1,387 research outputs found

    Keck Studies of M31's Stellar Halo

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    We present Keck 10-meter/LRIS spectra of candidate red giants in the halo of M31, located at a projected radius of R=19kpc on the minor axis. These spectroscopic targets have been selected using a combination of UBRI-based and morphological screening to eliminate background galaxies. Radial velocity measurements are used to separate M31 halo giants from foreground Milky Way dwarf stars, M31 disk stars, and residual background galaxies. The metallicity of each M31 halo giant is measured using standard photometric and spectroscopic techniques, the latter based on the strength of the CaII triplet. The various [Fe/H] estimates are in rough agreement with one another. The data reveal a large spread (>2dex) in [Fe/H] in M31's halo; there is no strong radial [Fe/H] gradient. LRIS and HIRES spectra are also presented for red giants in five dwarf spheroidal satellites of M31: AndI, AndIII, AndV, AndVI, and AndVII. There appears to be a significant metallicity spread in AndVI and possibly in AndI. The new radial velocity data on these outer dwarfs are used to constrain the total mass of M31: the best estimate is under 10^(12)Msun, somewhat less than the best estimate for the Milky Way.Comment: 12 pages, 7 figures, Proceedings of SPIE Conference: Discoveries and Research Prospects with 8-10 Meter Class Telescopes (Munich March 2000

    The Strategic Process: In Theory and Practice

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    Rather than a function delegated to the military in a time of emergency, the formulation and execution of national strategy has come to be recognized as a blend of military and political factors—the work of soldiers and statesmen together

    Mahan on the Use of the Sea

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    Inasmuch as trade overseas has traditionally played a significant part in the U.S. economy, the size of its Navy is an accurate indicator of the economic and political status Americans feel their country must occupy

    The National Higher Strategic Direction of War

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    I am approaching the subject from two sides. First, I in­tend to schematize it - see what the situation looks like in the abstract. Second, I intend to examine three cases - the United States, Great Britain and Germany - and see what was actually done to deal with such a situation in its concrete form

    Naval Command Course: Seapower in the Mediterranean

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    The discussion arranges itself in three parts: (1) an examination of stra­tegic significance; (2) a discussion of free world and related interests; and (3) the application of seapower, or, to put it in other terms, the strategic exploitation of the Mediterranean situation

    The Cause of War

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    The jump-off had better be a look at the extent to which the subject of war and its causes has been cluttered up by partial explanations - all of them laid on weak foundations - and built with strong conviction
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