3,022 research outputs found

    The BOSS Emission-Line Lens Survey. III. : Strong Lensing of Lyα\alpha Emitters by Individual Galaxies

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    We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey (BELLS) for GALaxy-Lyα\alpha EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Lyα\alpha emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure-mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BELLS, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy--LAE candidates selected from 1.4×106\approx 1.4 \times 10^6 galaxy spectra in the BOSS of the Sloan Digital Sky Survey III. These systems consist of massive galaxies at redshifts of approximately 0.5 strongly lensing LAEs at redshifts from 2--3. The compact nature of LAEs makes them an ideal probe of dark substructures, with a substructure-mass sensitivity that is unprecedented in other optical strong-lens samples. The magnification effect from lensing will also reveal the structure of LAEs below 100 pc scales, providing a detailed look at the sites of the most concentrated unobscured star formation in the universe. The source code used for candidate selection is available for download as a part of this release.Comment: 14 pages, 5 figures, accepted for publication in the ApJ (ApJ, 824, 86). Minor edits to match the ApJ published versio

    Noiseless method for checking the Peres separability criterion by local operations and classical communication

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    We present a method for checking Peres separability criterion in an arbitrary bipartite quantum state ρAB\rho_{AB} within local operations and classical communication scenario. The method does not require the prior state reconstruction and the structural physical approximation. The main task for the two observers, Alice and Bob, is to estimate some specific functions. After getting these functions, they can determine the minimal eigenvalue of ρABTB\rho^{T_{B}}_{AB}, which serves as an entanglement indicator in lower dimensions.Comment: 10 pages, 2 figure

    Effect of process parameters on forming quality of Mg alloy(MZ21)-Al alloy(7075) composite pipe

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    This paper mainly studies the effect of process parameters on the deformation mechanism of MZ21 magnesium alloy and 7075 aluminum alloy bimetal composite pipe in spinning process.The two parameters of spinning, the rotary wheel feed ratio and the double tube wall thinning rate were selected to study, and the influence rule of each process parameter on the forming quality of composite tube was simulated by Simufact software. Under different thinning rates of the total wall thickness, the coordinated deformation and the rebound law of the wall thickness of the composite pipe are obtained. The results provide a certain reference for the preparation of magnesium aluminum composite pipe and the selection of reasonable spinning parameters

    Research on the dynamic recrystallization law of cross wedge rolling (CWR) asymmetric hollow shaft

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    To improve mechanical properties of asymmetrical hollow shafts parts, the dynamic recrystallization of asymmetrical hollow shaft can be obtained by cross wedge rolling (CWR) technology. The Finite element model (FEM) is established using the DEFORM-3D software, the distribution of the dynamic recrystallization volume fraction is illustrated, and the law of average grain size distribution is analyzed. The microscopy results indicate that the grain size at the central area of cross-section is larger than that at lateral area, and the grain of the central part can be obviously refined, the whole microstructure homogeneity is improved, which have provided theoretical foundation for further improving the quality and mechanical properties of CWR asymmetrical hollow shafts parts

    Ionospheric Response to the Total Solar Eclipse of 22 July 2009 as Deduced from VLBI and GPS Data

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    A total solar eclipse occurred over China at latitudes of about 30 N on the morning of 22 July 2009, providing a unique opportunity to investigate the influence of the sun on the earth's upper ionosphere. GPS observations from Shanghai GPS Local Network and VLBI observations from stations Shanghai, Urumqi, and Kashima were used to observe the response of TEC to the total solar eclipse. From the GPS data reduction, the sudden decrease of TEC at the time of the eclipse, amounting to 2.8 TECU, and gradual increase of TEC after the eclipse were found by analyzing the diurnal variations. More distinctly, the variations of TEC were studied along individual satellite passes. The delay in reaching the minimum level of TEC with the maximum phase of eclipse was 5-10 min. Besides, we also compared the ionospheric activity derived from different VLBI stations with the GPS results and found a strong correlation between them
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