The redmapper galaxy cluster catalog from DES Science Verification data

We describe updates to the redMaPPer algorithm, a photometric red-sequence cluster finder specifically designed for large photometric surveys. The updated algorithm is applied to 150 {{deg}}2 of Science Verification (SV) data from the Dark Energy Survey (DES), and to the Sloan Digital Sky Survey (SDSS) DR8 photometric data set. The DES SV catalog is locally volume limited and contains 786 clusters with richness lambda \gt 20 (roughly equivalent to {M}{{500c}}≳ {10}14 {h}70-1 {M}o ) and 0.2\lt z\lt 0.9. The DR8 catalog consists of 26,311 clusters with 0.08\lt z\lt 0.6, with a sharply increasing richness threshold as a function of redshift for z≳ 0.35. The photometric redshift performance of both catalogs is shown to be excellent, with photometric redshift uncertainties controlled at the {sigma }z/(1+z)~ 0.01 level for z≲ 0.7, rising to ~0.02 at z~ 0.9 in DES SV. We make use of Chandra and XMM X-ray and South Pole Telescope Sunyaev--Zeldovich data to show that the centering performance and mass--richness scatter are consistent with expectations based on prior runs of redMaPPer on SDSS data. We also show how the redMaPPer photo-z and richness estimates are relatively insensitive to imperfect star/galaxy separation and small-scale star masks

The role of Ln³⁺ (Ln = Eu, Yb) in persistent red luminescence in MgGeO₃:Mn²⁺

In this paper, Mn2+ and Ln3+ (Ln = Eu, Yb) co-doped MgGeO3 phosphors were prepared using a solid state reaction technique, and their optical properties were investigated. Mn2+-doped samples exhibit persistent luminescence in the red region, peaking at 677 nm, because of the 4T1 → 6A1 transition of the Mn2+ ions under ultraviolet (UV) excitation. Based on the charge transfer (CT) transition of Eu3+ and the band-gap energy, energy level diagrams with divalent lanthanide ground states relative to the conduction and valence band edges were constructed. ΔE(Ln), (Ln = Eu, Yb), which represents the energy gaps between the divalent lanthanide ground states and the bottom of the conduction band, were found to be 0.95 and 0.52 eV, respectively. Compared to a Mn2+ singly-doped sample, the thermoluminescence (TL) glow curves of the Mn2+–Eu3+ co-doped sample and the Mn2+–Yb3+ co-doped sample showed an additional TL glow peak at approximately 502 and 332 K with trap depths (Etrap) of 1.49 and 0.99 eV, respectively. The correspondence of Etrap with ΔE(Ln) suggests that Eu3+ and Yb3+ themselves work as electron traps in the MgGeO3:Mn2+ phosphors. We have also demonstrated that the Mn2+–Eu3+ co-doped material could be a good probe with photo-stimulated functions for long-term in vivo imaging owing to its deeper trap depth.RST/Fundamental Aspects of Materials and Energ

An Imaging Ellipsometry Approach to Dissolved Oxygen Measurement on Surface Tethered Weak Polyelectrolyte Modified Electrode

Electro - total internal reflection ellipsometry has been reported as a phase sensitive ellipsometry technique to observe the redox reactions on the surface of the electrode. In this work, with the imaging ellipsometry, we have used Electro-total internal reflection imaging ellipsometry (Electro-TIRIE) to measure the dissolved oxygen concentration on the surface tethered weak polyelectrolyte brush, carboxylated poly(oligo(ethylene glycol) methacrylate-random-2-hydroxyethylmethacrylate), modified electrode. The cyclic voltammetry has shown despite the covering of the weak polyelectrolyte brush, the electrode could still reduce the dissolved oxygen and Electro-TIRIE technique could unveil the different swelling behavior of the brushes during the reduction. The difference may be attributed to the electro-active probe permeability of the brushes. With the imaging ellipsometry, we proposed a parallel dissolved oxygen measurement. Compared with our previous results, the optical signal noise ratio has been enhanced 10 times and the measurement time has reduced from 30 minutes to 10 minutes. (C) 2016 The Electrochemical Society. All rights reserved