XMM-Newton detection of two clusters of galaxies with strong SPT Sunyaev-Zel'dovich effect signatures

We report on the discovery of two galaxy clusters, SPT-CL J2332-5358 and SPT-CL J2342-5411, in X-rays. These clusters were also independently detected through their Sunyaev-Zel'dovich effect by the South Pole Telescope, and confirmed in the optical band by the Blanco Cosmology Survey. They are thus the first clusters detected under survey conditions by all major cluster search approaches. The X-ray detection is made within the frame of the XMM-BCS cluster survey utilizing a novel XMM-Newton mosaic mode of observations. The present study makes the first scientific use of this operation mode. We estimate the X-ray spectroscopic temperature of SPT-CL J2332-5358 (at redshift z=0.32) to T = 9.3 (+3.3/-1.9) keV, implying a high mass, M_{500} = 8.8 +/- 3.8 \times 10^{14} M_{sun}. For SPT-CL J2342-5411, at z=1.08, the available X-ray data doesn't allow us to directly estimate the temperature with good confidence. However, using our measured luminosity and scaling relations we estimate that T = 4.5 +/- 1.3 keV and M_{500} = 1.9 +/- 0.8 \times 10^{14} M_{sun}. We find a good agreement between the X-ray masses and those estimated from the Sunyaev-Zel'dovich effect.Comment: Submitted to A&A, 8 pages, 5 figures, 1 tabl

Advanced analog television study final report, 4 nov. - 19 dec. 1963

Information bandwidth reduction for analog television signals - Description of multiple interlace syste

Measurement of spin memory lengths in PdNi and PdFe ferromagnetic alloys

Weakly ferromagnetic alloys are being used by several groups in the study of superconducting/ferromagnetic hybrid systems. Because spin-flip and spin-orbit scattering in such alloys disrupt the penetration of pair correlations into the ferromagnetic material, it is desirable to have a direct measurement of the spin memory length in such alloys. We have measured the spin memory length at 4.2 K in sputtered Pd0.88Ni0.12 and Pd0.987Fe0.013 alloys using methods based on current-perpendicular-to-plane giant magnetoresistance. The alloys are incorporated into hybrid spin valves of various types, and the spin memory length is determined by fits of the Valet-Fert spin-transport equations to data of magnetoresistance vs. alloy thickness. For the case of PdNi alloy, the resulting values of the spin memory length are lsf(PdNi) = 2.8 +/- 0.5 nm and 5.4 +/- 0.6 nm, depending on whether or not the PdNi is exchange biased by an adjacent Permalloy layer. For PdFe, the spin memory length is somewhat longer, lsf(PdFe) = 9.6 +/- 2 nm, consistent with earlier measurements indicating lower spin-orbit scattering in that material. Unfortunately, even the longer spin memory length in PdFe may not be long enough to facilitate observation of spin-triplet superconducting correlations predicted to occur in superconducting/ferromagnetic hybrid systems in the presence of magnetic inhomogeneity.Comment: 7 pages, 8 figure

Final state interactions in two-particle interferometry

We reconsider the influence of two-particle final state interactions (FSI) on two-particle Bose-Einstein interferometry. We concentrate in particular on the problem of particle emission at different times. Assuming chaoticity of the source, we derive a new general expression for the symmetrized two-particle cross section. We discuss the approximations needed to derive from the general result the Koonin-Pratt formula. Introducing a less stringent version of the so-called smoothness approximation we also derive a more accurate formula. It can be implemented into classical event generators and allows to calculate FSI corrected two-particle correlation functions via modified Bose-Einstein "weights".Comment: 12 pages RevTeX, 2 ps-figures included, submitted to Phys. Rev.

Origin of entropy convergence in hydrophobic hydration and protein folding

An information theory model is used to construct a molecular explanation why hydrophobic solvation entropies measured in calorimetry of protein unfolding converge at a common temperature. The entropy convergence follows from the weak temperature dependence of occupancy fluctuations for molecular-scale volumes in water. The macroscopic expression of the contrasting entropic behavior between water and common organic solvents is the relative temperature insensitivity of the water isothermal compressibility. The information theory model provides a quantitative description of small molecule hydration and predicts a negative entropy at convergence. Interpretations of entropic contributions to protein folding should account for this result.Comment: Phys. Rev. Letts. (in press 1996), 3 pages, 3 figure

Effect of the source charge on charged-beam interferometry

We investigate quantal perturbations of the interferometric correlations of charged bosons by the Coulomb field of an instantaneous, charged source. The source charge increases the apparent source size by weakening the correlation at non-zero relative momenta. The effect is strongest for pairs with a small total momentum and is stronger for kaons than for pions of the same momenta. The experimental data currently available are well described by this effect without invoking Pratt's exploding source model. A simple expression is proposed to account for the effect.Comment: 9 pages TEX, 3 Postscript figures available at http://www.krl.caltech.edu/preprints/MAP.htm

Bose-Einstein Correlations of Pion Wavepackets

A wavepacket model for a system of free pions, which takes into account the full permutation symmetry of the wavefunction and which is suitable for any phase space parametrization is developed. The properties of the resulting mixed ensembles and the two-particle correlation function are discussed. A physical interpretation of the chaoticity lambda as localizat of the pions in the source is presented. Two techniques to generate test-particles, which satisfy the probability densities of the wavepacket state, are studied: 1. A Monte Carlo procedure in momentum space based on the standard Metropolis technique. 2. A molecular dynamic procedure using Bohm's quantum theory of motion. In order to reduce the numerical complexity, the separation of the wavefunction into momentum space clusters is discussed. In this context th influence of an unauthorized factorization of the state, i. e. the omissio of interference terms, is investigated. It is shown that the correlation radius remains almost uneffected, but the chaoticity parameter decreases substantially. A similar effect is observed in systems with high multiplic where the omission of higher order corrections in the analysis of two-part correlations causes a reduction of the chaoticity and the radius. The approximative treatment of the Coulomb interaction between pions and source is investigated. The results suggest that Coulomb effects on the co radii are not symmetric for pion pairs of different charges. For negative the radius, integrated over the whole momentum spectrum, increases substan while for positive pions the radius remains almost unchanged.Comment: 15 pages, 8 figures, 0.8 Mb, uses ljour2-macro, Submitted to Z. Phys. A (1997