Sunyaev-Zel'dovich observations using large-format millimeter arrays

Galaxy clusters are the largest gravitationally bound objects in the observable universe, and they are formed from the largest perturbations of the primordial matter power spectrum. During initial cluster collapse, matter is accelerated to supersonic velocities, and the baryonic component is heated as it passes through accretion shocks. This process stabilizes when the pressure of the bound matter prevents further gravitational collapse. Galaxy clusters are useful cosmological probes, because their formation progressively freezes out at the epoch when dark energy begins to dominate the expansion and energy density of the universe. A diverse set of observables, from radio through X-ray wavelengths, are sourced from galaxy clusters, and this is useful for self-calibration. The distributions of these observables trace a cluster's dark matter halo, which represents more than 80% of the cluster's gravitational potential. One such observable is the Sunyaev-Zel'dovich effect (SZE), which results when the ionized intercluster medium blueshifts the cosmic microwave background via Compton scattering. Great technical advances in the last several decades have made regular observation of the SZE possible. Resolved SZE science, such as is explored in this analysis, has benefitted from the construction of large-format camera arrays consisting of highly sensitive millimeter-wave detectors, such as Bolocam. Bolocam is a submillimeter camera, sensitive to 140 GHz and 268 GHz radiation, located at one of the best observing sites in the world: the Caltech Submillimeter Observatory on Mauna Kea in Hawaii. Bolocam fielded 144 of the original spider web NTD bolometers used in an entire generation of ground-based, balloon-borne, and satellite-borne millimeter wave instrumention. Over approximately six years, our group at Caltech has developed a mature galaxy cluster observational program with Bolocam. This thesis describes the construction of the instrument's full cluster catalog: BOXSZ. Using this catalog, I have scaled the Bolocam SZE measurements with X-ray mass approximations in an effort to characterize the SZE signal as a viable mass probe for cosmology. This work has confirmed the SZE to be a low-scatter tracer of cluster mass. The analysis has also revealed how sensitive the SZE-mass scaling is to small biases in the adopted mass approximation. Future Bolocam analysis efforts are set on resolving these discrepancies by approximating cluster mass jointly with different observational probes.

Oceanographic Profiling and Spectroradiometer Observations from the MOCE-2 Cruise: 28 March to 14 April 1993

This report contains results from the second cruise of the Modis Optical Characterization Experiment (MOCE). Data presented here were obtained on the Mexican Research Vessel El Puma between 29 March and 13 April along the Pacific coast of Baja California and in the Gulf of California. Three types of data are reported: high spectral resolution radiometry at three depths for 13 stations; salinity, temperature beam attenuation and chlorophyll-a fluorescence, profiles at the same stations; and total suspended matter and suspended organic carbon and nitrogen.(PDF is 90 pages.)

Oceanographic Profiling Observations from the MOBY-L7 Cruise: 25 to 30 June 1994

This report contains CTD profiling results from the seventh cruise to the Marine Optics Buoy (MOBY) site near the Island of Lanai. Data presented here were obtained on the University of Hawaii Research Vessel Moana Wave between 26 and 30 June 1994. Two types of data are reported: vertical profile observations of salinity, temperature beam attenuation and chlorophyll-a fluorescence, profiles; and total suspended matter and suspended organic carbon and nitrogen taken from water samplers at those stations.

Oceanographic Profiling Observations from the MOCE-3 Cruise: 27 October to 15 November 1994

This report contains results from the third cruise of the Marine Optical Characterization Experiment (Fig. 1). A variety of spectroradiometric observations of the upper water column and atmosphere were made by investigators from the University of Miami, NOAA, CHORS and MLML. Data presented here were obtained by oceanographic CTD profiler: salinity, temperatllre, dissolved oxygen, beam attenuation and chlorophyll-a fluorescence; and by water samplers: total suspended matter and suspended organic carbon and nitrogen, salinity, and dissolved oxygen.

Identifying and interpreting stratification in sedimentary rocks on Mars : insight from Rover and orbital observations and terrestrial field analogs

Sedimentary rocks on Mars provide insight into past aqueous and atmospheric processes, climate regimes, and potential habitability. The stratigraphic architecture of sedimentary rocks on Mars is similar to that of Earth, indicating that the processes that govern deposition and erosion on Mars can be reasonably inferred through reference to analogous terrestrial systems. This dissertation aims to understand Martian surface processes through the use of (1) ground-based observations from the Mars Exploration Rovers, (2) orbital data from the High Resolution Imaging Science Experiment onboard the Mars Reconnaissance Orbiter, and (3) the use of terrestrial field analogs to understand bedforms and sediment transport on Mars. Chapters 1 and 2 trace the history of aqueous activity at Meridiani Planum, through the reconstruction of eolian bedforms at Victoria crater, and the identification of a potential mudstone facies at Santa Maria crater. Chapter 3 uses Terrestrial Laser Scanning to study cross-bedding in pyroclastic surge deposits on Earth in order to understand sediment transport in these events and to establish criteria for their identification on Mars. The final chapter analyzes stratal geometries in the Martian North Polar Layered Deposits using tools for sequence stratigraphic analysis, to better constrain past surface processes and past climate conditions on Mars.

Survey of the shrimp stocks of the Sierra Leone inshore shelf : a summary report outlining objectives, observations and recommendations on the status of the Sierra Leone shrimp fishery

This report gives the species and catch-rates per hour of some commercial shrimp species caught in the course of a short survey of inshore shelf fishing grounds. Species seen in significant quantities were: Parapenneopsis atlantica, Parapenaeus longirostris, Penaeus kerathurus and Penaeus duorarum notialis

Dynamic rupture simulation integrated with earthquake observations

Dynamic rupture simulations are unique in their contributions to the study of earthquake physics. The current rapid development of dynamic rupture simulations poses several new questions: Do the simulations reflect the real world? Do the simulations have predictive power? Which one should we believe when the simulations disagree? This thesis illustrates how integration with observations can help address these questions and reduce the effects of non-uniqueness of both dynamic rupture simulations and kinematic inversion problems. Dynamic rupture simulations with observational constraints can effectively identify non-physical features inferred from observations. Moreover, the integrative technique can also provide more physical insights into the mechanisms of earthquakes. This thesis demonstrates two examples of such kinds of integration: dynamic rupture simulations of the M_w 9.0 2011 Tohoku-Oki earthquake and of earthquake ruptures in damaged fault zones:

(1) We develop simulations of the Tohoku-Oki earthquake based on a variety of observations and minimum assumptions of model parameters. The simulations provide realistic estimations of stress drop and fracture energy of the region and explain the physical mechanisms of high-frequency radiation in the deep region. We also find that the overridding subduction wedge contributes significantly to the up-dip rupture propagation and large final slip in the shallow region. Such findings are also applicable to other megathrust earthquakes.

(2) Damaged fault zones are usually found around natural faults, but their effects on earthquake ruptures have been largely unknown. We simulate earthquake ruptures in damaged fault zones with material properties constrained by seismic and geological observations. We show that reflected waves in fault zones are effective at generating pulse-like ruptures and head waves tend to accelerate and decelerate rupture speeds. These mechanisms are robust in natural fault zones with large attenuation and off-fault plasticity. Moreover, earthquakes in damaged fault zones can propagate at super-Rayleigh speeds that are unstable in homogeneous media. Supershear transitions in fault zones do not require large fault stresses. In the end, we present observations in the Big Bear region, where variability of rupture speeds of small earthquakes correlates with the laterally variable materials in a damaged fault zone.

Some observations on the absence of bacteria from acid waters in northwest England

This brief report concentrates on the effect of low pH on the initial stages of decomposition and the conditioning of incoming particulate carbon or detritus by microbes, particularly certain genera of filamentous bacteria. Although many previous reports have concentrated on bacterial decomposition processes, little attention has been given to the composition of the bacterial community and the role of its component parts, particularly in nutrient-poor waters which are provided with sources of organic carbon and reducing power in the form of poor quality detritus.

A note on freshwater research in China, with some observations on the algae from Doupe Pool, Guizhou Province

This article provides insights into a particular aspect of freshwater research in China and its wider implications for western researchers. The senior author has collaborated with Professor Zhang Zhaohui from Guizhou Normal University to investigate the travertines of China. Travertines are freshwater carbonate deposits accumulating in hard-water springs and rivers. In some areas they develop rapidly, forming picturesque ascades and magnificent travertine-dammed lakes. Some of China's most famous tourist sites are the result of travertine formation. The travertine-depositing environment is a unique fast-flowing ecosystem inhabited by specialist plants and animals. The authors examine the freshwater algae of the Doupe Pool travertine situated on the Beishuihei River in Guizhou Province and compare their distribution on travertines elsewhere in the world.

Observations of hydrogen and helium isotopes in solar cosmic rays

The isotopic composition of hydrogen and helium in solar cosmic rays provides a means of studying solar flare particle acceleration mechanisms since the enhanced relative abundance of rare isotopes, such as ²H, ³H and ³He, is due to their production by inelastic nuclear collisions in the solar atmosphere during the flare. In this work the Caltech Electron/Isotope Spectrometer on the IMP-7 spacecraft has been used to measure this isotopic composition. The response of the dE/dx-E particle telescope is discussed and alpha particle channeling in thin detectors is identified as an important background source affecting measurement of low values of (³He/⁴He).

The following flare-averaged results are obtained for the period, October, 1972 - November, 1973: (²H/¹H) = 7⁺¹⁰_-6 X 10^-6 (1.6 - 8.6 MeV/nuc), (³H/¹H) less than 3.4 x 10^-6 (1.2 - 6.8 MeV/nuc), (³He/⁴He) = (9 ± 4) x 10^-3, (³He/¹H) = (1.7 ± 0.7) x 10^-4 (3.1 - 15.0 MeV/nuc). The deuterium and tritium ratios are significantly lower than the same ratios at higher energies, suggesting that the deuterium and tritium spectra are harder than that of the protons. They are, however, consistent with the same thin target model relativistic path length of ~ 1 g/cm² (or equivalently ~ 0.3 g/cm² at 30 MeV/nuc) which is implied by the higher energy results. The ³He results, consistent with previous observations, would imply a path length at least 3 times as long, but the observations may be contaminated by small ³He rich solar events.

During 1973 three "³He rich events," containing much more ³He than ²H or ³H were observed on 14 February, 29 June and 5 September. Although the total production cross sections for ²H,³H and ³He are comparable, an upper limit to (²H/³He) and (³H/³He) was 0.053 (2.9-6.8 MeV/nuc), summing over the three events. This upper limit is marginally consistent with Ramaty and Kozlovsky's thick target model which accounts for such events by the nuclear reaction kinematics and directional properties of the flare acceleration process. The 5 September event was particularly significant in that much more ³He was observed than ⁴He and the fluxes of ³He and ¹H were about equal. The range of (³He/⁴He) for such events reported to date is 0.2 to ~ 6 while (³He/¹H) extends from 10^-3 to ~ 1. The role of backscattered and mirroring protons and alphas in accounting for such variations is discussed.

Observations of nitrogen and oxygen isotopes in the low energy cosmic rays

The isotopic composition of the enhanced low energy nitrogen and oxygen cosmic rays can provide information regarding the source of these particles. Using the Caltech Electron/Isotope Spectrometer aboard the IMP-7 satellite, a measurement of this isotopic composition was made. To determine the isotope response of the instrument, a calibration was performed, and it was determined that the standard range-energy tables were inadequate to calculate the isotope response. From the calibration, corrections to the standard range-energy tables were obtained which can be used to calculate the isotope response of this and similar instruments.

The low energy nitrogen and oxygen cosmic rays were determined to be primarily ^(14)N and ^(16)O. Upper limits were obtained for the abundances of the other stable nitrogen and oxygen isotopes. To the 84% confidence level the isotopic abundances are: ^(15)N/N ≤ 0.26 (5.6- 12.7 MeV/nucleon), ^(17)0/0 ≤ 0.13 (7.0- 11.8 MeV/nucleon), (18)0/0 ≤ 0.12 (7.0 - 11.2 MeV/nucleon). The nitrogen composition differs from higher energy measurements which indicate that ^(15)N, which is thought to be secondary, is the dominant isotope. This implies that the low energy enhanced cosmic rays are not part of the same population as the higher energy cosmic rays and that they have not passed through enough material to produce a large fraction of ^(15)N. The isotopic composition of the low energy enhanced nitrogen and oxygen is consistent with the local acceleration theory of Fisk, Kozlovsky, and Ramaty, in which interstellar material is accelerated to several MeV/nucleon. If, on the other hand, the low energy nitrogen and oxygen result from nucleosynthesis in a galactic source, then the nucleosynthesis processes which produce an enhancement of nitrogen and oxygen and a depletion of carbon are restricted to producing predominantly ^(14)N and ^(16)O.

Observations of 1-6 MeV Jovian electrons at 1 AU and a study of their propagation

The 1-6 MeV electron flux at 1 AU has been measured for the time period October 1972 to December 1977 by the Caltech Electron/Isotope Spectrometers on the IMP-7 and IMP-8 satellites. The non-solar interplanetary electron flux reported here covered parts of five synodic periods. The 88 Jovian increases identified in these five synodic periods were classified by their time profiles. The fall time profiles were consistent with an exponential fall with τ ≈ 4-9 days. The rise time profiles displayed a systematic variation over the synodic period. Exponential rise time profiles with τ ≈ 1-3 days tended to occur in the time period before nominal connection, diffusive profiles predicted by the convection-diffusion model around nominal connection, and abrupt profiles after nominal connection.

The times of enhancements in the magnetic field, │B│, at 1 AU showed a better correlation than corotating interaction regions (CIR's) with Jovian increases and other changes in the electron flux at 1 AU, suggesting that │B│ enhancements indicate the times that barriers to electron propagation pass Earth. Time sequences of the increases and decreases in the electron flux at 1 AU were qualitatively modeled by using the times that CIR's passed Jupiter and the times that │B│ enhancements passed Earth.

The electron data observed at 1 AU were modeled by using a convection-diffusion model of Jovian electron propagation. The synodic envelope formed by the maxima of the Jovian increases was modeled by the envelope formed by the predicted intensities at a time less than that needed to reach equilibrium. Even though the envelope shape calculated in this way was similar to the observed envelope, the required diffusion coefficients were not consistent with a diffusive process.

Three Jovian electron increases at 1 AU for the 1974 synodic period were fit with rise time profiles calculated from the convection-diffusion model. For the fits without an ambient electron background flux, the values for the diffusion coefficients that were consistent with the data were k_x = 1.0 - 2.5 x 10²¹ cm²/sec and k_y = 1.6 - 2.0 x 10²² cm²/sec. For the fits that included the ambient electron background flux, the values for the diffusion coefficients that were consistent with the data were k_x = 0.4 - 1.0 x 10²¹ cm²/sec and k_y = 0.8 - 1.3 x 10²² cm²/sec.

Abnormal phenomenon of ac Stark splitting in magneto-optical traps

We experimentally study the ac Stark splitting in D2 line of cold Rb-87 atoms. The frequency span between the Autler-Townes doublets is obviously larger than that derived from theoretical calculation. Two physical effects, which increase the effective Rabi frequency, contribute to the splitting broadening. First, atoms tend to distribute in strong lield places of a inhomogeneous red-detuned light field. Second, atoms reabsorb scattered light when they are huge in number and high in density.