Large-scale structure

We report the first detection of the gravitational lensing of the cosmic microwave background through a measurement of the four-point correlation function in the temperature maps made by the Atacama Cosmology Telescope. We verify our detection by calculating the levels of potential contaminants and performing a number of null tests. The resulting convergence power spectrum at 2-degree angular scales measures the amplitude of matter density fluctuations on comoving length scales of around 100 Mpc at redshifts around 1 to 3. The measured amplitude of the signal agrees with Lambda Cold Dark Matter cosmology predictions. Since the amplitude of the convergence power spectrum scales as the square of the amplitude of the density fluctuations, the 4-sigma detection of the lensing signal measures the amplitude of density fluctuations to 12%.

The modification of star formation (SF) in galaxy interactions is a complex process, with SF observed to be both enhanced in major mergers and suppressed in minor pair interactions. Such changes likely to arise on short timescales and be directly related to the galaxy-galaxy interaction time. Here we investigate the link between dynamical phase and direct measures of SF on different timescales for pair galaxies, targeting numerous star-formation rate (SFR) indicators and comparing to pair separation, individual galaxy mass and pair mass ratio. We split our sample into the higher (primary) and lower (secondary) mass galaxies in each pair and find that SF is indeed enhanced in all primary galaxies but suppressed in secondaries of minor mergers. We find that changes in SF of primaries are consistent in both major and minor mergers, suggesting that SF in the more massive galaxy is agnostic to pair mass ratio. We also find that SF is enhanced/suppressed more strongly for short-duration SFR indicators (e.g. Hα), highlighting recent changes to SF in these galaxies, which are likely to be induced by the interaction. We propose a scenario where the lower mass galaxy has its SF suppressed by gas heating or stripping, while the higher mass galaxy has its SF enhanced, potentially by tidal gas turbulence and shocks. This is consistent with the seemingly contradictory observations for both SF suppression and enhancement in close pairs.

We investigate the dependence of the galaxy luminosity function on geometric environment within the Galaxy And Mass Assembly (GAMA) survey. The tidal tensor prescription, based on the Hessian of the pseudo-gravitational potential, is used to classify the cosmic web and define the geometric environments: for a given smoothing scale, we classify every position of the surveyed region, 0.04 < z < 0.26, as either a void, a sheet, a filament or a knot. We consider how to choose appropriate thresholds in the eigenvalues of the Hessian in order to partition the galaxies approximately evenly between environments. We find a significant variation in the luminosity function of galaxies between different geometric environments; the normalization, characterized by φ * in a Schechter function fit, increases by an order of magnitude from voids to knots. The turnover magnitude, characterized by M * , brightens by approximately 0.5 mag from voids to knots. However, we show that the observed modulation can be entirely attributed to the indirect local-density dependence. We therefore find no evidence of a direct influence of the cosmic web on the galaxy luminosity function.

We explore trends in galaxy properties with Mpc-scale structures using catalogues of environment and large-scale structure from the Galaxy And Mass Assembly (GAMA) survey. Existing GAMA catalogues of large-scale structure, group, and pair membership allow us to construct galaxy stellar mass functions for different environmental types. To avoid simply extracting the known underlying correlations between galaxy properties and stellar mass, we create a mass matched sample of galaxies with stellar masses within 9.5 ≤ log M * /h −2 M ≤ 11 for each environmental population. Using these samples, we show that mass normalized galaxies in different large-scale environments have similar energy outputs, u − r colours, luminosities, and morphologies. Extending our analysis to group and pair environments, we show that galaxies that are not in groups or pairs exhibit similar characteristics to each other regardless of broader environment. For our mass controlled sample, we fail to see a strong dependence of Sérsic index or galaxy luminosity on halo mass, but do find that it correlates very strongly with colour. Repeating our analysis for galaxies that have not been mass controlled introduces and amplifies trends in the properties of galaxies in pairs, groups, and large-scale structure, indicating that stellar mass is the most important predictor of the galaxy properties we examine, as opposed to environmental classifications.

We present the first study of the isotropy of the all-sky distribution of morphological types of galaxies in the Local Universe out to around 200 Mpc using more than 60 000 galaxies from the HyperLeda database. We use a hemispherical comparison method where the sky is divided into two opposite hemispheres and the abundance distribution of the morphological types, T , are compared using the Kolmogorov-Smirnov (KS) test. By pointing the axis of symmetry of the hemisphere pairs to different directions in the sky, the KS statistic as a function of sky coordinates is obtained. For three samples of galaxies within around 100, 150, and 200 Mpc, we find a significant hemispherical asymmetry with a vanishingly small chance of occurring in an isotropic distribution. Astonishingly, regardless of this extreme significance, the observed hemispherical asymmetry for the three distance ranges is aligned with the celestial equator at the 97.1−99.8% confidence level and with the ecliptic at 94.6−97.6%, estimated using a Monte Carlo analysis. Shifting T values randomly within their uncertainties has a negligible effect on this result. When a magnitude limit of B ≤ 15 mag is applied to these samples, the galaxies within 100 Mpc show no significant anisotropy after randomization of T. However, the direction of the asymmetry in the samples within 150 and 200 Mpc and the same magnitude limit is found to be within an angular separation of 32 degrees from (l, b) = (123.7, 24.6) with a 97.2% and 99.9% confidence level, respectively. This direction is only 2.6 degrees away from the celestial north pole. Unless the Local Universe has a significant anisotropic distribution of galaxy morphologies aligned with the orientation or the orbit of the Earth (which would be a challenge for the Cosmological Principle), our results show that there seems to be a systematic bias in the classification of galaxy morphological types between the data from the northern and the southern equatorial sky. Further studies are absolutely needed to find the exact source of this anisotropy.

The Rana dynasty ruled Nepal from 1846 to 1951 and was responsible for the construction of a number of private and government Neoclassical- or Baroque-style palaces in Kathmandu and other parts of the country. Following the 2015 Gorkha (Nepal) earthquake, detailed damage assessments of these buildings were undertaken by local and international teams. Two case study buildings that suffered moderate structural damage are presented herein, the Kaiser Mahal Palace and the Ananda Niketan Palace. Kaiser Mahal was assessed prior to the 2015 Gorkha earthquake in order to develop potential seismic retrofitting options, and the results are compared with the damage observations made following the Gorkha earthquake. Ananda Niketan was only assessed after the Gorkha earthquake with an extensive damage evaluation, in-situ material testing and sample extraction, and the undertaking of a comprehensive detailed seismic assessment. The two case studies are presented herein, followed by a comparison b...

By explicit solution of the one-loop finiteness conditions for gauge and quartic scalarboson self-interaction coupling constants, a particular class of grand unified theories with vanishing Yukawa couplings as well as vanishing one-loop renormalization-group beta functions is constructed.

We present estimates of the non-linear bias of cosmological halo formation, spanning a wide range in the halo mass from ∼10 5 to ∼10 12 M , based upon both a suite of high-resolution cosmological N-body simulations and theoretical predictions. The halo bias is expressed in terms of the mean bias and stochasticity as a function of local overdensity (δ), under different filtering scales, which is realized as the density of individual cells in uniform grids. The sampled overdensities span a range wide enough to provide the fully non-linear bias effect on the formation of haloes. A strong correlation between δ and halo population overdensity δ h is found, along with sizable stochasticity. We find that the empirical mean halo bias matches, with good accuracy, the prediction by the peak-background split method based on the excursion set formalism, as long as the empirical, globally averaged halo mass function is used. Consequently, this bias formalism is insensitive to uncertainties caused by varying halo-identification schemes, and can be applied generically. We also find that the probability distribution function of biased halo numbers has wider distribution than the pure Poisson shot noise, which is attributed to the sub-cell-scale halo correlation. We explicitly calculate this correlation function and show that both overdense and underdense regions have positive correlation, leading to stochasticity larger than the Poisson shot noise in the range of haloes and halo-collapse epochs we study.

Some years ago, Hidding et al. suggest that the emergence of intricate and pervasive weblike structure of the Universe on Megaparsec scales can be approximated by a wellknown equation from fluid mechanics, the Burgers' equation. The solution to this equation can be obtained from a geometrical formalism. The resulting Adhesion formalism provides deep insight into the dynamics and topology of the Cosmic Web. It uncovers a direct connection between the conditions in the very early Universe and the complex spatial patterns that emerged out of these under the influence of gravity.

Recent simulations show the Epoch of Reionization (EoR) 21-cm signal to be inherently non-Gaussian whereby the error covariance matrix C ij of the 21-cm power spectrum (PS) contains a trispectrum contribution that would be absent if the signal were Gaussian. Using the binned power spectrum and trispectrum from simulations, here we present a methodology for incorporating these with the baseline distribution and system noise to make error predictions for observations with any radio-interferometric array. Here we consider the upcoming SKA-Low. Non-Gaussianity enhances the errors introducing a positive deviation relative to the Gaussian predictions. increases with observation time t obs and saturates as the errors approach the cosmic variance. Considering t obs = 1024 hours where a 5σ detection is possible at all redshifts 7 ≤ z ≤ 13, in the absence of foregrounds we find that the deviations are important at small k where we have ∼ 40-100 per cent at k ∼ 0.04 Mpc −1 for some of the redshifts and also at intermediate k (∼ 0.4 Mpc −1) where we have ∼ 200 per cent at z = 7. Non-Gaussianity also introduces correlations between the errors in different k bins, and we find both correlations and anticorrelations with the correlation coefficient value spanning −0.4 ≤ r ij ≤ 0.8. Incorporating the foreground wedge, continues to be important (> 50 per cent) at z = 7. We conclude that non-Gaussianity makes a significant contribution to the errors and this is important in the context of the future instruments that aim to achieve high-sensitivity measurements of the EoR 21-cm PS.

We write down the Lagrangian bias expansion in general relativity up to 4th order in terms of operators describing the curvature of an early-time hypersurface for comoving observers. They can be easily expanded in synchronous or comoving gauges. This is necessary for the computation of the one-loop halo bispectrum, where relativistic effects can be degenerate with a primordial non-Gaussian signal. Since the bispectrum couples scales, an accurate prediction of the squeezed limit behavior needs to be both non-linear and relativistic. We then evolve the Lagrangian bias operators in time in comoving gauge, obtaining non-local operators analogous to what is known in the Newtonian limit. Finally, we show how to renormalize the bias expansion at an arbitrary time and find that this is crucial in order to cancel unphysical 1/k 2 divergences in the large-scale power spectrum and bispectrum that could be mistaken for a contamination to the non-Gaussian signal.

We propose to apply a marked point process to automatically delineate filaments of the large-scale structure in redshift catalogues. We illustrate the feasibility of the idea on an example of simulated catalogues, describe the procedure, and characterize the results. We find the distribution of the length of the filaments, and suggest how to use this approach to obtain other statistical characteristics of filamentary networks.

Many statistical methods have been proposed in the last years for analyzing the spatial distribution of galaxies. Very few of them, however, can handle properly the border effects of complex observational sample volumes. In this paper, we first show how to calculate the Minkowski Functionals (MF) taking into account these border effects. Then we present a multiscale extension of the MF which gives us more information about how the galaxies are spatially distributed. A range of examples using Gaussian random fields illustrate the results. Finally we have applied the Multiscale Minkowski Functionals (MMF) to the 2dF Galaxy Redshift Survey data. The MMF clearly indicates an evolution of morphology with scale. We also compare the 2dF real catalog with mock catalogs and found that ΛCDM simulations roughly fit the data, except at the finest scale.

Higher order statistics are a useful and complementary tool for measuring the clustering of galaxies, containing information on the non-Gaussian evolution and morphology of large-scale structure in the Universe. In this work we present measurements of the three-point correlation function (3PCF) for 187 000 galaxies in the WiggleZ spectroscopic galaxy survey. We explore the WiggleZ 3PCF scale and shape dependence at three different epochs z = 0.35, 0.55 and 0.68, the highest redshifts where these measurements have been made to date. Using N-body simulations to predict the clustering of dark matter, we constrain the linear and non-linear bias parameters of WiggleZ galaxies with respect to dark matter, and marginalize over them to obtain constraints on σ 8 (z), the variance of perturbations on a scale of 8 h −1 Mpc and its evolution with redshift. These measurements of σ 8 (z), which have 10-20 per cent accuracies, are consistent with the predictions of the cold dark matter concordance cosmology and test this model in a new way.

We perform a joint determination of the distance-redshift relation and cosmic expansion rate at redshifts z = 0.44, 0.6 and 0.73 by combining measurements of the baryon acoustic peak and Alcock-Paczynski distortion from galaxy clustering in the WiggleZ Dark Energy Survey, using a large ensemble of mock catalogues to calculate the covariance between the measurements. We find that D A (z) = (1205 ± 114, 1380 ± 95, 1534 ± 107) Mpc and H(z) = (82.6 ± 7.8, 87.9 ± 6.1, 97.3 ± 7.0) km s −1 Mpc −1 at these three redshifts. Further combining our results with other baryon acoustic oscillation and distant supernovae datasets, we use a Monte Carlo Markov Chain technique to determine the evolution of the Hubble parameter H(z) as a stepwise function in 9 redshift bins of width ∆z = 0.1, also marginalizing over the spatial curvature. Our measurements of H(z), which have precision better than 7% in most redshift bins, are consistent with the expansion history predicted by a cosmological-constant dark-energy model, in which the expansion rate accelerates at redshift z < 0.7.

The growth history of large-scale structure in the Universe is a powerful probe of the cosmological model, including the nature of dark energy. We study the growth rate of cosmic structure to redshift z = 0.9 using more than 162,000 galaxy redshifts from the WiggleZ Dark Energy Survey. We divide the data into four redshift slices with effective redshifts z = [0.2, 0.4, 0.6, 0.76] and in each of the samples measure and model the 2-point galaxy correlation function in parallel and transverse directions to the lineof-sight. After simultaneously fitting for the galaxy bias factor we recover values for the cosmic growth rate which are consistent with our assumed ΛCDM input cosmological model, with an accuracy of around 20% in each redshift slice. We investigate the sensitivity of our results to the details of the assumed model and the range of physical scales fitted, making close comparison with a set of N-body simulations for calibration. Our measurements are consistent with an independent power-spectrum analysis of a similar dataset, demonstrating that the results are not driven by systematic errors. We determine the pairwise velocity dispersion of the sample in a non-parametric manner, showing that it systematically increases with decreasing redshift, and investigate the Alcock-Paczynski effects of changing the assumed fiducial model on the results. Our techniques should prove useful for current and future galaxy surveys mapping the growth rate of structure using the 2-dimensional correlation function.

A program to calculate the three-particle hyperspherical brackets is presented. Test results are listed and it is seen that the program is well applicable up to very high values of the hypermomentum and orbital momenta. The listed runs show that it is also very fast. Applications of the brackets to calculating interaction matrix elements and constructing hyperspherical bases for identical particles are described. Comparisons are done with the programs published previously.

The spectrum of primordial gravitational waves is one of the most robust inflationary observables, often thought of as a direct probe of the energy scale of inflation. We present a simple model, where the dynamics controlling this observable is very different than in the standard paradigm of inflation. The model is based on a peculiar finite density phase-the magnetic gaugid-which stems from a highly non-linear effective theory of a triplet of abelian gauge fields. The gaugid extends the notion of homogeneous isotropic solid, in that its spectrum of fluctuations includes helicity-2 phonons. We show how, upon implementing the gaugid to drive inflation, the helicity-2 phonon mixes with the graviton, significantly affecting the size of the primordial tensor spectrum. The rest of the features of the theory, in particular the vector and scalar perturbations, closely resemble those of solid inflation.

The Epoch of Reionization (EoR) 21-cm signal is expected to become increasingly non-Gaussian as reionization proceeds. We have used seminumerical simulations to study how this affects the error predictions for the EoR 21-cm power spectrum. We expect SNR = √ N k for a Gaussian random field where N k is the number of Fourier modes in each k bin. We find that non-Gaussianity is important at high SNR where it imposes an upper limit [SNR] l. For a fixed volume V, it is not possible to achieve SNR > [SNR] l even if N k is increased. The value of [SNR] l falls as reionization proceeds, dropping from ∼500 atx H I = 0.8−0.9 to ∼10 atx H I = 0.15 for a [150.08 Mpc] 3 simulation. We show that it is possible to interpret [SNR] l in terms of the trispectrum, and we expect [SNR] l ∝ √ V if the volume is increased. For SNR [SNR] l we find SNR = √ N k /A with A ∼ 0.95-1.75, roughly consistent with the Gaussian prediction. We present a fitting formula for the SNR as a function of N k , with two parameters A and [SNR] l that have to be determined using simulations. Our results are relevant for predicting the sensitivity of different instruments to measure the EoR 21-cm power spectrum, which till date have been largely based on the Gaussian assumption.

We study a cosmological scenario in which the DBI action governing the motion of a D3-brane in a higher-dimensional spacetime is supplemented with an induced gravity term. The latter reduces to the quartic Galileon Lagrangian when the motion of the brane is non-relativistic and we show that it tends to violate the null energy condition and to render cosmological fluctuations ghosts. There nonetheless exists an interesting parameter space in which a stable phase of quasi-exponential expansion can be achieved while the induced gravity leaves non trivial imprints. We derive the exact second-order action governing the dynamics of linear perturbations and we show that it can be simply understood through a bimetric perspective. In the relativistic regime, we also calculate the dominant contribution to the primordial bispectrum and demonstrate that large non-Gaussianities of orthogonal shape can be generated, for the first time in a concrete model. More generally, we find that the sign and the shape of the bispectrum offer powerful diagnostics of the precise strength of the induced gravity.

ZusammenfassungStaatliche Steuerungsimpulse erreichen nur dann die Akteure der Technikgestaltung, wenn sie die Eigenlogik und -dynamik technischer Systeme und Infrastrukturen berücksichtigen. Die bisherigen Ansätze zur politischen Technikgestaltung gingen nicht zuletzt deshalb oft ins Leere, weil sie den technischen Systemen zu wenig Aufmerksamkeit widmeten. In Anlehnung an die soziologischen Systemtheorien von Luhmann und Willke wird der Versuch unternommen, „Technik“ als teilautonomes, soziales Subsystem mit dem spezifischen Code der „technischen Effizienz“ zu rekonstruieren. Im Gegensatz zu Luhmanns Folgerung, daß politische Steuerung von Subsystemen unmöglich sei, wird im folgenden dargelegt, daß die analytische Rekonstruktion technischer Systeme als teilautonome Subsysteme die Voraussetzung erfolgreicher Techniksteuerung darstellt. Dazu bedarf es neben dieser theoretischen Einsicht auch einer genauen Betrachtung der Stuerungsinstrumente. Als Beispiele erfolgreicher Technikgesta...

Galaxies can be "pre-processed" in the low-density outskirts by ambient medium in the filaments or tidal interactions with other galaxies while falling into the cluster. In order to probe how early on and by which mechanisms galaxies can be affected before they enter high-density cluster environments, we are carrying out an atomic hydrogen (H i) imaging study of a sample of galaxies selected from three filamentary structures around the Virgo cluster. Our sample consists of 14 late-type galaxies, which are potentially interacting with their surroundings. The H i observations have been done using the Westerbork Synthesis Radio Telescope, the Giant Metrewave Radio Telescope, and the Jansky Very Large Array with column density sensitivity of ≈ 3-5 × 10 19 cm −2 in 3σ per channel, which is low enough to detect faint H i features in the outer disks of galaxies. In this work, we present the H i data of two galaxies that were observed with GMRT. We examine the H i morphology and kinematics to find the evidence for gas-gas and/or tidal interactions, and discuss which mechanism(s) could be responsible for pre-processing in these cases.

Distance measurement provide no constraints on curvature independent of assumptions about the dark energy, raising the question, how flat is our Universe if we make no such assumptions? Allowing for general evolution of the dark energy equation of state with 20 free parameters that are allowed to cross the phantom divide, w(z) = −1, we show that while it is indeed possible to match the first peak in the Cosmic Microwave Background with non-flat models and arbitrary Hubble constant, H0, the full WMAP7 and supernova data alone imply −0.12 < Ω k < 0.01(2σ). If we add an H0 prior, this tightens significantly to Ω k = 0.002 ± 0.009. These constitute the most conservative and model-independent constraints on curvature available today, and illustrate that the curvaturedynamics degeneracy is broken by current data, with a key role played by the Integrated Sachs Wolfe effect rather than the distance to the surface of last scattering. If one imposes a quintessence prior on the dark energy (−1 ≤ w(z) ≤ 1) then just the WMAP7 and supernova data alone force the Universe to near flatness: Ω k = 0.013 ± 0.012. Finally, allowing for curvature, we find that all datasets are consistent with a Harrison-Zel'dovich spectral index, ns = 1, at 2σ, illustrating the interplay between early and late-universe constraints.

Recent simulations show the Epoch of Reionization (EoR) 21-cm signal to be inherently non-Gaussian whereby the error covariance matrix C ij of the 21-cm power spectrum (PS) contains a trispectrum contribution that would be absent if the signal were Gaussian. Using the binned power spectrum and trispectrum from simulations, here we present a methodology for incorporating these with the baseline distribution and system noise to make error predictions for observations with any radio-interferometric array. Here we consider the upcoming SKA-Low. Non-Gaussianity enhances the errors introducing a positive deviation relative to the Gaussian predictions. increases with observation time t obs and saturates as the errors approach the cosmic variance. Considering t obs = 1024 hours where a 5σ detection is possible at all redshifts 7 ≤ z ≤ 13, in the absence of foregrounds we find that the deviations are important at small k where we have ∼ 40-100 per cent at k ∼ 0.04 Mpc −1 for some of the redshifts and also at intermediate k (∼ 0.4 Mpc −1) where we have ∼ 200 per cent at z = 7. Non-Gaussianity also introduces correlations between the errors in different k bins, and we find both correlations and anticorrelations with the correlation coefficient value spanning −0.4 ≤ r ij ≤ 0.8. Incorporating the foreground wedge, continues to be important (> 50 per cent) at z = 7. We conclude that non-Gaussianity makes a significant contribution to the errors and this is important in the context of the future instruments that aim to achieve high-sensitivity measurements of the EoR 21-cm PS.

In this paper we develop an inverse Bayesian approach to find the value of the unknown model parameter vector that supports the real (or test) data, where the data comprises measurements of a matrix-variate variable. The method is illustrated via the estimation of the unknown Milky Way feature parameter vector, using available test and simulated (training) stellar velocity data matrices. The data is represented as an unknown function of the model parameters, where this high-dimensional function is modelled using a high-dimensional Gaussian Process (GP). The model for this function is trained using available training data and inverted by Bayesian means, to estimate the sought value of the model parameter vector at which the test data is realised. We achieve a closed-form expression for the posterior of the unknown parameter vector and the parameters of the invoked GP, given test and training data. We perform model fitting by comparing the observed data with predictions made at different summaries of the posterior probability of the model parameter vector. As a supplement, we undertake a leave-one-out cross validation of our method.

This chapter provides an overview of semantic issues concerning manner and degree. This includes going over the theoretical questions that arise in the literature on VP modification and event semantics, as well as the research that has been carried out on gradable adjectives, scale structure and vagueness. This introduction further situates the papers and commentaries in this volume within this discussion. We end by outlining commonalities between manner and degree. Keywords Manner • Degree • Modification • Adjective • Adverb • Scale structure • Comparison class • Standard of comparison • Events • Kinds 1 Introduction This chapter provides an overview of semantic issues concerning manner and degree and situates the papers in this volume within this discussion. While manner is commonly associated with adverbial modification in the domain of events expressed by verbs, degrees are associated with gradable categories, most notably adjectives. However, since manner adverbs, more generally, are derived from adjectives, there is a close tie between adverbs expressing a manner of an event, modifying a verbal predicates, and adjectives that modify a nominal predicate. In fact, we will see that in many respects manner and degree can be seen as two sides of the same coin and that B B. Gehrke

We investigate the growth rate of structures in the local Universe. For this, we use as a cosmological tracer the HI line extra-galactic sources from the Arecibo Legacy Fast ALFA (ALFALFA) survey to obtain a measurement of the normalized growth rate parameter, fσ8, considered a powerful tool to constrain alternative models of gravity. For these analyses, we calculate the Local Group velocity due to the matter structures distribution in the ALFALFA catalogue and compare it with the Local Group velocity relative to the Cosmic Microwave Background frame to obtain the velocity scale parameter, β. Using Monte Carlo realizations and lognormal simulations, our methodology quantifies the errors introduced by shot-noise and partial sky coverage of the analysed data. The measurement of the velocity scale parameter β and the calculation of the matter fluctuation of the cosmological tracer, $\sigma _{8}^{\text{tr}}$, lead us to fσ8 = 0.46 ± 0.06 at $\bar{z} = 0.013$, in good agreement (at 1σ le...

It is a Rana-era building mixing Malla architecture with European Palladian (also called neoclassical) style building with a central courtyard system. It suffered damage during 2015 Gorkha earthquake. The block surrounding the northern courtyard was severely damaged, so after the earthquake it was demolished. Significant part of the building that stands is still operational and accommodates critical functions, thus its seismic safety is important. Initially, damage assessment was conducted and damage grade was assigned as per EMS-98 classification. Low strength of mud mortar masonry, heavy weight of the walls and floors, presence of long unsupported walls under flexible diaphragms, high ratio of openings, and absence of earthquake-resistant features are some of the seismic deficiencies of present building. To reduce seismic risk, existing materials were characterized, the present performance of the building was evaluated and deficiencies were identified. Based on the deficiencies, different intervention options were investigated, and finally retrofitting with steel plates and carbon fiber reinforced polymer (CFRP) bands were selected after detailed analysis and design.

Galaxy clusters grow by accreting galaxies from the field and along filaments of the cosmic web. As galaxies are accreted they are affected by their local environment before they enter (pre-processing), and traverse the cluster potential. Observations that aim to constrain pre-processing are challenging to interpret because filaments comprise a heterogeneous range of environments including groups of galaxies embedded within them and backsplash galaxies that contain a record of their previous passage through the cluster. This motivates using modern cosmological simulations to dissect the population of galaxies found in filaments that are feeding clusters, to better understand their history, and aid the interpretation of observations. We use zoom-in simulations from The ThreeHundred project to track haloes through time and identify their environment. We establish a benchmark for galaxies in cluster infall regions that supports the reconstruction of the different modes of pre-processin...

Upcoming wide-field surveys are well suited to studying the growth of galaxy clusters by tracing galaxy and gas accretion along cosmic filaments. We use hydrodynamic simulations of volumes surrounding 324 clusters from The ThreeHundred project to develop a framework for identifying and characterizing these filamentary structures and associating galaxies with them. We define three-dimensional reference filament networks reaching 5R200 based on the underlying gas distribution and quantify their recovery using mock galaxy samples mimicking observations such as those of the WEAVE Wide-Field Cluster Survey. Since massive galaxies trace filaments, they are best recovered by mass-weighting galaxies or imposing a bright limit (e.g. &gt;L*) on their selection. We measure the transverse gas density profile of filaments, derive a characteristic filament radius of ≃ 0.7–1 h−1Mpc, and use this to assign galaxies to filaments. For different filament extraction methods, we find that at R &gt; R200...

This article explores three usual estimators, noted as v 12 of the pairwise velocity, ψ 1 and ψ 2 of the observed two-point galaxy peculiar velocity correlation functions. These estimators are tested on mock samples of Cosmicflows-3 data set (Tully, Courtois & Sorce), derived from a numerical cosmological simulation, and also on a number of constrained realizations of this data set. Observational measurements errors and cosmic variance are taken into consideration in the study. The result is a local measurement of fσ 8 = 0.43(± 0.03) obs (± 0.11) cosmic out to z = 0.05, in support of a CDM cosmology.

Advances in technology easily collect a large amount of data in scientific research such as agricultural screening and micro-array experiments. We are particularly interested in data from one-way and crossed two-way designs that have a large number of treatment combinations but small replications with heteroscedastic variances. In this framework, several test statistics have been proposed in the literature. Even though the form of these proposed test statistics may be different, they all use limiting normal or chi-square distribution to conduct their tests. Such approximation approaches the true distribution very slowly when the sample size n i is small while the number of levels of treatments a gets large. A strategy to obtain better accuracy in the classical large sample size setting is to use the bootstrap procedure with studentized statistic. Unfortunately, the available bootstrap method fails when the number of treatment level combinations is large while the number of replications is small. The Fisher and Hall (1990) asymptotic pivotal statistic under large sample size setting is no longer pivotal under small sample size setting with large number of treatment levels. In the first part of this dissertation, we start with describing suitable bootstrap statistics and procedures for hypothesis tests in one-and two-way ANOVA with a large number of levels and small sample sizes. We prove that the theoretical type I error-rate of Akritas and Papadatos (2004) and Wang and Akritas (2006) test statistics and the corresponding bootstrap versions have accuracy of order O(1/ √ a). We then modify their statistics to obtain asymptotically pivotal statistics in our current framework. We prove that the theoretical type I error-rate of the bootstrap version of the pivotal statistics is accurate up to order O(1/ √ a). In the second part of the dissertation, we propose a new test statistic in one-way ANOVA which is asymptotically pivotal in the current setting. We improve the accuracy of approximation of the distribution of the test statistic by deriving asymptotic expansion of the statistic under the current framework and define a new test rejection region through Cornish-Fisher expansion of quantiles. The type I error-rate of the new test has a faster convergence rate and is accurate up to order O(1/a). Simulation studies show that our tests performs better in terms of type I error-rate but comparable power with that of Akritas and Papadatos (2004) in the large a small n i setting. The connection between our asymptotic expansions and bootstrap distribution in the large a, small n i setting is discussed. Our proposed test based on asymptotic expansion and Cornish-Fisher expansion of quantiles have both the advantage of higher accuracy and computational efficiency due to no resampling is needed.

We present a numerical study of the cosmic density vs. velocity divergence relation (DVDR) in the mildly non-linear regime. We approximate the dark matter as a nonrelativistic pressureless fluid, and solve its equations of motion on a grid fixed in comoving coordinates. Unlike N-body schemes, this method yields directly the volumeaveraged velocity field. The results of our simulations are compared with the predictions of the third-order perturbation theory (3PT) for the DVDR. We investigate both the mean 'forward' relation (density in terms of velocity divergence) and the mean 'inverse' relation (velocity divergence in terms of density), with emphasis on the latter. On scales larger than about 20 megaparsecs, our code recovers the predictions of 3PT remarkably well, significantly better than recent N-body simulations. On scales of a few megaparsecs, the DVDR predicted by 3PT differs slightly from the simulated one. In particular, approximating the inverse DVDR by a third-order polynomial turns out to be a poor fit. We propose a simple analytical description of the inverse relation, which works well for mildly non-linear scales.

We study the spherically averaged bispectrum of the 21-cm signal from the Epoch of Reionization (EoR). This metric provides a quantitative measurement of the level of non-Gaussianity of the signal, which is expected to be high. We focus on the impact of the light-cone (LC) effect on the bispectrum and its detectability with the future SKA-Low telescope. Our investigation is based on a single reionization LC model and an ensemble of 50 realizations of the 21-cm signal to estimate the cosmic variance errors. We calculate the bispectrum with a new, optimized direct estimation method, DviSukta, which calculates the bispectrum for all possible unique triangles. We find that the LC effect becomes important on scales $k_1 \lesssim 0.1\, {\rm Mpc}^{-1}$, where, for most triangle shapes, the cosmic variance errors dominate. Only for the squeezed limit triangles, the impact of the LC effect exceeds the cosmic variance. Combining the effects of system noise and cosmic variance we find that ∼3σ...

This work shows that the CMB polarization E and B modes can be measured in a clean manner in the real space by adopting a specific observing strategy: the detectors are configured to lie around a ring to observe an annulus of sky, where the antenna axis in each detector is oriented in the local radial direction. In particular, for the measurement of the weak B mode, the detector ring can be put in rotation about its axis. This additional degree of freedom allows each detector to directly measure the B-mode signal through long-term exposure to the sky without further data manipulation for removal of the E mode. We present the variances of the expected measured E and B-mode surface-brightness fluctuations as functions of the radius of the sky annulus. Both E and B modes have distinct features that can serve as the indicators for claiming detection. The temperature anisotropy-E mode correlation can also be constructed by the present method, though it is probably not optimized. Subject ...

The Cosmological Principle (CP)-the notion that the Universe is spatially isotropic and homogeneous on large scales-underlies a century of progress in cosmology. It is formulated through the Friedmann-Lemaître-Robertson-Walker (FLRW) cosmologies as the spacetime metric, and culminates in the successful and highly predictive Λ-Cold-Dark-Matter (ΛCDM) model. Yet, tensions have emerged within the ΛCDM model, most notably a statistically significant discrepancy in the value of the Hubble constant, H 0. Since the notion of cosmic expansion determined by a single parameter is intimately tied to the CP, implications of the H 0 tension may extend beyond ΛCDM to the CP itself. This review surveys current observational hints for deviations from the expectations of the CP, highlighting synergies and disagreements that warrant further study. Setting aside the debate about individual large structures, potential deviations from the CP include variations of cosmological parameters on the sky, discrepancies in the cosmic dipoles, and mysterious alignments in quasar polarizations and galaxy spins. While it is possible that a host of observational systematics are impacting results, it is equally plausible that precision cosmology may have outgrown the FLRW paradigm, an extremely pragmatic but non-fundamental symmetry assumption. CONTENTS G. Precision spectroscopy tests of the stability of fundamental couplings 49 H. Summary 52 V. Mysterious alignments 53 A. QSO polarization alignments 54 B. Large Quasar Group alignments 55 C.

The baryon acoustic oscillation (BAO) peak, seen in the cosmic matter distribution at redshifts up to [Formula: see text]3.5, reflects the continued expansion of the sonic horizon first identified in temperature anisotropies of the cosmic microwave background. The BAO peak position can now be measured to better than [Formula: see text]1% accuracy using galaxies and [Formula: see text]1.4–1.6% precision with Ly-[Formula: see text] forests and the clustering of quasars. In conjunction with the Alcock–Paczyński (AP) effect, which arises from the changing ratio of angular to spatial/redshift size of (presumed) spherically-symmetric source distributions with distance, the BAO measurement is viewed as one of the most powerful tools to use in assessing the geometry of the Universe. In this paper, we employ five BAO peak measurements from the final release of the Sloan Digital Sky Survey IV, at average redshifts [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see te...

Virgo is the nearest galaxy cluster; it is thus ideal for studies of galaxy evolution in dense environments in the local universe. It is embedded in a complex filamentary network of galaxies and groups, which represents the skeleton of the large-scale Laniakea supercluster. Here we assemble a comprehensive catalog of galaxies extending up to ∼12 virial radii in projection from Virgo to revisit the cosmic-web structure around it. This work is the foundation of a series of papers that will investigate the multiwavelength properties of galaxies in the cosmic web around Virgo. We match spectroscopically confirmed sources from several databases and surveys including HyperLeda, NASA Sloan Atlas, NASA/IPAC Extragalactic Database, and ALFALFA. The sample consists of ∼7000 galaxies. By exploiting a tomographic approach, we identify 13 filaments, spanning several megaparsecs in length. Long &gt;17 h –1 Mpc filaments, tend to be thin (&lt;1 h –1 Mpc in radius) and with a low-density contrast (...

An analysis of variations in the Hubble parameter (H0) with line-of-sight direction has been done in order to investigate anisotropy in the motion of the galaxies. Depending on the distance range available in the galaxy sample analyzed, H0 measurements can be used as a probe of intrinsic anisotropies at cosmological scales. At shorter scales, deviations from a smooth Hubble expansion flow are expected when galaxies participate in bulk flow motions towards great attractors. Using a galaxy catalogue that spans the distance range between 45 and 500 Mpc, a statistically robust detection of spatial anisotropy of 6.4 ± 1.4 km s-1 Mpc-1 in H0 has been found. Given the limited distance range of the catalogue, this anisotropy could be due to bulk motions.

We present a numerical study of the cosmic density versus velocity divergence relation (DVDR) in the mildly non-linear regime. We approximate the dark matter as a nonrelativistic pressureless fluid, and solve its equations of motion on a grid fixed in comoving coordinates. Unlike N-body schemes, this method yields directly the volume-averaged velocity field. The results of our simulations are compared with the predictions of the thirdorder perturbation theory (3PT) for the DVDR. We investigate both the mean`forward' relation (density in terms of velocity divergence) and the mean`inverse' relation (velocity divergence in terms of density), with emphasis on the latter. On scales larger than about 20 Mpc, our code recovers the predictions of the 3PT remarkably well and significantly better than in recent N-body simulations. On scales of a few Mpc, the DVDR predicted by 3PT differs slightly from the simulated one. In particular, approximating the inverse DVDR by a third-order polynomial turns out to give a poor fit. We propose a simple analytical description of the inverse relation, which works well for mildly non-linear scales.

We have used over 10,000 early-type galaxies from the 6dF Galaxy Survey (6dFGS) to construct the Fundamental Plane across the optical and near-infrared passbands. We demonstrate that a maximum likelihood fit to a multivariate Gaussian model for the distribution of galaxies in size, surface brightness and velocity dispersion can properly account for selection effects, censoring and observational errors, leading to precise and unbiased parameters for the Fundamental Plane and its intrinsic scatter. This method allows an accurate and robust determination of the dependencies of the Fundamental Plane on variations in the stellar populations and environment of early-type galaxies.

The Cosmological Principle (CP)-the notion that the Universe is spatially isotropic and homogeneous on large scales-underlies a century of progress in cosmology. It is formulated through the Friedmann-Lemaître-Robertson-Walker (FLRW) cosmologies as the spacetime metric, and culminates in the successful and highly predictive Λ-Cold-Dark-Matter (ΛCDM) model. Yet, tensions have emerged within the ΛCDM model, most notably a statistically significant discrepancy in the value of the Hubble constant, H 0. Since the notion of cosmic expansion determined by a single parameter is intimately tied to the CP, implications of the H 0 tension may extend beyond ΛCDM to the CP itself. This review surveys current observational hints for deviations from the expectations of the CP, highlighting synergies and disagreements that warrant further study. Setting aside the debate about individual large structures, potential deviations from the CP include variations of cosmological parameters on the sky, discrepancies in the cosmic dipoles, and mysterious alignments in quasar polarizations and galaxy spins. While it is possible that a host of observational systematics are impacting results, it is equally plausible that precision cosmology may have outgrown the FLRW paradigm, an extremely pragmatic but non-fundamental symmetry assumption. CONTENTS G. Precision spectroscopy tests of the stability of fundamental couplings 49 H. Summary 52 V. Mysterious alignments 53 A. QSO polarization alignments 54 B. Large Quasar Group alignments 55 C.

We provide in depth MCMC comparisons of two different models for the halo redshift space power spectrum, namely a variant of the commonly applied Taruya-Nishimichi-Saito (TNS) model and an effective field theory of large scale structure (EFTofLSS) inspired model. Using many simulation realisations and Stage IV survey-like specifications for the covariance matrix, we check each model's range of validity by testing for bias in the recovery of the fiducial growth rate of structure formation. The robustness of the determined range of validity is then tested by performing additional MCMC analyses using higher order multipoles, a larger survey volume and a more highly biased tracer catalogue. We find that under all tests, the TNS model's range of validity remains robust and is found to be much higher than previous estimates. The EFTofLSS model fails to capture the spectra for highly biased tracers as well as becoming biased at lower wavenumbers when considering a very large survey volume. Further, we find that the marginalised constraints on f for all analyses are stronger when using the TNS model.

We attempt to make a direct measurement of the weak lensing signal from the WMAP 7-year data. We apply the real-space implementation of the optimal quadratic estimator on the maps produced by the W-band Differencing Assemblies. We obtain a weak lensing amplitude parameter of A L = 0.99 ± 1.67 after correcting for several sources of bias. The error budget includes a contribution from the bias removal procedure. Despite the demonstrated insensitivity of the realspace estimator to uncorrelated noise, we conclude that this detection is not statistically significant. We expect that a full-sky, higher-sensitivity experiment such as Planck will allow us to make a more significant measurement.

The baryon acoustic oscillation (BAO) peak, seen in the cosmic matter distribution at redshifts up to ∼ 3.5, reflects the continued expansion of the sonic horizon first identified in temperature anisotropies of the cosmic microwave background. The BAO peak position can now be measured to better than ∼ 1% accuracy using galaxies, and ∼ 1.4 − 1.6% precision with Ly-α forrests and the clustering of quasars. In conjunction with the Alcock-Paczyński (AP) effect, which arises from the changing ratio of angular to spatial/redshift size of (presumed) spherically-symmetric source distributions with distance, the BAO measurement is viewed as one of the most powerful tools to use in assessing the geometry of the Universe. In this paper, we employ five BAO peak measurements from the final release of the Sloan Digital Sky Survey IV, at average redshifts z = 0.38, 0.51, 0.70, 1.48 and 2.33, to carry out a direct head-to-head comparison of the standard model, ΛCDM, and one of its principal competitors, known as the R h = ct universe. For completeness, we complement the AP diagnostic with a volume-averaged distance probe that assumes a constant comoving distance scale r d. Both probes are free of uncertain parameters, such as the Hubble constant, and are therefore ideally suited for this kind of model selection. We find that R h = ct is favored by these measurements over the standard model based solely on the AP effect, with a likelihood ∼ 75% versus ∼ 25%, while Planck-ΛCDM is favored over R h = ct based solely on the volumeaveraged distance probe, with a likelihood ∼ 80% versus ∼ 20%. A joint analysis using both probes produces an inconclusive outcome, yielding comparable likelihoods to both models. We are therefore not able to confirm with this work that the BAO data, on their own, support an accelerating Universe.

The search for alternative cosmological models is largely motivated by the growing discordance between the predictions of ΛCDM and the ever improving observations, such as the disparity in the value of H 0 measured at low and high redshifts. One model, in particular, known as the R h = ct universe, has been highly successful in mitigating or removing all of the inconsistencies. In this picture, however, the anisotropies in the cosmic microwave background (CMB) would have emerged at a redshift z ∼ 16, rather than via fluctuations in the recombination zone at z ∼ 1080. We demonstrate here that a CMB created in the early Universe, followed by scattering through a Pop III generated dust screen, cannot yet be ruled out by the current data. Indeed, the Planck measurements provide a hint of a ∼ 2 − 4% frequency dependence in the CMB power spectrum, which would be naturally explained as a variation in the optical depth through the dust, but not a Thomson scattering-dominated recombination environment. Upcoming measurements should be able to easily distinguish between these two scenarios, e.g., via the detection of recombination lines at z ∼ 1080, which would completely eliminate the dust reprocessing idea.