567 research outputs found

    New York v. United States: Federalism and the Disposal of Low-Level Radioactive Waste

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    Infrared Galaxies in the Field of the Massive Cluster Abell S1063: Discovery of a Luminous Kiloparsec-Sized HII Region in a Gravitationally Lensed IR-Luminous Galaxy at z=0.6z=0.6

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    Using the Spitzer Space Telescope and Herschel Space Observatory, we have conducted a survey of infrared galaxies in the field of the galaxy cluster Abell S1063 (AS1063) at z=0.347z=0.347, which is one of the most massive clusters known and a target of the HST CLASH and Frontier-Field surveys. The Spitzer/MIPS 24 μ\mum and Herschel/PACS & SPIRE images revealed that the core of AS1063 is surprisingly devoid of infrared sources, showing only a few detectable sources within the central r∼1′\sim1^{\prime}. There is, however, one particularly bright source (2.3 mJy at 24 μ\mum; 106 mJy at 160 μ\mum), which corresponds to a background galaxy at z=0.61z=0.61. The modest magnification factor (4.0×\times) implies that this galaxy is intrinsically IR-luminous (LIR=3.1×1011 L⊙_{\rm IR}=3.1\times10^{11}\ \rm L_{\odot}). What is particularly interesting about this galaxy is that HST optical/near-infrared images show a remarkably bright and large (1 kpc) clump at one edge of the disk. Our follow-up optical/near-infrared spectroscopy shows Balmer (Hα\alpha-H8) and forbidden emission from this clump ([OII] λ\lambda3727, [OIII] λλ\lambda\lambda4959,5007, [NII] λλ\lambda\lambda6548,6583), indicating that it is a HII region. The HII region appears to have formed in-situ, as kinematically it is part of a rotating disk, and there is no evidence of nearby interacting galaxies. With an extinction correction of AV=1.5_{\rm V}=1.5 mag, the star formation rate of this giant HII region is ∼\sim10 M⊙_{\odot} yr−1^{-1}, which is exceptionally large, even for high redshift HII regions. Such a large and luminous HII region is often seen at z∼2z\sim2 but quite rare in the nearby Universe.Comment: Accepted for publication in the Astrophysical Journal. 29 pages, 15 figure

    The Frequency of Barred Spiral Galaxies in the Near-IR

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    We have determined the fraction of barred galaxies in the H-band for a statistically well-defined sample of 186 spirals drawn from the Ohio State University Bright Spiral Galaxy survey. We find 56% of our sample to be strongly barred at H, while another 16% is weakly barred. Only 27% of our sample is unbarred in the near-infrared. The RC3 and the Carnegie Atlas of Galaxies both classify only about 30% of our sample as strongly barred. Thus strong bars are nearly twice as prevalent in the near-infrared as in the optical. The frequency of genuine optically hidden bars is significant, but lower than many claims in the literature: 40% of the galaxies in our sample that are classified as unbarred in the RC3 show evidence for a bar in the H-band, while for the Carnegie Atlas this fraction is 66%. Our data reveal no significant trend in bar fraction as a function of morphology in either the optical or H-band. Optical surveys of high redshift galaxies may be strongly biased against finding bars, as bars are increasingly difficult to detect at bluer rest wavelengths.Comment: LaTeX with AASTeX style file, 23 pages with 6 figures. Accepted for publication in The Astronomical Journal (Feb. 2000

    A complete census of Herschel-detected infrared sources within the HST Frontier Fields

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    We present a complete census of all Herschel-detected sources within the six massive lensing clusters of the HST Frontier Fields (HFF). We provide a robust legacy catalogue of 263 sources with Herschel fluxes, primarily based on imaging from the Herschel Lensing Survey and PEP/HerMES Key Programmes. We optimally combine Herschel, Spitzer and WISE infrared (IR) photometry with data from HST, VLA and ground-based observatories, identifying counterparts to gain source redshifts. For each Herschel-detected source we also present magnification factor (μ), intrinsic IR luminosity and characteristic dust temperature, providing a comprehensive view of dust-obscured star formation within the HFF. We demonstrate the utility of our catalogues through an exploratory overview of the magnified population, including more than 20 background sub-LIRGs unreachable by Herschel without the assistance gravitational lensing

    Polarization state of the optical near-field

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    The polarization state of the optical electromagnetic field lying several nanometers above complex dielectric structures reveals the intricate light-matter interaction that occurs in this near-field zone. This information can only be extracted from an analysis of the polarization state of the detected light in the near-field. These polarization states can be calculated by different numerical methods well-suited to near--field optics. In this paper, we apply two different techniques (Localized Green Function Method and Differential Theory of Gratings) to separate each polarisation component associated with both electric and magnetic optical near-fields produced by nanometer sized objects. The analysis is carried out in two stages: in the first stage, we use a simple dipolar model to achieve insight into the physical origin of the near-field polarization state. In the second stage, we calculate accurate numerical field maps, simulating experimental near-field light detection, to supplement the data produced by analytical models. We conclude this study by demonstrating the role played by the near-field polarization in the formation of the local density of states.Comment: 9 pages, 11 figures, accepted for publication in Phys. Rev.

    Security: Collective good or commodity?

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2008 Sage.The state monopoly on the legitimate use of violence in Europe and North America has been central to the development of security as a collective good. Not only has it institutionalized the state as the prime national and international security provider, it has helped to reduce the threat from other actors by either prohibiting or limiting their use of violence. The recent growth of the private security industry appears to undermine this view. Not only are private security firms proliferating at the national level; private military companies are also taking over an increasing range of military functions in both national defence and international interventions. This article seeks to provide an examination of the theoretical and practical implications of the shift from states to markets in the provision of security. Specifically, it discusses how the conceptualization of security as a commodity rather than a collective good affects the meaning and implementation of security in Western democracies.ESR
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