137 research outputs found

    Measurement of Reciprocity Failure in Near Infrared Detectors

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    Flux dependent non-linearity (reciprocity failure) in HgCdTe near infrared detectors can severely impact an instrument's performance, in particular with respect to precision photometric measurements. The cause of this effect is presently not understood. To investigate reciprocity failure, a dedicated test system was built. For flux levels between 1 and 50,000 photons/s, a sensitivity to reciprocity failure of approximately 0.1%/decade was achieved. A wavelength independent non-linearity due to reciprocity failure of about 0.35%/decade was measured in a 1.7 micron HgCdTe detector.Comment: 7 pages, 8 figure

    Impact of Systematics on SZ-Optical Scaling Relations

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    One of the central goals of multi-wavelength galaxy cluster cosmology is to unite all cluster observables to form a consistent understanding of cluster mass. Here, we study the impact of systematic effects from optical cluster catalogs on stacked SZ signals. We show that the optically predicted Y-decrement can vary by as much as 50% based on the current 2 sigma systematic uncertainties in the observed mass-richness relationship. Mis-centering and impurities will suppress the SZ signal compared to expectations for a clean and perfectly centered optical sample, but to a lesser degree. We show that the level of these variations and suppression is dependent on the amount of systematics in the optical cluster catalogs. We also study X-ray luminosity-dependent sub-sampling of the optical catalog and find that it creates Malmquist bias increasing the observed Y-decrement of the stacked signal. We show that the current Planck measurements of the Y-decrement around SDSS optical clusters and their X-ray counterparts are consistent with expectations after accounting for the 1 sigma optical systematic uncertainties using the Johnston mass richness relation.Comment: 6 pages, 4 figures. Revised to match version accepted in the Astrophysical Journa

    A Measurement of the Correlation of Galaxy Surveys with CMB Lensing Convergence Maps from the South Pole Telescope

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    We compare cosmic microwave background lensing convergence maps derived from South Pole Telescope (SPT) data with galaxy survey data from the Blanco Cosmology Survey, WISE, and a new large Spitzer/IRAC field designed to overlap with the SPT survey. Using optical and infrared catalogs covering between 17 and 68 deg^2 of sky, we detect a correlation between the SPT convergence maps and each of the galaxy density maps at >4σ, with zero correlation robustly ruled out in all cases. The amplitude and shape of the cross-power spectra are in good agreement with theoretical expectations and the measured galaxy bias is consistent with previous work. The detections reported here utilize a small fraction of the full 2500 deg^2 SPT survey data and serve as both a proof of principle of the technique and an illustration of the potential of this emerging cosmological probe

    Signal yields, energy resolution, and recombination fluctuations in liquid xenon

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    This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon re- combination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2-16 keV with 3^3H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.Comment: 11 pages, 12 figures, 3 table
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