Panel Reports—New Worlds, New Horizons in Astronomy and Astrophysics (2011) / Chapter Skim
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Appendix B: Glossary
Appendix B: Glossary
Pages 513-540
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Material along the line of sight absorbs light from the background source at wavelengths corresponding to atomic transitions that depend on its chemical composition, temperature and velocity. The pattern of absorption lines in the spectrum therefore yields information on the composition, temperature, and motion of the intervening matter.
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Adiabatic fluctuations: Adiabatic fluctuations are fluctuations in the density of dark matter, ordinary matter, and radiation with the ratio of the density of matter components to the density of the radiation components held spatially constant. AGN (quasar)
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Atacama Cosmology Telescope (ACT) : A 6-meter-diameter, millimeter-wavelength telescope on Cerro Toco in the Atacama Desert of northern Chile, used to study the cosmic microwave background radiation (CMB)
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Binary millisecond pulsars: Orbiting pairs of rapidly rotating neutron stars that emit radio signals. Black hole: A body so massive and dense that its gravity prevents even light from escaping.
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supported by quantum-mechanical electron degeneracy pressure above which a star will ultimately collapse into a neutron star or black hole. Charge parity symmetry: The combination of charge conjugation symmetry and parity symmetry, states that the laws of physics should be the same if a particle were interchanged with its antiparticle (charge conjugation symmetry)
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Compact stellar remnant: The endpoint of stellar evolution -- a white dwarf star, neutron star, or black hole. Compton: The Compton Gamma-Ray Observatory, launched in 1991 and deor bited in 2000.
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: A ground-based survey to study the nature of dark energy by observing the distributions of galaxies and clusters of galaxies, weak gravitational lensing, and supernovae. Dark matter: The hypothetical form of matter that dominates the mass budget of galaxies, clusters, and the universe and is thought to interact only through gravitational forces.
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Deconfined quark matter may have existed in the first few microseconds after the big bang and might exist inside the cores of dense neutron stars. Decretion: The centrifugal ejection of material.
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EMIR: Near-infrared multiobject spectrograph for the Gran Telescopio de Canarias. E-mode polarization: Component of the CMB polarization map that can be expressed as the gradient of a scalar field (and hence is curl free)
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Fossil field: Magnetic field left from a previous evolutionary phase. Fundamental plane: A relation between effective radius, surface brightness, and central velocity dispersion for elliptical galaxies.
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Short-duration (<2 seconds) GRBs may be produced by merging neutron stars.
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Gyrosynchrotron: The electromagnetic radiation emitted by a charged particle moving at relativistic velocities in a magnetic field. H II regions: Emission nebulae created when young, massive stars photoionize nearby gas clouds, composed mostly of hydrogen.
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: Physical behavior of bulk stellar gas, taking into account gravity, shocks, radiative cooling, photoionization, and other effects. Hydrodynamical simulations: Numerical simulations that attempt to model directly the observable baryonic component of the universe and dark matter by incorporating processes associated with gas physics in addition to N-body gravity, including shocks, radiative cooling, and photoionization, along with selected other processes relevant to the system being modeled.
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. The line provides diagnostics of the thermal and dynamical state of matter close to neutron stars and black holes and may be useful for measuring black hole spin.
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dark matter, and a vacuum energy (like the cosmological constant, Λ) , and with adiabatic nearly scale-invariant Gaussian random phase fluctuations.
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M-s relation: The strong correlation observed between the stellar velocity disper sion in galaxies, s, and the masses of their central black holes, M Magellanic Clouds: Two small galaxies (Large and Small Magellanic Clouds)
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However, the gas is still subject to forces due to magnetic fields, which can exert both pressure and tension. The proper treatment of MHD effects is essential to the study of black hole accretion and jets, and is important for many other problems of galaxy formation and evolution, such as star formation and the transport of energy in the atmospheres of galaxy clusters.
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Neutron skin: Thin layer of pure neutron matter covering the surface of many nuclei. Neutron star: A collapsed star with a mass comparable to that of the Sun crammed into the dimensions of a city, giving it a density comparable to that of an atomic nucleus.
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Examples include stellar winds, galactic winds powered by supernovae in star-forming galaxies, winds from the surfaces of accretion disks, and jets emerging from the vicinity of accreting black holes. PanStarrs-1: Panoramic Survey Telescope and Rapid Response System, a wide-field (1.8 meter)
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Planck: An ESA satellite launched in 2009 to map tiny fluctuations in the cosmic microwave background radiation. Planetary Systems and Star Formation (PSF)
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Red giant branch (RGB) : A phase of stellar evolution in which the stars have expanded their outer envelope in response to the extra energy generated by gravitational contraction, hydrogen shell fusion, and ultimately helium fusion in the core.
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Science Frontiers Panel (SFPs) : Five panels of scientists constituted by the National Research Council to write reports on science priorities for the Astro2010 Decadal Survey.
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Spectroscopic redshift: The recession velocity based on measuring the shift of spectral lines from their usual position. Spindown time: The characteristic time for a star to slow its rotation due to loss of angular momentum through its stellar wind and/or magnetic field.
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: The scattering of cosmic microwave background photons by the electrons in hot, ionized gas, which appears as a deficit or enhance ment (depending on observing frequency) in radio continuum maps.
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Superwind: A powerful outflow of hot gas from a starburst galaxy, driven by the combined effects of supernova explosions and winds from massive stars. Suzaku: Japanese X-ray satellite, launched in 2005, featuring high spectroscopic resolution and a very wide energy band.
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Ultradense matter: Exotic new states of matter, e.g., deconfined quark matter or Bose condensates. Ultrahigh-energy cosmic rays (UHECRs)
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: A 4-m-class, widefield telescope located at the Paranal Observatory in Chile and currently operated by the European Southern Observatory. Warm-hot intergalactic medium (WHIM)
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The main physical mecha nisms producing polarization in the X-ray band are thought to be synchrotron radiation (primarily from blazars) , Compton scattering from accretion disks, radia tive transfer in strong magnetic fields, and geometrical effects due to light bending in strong gravitational fields.
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