunspots and star-spots on sun-like stars are believed to arise when sections of these magnetic structures become buoyantly unstable and rise from the deep interior to the photosphere. Here we present the first 3-D global magnetohydrodynamic (MHD) simulation in which turbulent convection, stratification, and rotation combine to yield a dynamo that self-consistently generates buoyant magnetic loops. We simulate stellar convection and dynamo action in a spherical shell with solar stratification, but rotating three times faster than the current solar rate. Strong wreaths of toroidal magnetic field are realized by dynamo action in the convection zone. By turning to a dynamic Smagorinsky model for subgrid-scale turbulence, we here attain considerably reduced diffusion in our simulation. This permits the regions of strongest magnetic field in these wreaths to rise toward the top of the convection zone via a combination of magnetic buoyancy instabilities and advection by convective giant cells. Such a global simulation yielding buoyant loops represents a significant step forward in combining numerical models of dynamo action and flux emergence., 6 pages, 3 figures, accepted in ApJ Letters

Published
2011
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10. Convection and differential rotation properties of G and K stars computed with the ASH code

Author

Benjamin P. Brown, Allan Sacha Brun, Sean P. Matt, O. Do Cao, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [Madison], University of Wisconsin-Madison, STARS2, European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Convection, 010504 meteorology & atmospheric sciences, Stellar mass, Angular velocity, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rotation, 01 natural sciences, Luminosity, 0103 physical sciences, Differential rotation, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, convection, 0105 earth and related environmental sciences, Physics, Stars: rotation, turbulence, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Convection zone, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, hydrodynamics, Stars: interiors, Astrophysics::Earth and Planetary Astrophysics, Main sequence
Abstract

The stellar luminosity and depth of the convective envelope vary rapidly with mass for G- and K-type main sequence stars. In order to understand how these properties influence the convective turbulence, differential rotation, and meridional circulation, we have carried out 3D dynamical simulations of the interiors of rotating main sequence stars, using the anelastic spherical harmonic (ASH) code. The stars in our simulations have masses of 0.5, 0.7, 0.9, and 1.1 M_sun, corresponding to spectral types K7 through G0, and rotate at the same angular speed as the sun. We identify several trends of convection zone properties with stellar mass, exhibited by the simulations. The convective velocities, temperature contrast between up- and down-flows, and meridional circulation velocities all increase with stellar luminosity. As a consequence of the trend in convective velocity, the Rossby number (at a fixed rotation rate) increases and the convective turnover timescales decrease significantly with increasing stellar mass. The 3 lowest mass cases exhibit solar-like differential rotation, in a sense that they show a maximum rotation at the equator and minimum at higher latitudes, but the 1.1 M_sun case exhibits anti-solar rotation. At low mass, the meridional circulation is multi-cellular and aligned with the rotation axis; as the mass increases, the circulation pattern tends toward a unicellular structure covering each hemisphere in the convection zone., Comment: Accepted for publication in Astronomische Nachrichten; 11 pages, 8 figures

Published
2011
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11. Gas, dust and stars in the SCUBA galaxy, SMMJ02399-0136: the EVLA reveals a colossal galactic nursery

Author

Ivison, R. J., Smail, Ian, Papadopoulos, P. P., Wold, I., Richard, J., Swinbank, A. M., Kneib, J.-P., Owen, F. N., Royal Observatory Edinburgh (ROE), University of Edinburgh, Department of Physics, Durham University, Max-Planck-Institut für Radioastronomie (MPIFR), Department of Astronomy [Madison], University of Wisconsin-Madison, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), National Radio Astronomy Observatory (NRAO), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)

Subjects
radio continuum: galaxies, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Cosmology and Nongalactic Astrophysics (astro-ph.CO), galaxies: high-redshift, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], galaxies: individual: SMM J02399-0136, FOS: Physical sciences, galaxies: starburst, galaxies: evolution, Astrophysics - Cosmology and Nongalactic Astrophysics, infrared: galaxies
Abstract

We present new multi-wavelength observations of the first submm-selected galaxy, SMM J02399-0136 at z=2.8. These observations include mapping of the CO J=1-0 emission using elements of the Expanded VLA, as well as high-resolution 1.4-GHz imaging and optical/IR data from the VLA, HST, Spitzer and Keck. Together these new data provide fundamental insights into the mass and distribution of stars, gas and dust within this archetypal SMG. The CO J=1-0 emission, with its minimal excitation and density requirements, traces the bulk of the metal-rich molecular gas, and reveals a mass of ~10^11 M(sun), extending over ~5" (~25 kpc in the source plane), although there is tentative evidence that it may be significantly larger. Our data suggest that three or more distinct structures are encompassed by this molecular gas reservoir, including the BAL quasar from which the redshift of the SMG was initially determined. In particular, the new rest-frame near-IR observations identify a massive, obscured, starburst coincident with a previously known Ly-alpha cloud. This starburst dominates the far-IR emission from the system and requires a re-assessment of previous claims that the gas reservoir resides in a massive, extended disk around the BAL QSO. Instead it appears that SMM J02399-0136 comprises a merger between a far-IR-luminous, but highly obscured starburst, the BAL QSO host and a faint third component. Our findings suggest that this SMG and its immediate environment mark a vast and complex galactic nursery and that detailed studies of other SMGs are likely to uncover a similarly rich diversity of properties., Comment: in press at MNRAS; 8 pages; 4 figures, 3 in colour

Published
2010
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12. Large scale diffuse light in the Coma cluster: a multi-scale approach

Author

Adami, C., Mazure, A., Tresse, L., Slezak, E., Durret, F., Conselice, C. J., Cuillandre, J. C., Gallagher, J. S., Pelló, R., Picat, J. P., Ulmer, M. P., Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Services communs OMP (UMS 831), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy Caltech (PMA DIVISION), California Institute of Technology (CALTECH), Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), Department of Astronomy [Madison], University of Wisconsin-Madison, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), NWU, Dearborn Observatory (NWU), and Northwestern University Department of Physics and Astronomy

Subjects
010504 meteorology & atmospheric sciences, Scale (ratio), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Coma cluster, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], galaxies, 0103 physical sciences, Coma Cluster, Cluster (physics), Astrophysics::Solar and Stellar Astrophysics, clusters, Abell 1656, individual, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Spiral galaxy, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Star formation, Astrophysics (astro-ph), Astronomy and Astrophysics, Galaxy, Stars, general, Space and Planetary Science, Diffuse reflection
Abstract

We have obtained wide field images of the Coma cluster in the B, V, R and I bands with the CFH12K camera at CFHT. In order to search for large scale diffuse emission, we have applied to these images an iterative multi scale wavelet analysis and reconstruction technique which allowed to model all the sources (stars and galaxies) and subtract them from the original images. We found various concentrations of diffuse emission present in the central zone around the central galaxies NGC4874 and NGC4889. We characterize the positions, sizes and colors of these concentrations. Some sources do not seem to have strong star formation, while another one probably exhibits spiral-like color. One possible origin for the star forming diffuse emission sources is that in the region of the two main galaxies NGC4874 and NGC4889 spiral galaxies have recently been disrupted and star formation is still active in the dispersed material. We also use the characteristics of the sources of diffuse emission to trace the cluster dynamics. A scenario in which the group around NGC 4874 is moving north is consistent with our data., Comment: 11 pages, accepted in A&A, jpg figures

Published
2005
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13. High-resolution observations of interstellar Na i and Ca ii towards the southern opening of the ‘Local Interstellar Chimney’: probing the disc—halo connection

Author

Crawford , I. A., Lallement , Rosine, Price , R. J., Sfeir , D. M., Wakker , B. P., Welsh , B. Y., Department of Physics and Astronomy [UCL London], University College of London [London] ( UCL ), Service d'aéronomie ( SA ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Space Sciences Laboratory [Berkeley] ( SSL ), University of California [Berkeley], Department of Aerospace and Mechanical Engineering [Los Angeles] ( AME ), University of Southern California ( USC ), Department of Astronomy [Madison], and University of Wisconsin-Madison [Madison]

Subjects
Astrophysics::High Energy Astrophysical Phenomena, ISM: structure, Astrophysics::Cosmology and Extragalactic Astrophysics, [ SDU.ASTR.SR ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics::Galaxy Astrophysics, Galaxy: halo
Abstract

International audience; We present high-resolution (R= 400 000) observations of interstellar Ca ii and Na i absorption lines towards seven stars in the direction of the southern opening of the recently identified Local Interstellar Chimney. These lines of sight probe the lower Galactic halo (0.3 ≲|z|≲ 2.5 kpc), without the complication of sampling dense foreground interstellar material. In addition to components with velocities expected from Galactic rotation, these stars also exhibit components with negative local standard of rest velocities, which are contrary to the sense of Galactic rotation for the sightlines observed. After a discussion of possible origins for these peculiar velocities, we conclude that at least some of them result from gas falling towards the Galactic plane from distances of |z|≳ 300 pc. The narrow linewidths are generally inconsistent with temperatures as high as the ∼6000 K generally assumed for the so-called Lockman layer. Rather, the picture that emerges is one of a scattered, generally infalling, population of high-|z| diffuse clouds, seemingly not very different from those encountered in the local interstellar medium. Overall, we argue that our results are most consistent with a ‘Galactic fountain’ model.

Published
2002
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14. High-resolution observations of interstellar Na I and Ca II towards the southern opening of the ‘Local Interstellar Chimney’: probing the disc—halo connection

Author

Bart P. Wakker, Ian A. Crawford, Barry Y. Welsh, Rosine Lallement, D. M. Sfeir, R. J. Price, Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Department of Aerospace and Mechanical Engineering [Los Angeles] (AME), University of Southern California (USC), Department of Astronomy [Madison], University of Wisconsin-Madison, University of California [Berkeley], and University of California-University of California

Subjects
010504 meteorology & atmospheric sciences, Milky Way, Astrophysics::High Energy Astrophysical Phenomena, ISM: structure, Population, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galactic halo, 0103 physical sciences, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, education.field_of_study, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Local standard of rest, Astronomy, Astronomy and Astrophysics, Galactic plane, Galaxy: halo, Interstellar medium, Stars, es, Space and Planetary Science, Halo
Abstract

International audience; We present high-resolution (R= 400 000) observations of interstellar Ca ii and Na i absorption lines towards seven stars in the direction of the southern opening of the recently identified Local Interstellar Chimney. These lines of sight probe the lower Galactic halo (0.3 ≲|z|≲ 2.5 kpc), without the complication of sampling dense foreground interstellar material. In addition to components with velocities expected from Galactic rotation, these stars also exhibit components with negative local standard of rest velocities, which are contrary to the sense of Galactic rotation for the sightlines observed. After a discussion of possible origins for these peculiar velocities, we conclude that at least some of them result from gas falling towards the Galactic plane from distances of |z|≳ 300 pc. The narrow linewidths are generally inconsistent with temperatures as high as the ∼6000 K generally assumed for the so-called Lockman layer. Rather, the picture that emerges is one of a scattered, generally infalling, population of high-|z| diffuse clouds, seemingly not very different from those encountered in the local interstellar medium. Overall, we argue that our results are most consistent with a ‘Galactic fountain’ model.

Published
2002
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