[en] The investigation of the environmental effects on the mechanical and engineering properties of deep-sea sediments was initiated on June 15, 1980. The task is divided into three categories. First, the design and fabrication of a High Temperature Triaxial Compression Device (HITT). Second, an investigation of the mechanical and engineering properties of the deep-sea sediments at temperatures ranging from 277 to 473 degrees kelvin. Third, assist in the development of constitutive relationships and an analytical model which describe the temperature dependent creep deformations of the deep-sea sediments. The environmental conditions under which the soil specimens are to be tested are variations in temperature from 277 to 473 degrees kelvin. The corresponding water pressure will vary up to about 2.75 MPa as required to prevent boiling of the water and assure saturation of the test specimens. Two groups of tests are to be performed. First, triaxial compression tests during which strength measurements and constant head permeability determinations shall be made. Second, constant stress creep tests, during which axial and lateral strains shall be measured. In addition to the aforementioned variables, data shall also be acquired to incorporate the effects of consolidation history, strain rate, and heating rate. The bulk of the triaxial tests are to be performed undrained. The strength measurement tests are to be constant-rate-of-strain and the creep tests are to be constant-stress tests. The study of the mechanical properties of the deep-sea sediments as a function of temperature is an integrated program

[en] Galaxy groups can be characterized by the radius of decoupling from cosmic expansion, the radius of the caustic of second turnaround, and the velocity dispersion of galaxies within this latter radius. These parameters can be a challenge to measure, especially for small groups with few members. In this study, results are gathered pertaining to particularly well-studied groups over four decades in group mass. Scaling relations anticipated from theory are demonstrated and coefficients of the relationships are specified. There is an update of the relationship between light and mass for groups, confirming that groups with mass of a few times 10¹²M_⊙ are the most lit up while groups with more and less mass are darker. It is demonstrated that there is an interesting one-to-one correlation between the number of dwarf satellites in a group and the group mass. There is the suggestion that small variations in the slope of the luminosity function in groups are caused by the degree of depletion of intermediate luminosity systems rather than variations in the number per unit mass of dwarfs. Finally, returning to the characteristic radii of groups, the ratio of first to second turnaround depends on the dark matter and dark energy content of the universe and a crude estimate can be made from the current observations of Ω_matter∼0.15 in a flat topology, with a 68% probability of being less than 0.44.

[en] The consolidation, undrained strength, and creep properties of remolded illite have been investigated in a laboratory testing program. Samples of remolded illite were consolidated, both thermally and mechanically, and then subjected to undrained triaxial compression or constant stress level creep loading at temperatures of 4, 21.5, 40, 100, and 200⁰C. The material properties which are required to predict the volumetric and deviatoric strain induced by changes in the stress state or thermal field of the sample have been determined. Theoretical and empirical relationships have been developed to calculate the temperature dependent material properties

[en] A study of the group properties of galaxies in our immediate neighborhood provides a singular opportunity to observationally constrain the halo mass function, a fundamental characterization of galaxy formation. Detailed studies of individual groups have provided the coefficients of scaling relations between a proxy for the virial radius, velocity dispersion, and mass that usefully allow groups to be defined over the range ${10}^{10}\text{--}{10}^{15}$ M _⊙. At a second hierarchical level, associations are defined as regions around collapsed halos extending to the zero-velocity surface at the decoupling from cosmic expansion. The most remarkable result of the study emerges from the construction of the halo mass function from the sample. At ∼10¹² M _⊙, there is a jog from the expectation Sheth-Tormen function, such that halo counts drop by a factor ∼3 in all lower mass bins.

[en] A galaxy group catalog is built from the sample of the 2MASS Redshift Survey almost complete to K_s = 11.75 over 91% of the sky. Constraints in the construction of the groups were provided by scaling relations determined by close examination of well defined groups with masses between 10¹¹ and ${10}^{15}{M}_{\odot <!--\; ???\; -->}$. Group masses inferred from K_s luminosities are statistically in agreement with masses calculated from application of the virial theorem. While groups have been identified over the full redshift range of the sample, the properties of the nearest and farthest groups are uncertain and subsequent analysis has only considered groups with velocities between 3000 and 10,000 km s⁻¹. The 24,044 galaxies in this range are identified with 13,607 entities, 3461 of them with two or more members. A group mass function is constructed. The Sheth–Tormen formalism provides a good fit to the shape of the mass function for group masses above $6h^{-<!--\; ???\; -->1}\times <!--\; ??\; -->{10}^{12}{M}_{\odot <!--\; ???\; -->}$ but the count normalization is poor. Summing all the mass associated with the galaxy groups between 3000 and 10,000 km s⁻¹ gives a density of collapsed matter as a fraction of the critical density of ${\mathrm{\Omega <!--\; ??\; -->}}_{\mathrm{c}\mathrm{o}\mathrm{l}\mathrm{l}\mathrm{a}\mathrm{p}\mathrm{s}\mathrm{e}\mathrm{d}}=0.16$.

[en] In order to measure distances with minimal systematics using the correlation between galaxy luminosities and rotation rates it is necessary to adhere to a strict and tested recipe. We now derive a measure of rotation from a new characterization of the width of a neutral hydrogen line profile. Additionally, new photometry and zero-point calibration data are available. Particularly the introduction of a new linewidth parameter necessitates the reconstruction and absolute calibration of the luminosity-linewidth template. The slope of the new template is set by 267 galaxies in 13 clusters. The zero point is set by 36 galaxies with Cepheid or tip of the red giant branch distances. Tentatively, we determine H₀ ∼ 75 km s^–1 Mpc^–1. Distances determined using the luminosity-linewidth calibration will contribute to the distance compendium Cosmicflows-2.

[en] The Magellanic Stream (MS) might have grown out of tidal interactions at high redshift, when the young galaxies were close together, rather than from later interactions among the Magellanic Clouds and Milky Way (MW). This is illustrated in solutions for the orbits of Local Group (LG) galaxies under the cosmological condition of growing peculiar velocities at high redshift. Massless test particles initially near and moving with the Large Magellanic Cloud in these solutions end up with distributions in angular position and redshift similar to the MS, though with the usual overly prominent leading component that the MW corona might have suppressed. Another possible example of the effect of conditions at high redshift is a model primeval stream around the LG galaxy NGC 6822. Depending on the solution for LG dynamics, this primeval stream can end up with a position angle similar to the H I around this galaxy and a redshift gradient in the observed direction. The gradient is much smaller than observed but might have been increased by dissipative contraction. Presented also is an even more speculative illustration of the possible effect of initial conditions, primeval stellar streams around M31.

[en] The construction of the Cosmicflows-2 compendium of distances involves the merging of distance measures contributed by the following methods: (Cepheid) period-luminosity, tip of the red giant branch (TRGB), surface brightness fluctuation (SBF), luminosity-linewidth (TF), fundamental plane (FP), and Type Ia supernova (SNIa). The method involving SNIa is at the top of an interconnected ladder, providing accurate distances to well beyond the expected range of distortions to Hubble flow from peculiar motions. In this paper, the SNIa scale is anchored by 36 TF spirals with Cepheid or TRGB distances, 56 SNIa hosts with TF distances, and 61 groups or clusters hosting SNIa with Cepheid, SBF, TF, or FP distances. With the SNIa scale zero-point set, a value of the Hubble constant is evaluated over a range of redshifts 0.03 < z < 0.5, assuming a cosmological model with Ω_m = 0.27 and Ω_Λ = 0.73. The value determined for the Hubble constant is H₀ = 75.9 ± 3.8 km s^–1 Mpc^–1.

[en] We generate the peculiar velocity field for the Two Micron All-Sky Redshift Survey (2MRS) catalog using an orbit-reconstruction algorithm. The reconstructed velocities of individual objects in 2MRS are well correlated with the peculiar velocities obtained from high-precision observed distances within 3000 km s^-1. We estimate the mean matter density to be Ω_m = 0.31 ± 0.05 by comparing observed to reconstructed velocities in this volume. The reconstructed motion of the Local Group in the rest frame established by distances within 3000 km s^-1 agrees with the observed motion and is generated by fluctuations within this volume, in agreement with observations. Having tested our method against observed distances, we reconstruct the velocity field of 2MRS in successively larger radii, to study the problem of convergence toward the cosmic microwave background (CMB) dipole. We find that less than half of the amplitude of the CMB dipole is generated within a volume enclosing the Hydra-Centaurus-Norma supercluster at around 40 h ^-1 Mpc. Although most of the amplitude of the CMB dipole seems to be recovered by 120 h ^-1 Mpc, the direction does not agree and hence we observe no convergence up to this scale. Due to dominant superclusters such as Shapley or Horologium-Reticulum in the southern hemisphere at scales above 120 h ^-1 Mpc, one might need to go well beyond 200 h ^-1 Mpc to fully recover the dipole vector. We develop a statistical model which allows us to estimate cosmological parameters from the reconstructed growth of convergence of the velocity of the Local Group toward the CMB dipole motion. For scales up to 60 h ^-1 Mpc, assuming a Local Group velocity of 627 km s^-1, we estimate Ω_m h ² = 0.11 ± 0.06 and σ₈ = 0.9 ± 0.4, in agreement with WMAP5 measurements at the 1σ level. However, for scales up to 100 h ^-1 Mpc, we obtain Ω_m h ² = 0.08 ± 0.03 and σ₈ = 1.0 ± 0.4, which agrees at the 1σ to 2σ level with WMAP5 results.

[en] We study the effect of surface brightness on the mass–metallicity relation using nearby galaxies whose gas content and metallicity profiles are available. Previous studies using fiber spectra indicated that lower surface brightness galaxies have systematically lower metallicities for their stellar mass, but the results were uncertain because of aperture effects. With stellar masses and surface brightnesses measured at Wide-field Infrared Explorer W1 and W2 bands, we re-investigate the surface brightness dependence with spatially resolved metallicity profiles and find similar results. We further demonstrate that the systematical difference cannot be explained by the gas content of galaxies. For two galaxies with similar stellar and gas masses, the one with lower surface brightness tends to have a lower metallicity. Using chemical evolution models, we investigate the inflow and outflow properties of galaxies of different masses and surface brightnesses. We find that, on average, high mass galaxies have lower inflow and outflow rates relative to the star formation rate. On the other hand, galaxies with a lower surface brightness experience stronger inflow than galaxies with a higher surface brightness of a similar mass. The surface brightness effect is more significant for low-mass galaxies. We discuss implications on the different inflow properties between low and high surface brightness galaxies, including star formation efficiency, environment, and mass assembly history