7,850 research outputs found

    Galaxy Clusters Selected via the Sunyaev–Zel'dovich Effect in the SPTpol 100-square-degree Survey

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    We present a catalog of galaxy cluster candidates detected in 100 square degrees surveyed with the SPTpol receiver on the South Pole Telescope. The catalog contains 89 candidates detected with a signal-to-noise ratio greater than 4.6. The candidates are selected using the Sunyaev–Zel'dovich effect at 95 and 150 GHz. Using both space- and ground-based optical and infrared telescopes, we have confirmed 81 candidates as galaxy clusters. We use these follow-up images and archival images to estimate photometric redshifts for 66 galaxy clusters and spectroscopic observations to obtain redshifts for 13 systems. An additional two galaxy clusters are confirmed using the overdensity of near-infrared galaxies only and are presented without redshifts. We find that 15 candidates (18% of the total sample) are at redshift z ≥ 1.0, with a maximum confirmed redshift of z_(max) = 1.38±0.10. We expect this catalog to contain every galaxy cluster with M_(500c) > 2.6×10¹⁴M⊙h⁻¹₇₀ and z > 0.25 in the survey area. The mass threshold is approximately constant above z = 0.25, and the complete catalog has a median mass of approximately M_(500c) > 2.7×10¹⁴M⊙h⁻¹₇₀. Compared to previous SPT works, the increased depth of the millimeter-wave data (11.2 and 6.5 μK-arcmin at 95 and 150 GHz, respectively) makes it possible to find more galaxy clusters at high redshift and lower mass

    Constraints on Cosmological Parameters from the 500 deg² SPTPOL Lensing Power Spectrum

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    We present cosmological constraints based on the cosmic microwave background (CMB) lensing potential power spectrum measurement from the recent 500 deg² SPTPOL survey, the most precise CMB lensing measurement from the ground to date. We fit a flat ΛCDM model to the reconstructed lensing power spectrum alone and in addition with other data sets: baryon acoustic oscillations (BAO), as well as primary CMB spectra from Planck and SPTPOL. The cosmological constraints based on SPTPOL and Planck lensing band powers are in good agreement when analyzed alone and in combination with Planck full-sky primary CMB data. With weak priors on the baryon density and other parameters, the SPTPOL CMB lensing data alone provide a 4% constraint on σ₈Ω^(0.25)_m = 0.593 ± 0.025. Jointly fitting with BAO data, we find σ₈ = 0.779±0.023, Ω_m = 0.368^(+0.032)_(−0.037), and H₀ = 72.0^(+2.1)_(−2.5)kms⁻¹ Mpc⁻¹, up to 2σ away from the central values preferred by Planck lensing + BAO. However, we recover good agreement between SPTPOL and Planck when restricting the analysis to similar scales. We also consider single-parameter extensions to the flat ΛCDM model. The SPTPOL lensing spectrum constrains the spatial curvature to be Ω_K = −0.0007±0.0025 and the sum of the neutrino masses to be ∑m_ν < 0.23 eV at 95% C.L. (with Planck primary CMB and BAO data), in good agreement with the Planck lensing results. With the differences in the signal-to-noise ratio of the lensing modes and the angular scales covered in the lensing spectra, this analysis represents an important independent check on the full-sky Planck lensing measurement

    Development of high energy density primary batteries Fourth quarterly report, 22 Mar. - 21 Jun. 1966

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    High energy density primary batteries for space flight applications - electrolyte systems, cell systems, and positive electrode constructio

    Materials Review

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    Alfred Haywood: A Biography

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    Alfred Haywood was a successful businessman and public servant who lived, worked, and served in the city of Savannah for almost half a century. Mr. Haywood not only made his mark in the local business world but also, through civic participation, and a significant contribution to the growth and development of the city. Born in Oxford, England, in the year 1817, the son of Ebenezer and Elizabeth Haywood, he married Mary Fagan, a native of Ireland, in Liverpool, February 2, 1834. They immigrated to New York soon thereafter. While living in New York with his father, two children were born to the couple, a daughter Margaret, in 1836, and a son Ebenezer, in 1837)https://digitalcommons.georgiasouthern.edu/sav-bios-lane/1095/thumbnail.jp

    U.S. Military Intelligence in Mexico, 1917-1927: An Analysis

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    The Military Intelligence Division (MID) was the U.S. Army\u27s intelligence agency that reported to the Chief of Staff within the War Department. During the years 1917- 1927, the MID routinely conducted surveillance of Mexico, including: espionage, mail censorship, radio intercepts, intelligence gathering, and development of plans for the invasion of Mexico. This study utilizes a tripartite model to evaluate the production and analysis of military intelligence by the MID in Mexico during the period 1917-1927. First, the organization and development of the Military Intelligence Division from its origins in 1885 through the year 1927 is explored with sections on institutional history and objects of investigation. Second, a quantitative analysis of intelligence documents identifies the focus and priorities of the MID in Mexico. Third, a textual analysis of intelligence documents makes use of a cross-cultural framework to demonstrate the prevailing attitudes, perspectives and world views of the MID toward the Mexican state and its peoples. The thesis question as to whether the U.S. Military Intelligence Division created an accurate and complete picture of reality of Mexico is answered in the negative. The MID perspective was colored by cultural bias, ignorance, and misunderstanding. Ultimately, the MID failed to grasp the reality of Mexico because it failed to ask the right questions. It seriously misunderstood the nature of Mexico and its peoples, especially in its relationship with the United States .. The particular model developed for this study lends itself to the possibility of further research in the area of international history and cross-cultural studies. The use of multiple analysis techniques provides a more comprehensive picture of the various factors involved that influence historical events
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