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In this thesis we study several dynamical processes involving black holes in four and higher dimensions. First, using perturbative techniques, we compare the massless and massive scalar radiation emitted by a particle radially infalling into a Schwarzchild black hole. We show that the late-time waveform of massive scalar perturbations is dominated by a universal oscillatory decaying tail, which appears due to curvature effects. We also show that the energy spectrum is in perfect agreement with a ZFL calculation once no-hair properties of black holes are taken into account. In the second part, we study the phenomenon of superradiance in higher dimensions and conjecture that the maximum energy extracted from a rotating black hole can be understood in terms of the ergoregion proper volume. We then study some consequences of superradiance in the dynamics of moons orbiting around higher-dimensional rotating black holes. In four-dimensional spacetime, moons around black holes generate low-amplitude tides, and the energy extracted from the hole's rotation is always smaller than the gravitational radiation lost to infinity. We show that in dimensions larger than five the energy extracted from the black hole through superradiance is larger than the energy carried out to infinity. Our results lend strong support to the conjecture that tidal acceleration is the rule, rather than the exception, in higher dimensions. Superradiance dominates the energy budget and moons "outspiral"; for some particular orbital frequency, the energy extracted at the horizon equals the energy emitted to infinity and "floating orbits" generically occur. We give an interpretation of this phenomenon in terms of the membrane paradigm and of tidal acceleration due to energy dissipation across the horizon.

This article is from PLoS ONE , volume 9 . Abstract Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry to investigate temporal variations in trace elements in soil profiles of the three salt marshes, assess the enrichment levels and ecological risks of these trace elements in three sampling seasons and identify their influencing factors. Trace elements did not change significantly along soil profiles at each site in each sampling season. The highest value for each sampling site was observed in summer and the lowest one in fall. Soils in both P. australis and S. salsa wetlands tended to have higher trace element levels than those in T. chinensis wetland. Compared to other elements, both Cd and As had higher enrichment factors exceeding moderate enrichment levels. However, the toxic unit (TU) values of these trace elements did not exceed probable effect levels. Correlation analysis showed that these trace elements were closely linked to soil properties such as moisture, sulfur, salinity, soil organic matter, soil texture and pH values. Principal component analysis showed that the sampling season affected by the flow-sediment regulation regime was the dominant factor influencing the distribution patterns of these trace elements in soils, and plant community type was another important factor. The findings of this study could contribute to wetland conservation and management in coastal regions affected by the hydrological engineering.

Coastal currents and water column stratification frequently are determined by local phenomena that interact to produce complex dynamics. A process study was designed to assess the role of tides over a coastal shelf break as a local source of internal waves spatially-inhomogeneous, baroclinic residual currents, and internal mixing. The temporal evolution of three dimensional stratification and currents were characterized within a 4Kmx4Km box close to the mouth of Monterey Canyon, California. Strong, baroclinic, unidirectional, spatially inhomogeneous jet-like currents were observed with 24 hour periods, together with the occurrence of semidiurnal thermocline oscillations and vertically mixed layers. The linear theory of Baines predicts the existence of significant tidally forced internal waves in the area, with an interfacial mode at the thermocline decoupled from the internal waves propagating in the weaker stratification below. A ray tracing method is developed to study the nonlinear propagation of these tidally forced internal waves by considering wave advection and straining by the topographically controlled barotropic tidal flow while neglecting internal wave-wave interactions. It is found that nonlinear interaction of tidally forced internal waves with the topographically controlled barotropic tidal flow is a mechanism capable of forcing residual currents and internal wave shear instabilities that are capable of creating internal mixed layers similar to those observed at the mouth of Monterey Canyon.

The disruption of a star by the tidal field of a massive black hole is the final outcome of a chain of complex dynamical processes in the host galaxy. I introduce the "loss cone problem", and describe the many theoretical and numerical challenges on the path of solving it. I review various dynamical channels by which stars can be supplied to a massive black hole, and the relevant dynamical relaxation / randomization mechanisms. I briefly mention some "exotic" tidal disruption scenarios, and conclude by discussing some new dynamical results that are changing our understanding of dynamics near a massive black hole, and may well be relevant for tidal disruption dynamics.

Earth System Models predict climate extremes that will impact regional and global hydrology. Aquatic-terrestrial transition zones like wetlands are subjected to the immediate consequence of climate change with shifts in the magnitude and dynamics of hydrologic flow. Such fluctuating hydrology can alter the nature and rate of biogeochemical transformations and significantly impact the carbon balance of the ecosystem. We tested the impacts of fluctuating hydrology and, specifically, the role of antecedent moisture conditions in determining the dominant carbon loss mechanisms in soils sampled from a tidal freshwater wetland system in the lower Columbia River, WA, USA. Our objective was to understand shifts in biogeochemical processes in response to changing soil moisture, based on soil respiration and methane production rates, and to elucidate such responses based on the observed electron acceptor and metabolite profiles under laboratory conditions. Metabolomics and biogeochemical process rates provided evidence that soil redox was the principal factor driving metabolic function. Fluctuating redox conditions altered terminal electron acceptor and donor availability and recovery strengths of their concentrations in soil such that a disproportionate release of carbon dioxide stemmed from alternative anaerobic degradation processes like sulfate and iron reduction compared to carbon loss due to methanogenesis. Our results show that extended and short-term saturation created conditions conducive to increasing metabolite availability for anaerobic decomposition processes, with a significant lag in methanogenesis. In contrast, extended drying caused a cellular-level stress response and rapid recycling of alternate electron acceptors.

In a previous paper, we developed tools for studying the horizon geometry of a Kerr black hole that is tidally distorted by a binary companion using techniques that require large mass ratios but can be applied to any bound orbit and allow for arbitrary black hole spin. We now apply these tools to generic Kerr black hole orbits. This allows us to investigate horizon dynamics: the tidal field perturbing the horizon's geometry varies over a generic orbit, with significant variations for eccentric orbits. Many of the features of the horizon's behavior found previously carry over to the dynamical case in a natural way. In particular, we find significant offsets between the applied tide and the horizon's response. This leads to bulging in the horizon's geometry which can lag or lead the orbit, depending upon the hole's rotation and the orbit's geometry. An interesting and apparently new feature we find are small-amplitude, high-frequency oscillations in the horizon's response. We have not been able to identify a mechanism for producing these oscillations, but find that they appear most clearly when rapidly rotating black holes are distorted by very strong-field orbits.

Approximate analytic evaluation of tidal waves

We point out novel consequences of general relativity involving tidal dynamics of ultrarelativistic relative motion. Specifically, we use the generalized Jacobi equation and its extension to study the force-free dynamics of relativistic flows near a massive rotating source. We show that along the rotation axis of the gravitational source, relativistic tidal effects strongly decelerate an initially ultrarelativistic flow with respect to the ambient medium, contrary to Newtonian expectations. Moreover, an initially ultrarelativistic flow perpendicular to the axis of rotation is strongly accelerated by the relativistic tidal forces. The astrophysical implications of these results for jets and ultrahigh energy cosmic rays are briefly mentioned.

This final report summarizes the results of field investigations along the German North Sea coast performed through support from the Office of Naval Research during the summers of 1978 and 1979. The investigated coastline, the East Friesian Islands, is composed of a series of barrier islands separated by large and deep tidal inlets. The wave energy is high (compared to the barrier island coastline of the eastern United States) and the tide range is about 2.5 meters. Tidal inlets represent perhaps the most dynamic of all coastal and shallow marine environments. To the navigator this implies continuously shifting channels and shoals, and to the beach developer or property owner it implies great uncertainty about future shoreline positions. To the geologists the tidal inlets represent major sediment sinks in the littoral transport system, sinks which may account for a significant percentage of the sandy components of shallow marine facies in the rock record. Investigation of sediment dynamics in the East Friesian inlets was undertaken with the objective of understanding the pattern of sediment bypassing of the inlet from updrift to downdrift shores. Only if this could be determined in detail would it be possible to predict, with adequate precision, the migration of navigation channels, the patterns of erosion and depositon on adjacent shores and the sedimentary facies of the inlet fill itself.

During 1992 and 1993 experiments were conducted in the shallow east side of Great Bay, New Hampshire. These experiments were conducted to better understand the morphodynamics and evolutionary tendencies of shallow tidal embayments and intertidal flats. Hardware and software used in the collection of data are described. Discussed also are techniques used to collect data. Six pressure temperature loggers (PTL) and one current meter (TCSWG) were developed for the experiments. Both instruments are internally powered an internally recording. The instruments were developed because no company was found that manufactured a similar instrument within the price range of the project.

It has been suggested that the 170 day period in the light curve of the low mass X-ray binary 4U 1820-30 arises from the presence of a third body with a large inclination to the binary orbit. We show that this long period motion arises if the system is librating around the stable fixed point in a Kozai resonance. We demonstrate that mass transfer drives the system toward this fixed point, and calculate, both analytically and via numerical integrations, that the period of libration is of order 170 days when the mutual inclination is near the Kozai critical value. The non-zero eccentricity of the binary, combined with tidal dissipation, implies that the rate of change of the binary period would be slower than, or even of opposite sign to, that implied by standard mass transfer models. If the 170 day period results from libration, then, contrary to appearances, the orbital period of the inner binary is increasing with time; in that case, (e/0.009)^2Q/k_2 > 2.5 x 10^9, where k_2 = 0.01 is the tidal Love number and e = 0.009 is the fiducial eccentricity of the inner binary. It appears unlikely that the observed negative period derivative results from the smaller than expected (but positive) value of \dot P combined with the previously suggested acceleration of the system in the gravitational field of the host globular cluster NGC 6624. The discrepancy between the observed and expected period derivative requires further investigation.

Objectives are: 1) To determine the feedbacks between waves, tidal fluxes and tidal channels in muddy coastlines 2) To link the geotechnical properties of sediment substrates to the spatial and hydrodynamic characteristics of tidal channels 3) To develop new morphological indicators of tidal flat morphodynamics that can be easily derived from remote sensing images. To link these indicators to mechanical properties of tidal flat substrates 4) To compare the results of the MURI project Mechanisms of Fluid Mud Interactions under Waves to wave measurements at the shoreline. 5) To integrate high resolution hydrodynamic measurements within ongoing research activities at the Willapa Bay Tidal Flats DRI location.

In our current interpretation of the hierarchical structure of the universe it is well established that galaxies collide and merge with each other during their lifetime. If massive black holes (MBHs) reside in galactic centres, we expect them to form binaries in galactic nuclei surrounded by a circumbinary disc. If cooling is efficient enough, the gas in the disc will clump and trigger stellar formation in situ. In this first paper we address the evolution of the binary under the influence of the newly formed stars, which form individually and also clustered. We use SPH techniques to evolve the gas in the circumbinary disc and to study the phase of star formation. When the amount of gas in the disc is negligible, we further evolve the system with a high-accurate direct-summation $N-$body code to follow the evolution of the stars, the innermost binary and tidal disruption events (TDEs). For this, we modify the direct N-body code to (i) include treatment of TDEs and to (ii) include "gas cloud particles" that mimic the gas, so that the stellar clusters do not disolve when we follow their infall on to the MBHs. We find that the amount of stars disrupted by either infalling stellar clusters or individual stars is as large as 10^{-4}/yr per binary, higher than expected for typical galaxies.

Tidal interactions between disc galaxies depend on galaxy structure, but the details of this relationship are incompletely understood. I have constructed a three-parameter grid of bulge/disc/halo models broadly consistent with $\Lambda$CDM, and simulated an extensive series of encounters using these models. Halo mass and extent strongly influence the dynamics of orbit evolution. In close encounters, the transfer of angular momentum mediated by the dynamical response of massive, extended haloes can reverse the direction of orbital motion of the central galaxies after their first passage. Tidal response is strongly correlated with the ratio $v_\mathrm{e} / v_\mathrm{c}$ of escape to circular velocity within the participating discs. Moreover, the same ratio also correlates with the rate at which tidal tails are reaccreted by their galaxies of origin; consequently, merger remnants with `twin tails', such as NGC 7252, may prove hard to reproduce unless $(v_\mathrm{e} / v_\mathrm{c})^2 \lesssim 5.5$. The tidal morphology of an interacting system can provide useful constraints on progenitor structure. In particular, encounters in which halo dynamics reverses orbital motion exhibit a distinctive morphology which may be recognized observationally. Detailed models attempting to reproduce observations of interacting galaxies should explore the likely range of progenitor structures along with other encounter parameters.

- To quantify the relationships between resuspension of fine material in the shelf by wind waves, tidal channels hydrodynamics, and sediment supply to coastal marshes. - To develop predictive, high-resolution models for the hydrodynamics and sediment dynamics of tidal channels in muddy coastal environments - To develop methods to predict the long-term evolution of tidal channels in muddy coastlines as a function of sediment availability, hydrodynamics, and climate change. OBJECTIVES To determine the feedbacks between waves, tidal fluxes and tidal channels in muddy coastlines To link the geotechnical properties of sediment substrates to the spatial and hydrodynamic characteristics of tidal channels To develop new morphological indicators of tidal flat morphodynamics that can be easily derived from remote sensing images. To link these indicators to mechanical properties of tidal flat substrates To compare the results of the MURI project Mechanisms of Fluid Mud Interactions under Waves to wave measurements at the shoreline. To integrate high resolution hydrodynamic measurements within ongoing research activities at the Willapa Bay Tidal Flats DRI location.

Two papers on tidal dissipation were completed and published. The first of these extended our earlier work, which focused on the dominant M2 constituent, to include 7 additional constituents. In addition to confirming a total deep water dissipation total very close to 1 TW, this study demonstrated significant differences in the distribution of dissipation between diurnal and semi-diurnal constituents. The second paper involved an extensive modeling study of tides in the present day and the last glacial maximum. In this study we showed that accuracy of tidal solutions for the present day Ocean were significantly improved by including a parameterization of internal tide drag over rough topography in the deep ocean. It was also demonstrated that a complete self-consistent treatment of Ocean self attraction and tidal loading was required for accurate solutions.

The specific scientific objectives of this study, to be carried out in collaboration with the Tidal Flat investigators, are: a) To describe the geomorphologic changes using historical satellite imagery. b) To improve our understanding of the dynamics of tidal flats during various phases of the tidal cycle using satellite SAR image data. c) Support the on-going experimental measurement phases with new satellite data acquisitions. d) To determine how SAR signatures can be related to the sedimentary and geotechnical properties of the tidal flat. e) To generate high resolution wind maps for improved understanding of the wind forcing variability and turbulence over tidal flats. f) To provide spatial snapshots of the dynamics during the flooding and ebbing stages governing tidal flats. g) Radar imaging of the wave field and translation of the images into snapshots of ?elevation maps of the surface using both satellite and ship or floating platform based sensors. h) Measurements of the wave field and the atmosphere above the wave field using ASIS buoys to generate data sets that could be compared to wave models and radar both in the spectral and phase-resolved domains, and leads to a better understanding how the wind profile, fluxes, coefficient of drag vary with respect to differing wind and wave conditions. i) Measurements of breaking using acoustic and microwave means as well as in-situ sensors locally.

White dwarfs (WDs) can be tidally disrupted only by massive black holes (MBHs) with masses less than $\sim10^5 M_\odot$. These tidal interactions feed material to the MBH well above its Eddington limit, with the potential to launch a relativistic jet. The corresponding beamed emission is a promising signpost to an otherwise quiescent MBH of relatively low mass. We show that the mass transfer history, and thus the lightcurve, are quite different when the disruptive orbit is parabolic, eccentric, or circular. The mass lost each orbit exponentiates in the eccentric-orbit case leading to the destruction of the WD after several tens of orbits. We examine the stellar dynamics of clusters surrounding MBHs to show that single-passage WD disruptions are substantially more common than repeating encounters. The $10^{49}$ erg s$^{-1}$ peak luminosity of these events makes them visible to cosmological distances. They may be detectible at rates of as many as tens per year by instruments like Swift. In fact, WD-disruption transients significantly outshine their main-sequence star counterparts, and are the most likely tidal interaction to be detected arising from MBHs with masses less than $10^5 M_\odot$. The detection or non-detection of such WD-disruption transients by Swift is, therefore, a powerful tool to constrain lower end of the MBH mass function. The emerging class of ultra-long gamma ray bursts all have peak luminosities and durations reminiscent of WD disruptions, offering a hint that WD-disruption transients may already be present in existing datasets.

Tidal dwarf galaxies (TDGs) are recycled objects that form within the collisional debris of interacting/merging galaxies. They are expected to be devoid of non-baryonic dark matter, since they can form only from dissipative material ejected from the discs of the progenitor galaxies. We investigate the gas dynamics in a sample of six bona-fide TDGs around three interacting and post-interacting systems: NGC 4694, NGC 5291, and NGC 7252 ("Atoms for Peace"). For NGC 4694 and NGC 5291 we analyse existing HI data from the Very Large Array (VLA), while for NGC 7252 we present new HI observations from the Jansky VLA together with long-slit and integral-field optical spectroscopy. For all six TDGs, the HI emission can be described by rotating disc models. These HI discs, however, have undergone less than a full rotation since the time of the interaction/merger event, raising the question of whether they are in dynamical equilibrium. Assuming that these discs are in equilibrium, the inferred dynamical masses are consistent with the observed baryonic masses, implying that TDGs are devoid of dark matter. This puts constraints on putative "dark discs" (either baryonic or non-baryonic) in the progenitor galaxies. Moreover, TDGs seem to systematically deviate from the baryonic Tully-Fisher relation. These results provide a challenging test for alternative theories like MOND.

Coastal currents and water column stratification frequently are determined by local phenomena that interact to produce complex dynamics. A process study was designed to assess the role of tides over a coastal shelf break as a local source of internal waves spatially-inhomogeneous, baroclinic residual currents, and internal mixing. The temporal evolution of three dimensional stratification and currents were characterized within a 4km x 4km box close to the mouth of Monterey Canyon, California. Strong, baroclinic, unidirectional, spatially inhomogeneous jet-like currents were observed with 24 hour periods, together with the occurrence of semidiurnal thermocline oscillations and vertically mixed layers. The linear theory of Baines (1982) predicts the existence of significant tidally forced internal waves in the area, with an interfacial mode at the thermocline decoupled from the internal waves propagating in the weaker stratification below. A ray tracing method is developed to study the nonlinear propagation of these tidally forced internal waves by considering wave advection and straining by the topographically controlled barotropic tidal flow while neglecting internal wave-wave interactions. It is found that nonlinear interaction of tidally forced internal waves with the topographically controlled barotropic tidal flow is mechanism capable of forcing residual currents and internal wave shear instabilities that are capable of creating internal mixed layers similar to those observed at the mouth of Monterey Canyon.

xiii, 328 p. : 19 cm

Research performed under this AFOSR contract targeted anticipated neutral atmosphere influences on the seeding, character, and statistics of equatorial plasma bubbles (EPBs). We employed several approaches, including 1) a large measurement program in Brazil, 2) analyses of correlative satellite data, and 3) numerical modeling of gravity wave dynamics that we expect to have significant influences on plasma dynamics in the ionosphere. Our SpreadFEx-2 field program focused on the onset of the EPB season, October to December of 2009, 2010, and 2011 and employed much enhanced instrumentation compared to our 2005 SpreadFEx measurements. Enhancements included 1) FPIs measuring F-layer winds in Brazil, 2) 6300 imagers enabling tomography of EPB structures, and 3) CERTO beacon receivers for correlative studies with the C/NOFS satellite. The FPIs and imagers demonstrated the relative motions between neutral winds and EPBs to be a function of time and likely altitude. CHAMP data revealed the nature of the migrating tides at 400 km. their variations with season and the solar cycle, and the seasonal variations in gravity wave responses at 300 km during 2010. Numerical studies of gravity waves addressed instability dynamics and penetration from specific sources that we expect to be especially important in the ionosphere.

In interacting galaxies, strong tidal forces disturb the global morphology of the progenitors and give birth to the long stellar, gaseous and dusty tails often observed. In addition to this destructive effect, tidal forces can morph into a transient, protective setting called compressive mode. Such modes then shelter the matter in their midst by increasing its gravitational binding energy. This thesis focuses on the study of this poorly known regime by quantifying its properties thanks to numerical and analytical tools applied to a spectacular merging system of two galaxies, commonly known as the Antennae galaxies. N-body simulations of this pair yield compressive modes in the regions where observations reveal a burst of star formation. Furthermore, characteristic time- and energy scales of these modes match well those of self-gravitating substructures such as star clusters and tidal dwarf galaxies. These results suggest that the compressive modes of tidal fields plays an important role in the formation and evolution of young clusters, at least in a statistical sense, over a lapse of ~10 million years. Preliminary results from simulations of stellar associations highlight the importance of embedding the clusters in the evolving background galaxies to account precisely for their morphology and internal evolution.

We develop a description of tidal effects in astrophysical systems using effective field theory techniques. While our approach is equally capable of describing objects in the Newtonian regime (e.g. moons, rocky planets, main sequence stars, etc.) as well as relativistic objects (e.g. neutron stars and black holes), in this paper we focus special attention on the Newtonian regime. In this limit, we recover the dynamical equations for the "weak friction model" with additional corrections due to tidal and rotational deformations.

[Abridged] We consider the dynamics of a system of hot super-Earths or Neptunes such as HD 40307. We show that, as tidal interaction with the central star leads to small eccentricities, the planets in this system could be undergoing resonant coupling even though the period ratios depart significantly from very precise commensurability. In a three planet system, this is indicated by the fact that resonant angles librate or are associated with long term changes to the orbital elements. We propose that the planets in HD 40307 were in a strict Laplace resonance while they migrated through the disc. After entering the disc inner cavity, tidal interaction would cause the period ratios to increase from two but with the inner pair deviating less than the outer pair, counter to what occurs in HD 40307. However, the relationship between these pairs that occurs in HD 40307 might be produced if the resonance is impulsively modified by an event like a close encounter shortly after the planetary system decouples from the disc. We find this to be in principle possible for a small relative perturbation on the order of a few 1.d-3 but then we find that evolution to the present system in a reasonable time is possible only if the masses are significantly larger than the minimum masses and tidal dissipation is very effective. On the other hand we found that a system like HD 40307 with minimum masses and more realistic tidal dissipation could be produced if the eccentricity of the outermost planet was impulsively increased to about 0.15. The form of resonantly coupled tidal evolution we consider here is quite general and could be of greater significance for systems with inner planets on significantly shorter orbital periods characteristic of for example CoRoT 7 b.

We study the relative motion of nearby free test particles in cosmological spacetimes, such as the FLRW and LTB models. In particular, the influence of spatial inhomogeneities on local tidal accelerations is investigated. The implications of our results for the dynamics of the solar system are briefly discussed. That is, on the basis of the models studied in this paper, we estimate the tidal influence of the cosmic gravitational field on the orbit of the Earth around the Sun and show that the corresponding temporal rate of variation of the astronomical unit is negligibly small.

Our long terms goals are to understand sediment transport processes, the relevant physical forcing processes and the resulting morphologic evolution of river mouths and tidal inlets and shoals. Specific goals include understanding bedform characteristics (ripple to sandwave and sandbar scale) in relation to wave- and current-forced mean and turbulent flow. Objectives: 1. Quantify morphological change associated with storms and tidal forcing, and quantify the physical mechanisms causing the change (i.e., the specific wave-current-bathymetry interactions leading to divergence of sediment transport). 2. Measure the currents, sediment-transport processes and bedform evolution in the bottom boundary layer in the energetic ebb-tidal shoals, where nonlinear interactions between waves and tidal currents are critically important to the sediment transport and the morphological response to changing forcing conditions. 3. Develop instrumentation to make essential measurements for objectives 1 and 2. This includes a surface running REMUS-100 with a carrier phase GPS antenna that will remain exposed, and a multi-beam system for bathymetric surveys. Our Dopplers profilers are also in the process of being upgraded to bistatic convergent beam sampling for better resolution of near bed turbulence

Fermi coordinates are directly constructed in de Sitter and Goedel spacetimes and the corresponding exact coordinate transformations are given explicitly. The quasi-inertial Fermi coordinates are then employed to discuss the dynamics of a free test particle in these spacetimes and the results are compared to the corresponding generalized Jacobi equations that contain only the lowest-order tidal terms. The domain of validity of the generalized Jacobi equation is thus examined in these cases. Furthermore, the difficulty of constructing explicit Fermi coordinates in black-hole spacetimes is demonstrated.

(Abbreviated) We investigate the dynamical mechanisms responsible for producing tidal tails from dwarf satellites using N-body simulations. We identify two important dynamical co-conspirators: 1) the points where the attractive force of the host halo and satellite are balanced do not occur at equal distances from the satellite centre or at the same equipotential value for massive satellites, breaking the morphological symmetry of the leading and trailing tails; and 2) the escaped ejecta in the leading (trailing) tail continues to be decelerated (accelerated) by the satellite's gravity leading to large offsets of the ejecta orbits from the satellite orbit. The effect of the satellite's self gravity decreases only weakly with a decreasing ratio of satellite mass to host halo mass, demonstrating the importance of these effects over a wide range of subhalo masses. Not only will the morphology of the leading and trailing tails for massive satellites be different, but the observed radial velocities of the tails will be displaced from that of the satellite orbit; both the displacement and the peak radial velocity is proportional to satellite mass. If the tails are assumed to follow the progenitor satellite orbits, the tails from satellites with masses greater than 0.0001 of the host halo virial mass in a spherical halo will appear to indicate a flattened halo. Therefore, a constraint on the Milky Way halo shape using tidal streams requires mass-dependent modelling. Similarly, we compute the the distribution of tail orbits both in E_{r}-r^{-2} space and in E-L_{z} space, advocated for identifying satellite stream relics. The acceleration of ejecta by a massive satellite during escape spreads the velocity distribution and obscures the signature of a well-defined ``moving group'' in phase space.

We present a brief history of Galactic astrophysics, and explain the origin of halo substructure in the Galaxy. We motivate our study of tidal streams by highlighting the tight constraints that analysis of the trajectories of tidal streams can place on the form of the Galactic potential. We address the reconstruction of orbits from observations of tidal streams. We upgrade the scheme reported by Binney (2008) and Jin & Lynden-Bell (2007), which reconstructs orbits from streams using radial-velocity measurements, to allow it to work with erroneous input data. The upgraded algorithm can correct for both statistical error on observations, and systematic error due to streams not delineating individual orbits, and given high-quality but realistic input data, it can diagnose the potential with considerable accuracy. We complement the work of Binney (2008) by deriving a new algorithm, which reconstructs orbits from streams using proper-motion data rather than radial velocities. We show that the new algorithm has a similar potency for diagnosing the Galactic potential. We explore the concept of Galactic parallax, which arises in connection with our proper-motion study. Galactic parallax allows trigonometric distance calculation to stars at 40 times the range of conventional parallax, although its applicability is limited to only those stars in tidal streams. We examine from first principles the mechanics of tidal stream formation and propagation. We find that the mechanics of tidal streams has a natural expression in terms of action-angle variables. We find that tidal streams in realistic galaxy potentials will generally not delineate orbits, and that attempting to constrain the Galactic potential by assuming that they do can lead to large systematic error. We show that we can accurately predict the real-space trajectories of streams, even when they differ significantly from orbits.

We study the tidal history of an icy moon, basing our approach on a dissipation model, which combines viscoelasticity with anelasticity and takes into account the microphysics of attenuation. We apply this approach to Iapetus, the most remote large icy moon in the Saturnian system. Different authors provide very different estimates for Iapetus s despinning timescale, by several orders of magnitude. One reason for these differences is the choice of the dissipation model used for computing the spin evolution. As laboratory data on viscoelastic properties of planetary ices are sparse, many studies relied on dissipation models that turned out to be inconsistent with experiment. A pure water ice composition, generally assumed in the previous studies of the kind, yields despinning times of the order of 3.7 Gyr for most initial conditions. We demonstrate that through accounting for the complexity of the material (like second phase impurities) one arrives at despinning times as short as 0.9 Gyr. A more exact estimate will remain unavailable until we learn more about the influence of impurities on ice dissipation. By including the triaxial shape caused torque, we encounter a chaotic behavior at the final stage of despinning, with the possibility of entrapments in the intermediate resonances. The duration of these entrapments turns out to be sensitive to the dissipation model. No long entrapments have been found for Iapetus described with our laboratory based dissipation model.

I present an organic description of the regimes of collisionless tidal streams and define the orderings between the physical quantities that shape their morphology. Three fundamental dichotomies are identified in the form of dimensionless inequalities. These govern i) the speed of the stream's growth, ii) its internal coherence, iii) its thickness or opening angles. The mechanisms that regulate such main properties are analysed. The slope of the host's density profile influences the speed of the stream's growth, in both length and width, as steeper profiles enhance differential streaming. Internal coherence is the requirement for the appearance of substructure in tidal debris, and I concentrate on the `feathering' typical of GC streams. Overdensities are associated with minima in the relative streaming velocity of the stream members. For streams with high circularity, these are caused by the epicyclic oscillations of stars; however, for highly non-circular progenitor's orbits, substructure is caused by the oscillating differences in energy and actions with which material is shed at different orbital phases of the progenitor. This modulation results in different streaming speeds: the streakline of material shed between two successive apocentric passages is folded along its length, pulled at its centre by the faster streaming of particles released near pericenter, which are therefore more widely scattered. When the stream is coherent enough, this mechanism is potentially capable of generating a bimodal profile in the density distributions of the longer wraps of more massive progenitors, which I dub `bifurcations'. The conditions for internal coherence are explored and I comment on the cases of Palomar 5, Willman 1, the Anticenter and Sagittarius' streams. Analytical methods are accompanied by numerical experiments, performed using a purposely built generative model, also presented here.

NGC 205 is the nearest example of a dwarf elliptical (dE) galaxy and the prototype of this enigmatic galaxy class. Photometric evidence suggests that NGC 205, a close satellite of the M31 galaxy, is tidally interacting with its parent galaxy. We present stellar radial velocity measurements out to a projected radius of 20' (5 kpc) in NGC 205 based on Keck/DEIMOS multislit spectroscopic observations of 725 individual red giant branch stars. Our kinematic measurements extend from the center out to six times the effective radius of NGC 205, well past the expected tidal radius. The contamination in our kinematic sample from M31 field stars is estimated to be a few percent based on maximum likelihood fits. We measure a maximum major-axis rotation speed for the body of NGC 205 of 11+/- 5 kms; this is the first dE galaxy in which the maximum rotation velocity has been measured. Combined with the velocity dispersion, we conclude that NGC 205 is supported by a combination of rotation and random motions. At a major-axis distance of 4.5' (1 kpc), the velocity profile of NGC 205 turns over; stars beyond this radius are moving counter to the rotation of the inner part of the galaxy. The turnover radius is coincident with the onset of isophotal twisting and the estimated tidal radius, suggesting that the outer kinematics of NGC 205 are dominated by gravitational interactions with the nearby M31 galaxy. The motion of stars beyond a radius of 4.5' implies that NGC 205 is in a prograde encounter with its parent galaxy M31.

LONG-TERM GOALS: *To link the geotechnical properties of sediment substrates to the spatial and hydrodynamic characteristics of tidal channels *To develop new morphological indicators of tidal flat morphodynamics that can be easily derived from remote sensing images. To link these indicators to mechanical properties of tidal flat substrates

In a previous work (Callegari and Yokoyama 2007, Celest. Mech. Dyn. Astr. vol. 98), the main features of the motion of the pair Enceladus-Dione were analyzed in the frozen regime, i.e., without considering the tidal evolution. Here, the results of a great deal of numerical simulations of a pair of satellites similar to Enceladus and Dione crossing the 2:1 mean-motion resonance are shown. The resonance crossing is modeled with a linear tidal theory, considering a two-degrees-of-freedom model written in the framework of the general three-body planar problem. The main regimes of motion of the system during the passage through resonance are studied in detail. We discuss our results comparing them with classical scenarios of tidal evolution of the system. We show new scenarios of evolution of the Enceladus-Dione system through resonance not shown in previous approaches of the problem.

We assess the extent to which the PSCz survey encapsulates the complete or major share of matter inhomogeneities responsible for the external tidal forces affecting the peculiar velocity flow within the Local Supercluster [LS]. We investigate this issue on the basis of mock galaxy catalogs drawn from two large Nbody simulations of cosmic structure formation in two different cosmological scenarios. From these a variety of datasets is selected imitating the observational conditions of either the volume-limited LS mimicking NBG catalog or the deeper magnitude-limited PSCz catalog. The mildly nonlinear dynamics in the mock NBG and PSCz velocities are analyzed by means of an optimized implementation of the Least Action Principle, the Fast Action Method [FAM]. By comparing the modeled and true velocities of the corresponding mock catalogs we assess the extent and nature of the external tidal influence on the LS volume. We find that the dynamics in the inner 30Mpc/h volume is strongly affected by the external forces. Most of the external forces can be traced back to a depth of no more than 100Mpc/h. This is concluded from the fact that the FAM reconstructions of the 100Mpc/h PSCz volume appear to have included most gravitational influences. In addition, we demonstrate that for all considered cosmological models the bulk flow and shear components of the tidal velocity field generated by the external distribution of PSCz galaxies provides sufficient information for representing the full external tidal force field.

The motion of free nearby test particles relative to a stable equatorial circular geodesic orbit about a Kerr source is investigated. It is shown that the nonlinear generalized Jacobi equation can be transformed in this case to an autonomous form. Tidal dynamics beyond the critical speed c/sqrt(2) is studied. We show, in particular, that a free test particle vertically launched from the circular orbit parallel or antiparallel to the Kerr rotation axis is tidally accelerated if its initial relative speed exceeds c/sqrt(2). Possible applications of our results to high-energy astrophysics are briefly mentioned.

We examine the consequences of a model in which relativistic jets can be triggered in quiescent massive black holes when a geometrically thick and hot accretion disk forms as a result of the tidal disruption of a star. To estimate the power, thrust and lifetime of the jet, we use the mass accretion history onto the black hole as calculated by detailed hydrodynamic simulations of the tidal disruption of stars. We go on to determine the states of the interstellar medium in various types of quiescent galactic nuclei, and describe how this external matter can affect jets propagating through it. We use this information, together with a two-dimensional hydrodynamic model of the structure of the relativistic flow, to study the dynamics of the jet, the propagation of which is regulated by the density stratification of the environment and by its injection history. The breaking of symmetry involved in transitioning from one to two dimensions is crucial and leads to qualitatively new phenomena. Many of the observed properties of the Swift 1644+57/GRB 110328A event can be understood as resulting from accretion onto and jets driven by a $10^6 M_\odot$ central mass black hole following the disruption of sun-like star. With the inclusion of a stochastic contribution to the luminosity due to variations in the feeding rate driven by instabilities near the tidal radius, we find that our model can explain the X-ray light curve without invoking a rarely-occurring deep encounter. In conjunction with the number density of black holes in the local universe, we hypothesize that the conditions required to produce the Swift event are not anomalous, but are in fact representative of the jet-driven flare population arising from tidal disruptions. [abridged]

With the discovery during the past decade of a large number of extrasolar planets orbiting their parent stars at a distance lower than 0.1 astronomical unit (and the launch and the preparation of dedicated space missions such as CoRoT and KEPLER), with the position of inner natural satellites around giant planets in our Solar System and with the existence of very closed but separated binary stars, tidal interaction has to be carefully studied. In particular, a question arises about the validity of usual approximations used in the modelling of this interaction. The purpose of this paper is to examine the step beyond the ponctual approximation for the tidal perturber. To achieve this aim, the gravitational interaction between two extended bodies and more precisely the interaction between mass multipole moments of their gravitational fields and the associated tidal phenomena are studied. Use of Cartesian Symmetric Trace Free (STF) tensors, of their relation with spherical harmonics and of the Kaula's transform enables to derive analytically the tidal and mutual interaction potentials as well as the associated disturbing functions in extended bodies systems. The tidal and mutual interaction potentials of two extended bodies are derived. Next, the external gravitational potential of such tidally disturbed extended body is obtained, using the Love's number theory, as well as the associated disturbing function. Finally, the dynamical evolution equations for such systems are given in their more general form without any linearization. The dynamical equations for the gravitational and tidal interactions between extended bodies and associated dynamics are derived in a form where they could be directly implemented to perform coherent numerical simulations of planetary systems or multiple stars tidal evolution.

We present a combined analysis of the kinematics of the Large Magellanic Cloud through its HI gas, carbon stars, and red supergiant stars. After correcting the line-of-sight velocities for the recent accurate measurement of the LMC's space motion, we find that each kinematic tracer clearly defines a flat rotation curve with similar shape but different amplitude for each tracer: 61 km/s for the carbon stars, 80 km/s for the HI, and 107 km/s for the red supergiants. Previously identified tidal HI features are seen to harbor numerous carbon stars, with the tidally disturbed stars comprising 7-15% of the total sample. This discovery implies that we cannot depend on the carbon star sample alone to construct a reliable model of the LMC's gravitational potential. We also find red supergiants with peculiar kinematics, but their association with tidal features is unclear, and may instead be interacting with supergiant HI shell SGS4. In addition, although the local velocity dispersion of the red supergiants is small, ~8 km/s, their velocity dispersion about the carbon star rotation solution is 17 km/s, equal to the velocity dispersion of the carbon stars themselves. We thus appear to be witnessing the tidal heating of the LMC's stellar disk.

1How to Tell the Birds from the Flowers

By Robert Williams Wood

How do you tell apart a parrot from a carrot? A plover from a clover? A bay from a jay? Although there are several ways of differentiating, R. W. Wood’s use of pun and rhyme is one of the most entertaining! (Summary by Andrea L.)

2Chronicles of Canada Volume 08 - Great Fortress: A Chronicle of Louisbourg 1720-1760

By William Wood

Louisbourg was no mere isolated stronghold which could be lost or won without affecting the wider issues of oversea dominion. On the contrary, it was a necessary link in the chain of waterside posts which connected France with America by way of the Atlantic, the St Lawrence, the Great Lakes, and the Mississippi. But since the chain itself and all its other links, and even the peculiar relation of Louisbourg to the Acadians and the Conquest, have been fully described elsewhere in the Chronicles of Canada, the present volume only tries to tell the purely individual tale. (Summary from Book preface)

3Chronicles of Canada Volume 10 - A Chronicle of Montcalm

By William Wood

Montcalm is, of course, a very prominent character in every history of New France. This book gives a brief history of the Montcalm family in France and its importance in wars. It continues with its descendant as he moves to Canada and defends the French colony of Ticonderoga. Summary by Esther.

4Chronicles of Canada Volume 11 - The Winning of Canada: a Chronicle of Wolfe

By William Wood

Any life of Wolfe can be artificially simplified by treating his purely military work as something complete in itself and not as a part of a greater whole. But, since such treatment gives a totally false idea of his achievement, this little sketch, drawn straight from original sources, tries to show him as he really was, a co-worker with the British fleet in a war based entirely on naval strategy and inseparably connected with international affairs of world-wide significance. The only simplification attempted here is that of arrangement and expression. (Author's Note)

5Chronicles of Canada Volume 12 - The Father of British Canada; A Chronicle of Carleton

By William Wood

Carleton’s first eight years as governor of Canada were almost entirely occupied with civil administration. The next four were equally occupied with war.This is the account of how Carleton and his multiracial army fought off the American invasion of Quebec. It is the first time French and British troops worked together to defend Canada. Summary by Esther.

6Chronicles of Canada Volume 14 - The War With the United States: A Chronicle of 1812

By William Wood

"International disputes that end in war are not generally questions of absolute right and wrong. They may quite as well be questions of opposing rights. But, when there are rights on both sides; it is usually found that the side which takes the initiative is moved by its national desires as well as by its claims of right. <BR><BR> This could hardly be better exemplified than by the vexed questions which brought about the War of 1812." <BR><BR> This volume of the Chronicles of Canada series explains both the causes of the War of 1812 and the campaigns of the war from a primarily Canadian viewpoint, a perspective that is very often missed in writings on this Americo-British conflict. (By Sibella)

7East Lynne

By Mrs. Henry Wood

Ellen Wood (1814-1887) was an English novelist, better known as Mrs. Henry Wood. She wrote over 30 novels, many of which (especially East Lynne which was a Victorian best seller and is still sometimes performed as a drama) enjoyed remarkable popularity. <br><br> Lady Isabel Carlyle, a beautiful and refined young woman, leaves her hard-working but neglectful lawyer-husband and her infant children to elope with an aristocratic suitor. After he deserts her, and she bears their illegitimate child, Lady Isabel disguises herself and takes the position of governess in the household of her husband and his new wife". <br> Summary by Wikipedia

8Chronicles of Canada Volume 16 - The War Chief of the Six Nations: A Chronicle of Joseph Brant

By Louis Aubrey Wood

'Thayendanegea!' <BR><BR>The name was taken from the great book of nature. It was a birth-name of the Mohawks meaning two sticks of wood bound together, a sign of strength; and the woman hoped that her tiny child might one day be a man of valour among the Mohawks. Could she have but known it, her desire was to be more than realized, for in vigour of mind and body he was destined to surpass all the offspring of his race.<BR><BR>Joseph Brant was his English name and this is his story.<BR><BR>Summary from chapter one.

In this anthology of true crime tales, editor Walter Wood interviews those who were touched by the crimes recounted, sometimes as an acquaintance of the deceased or criminal or in the course of their professional duties. This work provides a personal look at some of the most sensational crimes and scandals of late 19th and early 20th century Britain. (Summary by Nullifidian)

10Channings

By Mrs. Henry Wood

This is a saga about life in a small town in England during the Victorian era. The "stars" of this saga are the Channings. Mr. Channing was ill and, because of his poverty, his six children have to work. Many things happen during this saga: a man confesses to a theft which he thinks his brother did, a lady is engaged to a gentleman much above her station, and so much more. But in the middle of all this you can find plenty of family love. (Summary by Stav Nisser)

11Chronicles of Canada Volume 31 - All Afloat: A Chronicle of Craft and Waterways

By William Wood

No exhaustive Canadian 'water history' can possibly be attempted here. That would require a series of its own. But at least a first attempt will be made to give some general idea of what such a history would contain in fuller detail: of the kayaks and canoes the Eskimos and Indians used before the white man came, and use today; of the small craft moved by oar and sail that slowly displaced those moved only by the paddle; of the sailing vessels proper, and how they plied along Canadian waterways, and on all the Seven Seas; of the steamers, which shed so much forgotten lustre on Canadian enterprise; of the teeming fisheries which the far-seeing Lord Bacon rightly thought 'richer treasures than the mines of Mexico and of Peru'; of the Dominion's trade and government relations with nations that 'have their business in great waters'; and, finally, of that guardian Navy, without whose freely given care the 'water history' of Canada could never have been made at all. (Summary modified from the text)

12Chronicles of Canada Volume 21 - The Red River Colony: A Chronicle of the Beginnings of Manitoba

By Louis Aubrey Wood

This, volume 21 of the Chronicles of Canada series, describes the settlement of the Red River Colony by Lord Selkirk, and the struggles it had against the North-West Company. The fledgling settlement eventually became the city of Manitoba. - Summary by TriciaG

13In the Line of Battle

By Walter Wood

“A COLLECTION OF absolutely authentic accounts by privates and non-commissioned officers.... We see a great simplicity and directness of observation and recital, so admirable that one page of such writing is worth all the folios of the war experts and correspondents, not to say romancers and publicists.” The Athenæum. <br><br> “THE HUMAN SIDE, the naked horror and simple glory of actual conflict, is what Mr. Wood’s soldiers are concerned with, and the stories they tell give a clearer picture of this side of war than can be found in any other form.” Pall Mall Gazette. <br><br> “A VERY REAL and deeply affecting book, and the editor has done a valuable work in collecting these poignant, odd, whimsical, terrible stories together.” Westminster Gazette. <br><br> “NO MAN WHO boasts a heart, least of all any man of young limbs, will read these soldiers’ simple stories without a quickening of the pulse. They are at once a great stimulus and a great memorial.” Daily Telegraph.

Citizen, colonist, pioneer! These three words carry the history of the United States back to its earliest form in 'the New World called America.' But who prepared the way for the pioneers from the Old World and what assured their safety in the New? The title of the present volume, Elizabethan Sea-Dogs gives the only answer. It was during the reign of Elizabeth, the last of the Tudor sovereigns of England, that Elizabethans won the command of the sea under the consummate leadership of Sir Francis Drake, the first of the modern admirals. Drake and his companions are known to fame as Sea-Dogs. They won the English right of way into Spain's New World. And Anglo-American history begins with that century of maritime adventures and naval war in which English sailors blazed and secured the long sea-trail for the men of every other kind who found or sought their fortunes in America - Summary from the Prefatory Note<br><br> <b>Group:</b> <a href="https://librivox.org/group/609">Chronicles of America Series</a>

15Story of a Loaf of Bread

By Thomas Barlow Wood

According to the author in the preface, he has "ventured to write this little book with some diffidence, for it deals with farming, milling and baking, subjects on which everyone has his own opinion." The earlier chapters give a brief sketch of the growing and marketing of wheat, followed by chapters on various aspects that impact the quality of wheat, the baking process and the characteristic of the final product, bread. The author aimed at making the reader realise that the farmer’s share in the production of the staple food of the people is by no means the simple affair it appears to be. - Summary by Leni

16Untempered Wind

By Joanna E. Wood

Upon publication of “The Untempered Wind” in 1894, Joanna Wood quickly rose to international prominence, becoming in the next few years the most highly paid fiction-writer in Canada. In this novel, we find a detailed picture of village life. The narrative weaves through a variety of character types: the refined and the coarse, the humble and the self-righteous, the virtuous and the vicious. All these types are measured according to their treatment of Myron Holder, a young unwed mother — a “fallen woman” in the eyes of this “spiteful, narrow-minded village.” An early reviewer extolled Wood as Canada’s Charlotte Brontë, because of her sympathetic treatment of a disadvantaged woman trying to forge an independent life. An even more apt comparison might be to Thomas Hardy: like Hardy's characters, Myron is buffeted by cruel, relentless Fate — the “untempered wind” of the title. In “Silenced Sextet” (a 1993 study of once-popular Canadian women writers who subsequently dropped out of the public eye), Joanna Wood is seen as an important figure in the development of realism in Canadian literature: “No nineteenth-century writer better presents the sound, smell, and feel of day-to-day village life in this country.” - Summary by Bruce Pirie

17Narratives of Colored Americans

By Abigail Mott and Mary Sutton Wood

Abigail Mott was a Quaker and abolitionist from New York who, along with fellow Quaker M. S. Wood, has compiled a provocative collection of stories of “Colored Americans.” They range from well-known figures such as Phillis Wheatley and Sojourner Truth to the common men and women who give poignant insights of their life. Selections consist of short anecdotes, essays, stories, letters and poetry. Many have strong religious and spiritual themes. - Summary by Larry Wilson

<i>The Wedding-day in all Ages and Countries</i> is the title of a new work from the press of Harper & Brothers. In this book we find an exhaustive record of all the ceremonies pertaining to betrothal and marriage now existing, or that have existed, so far as they can be gleaned from history, in the different countries of the globe. The material thus gathered is abundantly curious. Ceremonies connected with marriage have varied greatly, and yet they seem, through all changes, to possess certain family resemblances. Almost all peoples have delighted in surrounding this event with a vast amount of ceremonious details, and, although our modern life is charged with overdoing it, yet the most pretentious celebration of our fashionable life is simplicity itself compared to what it is in some other countries, or has been in other ages. This work not only gives an account of marriage ceremonies, but includes the superstitions and folk-lore that have prevailed at different times in connection with an event which every age has seemed to consider one of the most interesting in the life of man. - Summary by Appleton's Journal of Literature Science and Art