9 research outputs found

    A TIME-SHARED COMPUTER DATA COLLECTION SYSTEM AT THE BROOKHAVEN GRAPHITE RESEARCH REACTOR

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    The on-line system for simultaneous data collection from two physically unrelated neutron time-of-flight experiments is described. A transistorized, digital computer with a 2048, 24 bit word memory provides 1024 and 256channel time analyzers, clocks, and total events and monitor scalers for fast and slow neutron chopper experiments, respectively. (D.C.W.

    COMPUTER-CENTERED DATA HANDLING SYSTEMS

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    The advantages and disadvantages of a stored-program digital computer as a data gathering, analyzing, and control tool for experimental research, are outlined. The advantages of computers in high-energy, low-energy, and neutron physics research are listed. A survey is presented of the applications of computers in multiparameter analysis, concurrent data reduction, and multi- experiment research, with examples of each application. Effects of computer use on research techniques are discussed. (D.L.C.

    A submillimetre galaxy at z = 4.76 in the LABOCA survey of the Extended Chandra Deep Field-South

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    We report on the identification of the highest redshift submillimetre-selected source currently known LESS J033229.4−275619. This source was detected in the Large Apex Bolometer Camera (LABOCA) Extended Chandra Deep Field-South (ECDF-S) Submillimetre Survey (LESS), a sensitive 870-μm survey (σ_(870 μm)∼ 1.2 mJy) of the full 30 × 30 arcmin_2 ECDF-S with the LABOCA on the Atacama Pathfinder Experiment telescope. The submillimetre emission is identified with a radio counterpart for which optical spectroscopy provides a redshift of z= 4.76 . We show that the bolometric emission is dominated by a starburst with a star formation rate of ∼1000 M_⊙ yr^(−1), although we also identify a moderate luminosity active galactic nucleus (AGN) in this galaxy. Thus it has characteristics similar to those of z∼ 2 submillimetre galaxies (SMGs), with a mix of starburst and obscured AGN signatures. This demonstrates that ultraluminous starburst activity is not just restricted to the hosts of the most luminous (and hence rare) quasi-stellar objects at z∼ 5 , but was also occurring in less extreme galaxies at a time when the Universe was less than 10 per cent of its current age. Assuming that we are seeing the major phase of star formation in this galaxy, then we demonstrate that it would be identified as a luminous distant red galaxy at z∼ 3 and that the current estimate of the space density of z > 4 SMGs is only sufficient to produce ≳10 per cent of the luminous red galaxy population at these early times. However, this leaves open the possibility that some of these galaxies formed through less intense, but more extended star formation events. If the progenitors of all of the luminous red galaxies at z∼ 3 go through an ultraluminous starburst at z≳ 4 then the required volume density of z > 4 SMGs will exceed that predicted by current galaxy formation models by more than an order of magnitude

    The Universe at High Redshift

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