My dissertation focuses on a relatively new field of study: the region immediately around galaxies known as the circumgalactic medium (CGM). The CGM holds vast quantities of mass and metals, yet its connection to galaxies is not well understood. My work uses cosmological hydrodynamic simulations and comparisons to data from Hubble's Cosmic Origins Spectrograph (COS) to understand the CGM's connection to galaxy evolution, gas accretion, outflows, star formation, and baryon cycling. This includes studies of the CGM's extent and physical conditions; the cause and nature of outflows; gas dynamics, including the first comprehensive study of tracers of inflowing and outflowing gas at low redshift (z=0.25); and direct comparison of theoretical results to observational data. Chapter 1 introduces my research and show its connection to galaxy evolution. Chapter 2 investigates hydrogen and metal line absorption around low-redshift galaxies in cosmological hydrodynamic simulations. This chapter studies different models for stellar outflows, physical conditions, and dependencies on halo mass. Chapter 3 examines the flow of gas into, out of, and around galaxies using a novel particle tracking technique. This chapter examines the baryon cycle in detail for our preferred model of stellar outflows. Chapter 4 compares our model results, including two separate prescriptions for outflows, with data from COS. We contrast these wind models, showing how they cycle baryons differently, and show degeneracies in observational diagnostics. In Chapter 5, I summarize and discuss plans for future research in this field, and how it can be more fully leveraged to understand galaxy evolution.

I investigate the chemical evolution of the Universe in a series of cosmological hydrodynamic simulations with the purpose of finding a self-consistent evolutionary scenario of galaxy formation able to reproduce key observables focusing on the enrichment of the intergalactic medium (IGM). The most successful models I run and analyze use the scalings of momentum-driven feedback whereby UV photons generated during the Main Sequence stage accelerate dust-driven winds while providing a significantly larger energy budget than from supernovae alone. The success of this outflow model relies on its ability to drive highly mass-loaded winds from small galactic haloes. These feedback relations, supported by observations of local starburst, are inserted into simulations at all epochs, reproducing observables including the C IV column density and linewidth distributions at z=6->1.5 and the O VI forest at z=0-0.5. Outflows at z>=5 propagate early nucleosynthetic products traced by C IV and lower ionization species into an otherwise metal-free IGM. Continual outflows at the peak ages of star formation (z=5->1.5) produce a non-evolving cosmic mass density of C IV despite continual enrichment increasing IGM metallicity by a factor of ten. The z=0-0.5 O VI forest is composed of weaker absorbers tracing photo-ionized diffuse IGM metals, sometimes injected by primordial galaxies, and stronger absorbers tracing recently injected metals, often unable to escape their parent haloes and sometimes collisionally ionized. Tracking the individual histories of metals in outflows shows the average outflow travels ~100 physical kpc and returns to galaxies on an average timescale of 1-2 Gyr; this result implies metals in superwinds do not remain in the IGM for a Hubble time and are more likely to rejoin galaxies. Metal absorbers aligned with Lyman-alpha are examined in detail, finding that the two often trace different phases of gas with the former tracing an inhomogeneous distribution of metals exhibiting turbulence imparted during the outflow phase dissipating on a Hubble timescale. I find this is the first model to self-consistently reproduce the wide range of IGM observables spanning the history of heavy metal production while being consistent with key galaxy observables. The link between star formation and galactic superwinds requires that a successful model of galaxy formation reproduces both the evolution of galaxies and the IGM.

Damped Lyman α systems (DLAs) are useful probes of the chemical enrichment of the universe as they provide accurate abundance measurements of many chemical species. Using a sample of 30 DLAs (with large metal column densities) observed with the High Resolution Echelle Spectrometer on the Keck I telescope, the abundances of several elements (i.e. iron, zinc, chromium, silicon, sulphur, phosphorus, manganese, and boron) are derived and presented. A comparison is drawn between the abundances from these metal-rich DLAs with literature samples encompassing the largest compilation of high resolution observations of other DLAs, and stars from the Milky Way and its satellite galaxies to understand the astrophysical nature of DLAs. Furthermore, the first ever extragalactic study of boron is presented. Using the sample of 30 metal-rich DLAs, two 3σ detections and one near detection 2.97σ) were found. From the comparison of [B/O] and, for the first time, [B/S], with studies in the Milky Way, there appears to be an excess of boron relative to its parent nucleus (oxygen) in these three DLA systems, suggesting that there may be a higher cosmic ray flux in DLAs than in the Milky Way. / Graduate / 0606

Damped Lyman α systems (DLAs) are useful probes of the chemical enrichment of the universe as they provide accurate abundance measurements of many chemical species. Using a sample of 30 DLAs (with large metal column densities) observed with the High Resolution Echelle Spectrometer on the Keck I telescope, the abundances of several elements (i.e. iron, zinc, chromium, silicon, sulphur, phosphorus, manganese, and boron) are derived and presented. A comparison is drawn between the abundances from these metal-rich DLAs with literature samples encompassing the largest compilation of high resolution observations of other DLAs, and stars from the Milky Way and its satellite galaxies to understand the astrophysical nature of DLAs. Furthermore, the first ever extragalactic study of boron is presented. Using the sample of 30 metal-rich DLAs, two 3σ detections and one near detection 2.97σ) were found. From the comparison of [B/O] and, for the first time, [B/S], with studies in the Milky Way, there appears to be an excess of boron relative to its parent nucleus (oxygen) in these three DLA systems, suggesting that there may be a higher cosmic ray flux in DLAs than in the Milky Way. / Graduate / 0606

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-23T21:14:44Z No. of bitstreams: 1 NathaliaMattosNovaesDaRocha_DISSERT.pdf: 8902893 bytes, checksum: 548054835dc66d4ee903a6646b0226ac (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-28T18:39:22Z (GMT) No. of bitstreams: 1 NathaliaMattosNovaesDaRocha_DISSERT.pdf: 8902893 bytes, checksum: 548054835dc66d4ee903a6646b0226ac (MD5) / Made available in DSpace on 2016-06-28T18:39:22Z (GMT). No. of bitstreams: 1 NathaliaMattosNovaesDaRocha_DISSERT.pdf: 8902893 bytes, checksum: 548054835dc66d4ee903a6646b0226ac (MD5) Previous issue date: 2015-09-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Descoberto em 1963, 3C 273 foi o segundo quasar identificado e catalogado no Terceiro Cat?logo de Cambridge para r?dio fontes, e o primeiro para o qual as linhas de emiss?o foram identificadas com uma sequ?ncia de hidrog?nio desviada para o vermelho. Ele ? o quasar mais brilhante da esfera celeste, o mais estudado, analisado, e com uma resultante abund?ncia de dados dispon?veis em uma vasta literatura. A an?lise precisa dos desvios das linhas espectrais de quasares, fornece informa??o suficiente para p?r em prova a varia??o das constantes fundamentais da natureza e similarmente da taxa de expans?o do universo. A an?lise da variabilidade das curvas de luz desses corpos, e a consequente precis?o das suas periodicidades, ? de suma import?ncia pois proporciona uma efic?cia nas observa??es deles, possibilita uma maior compreens?o dos seus fen?menos f?sicos, e torna fact?vel a realiza??o de observa??es espectrais em datas mais exatas (momentos nos quais suas curvas de luz apresentam picos acentuados e, por conseguinte, espectros mais ricos em informa??o). Na presente disserta??o, vinte e oito curvas de luz do quasar 3C 273 s?o estudadas, abrangendo todas as faixas do espectro eletromagn?tico (da emiss?o r?dio aos raios gama), totalizando na an?lise de quatro curvas de luz para cada faixa. Aplicamos o m?todo da Transformada Wavelet Cont?nua do tipo Morlet de ordem w = 06 e obtivemos resultados precisos e coerentes com a literatura. / Discovered in 1963, 3C 273 was the second quasar identified and cataloged in the Third Cambridge Catalog for radio sources, and the first one for which emission lines were identified with a hydrogen sequence redshifted. It is the brightest quasar of the celestial sphere, the most studied, analyzed, and with a resulting abundance of data available in a vast literature. The accurate analysis of the deviations of the spectral lines of quasars provides enough information to put in evidence the variation of fundamental constants of nature and similarly the universe expansion rate. The analysis of the variability of the light curves of these bodies, and the consequent accuracy of their periodicity, is of utmost importance as it provides an efficiency of their observations, enables a greater understanding of the physical phenomena, and makes it possible to conduct spectral observations on more accurate dates (when their light curves show pronounced peaks and therefore richer spectra information). In this master?s thesis twenty eight light curves from the quasar 3C 273 are studied, covering all the electromagnetic spectrum wavebands (radio emission to gamma rays), totaling in the analysis of four light curves for each waveband. We have applied the method of Continuous Wavelet Transform using the sixth-order (!0 = 6) Morlet wavelet function, and obtained excellent results in accordance with the literature.

Neste trabalho realizamos cálculos teóricos das razões de povoamento dos níveis de estrutura fina do C0, C+ e Si+ considerando em detalhes os efeitos dos diversos mecanismos de excitação: colisões, fluorescência e a radiação cósmica de fundo. Empregamos dados atômicos recentes coletados na literatura na resolução das equações de equilíbrio estatístico pertinentes. A confrontação das razões de povoamento calculadas com as razões de densidades de coluna observadas disponíveis na literatura nos permite obter informações acerca das condições físicas (densidades volumétricas, intensidade de um campo de radiação UV presente, temperatura da radiação cósmica de fundo) e propriedades (dimensão característica e massa) dos sistemas damped Lyman a e Lyman Limit vistos em absorção no espectro de QSOs. Como um aparte, e por sua relação com o tema do trabalho, também investigamos a lei de temperatura da radiação cósmica de fundo. / In this work we perform theoretical calculations of the population ratios of fine structure levels of C0, C+ and Si+ considering in detail the effect of the various excitation mechanisms: collisions, fluorescence and the cosmic background radiation. We employ recent atomic data, gathered in the literature, to solve the related statistical equilibrium equations. The comparison of the calculated population ratios with the observed column densities ratios available in the literature allows us to obtain informations regarding the physical conditions (volume densities, intensity of a UV radiation field present, temperature of the cosmic background radiation) and properties (characteristic size and mass) of damped Lyman a and Lyman Limit systems seen in absorption in spectra of QSOs. We also investigate the temperature law of the cosmic background radiation, which bears a tight relationship with this work.

Massive galaxies evolve through different phases including starburst-dominated and active galactic nuclei (AGN)-dominated phases. These phases are predicted to be prevalent at earlier times (z ∼ 2 − 3). In this thesis I present high-sensitivity observations from the Atacama Large Millimeter/submillimeter Array to investigate mid-J (Jupper = 4 and 5) CO emission in nine Wide-field Infrared Survey Explorer-selected hyperluminous, hot dust-obscured galaxies (Hot DOGs). These sources are thought to represent a transition phase between starburst- and AGN-dominated galaxies at z ≈ 2.5 − 5. All nine sources are detected in continuum and line emission. I conclude that the sources are gas-rich with Mgas ≈ 1010−11 M . Previous far-infrared spectral energy distribution decomposition revealed that six of the sources have significant cold dust components suggesting high star-formation rates (SFR ≈ 2000 − 9000 M  yr−1 ). The molecular gas in the sources is shown to follow roughly the same star-formation trend as a smaller sample of Hot DOGs and other populations of star-forming and quasar-host galaxies at low- and high-redshift. The resolved CO emission line data displays large velocity dispersions (FWHM ≈ 400 − 900 km s−1 ) consistent with other high-z star-forming and quasar-host galaxies. For a subset of the sources, the line data shows disturbed morphologies and velocity gradients possibly consistent with rotation or galaxy interaction. The results from this analysis suggest that the studied sources are heavily dust-obscured quasars undergoing extreme starburst episodes. The estimated gas and dynamical masses of the sources are consistent with other populations of massive galaxies at low- and high-z, indicating that they likely represent a stage in the evolution of massive galaxies. / <p>Presentaiton given over zoom platform during COVID-19 pandemic.</p>

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Theoretical work in quantum information has demonstrated that a classical hidden-variable model of an entangled singlet state can explain nonclassical correlations observed in tests of Bell’s inequality if while measuring the Bell correlation, the underlying probability distribution of the hidden-variable changes depending on the measurement basis. To rule out this possibility, distant quasars can be utilized as random number generators to set measurement bases in an experimental test of Bell’s inequality. Here we report on the design and characterization of a device that uses the color of incoming quasar photons to output a random bit with nanosecond latency. Through the 1-meter telescope at JPL Table Mountain Observatory, we observe and generate random bits from quasars with redshifts z = 0.1−3.9. In addition, we formulate a mathematical model that quantifies the fidelity of the bits generated.