16130045
Isolating the Decay Rate of Cosmological Gravitational Potential
The decay rate of cosmological gravitational potential measures the deviation from Einstein-de Sitter universe and can put strong constraints on the nature of dark energy and gravity. The usual method to measure this decay rate is through the integrated Sachs-Wolfe (ISW) effect-large-scale structure (LSS) cross-correlation. However, the interpretation of the measured correlation signal is complicated by galaxy bias and the matter power spectrum. This could bias and/or degrade its constraints on the nature of dark energy and gravity. But combining the lensing-LSS cross-correlation measurements, the decay rate of gravitational potential can be isolated. For any given narrow redshift bin of LSS, the ratio of the two cross-correlations directly measures H(z)/W(χ, χs), where D is the linear growth factor of the gravitational potential, H is the Hubble constant at redshift z, W(χ, χs) is the lensing kernel, and χ and χs are the comoving angular diameter distance to lens and source, respectively. This method is optimal in the sense that (1) the measured quantity is essentially free of systematic errors and is only limited by cosmic variance, and (2) the measured quantity depends only on several cosmological parameters and can be predicted from first principles unambiguously. Although fundamentally limited by the inevitably large cosmic variance associated with the ISW measurements, it can still put useful independent constraints on the amount of dark energy and its equation of state. It can also provide a powerful test of modified gravity and can distinguish the Dvali-Gabadadze-Porrati model from ΛCDM at >2.5 σ confidence level.
124560798
Lensing of 21cm Absorption "Halos" of First Galaxies
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
6161166
Dimming of Supernovae and Gamma-Ray Busts by Compton Scattering and Its Cosmological Implications
Free electrons deplete photons from Type Ia supernovae through the (inverse) Compton scattering. This Compton dimming increases with redshift and reaches 0.004 mag at z = 1 and 0.01 mag at z = 2. Although far from sufficient to invalidate the existence of dark energy, it can bias constraints on dark energy at a level nonnegligible for future supernova surveys. This effect is correctable and should be incorporated in supernova analysis. The Compton dimming has similar impact on cosmology based on gamma-ray bursts as standard candles.
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.
15276899
The effect of cluster magnetic field on the Sunyaev–Zel'dovich power spectrum
Precision measurements of the Sunyaev–Zel'dovich (SZ) effect in upcoming blank sky surveys require theoretical understanding of all physical processes with ≳10 per cent effects on the SZ power spectrum. We show that the observed cluster magnetic field could reduce the SZ power spectrum by ∼20 per cent at l∼ 4000, where the SZ power spectrum will be precisely measured by the Sunyaev–Zel'dovich array (SZA) and the Atacama Cosmology Telescope (ACT). At smaller scale, this effect is larger and could reach a factor of several. Such an effect must be considered for an unbiased interpretation of the SZ data. Although the magnetic effect on the SZ power spectrum is very similar to that of radiative cooling, it is measurable by multiband cosmic microwave background polarization measurement.
28389230
Higher Order Modes in Third Harmonic Cavities at FLASH
Transverse modes in the 3.9 GHz cavities, designed and fabricated by FNAL, are reported on. These modes have the potential to cause significant emittance dilution if they are not sufficiently suppressed. Recent probebased-experiments have indicated significant discrepancies between modes predicted in stand-alone 9cell cavities compared to those in 4-cavity modules. We employ the code HFSS [1] to analyze these modes, coupled through beam tubes whose cut-off is above that of the first dipole band.
122389578
The order parameter field for cosmic string, inflation and dark energy
We present a whole frame for the cosmic strings, inflation and dark energy with the complex scalar field which can be regarded as the order parameter of our universe. One can find that the comic strings emerge in the zeros of the complex scalar field in the early universe. And with the evolution of complex scalar field, inflation and dark energy can be understood in this frame.
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.
121368498
THE TOPOLOGICAL STRUCTURE OF SINGLE VORTEX IN THE FF STATE
In this paper, we study the coexistence of the vortex and the FF state by using the generalized Ginzburg–Landau (GL) functional with the applied magnetic field, and obtain the numeric solutions. Furthermore, we investigate the topological structure of the vortex and find that the property of vortices relies heavily on the modulation q along z-axis. There is no topological vortex when q < qp, and the value is more favorable for the topological vortex. Moreover the magnetic field at the core of the vortex is obtained for the topological vortex.
118972486
Transverse force on a moving vortex with the acoustic geometry
Abstract We consider the transverse force on a moving vortex with the acoustic metric using the φ -mapping topological current theory. In the frame of effective space–time geometry the vortex appear naturally by virtue of the vortex tensor in the Lorentz space–time and we show that it is just the vortex derived with the order parameter in the condensed matter. With the usual Lagrangian we obtain the equation of motion for the vortex. At last, we show that the transverse force on the moving vortex in our equation is just the usual Magnus force in a simple model.