1663219
CARS: the CFHTLS-Archive-Research Survey II. Weighing dark matter halos of Lyman-break galaxies at z = 3-5
Aims. We measure the clustering properties for a large samples of u- (z ~ 3), g- (z ~ 4), and r- (z ~ 5) dropouts from the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) Deep fields. 
 
Methods. Photometric redshift distributions along with simulations allow us to de-project the angular correlation measurements and estimate physical quantities such as the correlation length, halo mass, galaxy bias, and halo occupation as a function of UV luminosity. 
 
Results. For the first time we detect a significant one-halo term in the correlation function at z ~ 5 . The comoving correlation lengths and halo masses of LBGs are found to decrease with decreasing rest-frame UV-luminosity. No significant redshift evolution is found in either quantity. The typical halo mass hosting an LBG is M ≳ 10^(12)h^(-1) M⊙ and the halos are typically occupied by less than one galaxy. Clustering segregation with UV luminosity is clearly observed in the dropout samples, however redshift evolution cannot clearly be disentangled from systematic uncertainties introduced by the redshift distributions. We study a range of possible redshift distributions to illustrate the effect of this choice. Spectroscopy of representative subsamples is required to make high-accuracy absolute measurements of high-z halo masses.
15490282
The galaxy-dark matter bias in the Garching-Bonn Deep Survey
We measured the bias and correlation factor of galaxies with respect to the dark matter using the aperture statistics including the aperture mass from weak gravitational lensing. The analysis was performed for three galaxy samples selected by R-band magnitudes; the median redshifts of the samples were $\ave{z}=0.34,0.49$ and 0.65, respectively. The brightest sample has the strongest peak in redshift and can therefore be most accurately represented by a single redshift. The data used is the GaBoDS, and the COMBO-17 survey for an accurate estimate of the redshift distribution of the galaxies. Assuming the currently favoured $\Lambda\rm CDM$ model as cosmology, we obtained values for the linear stochastic galaxy-dark matter bias on angular scales $1^\prime\le\theta\le20^\prime$. Averaging the measurements for the bias over the range $4^\prime\le \theta_{\rm ap}\le 18^\prime$, weighting with the cosmic variance error, yields $b=0.89(5), 0.79(5), 0.89(5)$, respectively ($1\sigma$). As for the correlation factor $r$ we see, as Hoekstra et al. (2002), a slight increase to $r=1$ in the last angular bin from an almost constant value on smaller scales; the weighted average here over the same range as before is $r=0.8(1), 0.8(1), 0.5(1)$, respectively (abridged).
8253626
The non-Gaussianity of the cosmic shear likelihood or How odd is the Chandra Deep Field South?
Aims. We study the validity of the approximation of a Gaussian cosmic shear likelihood. We estimate the true likelihood for a fiducial cosmological model from a large set of ray-tracing simulations and investigate the impact of non-Gaussianity on cosmological parameter estimation. We investigate how odd the recently reported very low value of σ8 really is as derived from the Chandra Deep Field South (CDFS) using cosmic shear by taking the non-Gaussianity of the likelihood into account, as well as the possibility of biases coming from the way the CDFS was selected. Methods. A brute force approach to estimating the likelihood from simulations must fail because of the high dimensionality of the problem. We therefore use independent component analysis to transform the cosmic shear correlation functions to a new basis, in which the likelihood approximately factorises into a product of one-dimensional distributions. Results. We find that the cosmic shear likelihood is significantly non-Gaussian. This leads to both a shift of the maximum of the posterior distribution and a significantly smaller credible region compared to the Gaussian case. We re-analyse the CDFS cosmic shear data using the non-Gaussian likelihood in combination with conservative galaxy selection criteria that minimise calibration uncertainties. Assuming that the CDFS is a random pointing, we find σ8 = 0.68 +0.09 −0.16 for fixed Ωm = 0.25. In a WMAP5-like cosmology, a value equal to or lower than this would be expected in ≈5% of the times. Taking biases into account arising from the way the CDFS was selected, which we model as being dependent on the number of haloes in the CDFS, we obtain σ8 = 0.71 +0.10 −0.15 . Combining the CDFS data with the parameter constraints from WMAP5 yields Ωm = 0.26 +0.03 −0.02 and σ8 = 0.79 +0.04 −0.03 for a flat universe.
119100161
CFHTLenS: the Canada-France-Hawaii Telescope Lensing Survey - imaging data and catalogue products
We present data products from the Canada–France–Hawaii Telescope Lensing Survey (CFHTLenS). CFHTLenS is based on the Wide component of the Canada–France–Hawaii Telescope Legacy Survey (CFHTLS). It encompasses 154 deg^2 of deep, optical, high-quality, sub-arcsecond imaging data in the five optical filters u*g′r′i′z′. The scientific aims of the CFHTLenS team are weak gravitational lensing studies supported by photometric redshift estimates for the galaxies. This paper presents our data processing of the complete CFHTLenS data set. We were able to obtain a data set with very good image quality and high-quality astrometric and photometric calibration. Our external astrometric accuracy is between 60 and 70 mas with respect to Sloan Digital Sky Survey (SDSS) data, and the internal alignment in all filters is around 30 mas. Our average photometric calibration shows a dispersion of the order of 0.01–0.03 mag for g′r′i′z′ and about 0.04 mag for u* with respect to SDSS sources down to i_(SDSS) ≤ 21. We demonstrate in accompanying papers that our data meet necessary requirements to fully exploit the survey for weak gravitational lensing analyses in connection with photometric redshift studies. In the spirit of the CFHTLS, all our data products are released to the astronomical community via the Canadian Astronomy Data Centre at http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/CFHTLens/query.html. We give a description and how-to manuals of the public products which include image pixel data, source catalogues with photometric redshift estimates and all relevant quantities to perform weak lensing studies.
16212970
Relative clustering and the joint halo occupation distribution of red-sequence and blue-cloud galaxies in COMBO-17
This paper studies the relative spatial distribution of red-sequence and blue-cloud galaxies, and their relation to the dark matter distribution in the COMBO-17 survey as function of scale down to z ~ 1. We measure the second-order auto- and cross-correlation functions of galaxy clustering and express the relative biasing by using aperture statistics. Also estimated is the relation between the galaxies and the dark matter distribution exploiting galaxy-galaxy lensing (GGL). All observables are further interpreted in terms of a halo model. To fully explain the galaxy clustering cross-correlation function with a halo model, we introduce a new parameter, R, that describes the statistical correlation between numbers of red and blue galaxies within the same halo. We find that red and blue galaxies are clearly differently clustered, a significant evolution of the relative clustering with redshift is not found. There is evidence for a scale-dependence of relative biasing: the linear relative bias factor varies slightly between b ~ 1.7 ± 0.5 and ~2.2 ± 0.1 on spatial scales between roughly 100 h -1 kpc and 7h -1 Mpc, respectively. The linear correlation coefficient of galaxy number densities drops from a value near unity on large scales to r ~ 0.6 ± 0.15. Both biasing trends, the GGL and with some tension the galaxy numbers can be explained consistently within a halo model. Red galaxies typically start to populate haloes with masses starting from ≥10 12.1 ±0.2 h -1 M ⊙ , blue galaxies from ≥10 11.2±0.1 h -1 M ⊙ . For the cross-correlation function, one requires a halo occupation distribution (HOD) variance that becomes Poisson even for relatively small occupancy numbers. This rules out for our samples with high confidence a 'Poisson satellite' scenario, as found in semi-analytical models. We compare different model flavours, with and without galaxies at the halo centres, using Bayesian evidence. The result is inconclusive. However, red galaxies have to be concentrated towards the halo centre either by a red central galaxy or by a concentration parameter above that of dark matter. The value of R depends on the presence or absence of central galaxies: if no central galaxies or only red central galaxies are allowed, R is consistent with zero, whereas a positive correlation R = +0.5 ± 0.2 is needed if both blue and red galaxies can have central galaxies.
119192831
Towards an understanding of third-order galaxy-galaxy lensing
Context. Third-order galaxy-galaxy lensing (G3L) is a next generation galaxy-galaxy lensing (GGL) technique that either measures the excess shear about lens pairs or the excess shear-shear correlations about lenses. From their definition it is clear that these statistics assess the three-point correlations between galaxy positions and projected matter density. Aims. For future applications of these novel statistics, we aim at a more intuitive understanding of G3L to isolate the main features that possibly can be measured. Methods. We construct a toy model (“isolated lens model”; ILM) for the distribution of galaxies and associated matter to determine the measured quantities of the two G3L correlation functions and traditional GGL in a simplified context. The ILM presumes single lens galaxies to be embedded inside arbitrary matter haloes that, however, are statistically independent (“isolated”) from any other halo or lens position. Clusters of galaxies and their common cluster matter haloes are a consequence of clustering smaller haloes. In particular, the average mass-to-galaxy number ratio of clusters of any size cannot change in the ILM. Results. GGL and galaxy clustering alone cannot distinguish an ILM from any more complex scenario. The lens-lens-shear correlator in combination with second-order statistics enables us to detect deviations from a ILM, though. This can be quantified by a difference signal defined in the paper. We demonstrate with the ILM that this correlator picks up the excess matter distribution about galaxy pairs inside clusters, whereas pairs with lenses well separated in redshift only suppress the overall amplitude of the correlator. The amplitude suppression can be normalised. The lens-lens-shear correlator is sensitive to variations among matter haloes. In principle, it could be devised to constrain the ellipticities of haloes, without the need for luminous tracers, or maybe even random halo substructure.
16157496
Universal amplitude ratios of the renormalization group: two-dimensional tricritical Ising model.
The scaling form of the free energy near a critical point allows for the definition of various thermodynamical amplitudes and the determination of their dependence on the microscopic nonuniversal scales. Universal quantities can be obtained by considering special combinations of the amplitudes. Together with the critical exponents they characterize the universality classes and may be useful quantities for their experimental identification. We compute the universal amplitude ratios for the tricritical Ising model in two dimensions by using several theoretical methods from perturbed conformal field theory and scattering integrable quantum field theory. The theoretical approaches are further supported and integrated by results coming from a numerical determination of the energy eigenvalues and eigenvectors of off-critical systems in an infinite cylinder.
117969814
Mutation of Andreev into Majorana bound states in long superconductor-normal and superconductor-normal-superconductor junctions
We study one-dimensional topological SN and SNS long junctions obtained by placing a topological insulating nanowire in the proximity of either one or two SC finite-size leads. Using the Majorana Polarization order parameter (MP) introduced in Phys. Rev. Lett. 108, 096802 (2012)(arxiv:1109.5697) we find that the extended Andreev bound states (ABS) of the normal part of the wire acquire a finite MP: for a finite-size SN junction the ABS spectrum exhibits a zero-energy extended state which carries a full Majorana fermion, while the ABS of long SNS junctions with phase difference $\pi$ transform into two zero-energy states carrying two Majorana fermions with the same MP. Given their extended character inside the whole normal link, and not only close to an interface, these Majorana-Andreev states can be directly detected in tunneling spectroscopy experiments.
17405363
Coupled Ising models with disorder
In this paper we study the phase diagram of two Ising planes coupled by a standard spin-spin interaction with bond randomness in each plane. The whole phase diagram is analysed with the help of Monte Carlo simulations and field theory arguments.
119377774
2D FRACTIONAL SUPERSYMMETRY FOR RATIONAL CONFORMAL FIELD THEORY : APPLICATION FOR THIRD-INTEGER SPIN STATES
A 2D fractional supersymmetry theory is algebraically constructed. The Lagrangian is derived using an adapted superspace including, in addition to a scalar field, two fields with spins 13, 23 This theory turns out to be a rational conformal field theory. The symmetry of this model goes beyond the super-Virasoro algebra and connects these third-integer spin states. Besides the stress-momentum tensor, we obtain a supercurrent of spin 43. Cubic relations are involved in order to close the algebra; the basic algebra is no longer a Lie or a super-Lie algebra. The central charge of this model is found to be 53 Finally, we analyze the form that a local invariant action should take.
119273967
Josephson effect in superconducting wires supporting multiple Majorana edge states
We study superconducting-normal-superconducting (SNS) Josephson junctions in one-dimensional topological superconductors which support more than one Majorana end mode. The variation of the energy spectrum with the superconducting phase is investigated by combining numerical diagonalizations of tight-binding models describing the SNS junction together with an analysis of appropriate low-energy effective Hamiltonians. We show that the four pi-periodicity characteristic of the fractional dc Josephson effect is preserved. Additionally, the ideal conductance of a NS junction with a topological supraconductor, hosting two Majorana modes at its ends, is doubled compared to the single Majorana case. Last, we illustrate how a nonzero superconducting phase gradient can potentially destroy the phases supporting multiple Majorana end states.