119091401
The dark flow induced small-scale kinetic Sunyaev–Zel'dovich effect
Recently, Kashlinsky et al. reported a discovery of a similar to 10(3) km s(-1) bulk flow of the Universe out to z similar or equal to 0.3, through the dark flow induced cosmic microwave background (CMB) dipole in directions of clusters. We point out that, if this dark flow exists, it will also induce observable CMB temperature fluctuations at multipole l similar to 10(3), through modulation of the inhomogeneous electron distribution on the uniform dark flow. The induced small-scale kinetic Sunyaev-Zel'dovich (SZ) effect will reach similar to 1 mu K-2 at multipole 10(3) less than or similar to l less than or similar to 10(4), only a factor of similar to 2 smaller than the conventional kinetic SZ effect. Furthermore, it will be correlated with the large-scale structure (LSS) and its correlation with Two-Micron All-Sky Survey (2MASS) galaxy distribution reaches 0.3 mu K at l = 10(3), under a directional dependent optimal weighting scheme. We estimate that, Wilkinson Microwave Anisotropy Probe plus 2MASS should already be able to detect this dark flow induced small-scale kinetic SZ effect with similar to 6 sigma confidence. Deeper galaxy surveys such as the Sloan Digital Sky Survey can further improve the measurement. Planck plus existing galaxy surveys can reach greater than or similar to 14 sigma detection. Existing CMB-LSS cross-correlation measurements shall be reanalysed to test the existence of the dark flow and, if it exists, shall be used to eliminate possible bias on the integrated Sachs-Wolfe effect measurement through the CMB-LSS cross-correlation.
14253775
SELF CALIBRATION OF GALAXY BIAS IN SPECTROSCOPIC REDSHIFT SURVEYS OF BARYON ACOUSTIC OSCILLATIONS
Baryon acousticoscillation (BAO)isapowerfulprobeon theexpansion oftheuniverse,sheddinglight on elusive dark energy and gravity atcosm ologicalscales. BAO m easurem entsthrough biased trac- ersofthe underlying m atterdensityeld,asm ostproposalsdo,can reach high statisticalaccuracy. However,possible scale dependence in biasm ay induce non-negligiblesystem aticalerrors,especially forthem ostam bitiousspectroscopicsurveysproposed.W eshow thatprecision spectroscopicredshift inform ation availablein thesesurveysallowsfor selfcalibration ofthegalaxybiasand itsstochasticity, as function ofscale and redshift. Through the eect ofredshift distortion,one can sim ultaneously m easure the realspace powerspectra ofgalaxies,galaxy-velocity and velocity,respectively. Atrel- evantscalesofBAO,galaxy velocity faithfully tracesthatofthe underlying m atter. This valuable feature enablesa ratherm odelindependentway to m easure the galaxy biasand itsstochasticity by com paring the three power spectra. For the square kilom eter array (SKA),this selfcalibration is statistically accurateto correctfor1% levelshiftin BAO peak positionsinduced by biasscaledepen- dence.Furtherm ore,wend thatSKA isabletodetectBAO in thevelocity powerspectrum ,opening a new window forBAO cosm ology. Subjectheadings: cosm ology:distancescale{large-scalestructureofuniverse{theory 1. IN TRO D U CTIO N
31711511
Probing gravity at cosmological scales by measurements which test the relationship between gravitational lensing and matter overdensity.
The standard cosmology is based on general relativity (GR) and includes dark matter and dark energy and predicts a fixed relationship between the gravitational potentials responsible for gravitational lensing and the matter overdensity. Alternative theories of gravity often make different predictions. We propose a set of measurements which can test this relationship, thereby distinguishing between dark energy or matter models and models in which gravity differs from GR. Planned surveys will be able to measure E(G), an observational quantity whose expectation value is equal to the ratio of the Laplacian of the Newtonian potentials to the peculiar velocity divergence, to percent accuracy. This will easily separate alternatives such as the cold dark matter model with a cosmological constant, Dvali-Gabadadze-Porrati, TeVeS, and f(R) gravity.
16733931
Cross correlations of the cosmic infrared background
The cosmic infrared background (CIB) is a sensitive measure of the star formation history. But this background is overwhelmed by foregrounds, which bias the CIB mean flux and auto correlation measurement severely. Since dominant foregrounds do not correlate with the large scale structure, the cross correlation of CIB with galaxies is free of such foregrounds and presents as an unbiased measure of the star formation history. This also allows the measurement of CIB based on integrated intensity, whose theoretical prediction is based on energy conservation, thus is fairly model independent and robust. The redshift information of CIB sources can be directly recovered with the aid of galaxy photometric redshifts. In the far IR region, correlation signal is around 10% at degree scale. Combining FIRAS and SDSS, the cross correlation can be measured with 20% accuracy (statistical and systematics errors) at $l\sim 40$. Such measurement would allow the measurement of star formation rate with comparable accuracies to $z\sim 1$. Future CIB experiments with $1^{\circ}$ resolution are able to measure the star formation rate with 10% accuracy to $z\sim 1.5$. Secondary CMB anisotropies arising from the large scale structure correlate with CIB. The correlation strength is about $0.5\mu$K at $\sim 10^{\circ}$ (the integrated Sachs-Wolfe effect) and $\sim -0.3\mu$K at $\sim 1^{\circ}$ (the Sunyaev Zeldovich effect, Rayleigh-Jeans regime). FIRAS+WMAP would allow the measurement of the ISW effect with $\ga 5\sigma$ confidence. Its detection helps to constrain the amount of dark energy and far IR emissivity bias.
119293147
A proposal on the galaxy intrinsic alignment self-calibration in weak lensing surveys
The galaxy intrinsic alignment causes the galaxy ellipticity-ellipticity power spectrum between two photometric redshifts to decrease faster with respect to the redshift separation Delta z(P), for fixed mean redshift. This offers a valuable diagnosis on the intrinsic alignment. We show that the distinctive dependences of the GG, II and GI correlations on Delta z(P) over the range vertical bar Delta z(P)vertical bar less than or similar to 0.2 can be understood robustly without strong assumptions on the intrinsic alignment. This allows us to measure the intrinsic alignment within each conventional photo-z bin of typical size greater than or similar to 0.2, through lensing tomography of photo-z bin size similar to 0.01. Both the statistical and systematical errors in the lensing cosmology can be reduced by this self-calibration technique.
17627683
Confirmation of the Copernican principle at Gpc radial scale and above from the kinetic Sunyaev-Zel'dovich effect power spectrum.
The Copernican principle, a cornerstone of modern cosmology, remains largely unproven at the Gpc radial scale and above. Here will show that violations of this type will inevitably cause a first order anisotropic kinetic Sunyaev-Zel'dovich effect. If large scale radial inhomogeneities have an amplitude large enough to explain the "dark energy" phenomena, the induced kinetic Sunyaev-Zel'dovich power spectrum will be much larger than the Atacama Cosmology Telescope and/or South Pole Telescope upper limit. This single test confirms the Copernican principle and rules out the adiabatic void model as a viable alternative to dark energy.
119277808
Knot topology in QCD
Abstract We consider topological structure of classical vacuum solutions in quantum chromodynamics. Topologically non-equivalent vacuum configurations are classified by non-trivial second and third homotopy groups for coset of the color group SU ( N ) ( N = 2 , 3 ) under the action of maximal Abelian stability group. Starting with explicit vacuum knot configurations we study possible exact classical solutions. Exact analytic non-static knot solution in a simple CP 1 model in Euclidean space–time has been obtained. We construct an ansatz based on knot and monopole topological vacuum structure for searching new solutions in SU ( 2 ) and SU ( 3 ) QCD. We show that singular knot-like solutions in QCD in Minkowski space–time can be naturally obtained from knot solitons in integrable CP 1 models. A family of Skyrme type low energy effective theories of QCD admitting exact analytic solutions with non-vanishing Hopf charge is proposed.
55635310
Study of Beam Diagnostics with Trapped Modes in Third Harmonic Superconducting Cavities at FLASH
Off-axis beams passing through an accelerating cavity excite dipole modes among other higher order modes (HOMs). These modes have linear dependence on the transverse beam offset from the cavity axis. Therefore they can be used to monitor the beam position within the cavity. The fifth dipole passband of the third harmonic superconducting cavities at FLASH has modes trapped within each cavity and do not propagate through the adjacent beam pipes, while most other cavity modes do. This could enable the beam position measurement in individual cavities. This paper investigates the possibility to use the fifth dipole band for beam alignment in the third harmonic cavity module. Simulations and measurements both with and without beam-excitations are presented. Various analysis methods are used and compared. A good correlation of HOM signals to the beam position is observed.
119898079
Topological objects in the O(3) nonlinear sigma model
We study the topological defects in the nonlinear O(3) sigma model in terms of the decomposition of U(1) gauge potential. Time-dependent baby skyrmions are discussed in the (2+1)-dimensional spacetime with the CP1 field. Furthermore, we show that there are three kinds of topological defects–vortex lines, point defects and knot exist in the (3+1)-dimensional model, and their topological charges, locations and motions are determined by the ϕ-mapping topological current theory.
44301996
BEAM-BASED HOM STUDY IN THIRD HARMONIC SC CAVITIES FOR BEAM ALIGNMENT AT FLASH*
An electron beam entering an accelerator cavity excites higher order modes (HOM). These are radiated to HOM couplers and subsequently damped. They can also be used to facilitate beam position monitoring. The modes excited by off-axis beams are the focus of this study. Results are presented on the first analysis of HOM dependency on the beam position for the third harmonic cavities at FLASH. The analysis is based on the beampipe and cavity dipole modes. Various analysis methods are used and compared to satisfy the needs emerging from the characteristics of those modes. The electric center of each mode is observed by looking for the minima of the HOM signals of different beam positions. A single electron bunch per RF pulse is used.
118380199
Reconstructing the interaction between dark matter and holographic dark energy
We reconstruct the interaction rate between dark matter and the holographic dark energy with the parametrized equation of states and the future event horizon as the infrared cutoff length. It is shown that the observational constraints from the 192 type Ia Supernovae (SnIa) and baryon acoustic oscillation (BAO) measurement permit the negative interaction in the wide region. Moreover, the usual phenomenological descriptions cannot describe the reconstructed interaction well for many cases. The other possible interaction is also discussed.