subject:(Dark energy)

Cornell University

1. Kumar, Naresh. Dark Aspects Of Cosmology .

Degree: 2012, Cornell University

► This thesis investigates aspects of dark matter and dark energy and constraints that can be imposed on them from current and future observations. Specifically, we… (more)

Subjects/Keywords: Dark matter; Dark energy; Cosmology

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APA (6^th Edition):

Kumar, N. (2012). Dark Aspects Of Cosmology . (Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/31115

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kumar, Naresh. “Dark Aspects Of Cosmology .” 2012. Thesis, Cornell University. Accessed December 13, 2019. http://hdl.handle.net/1813/31115.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kumar, Naresh. “Dark Aspects Of Cosmology .” 2012. Web. 13 Dec 2019.

Vancouver:

Kumar N. Dark Aspects Of Cosmology . [Internet] [Thesis]. Cornell University; 2012. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/1813/31115.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kumar N. Dark Aspects Of Cosmology . [Thesis]. Cornell University; 2012. Available from: http://hdl.handle.net/1813/31115

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Leiden University

2. Beer, Thomas de. The Chaplygin Gas and Modelling Dark Matter Haloes.

Degree: 2017, Leiden University

URL: http://hdl.handle.net/1887/51883

► Dark matter and dark energy are among the top unsolved mysteries within today’s physics and astronomy. These unknown phenomena are each supposed to explain a… (more)

Subjects/Keywords: chaplygin gas unified dark matter dark energy

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APA (6^th Edition):

Beer, T. d. (2017). The Chaplygin Gas and Modelling Dark Matter Haloes. (Masters Thesis). Leiden University. Retrieved from http://hdl.handle.net/1887/51883

Chicago Manual of Style (16^th Edition):

Beer, Thomas de. “The Chaplygin Gas and Modelling Dark Matter Haloes.” 2017. Masters Thesis, Leiden University. Accessed December 13, 2019. http://hdl.handle.net/1887/51883.

MLA Handbook (7^th Edition):

Beer, Thomas de. “The Chaplygin Gas and Modelling Dark Matter Haloes.” 2017. Web. 13 Dec 2019.

Vancouver:

Beer Td. The Chaplygin Gas and Modelling Dark Matter Haloes. [Internet] [Masters thesis]. Leiden University; 2017. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/1887/51883.

Council of Science Editors:

Beer Td. The Chaplygin Gas and Modelling Dark Matter Haloes. [Masters Thesis]. Leiden University; 2017. Available from: http://hdl.handle.net/1887/51883

Texas A&M University

3. Zhao, Gang. Dark world and the standard model.

Degree: 2009, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-1840

► The most popular way to achieve accelerated expansion of the universe is by introducing a scalar field in which motion of state varies with time.… (more)

Subjects/Keywords: dark energy; dark matter; droplet; standard model

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APA (6^th Edition):

Zhao, G. (2009). Dark world and the standard model. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1840

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Zhao, Gang. “Dark world and the standard model.” 2009. Thesis, Texas A&M University. Accessed December 13, 2019. http://hdl.handle.net/1969.1/ETD-TAMU-1840.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Zhao, Gang. “Dark world and the standard model.” 2009. Web. 13 Dec 2019.

Vancouver:

Zhao G. Dark world and the standard model. [Internet] [Thesis]. Texas A&M University; 2009. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1840.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhao G. Dark world and the standard model. [Thesis]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1840

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

4. Gardikiotis, Antonios. Search for axions via astrophysical obsevations.

Degree: 2015, University of Patras; Πανεπιστήμιο Πατρών

URL: http://hdl.handle.net/10442/hedi/36125

►

The present thesis has purpose the axion research (Dark Matter particles) by Astrophysical observations. The main activity has been established in CAST (Cern Axion Solar… (more)

▼

The present thesis has purpose the axion research (Dark Matter particles) by Astrophysical observations. The main activity has been established in CAST (Cern Axion Solar Telescope) in Geneva. In this thesis the axion detection prospects are defined in parallel with the detector's data analysis. An engineering approach is also given as main and substantial part (fluid dynamics) for the CAST physics reliability. The research is ongoing to the Dark Energy sector willing to explore the possibility of chameleons (dark energy particles) through radiation pressure.

Η παρούσα εργασία έχει ως σκοπό την αναζήτηση αξιονίων (σωματιδίων Σκοτεινής Ύλης) μέσα από αστροφυσικές παρατηρήσεις. Από τις πρώτες παρατηρήσεις της ταχύτητας περιστροφής αστέρων σε σμήνη Γαλαξιών από τον Zwicky και μετά, έγινε σαφές στην επιστημονική κοινότητα πως η ύπαρξη σκοτεινής ύλης καθώς και η κατανόηση της είναι θεμελιώδους σημασίας για την Κοσμολογία. Το ποσοστό της σκοτεινής ύλης του σύμπαντος (~21%), σε σχέση με το αυτό της ύλης που παρατηρούμε (~4%), καθιστά σαφή την αναγκαιότητα για εντατική έρευνα στο πεδίο αυτό της Φυσικής. Ανάγκη δε, προκύπτει επίσης για την εξερεύνηση της σκοτεινής ενέργειας η οποία αποτελεί το υπόλοιπο ~75% του Σύμπαντος. Ένα μικρό μέρος της παρούσας έρευνας στο CERN έχει επικεντρωθεί και στην μελέτη Σκοτεινής ενέργειας καθώς, το πείραμα μέσα από το οποίο προσεγγίζεται η αναζήτηση αξιονίων (CAST – CERN Axion Solar Telescope), προσανατολίζεται συγχρόνως στην έρευνα σωματιδίων Σκοτεινής ενέργειας (χαμαιλέοντες) .

Subjects/Keywords: Αξιόνια; axion; Dark matter; Dark energy

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APA (6^th Edition):

Gardikiotis, A. (2015). Search for axions via astrophysical obsevations. (Thesis). University of Patras; Πανεπιστήμιο Πατρών. Retrieved from http://hdl.handle.net/10442/hedi/36125

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Gardikiotis, Antonios. “Search for axions via astrophysical obsevations.” 2015. Thesis, University of Patras; Πανεπιστήμιο Πατρών. Accessed December 13, 2019. http://hdl.handle.net/10442/hedi/36125.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Gardikiotis, Antonios. “Search for axions via astrophysical obsevations.” 2015. Web. 13 Dec 2019.

Vancouver:

Gardikiotis A. Search for axions via astrophysical obsevations. [Internet] [Thesis]. University of Patras; Πανεπιστήμιο Πατρών; 2015. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/10442/hedi/36125.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Gardikiotis A. Search for axions via astrophysical obsevations. [Thesis]. University of Patras; Πανεπιστήμιο Πατρών; 2015. Available from: http://hdl.handle.net/10442/hedi/36125

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Illinois – Urbana-Champaign

5. Alizadeh, Esfandiar. Topics in cosmology: structure formation, dark energy and recombination.

Degree: PhD, 0240, 2011, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/26155

► The field of theoretical cosmology consists of numerous, inter-related branches, whose ambitious goal is to uncover the history of the universe from its beginning… (more)

▼ The field of theoretical cosmology consists of numerous, inter-related branches, whose ambitious goal is to uncover the history of the universe from its beginning to its future. Achieving this, no doubt, requires a deep understanding of many areas of physics. In this thesis I touch upon a few of these areas in which I worked during my PhD studies. Chapter~(\ref{ch:accretion}) describes our work in finding the accretion and merger history of dark matter halos. Dark matter halos are the collapsed dark matter structures in the late time evolution of the universe, whose existence is vital for the formation of galaxies in the Universe as they act as the potential wells where normal matter (collectively called Baryons) can accumulate, cool, and form stars. It is then no surprise that the properties of galaxies depends on the properties of the dark matter halo in which it resides, including its merger history, i.e. the number of times it merged with other halos. Even though these merger rates can be calculated theoretically for infinitesimal time steps, in order to find the merger history over an extended period of time one had to use either Monte-Carlo simulations to build up the total rates of merging and accreting from the infinitesimal rates or use N-body simulations. In chapter~(\ref{ch:accretion}) we show how we used random walk formalism to write down an {\it analytical} (integral) equation for the merger history of halos. We have solved this equation numerically and find very good agreement with Monte-Carlo simulations. This work can be used in theories of galaxy formation and evolution. We then switch from the overdense regions of the Universe, halos, to the underdense ones, voids. These structures have not attracted as much attention from cosmologists as their overdense counterparts in probing the cosmological models. We show here that the shapes of voids as a probe can be of use for future surveys to pin down the equation of state of the dark energy, i.e. the ratio of its pressure to its energy density. As first approximation, voids can be considered to be ellipsoids whose axis ratio evolution depends on the cosmological parameters. This, together with the fact that the initial distribution of the axis ratios is known (because the intial density field is Gaussian) can be used to infer the equation of state of the dark energy statistically from the observation of voids at different redshifts and with different sizes. The standard method of Fisher matrices is then used to forecast how well a future survey can measure the equation of state. We find promising results with constraints coming from void ellipticity measurements comparable to those of other standard methods. Chapter~(\ref{ch:H2}) goes farther back in the history of the Universe. During the {\it recombination} era, when the Universe was around a thousandth of its present size, it became cool enough that free electrons got captured by free protons to make hydrogen atoms. Consequently, the Thompson scattering of photons off of free… Advisors/Committee Members: Wandelt, Benjamin D. (advisor), Fields, Brian D. (Committee Chair), Wandelt, Benjamin D. (committee member), Thaler, Jonathan J. (committee member), Weissman, Michael B. (committee member).

Subjects/Keywords: Cosmology; Dark Matter Halos; Dark Energy; Recombination

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APA (6^th Edition):

Alizadeh, E. (2011). Topics in cosmology: structure formation, dark energy and recombination. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/26155

Chicago Manual of Style (16^th Edition):

Alizadeh, Esfandiar. “Topics in cosmology: structure formation, dark energy and recombination.” 2011. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed December 13, 2019. http://hdl.handle.net/2142/26155.

MLA Handbook (7^th Edition):

Alizadeh, Esfandiar. “Topics in cosmology: structure formation, dark energy and recombination.” 2011. Web. 13 Dec 2019.

Vancouver:

Alizadeh E. Topics in cosmology: structure formation, dark energy and recombination. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2011. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/2142/26155.

Council of Science Editors:

Alizadeh E. Topics in cosmology: structure formation, dark energy and recombination. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/26155

Universiteit Utrecht

6. Woude, D.C. van der. Late-time quantum backreaction of a nonminimally coupled massless scalar on FLRW.

Degree: 2014, Universiteit Utrecht

URL: http://dspace.library.uu.nl:8080/handle/1874/297088

► We investigate whether quantum fluctuations can have a significant impact on the evolution of the universe, by studying the (late-time) backreaction of a massless scalar… (more)

▼ We investigate whether quantum fluctuations can have a significant impact on the evolution of the universe, by studying the (late-time) backreaction of a massless scalar field with a possible coupling xi to the Ricci scalar on an FLRW background. The main motivation for this work is the observed late-time acceleration of the universe, for which no satisfactory explanation has been given yet. At the same time, cosmological perturbation theory establishes that we can take quantum fluctuations in a gravitational setting seriously, and some of their effects are well studied and in agreement with observations. This opens up the question if the energy density and pressure of these quantum fluctuations could account for the observed late-time acceleration of the universe. In addition to the usually assumed history of the universe (an inflationary, radiation and matter dominated period), we assume an initial radiation period in order to resolve IR divergences that are otherwise present in two point correlation functions for nonzero ξ. We canonically quantize the field and compute the one loop expectation value of the energy-momentum tensor with respect to the Bunch-Davies vacuum during radiation and matter domination. We compare the expectation values with the background quantities in order to estimate the significance of the quantum backreaction. For xi<0, we find that this backreaction can become significant, but the quantum energy density is negative during inflation and radiation. For xi<-0.057, the quantum energy density becomes comparable to the background energy density already during inflation, which makes late-time predictions for these values unreliable. For -0.057<xi<0, we find a transient phenomenon when the conformal Hubble rate becomes comparable to the conformal Hubble rate at the beginning of inflation. That is, when those scales become comparable, the quantum energy density goes from a period where it is negative but grows with respect to the background to a period where it is positive but decays with respect to the background. In between, there is a period where the energy density seems to grow from negative to positive rather quickly and during which the quantum fluid has negative pressure. We can tune the duration of inflation and the value of xi such that the backreaction is not too big during inflation and radiation and for which this transient behavior becomes significant at low redshift, rendering it potentially observable. Advisors/Committee Members: Prokopec, T..

Subjects/Keywords: cosmology; quantum; backreaction; dark; energy

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APA (6^th Edition):

Woude, D. C. v. d. (2014). Late-time quantum backreaction of a nonminimally coupled massless scalar on FLRW. (Masters Thesis). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/297088

Chicago Manual of Style (16^th Edition):

Woude, D C van der. “Late-time quantum backreaction of a nonminimally coupled massless scalar on FLRW.” 2014. Masters Thesis, Universiteit Utrecht. Accessed December 13, 2019. http://dspace.library.uu.nl:8080/handle/1874/297088.

MLA Handbook (7^th Edition):

Woude, D C van der. “Late-time quantum backreaction of a nonminimally coupled massless scalar on FLRW.” 2014. Web. 13 Dec 2019.

Vancouver:

Woude DCvd. Late-time quantum backreaction of a nonminimally coupled massless scalar on FLRW. [Internet] [Masters thesis]. Universiteit Utrecht; 2014. [cited 2019 Dec 13]. Available from: http://dspace.library.uu.nl:8080/handle/1874/297088.

Council of Science Editors:

Woude DCvd. Late-time quantum backreaction of a nonminimally coupled massless scalar on FLRW. [Masters Thesis]. Universiteit Utrecht; 2014. Available from: http://dspace.library.uu.nl:8080/handle/1874/297088

University of Manchester

7. Pediani, Steven. Dark energy and large scale structure.

Degree: PhD, 2011, University of Manchester

URL: https://www.research.manchester.ac.uk/portal/en/theses/dark-energy-and-large-scale-structure(44224ea0-265c-4d78-931a-298d79d3ab9d).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542709

► Currently one of the most exciting problems in cosmology is the nature of dark energy, which is responsible for the late time accelerated expansion of… (more)

Subjects/Keywords: 520; Elastic Dark Energy; Cosmology

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APA (6^th Edition):

Pediani, S. (2011). Dark energy and large scale structure. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/dark-energy-and-large-scale-structure(44224ea0-265c-4d78-931a-298d79d3ab9d).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542709

Chicago Manual of Style (16^th Edition):

Pediani, Steven. “Dark energy and large scale structure.” 2011. Doctoral Dissertation, University of Manchester. Accessed December 13, 2019. https://www.research.manchester.ac.uk/portal/en/theses/dark-energy-and-large-scale-structure(44224ea0-265c-4d78-931a-298d79d3ab9d).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542709.

MLA Handbook (7^th Edition):

Pediani, Steven. “Dark energy and large scale structure.” 2011. Web. 13 Dec 2019.

Vancouver:

Pediani S. Dark energy and large scale structure. [Internet] [Doctoral dissertation]. University of Manchester; 2011. [cited 2019 Dec 13]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/dark-energy-and-large-scale-structure(44224ea0-265c-4d78-931a-298d79d3ab9d).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542709.

Council of Science Editors:

Pediani S. Dark energy and large scale structure. [Doctoral Dissertation]. University of Manchester; 2011. Available from: https://www.research.manchester.ac.uk/portal/en/theses/dark-energy-and-large-scale-structure(44224ea0-265c-4d78-931a-298d79d3ab9d).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542709

University of Oklahoma

8. Chuang, Chia-Hsun. Probing Dark Energy Using Galaxy Clustering Data.

Degree: PhD, 2011, University of Oklahoma

URL: http://hdl.handle.net/11244/318805

Our results represent the first measurements of H(z) and DA(z) from galaxy clustering data. Our work has significant implications for future surveys in establishing the feasibility of measuring both H(z) and DA(z) from galaxy clustering data. Advisors/Committee Members: Wang, Yun (advisor).

Subjects/Keywords: Dark energy (Astronomy); Galaxies – Clusters

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APA (6^th Edition):

Chuang, C. (2011). Probing Dark Energy Using Galaxy Clustering Data. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/318805

Chicago Manual of Style (16^th Edition):

Chuang, Chia-Hsun. “Probing Dark Energy Using Galaxy Clustering Data.” 2011. Doctoral Dissertation, University of Oklahoma. Accessed December 13, 2019. http://hdl.handle.net/11244/318805.

MLA Handbook (7^th Edition):

Chuang, Chia-Hsun. “Probing Dark Energy Using Galaxy Clustering Data.” 2011. Web. 13 Dec 2019.

Vancouver:

Chuang C. Probing Dark Energy Using Galaxy Clustering Data. [Internet] [Doctoral dissertation]. University of Oklahoma; 2011. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/11244/318805.

Council of Science Editors:

Chuang C. Probing Dark Energy Using Galaxy Clustering Data. [Doctoral Dissertation]. University of Oklahoma; 2011. Available from: http://hdl.handle.net/11244/318805

University of Pennsylvania

9. Brout, Dillon. Measuring Cosmic Acceleration And Constraining Dark Energy Models With Transients Discovered In The Dark Energy Survey.

Degree: 2019, University of Pennsylvania

URL: https://repository.upenn.edu/edissertations/3394

► Now 20 years after the discovery of the accelerating universe, distance measurements from Type Ia supernovae over a large span in redshift remain a vital… (more)

Subjects/Keywords: Cosmology; Dark Energy; Dark Energy Survey; Supernovae; Astrophysics and Astronomy; Physics

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APA (6^th Edition):

Brout, D. (2019). Measuring Cosmic Acceleration And Constraining Dark Energy Models With Transients Discovered In The Dark Energy Survey. (Thesis). University of Pennsylvania. Retrieved from https://repository.upenn.edu/edissertations/3394

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Brout, Dillon. “Measuring Cosmic Acceleration And Constraining Dark Energy Models With Transients Discovered In The Dark Energy Survey.” 2019. Thesis, University of Pennsylvania. Accessed December 13, 2019. https://repository.upenn.edu/edissertations/3394.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Brout, Dillon. “Measuring Cosmic Acceleration And Constraining Dark Energy Models With Transients Discovered In The Dark Energy Survey.” 2019. Web. 13 Dec 2019.

Vancouver:

Brout D. Measuring Cosmic Acceleration And Constraining Dark Energy Models With Transients Discovered In The Dark Energy Survey. [Internet] [Thesis]. University of Pennsylvania; 2019. [cited 2019 Dec 13]. Available from: https://repository.upenn.edu/edissertations/3394.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Brout D. Measuring Cosmic Acceleration And Constraining Dark Energy Models With Transients Discovered In The Dark Energy Survey. [Thesis]. University of Pennsylvania; 2019. Available from: https://repository.upenn.edu/edissertations/3394

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

10. Olivari, Lucas Collis. Influência da Transferência de Momento-Energia na Interação entre Matéria e Energia escura.

Degree: Mestrado, Física, 2014, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-25092014-133708/ ;

►

Neste trabalho, estudamos modelos cosmológicos em que a energia escura foi tratada como um campo de matéria que interage com a matéria escura. Três modelos… (more)

▼

Neste trabalho, estudamos modelos cosmológicos em que a energia escura foi tratada como um campo de matéria que interage com a matéria escura. Três modelos distintos foram considerados. O primeiro trata tanto a matéria escura fria quanto a energia escura como fluidos perfeitos. O termo de interação entre eles é dado por uma expressão com origem fenomenológica que postulamos existir na equação de balanço entre esses dois fluidos. Dadas as equações no universo plano de Friedmann-Robertson-Walker (FRW), pudemos escrever uma versão covariante para as equações de balanço. Com isso, as equações de balanço em um universo de FRW perturbado linearmente foram obtidas. Isso, por sua vez, permitiu que a estabilidade das equações diferenciais obtidas fosse estudada. O segundo modelo tem origem em modelos de f(R). Esses modelos propõem uma generalização da Relatividade Geral ao considerar a ação da gravidade como um funcional do escalar de Ricci, R. Através de uma transformação conforme, foi possível reinterpretar os modelos de f(R) como modelos em que um campo escalar canônico, que representa a energia escura, interage com os campos da matéria. Através do princípio da ação, obtivemos as equações de movimento e o tensor de energia-momento para nosso sistema. Com o campo escalar sendo interpretado como um fluido perfeito, pudemos, por fim, obter equações de balanço entre fluidos perfeitos tanto no nível de fundo quanto no universo perturbado linearmente. O terceiro modelo começa com a lagrangiana, em um espaço-tempo de FRW, de um campo escalar canônico, que representa a energia escura, e um campo fermiônico de spin-1/2, que representa a matéria escura. Um termo de interação de Yukawa entre esses campos foi postulado existir na lagrangiana. Novamente através do princípio da ação, obtivemos as equações de movimento e o tensor de energia-momento para esses campos. Essas equações de movimento puderam, por fim, ser reescritas como equações de balanço entre fluidos perfeitos tanto no nível de fundo quanto no universo perturbado linearmente.

In this work we studied cosmological models in which the dark energy was treated as a field of matter that interacts with dark matter. Three different models were considered. The first one treats both the cold dark matter and the dark energy as perfect fluids. The interaction term between them is given by a expression with phenomenological origin that we postulated to exist in the balance equations between these two fluids. Given the equations in the flat Friedmann-Robertson-Walker (FRW) universe, we wrote a covariant version of the balance equations. Thus, the balance equations in a linearly perturbed FRW universe were obtained. This, in turn, allowed the stability of the obtained differential equations to be studied. The second model comes from f(R) models. These models propose a generalization of General Relativity by considering the action for gravity as a functional of the Ricci scalar, R. Through a conformal transformation, it was possible to reinterpret the f(R) models as models in which…

Advisors/Committee Members: Abdalla, Elcio.

Subjects/Keywords: Cosmologia; Cosmology; Dark energy; Dark matter; Energia escura; Matéria escura

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APA (6^th Edition):

Olivari, L. C. (2014). Influência da Transferência de Momento-Energia na Interação entre Matéria e Energia escura. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/43/43134/tde-25092014-133708/ ;

Chicago Manual of Style (16^th Edition):

Olivari, Lucas Collis. “Influência da Transferência de Momento-Energia na Interação entre Matéria e Energia escura.” 2014. Masters Thesis, University of São Paulo. Accessed December 13, 2019. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-25092014-133708/ ;.

MLA Handbook (7^th Edition):

Olivari, Lucas Collis. “Influência da Transferência de Momento-Energia na Interação entre Matéria e Energia escura.” 2014. Web. 13 Dec 2019.

Vancouver:

Olivari LC. Influência da Transferência de Momento-Energia na Interação entre Matéria e Energia escura. [Internet] [Masters thesis]. University of São Paulo; 2014. [cited 2019 Dec 13]. Available from: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-25092014-133708/ ;.

Council of Science Editors:

Olivari LC. Influência da Transferência de Momento-Energia na Interação entre Matéria e Energia escura. [Masters Thesis]. University of São Paulo; 2014. Available from: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-25092014-133708/ ;

11. Costa, André Alencar da. Observational Constraints on Models with an Interaction between Dark Energy and Dark Matter.

Degree: PhD, Física, 2014, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-20012015-123002/ ;

►

In this thesis we go beyond the standard cosmological LCDM model and study the effect of an interaction between dark matter and dark energy. Although… (more)

Subjects/Keywords: Cosmologia; Cosmology; Dark Energy; Dark Matter; Energia Escura; Matéria Escura

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APA (6^th Edition):

Costa, A. A. d. (2014). Observational Constraints on Models with an Interaction between Dark Energy and Dark Matter. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/43/43134/tde-20012015-123002/ ;

Chicago Manual of Style (16^th Edition):

Costa, André Alencar da. “Observational Constraints on Models with an Interaction between Dark Energy and Dark Matter.” 2014. Doctoral Dissertation, University of São Paulo. Accessed December 13, 2019. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-20012015-123002/ ;.

MLA Handbook (7^th Edition):

Costa, André Alencar da. “Observational Constraints on Models with an Interaction between Dark Energy and Dark Matter.” 2014. Web. 13 Dec 2019.

Vancouver:

Costa AAd. Observational Constraints on Models with an Interaction between Dark Energy and Dark Matter. [Internet] [Doctoral dissertation]. University of São Paulo; 2014. [cited 2019 Dec 13]. Available from: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-20012015-123002/ ;.

Council of Science Editors:

Costa AAd. Observational Constraints on Models with an Interaction between Dark Energy and Dark Matter. [Doctoral Dissertation]. University of São Paulo; 2014. Available from: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-20012015-123002/ ;

12. Graef, Leila Lobato. Um modelo para decaimento da energia escura.

Degree: Mestrado, Física, 2012, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-08082012-150548/ ;

►

Neste trabalho discutimos um modelo baseado em teoria de campos para descrever a energia escura, no qual ela é representada por uma partícula ultra-leve situada… (more)

Subjects/Keywords: Dark energy; Dark Matter; Energia Escura; Matéria escura

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APA (6^th Edition):

Graef, L. L. (2012). Um modelo para decaimento da energia escura. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/43/43134/tde-08082012-150548/ ;

Chicago Manual of Style (16^th Edition):

Graef, Leila Lobato. “Um modelo para decaimento da energia escura.” 2012. Masters Thesis, University of São Paulo. Accessed December 13, 2019. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-08082012-150548/ ;.

MLA Handbook (7^th Edition):

Graef, Leila Lobato. “Um modelo para decaimento da energia escura.” 2012. Web. 13 Dec 2019.

Vancouver:

Graef LL. Um modelo para decaimento da energia escura. [Internet] [Masters thesis]. University of São Paulo; 2012. [cited 2019 Dec 13]. Available from: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-08082012-150548/ ;.

Council of Science Editors:

Graef LL. Um modelo para decaimento da energia escura. [Masters Thesis]. University of São Paulo; 2012. Available from: http://www.teses.usp.br/teses/disponiveis/43/43134/tde-08082012-150548/ ;

Universidade do Rio Grande do Norte

13. Silva, Heydson Henrique Brito da. Setor escuro do universo: uma análise termodinâmica .

Degree: 2014, Universidade do Rio Grande do Norte

URL: http://repositorio.ufrn.br/handle/123456789/16627

► Significant observational effort has been directed to unveiling the nature of the so-called dark energy. However, given the large number of theoretical possibilities, it is… (more)

Subjects/Keywords: Energia escura. Matéria escura. Termodinâmica; Dark energy. Dark matter. Thermodynamics

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APA (6^th Edition):

Silva, H. H. B. d. (2014). Setor escuro do universo: uma análise termodinâmica . (Doctoral Dissertation). Universidade do Rio Grande do Norte. Retrieved from http://repositorio.ufrn.br/handle/123456789/16627

Chicago Manual of Style (16^th Edition):

Silva, Heydson Henrique Brito da. “Setor escuro do universo: uma análise termodinâmica .” 2014. Doctoral Dissertation, Universidade do Rio Grande do Norte. Accessed December 13, 2019. http://repositorio.ufrn.br/handle/123456789/16627.

MLA Handbook (7^th Edition):

Silva, Heydson Henrique Brito da. “Setor escuro do universo: uma análise termodinâmica .” 2014. Web. 13 Dec 2019.

Vancouver:

Silva HHBd. Setor escuro do universo: uma análise termodinâmica . [Internet] [Doctoral dissertation]. Universidade do Rio Grande do Norte; 2014. [cited 2019 Dec 13]. Available from: http://repositorio.ufrn.br/handle/123456789/16627.

Council of Science Editors:

Silva HHBd. Setor escuro do universo: uma análise termodinâmica . [Doctoral Dissertation]. Universidade do Rio Grande do Norte; 2014. Available from: http://repositorio.ufrn.br/handle/123456789/16627

14. Sanjay Sarkar. A study of dark matter and dark energy;.

Degree: Mathematics, 2014, Gauhati University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/20316

newline

Advisors/Committee Members: Chandra Rekha Mahanta.

Subjects/Keywords: Dark energy; Dark matter; Mathematics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sarkar, S. (2014). A study of dark matter and dark energy;. (Thesis). Gauhati University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/20316

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Sarkar, Sanjay. “A study of dark matter and dark energy;.” 2014. Thesis, Gauhati University. Accessed December 13, 2019. http://shodhganga.inflibnet.ac.in/handle/10603/20316.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Sarkar, Sanjay. “A study of dark matter and dark energy;.” 2014. Web. 13 Dec 2019.

Vancouver:

Sarkar S. A study of dark matter and dark energy;. [Internet] [Thesis]. Gauhati University; 2014. [cited 2019 Dec 13]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/20316.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sarkar S. A study of dark matter and dark energy;. [Thesis]. Gauhati University; 2014. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/20316

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Universidade do Rio Grande do Norte

15. Silva, Heydson Henrique Brito da. Setor escuro do universo: uma análise termodinâmica .

Degree: 2014, Universidade do Rio Grande do Norte

URL: http://repositorio.ufrn.br/handle/123456789/16627

► Significant observational effort has been directed to unveiling the nature of the so-called dark energy. However, given the large number of theoretical possibilities, it is… (more)

Subjects/Keywords: Energia escura. Matéria escura. Termodinâmica; Dark energy. Dark matter. Thermodynamics

Record Details Similar Records Cite « Share

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Silva, H. H. B. d. (2014). Setor escuro do universo: uma análise termodinâmica . (Thesis). Universidade do Rio Grande do Norte. Retrieved from http://repositorio.ufrn.br/handle/123456789/16627

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Silva, Heydson Henrique Brito da. “Setor escuro do universo: uma análise termodinâmica .” 2014. Thesis, Universidade do Rio Grande do Norte. Accessed December 13, 2019. http://repositorio.ufrn.br/handle/123456789/16627.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Silva, Heydson Henrique Brito da. “Setor escuro do universo: uma análise termodinâmica .” 2014. Web. 13 Dec 2019.

Vancouver:

Silva HHBd. Setor escuro do universo: uma análise termodinâmica . [Internet] [Thesis]. Universidade do Rio Grande do Norte; 2014. [cited 2019 Dec 13]. Available from: http://repositorio.ufrn.br/handle/123456789/16627.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Silva HHBd. Setor escuro do universo: uma análise termodinâmica . [Thesis]. Universidade do Rio Grande do Norte; 2014. Available from: http://repositorio.ufrn.br/handle/123456789/16627

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Edinburgh

16. Rowe, Barnaby Thomas Peter. Cosmological applications of weak gravitational flexion.

Degree: 2008, University of Edinburgh

URL: http://hdl.handle.net/1842/3502

► Modern cosmology has reached an important juncture, at which the ability to make measurements of unprecedented accuracy has led to conclusions that are a fundamental… (more)

▼ Modern cosmology has reached an important juncture, at which the ability to make measurements of unprecedented accuracy has led to conclusions that are a fundamental challenge to natural science. The discovery that, in our current best model, the dynamics of the Universe are completely dominated by unseen dark matter and dark energy can do little but completely alter the shape of physics research in the 21st Century. Unfortunately,much of our insight into these phenomenamust come from observations of visible matter alone; this raises serious problems, as the tracing of dark matter by visible matter is as yet poorly understood. Gravitational lensing offers strong prospects for probing the interwoven history of dark and visible matter, as mass in any form may be detected where it exists untraced by baryons. In this Thesis I describe advances made in the field of weak gravitational lensing, which constrains the properties of the matter distribution on cosmological scales using a statistical analysis of the coherent gravitational distortions of distant galaxy images. I summarize the development of gravitational flexion, a higher order extension to traditional weak lensing, and describe my work done to bring the study of flexion to a stage where it may be employed to make accurate cosmological measurements. I show how flexion is sensitive to matter structure on smaller physical scales than existing lensing techniques and, therefore, promises to shed new light upon key untested predictions of cosmological models if it can be measured to sufficient accuracy. I discuss the success of my efforts in this direction, and describe the issues to be encountered in the careful analysis of this subtle gravitational signal. This research has involved advances in many areas: the calculation of theoretical flexion predictions, the refinement of image analysis methods for accurate galaxy shape estimation, and the practical application of these new flexion techniques to extragalactic imaging data. The culmination of these efforts is a new maximum likelihood analysis of the galaxy-galaxy lensing signal in the Hubble Space Telescope Galaxy Evolution from Morphology and SEDs (GEMS) Survey, incorporating improvements and modifications necessary for the combination of flexion with traditional weak lensing measurements. The results of this work, and particularly the extent to which measurements of flexion provide extra cosmological insight, are discussed in detail. The conclusion is a summary of all that has been learned about the use of flexion as an accurate probe of cosmology, and a discussion of its prospects for answering some of the many questions that remain about dark matter. Within the next few year wide-area survey telescopes will begin imaging huge volumes of deep space, with the measurement of the gravitational lensing signal being given high priority in the analysis of these data. Within this context, the primary inquiry of this Thesis is the extent to which the application of flexion measurement techniques will help shed new light…

Subjects/Keywords: 520; cosmology; Dark energy (Astronomy); Dark matter (Astronomy)

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APA (6^th Edition):

Rowe, B. T. P. (2008). Cosmological applications of weak gravitational flexion. (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/3502

Chicago Manual of Style (16^th Edition):

Rowe, Barnaby Thomas Peter. “Cosmological applications of weak gravitational flexion.” 2008. Doctoral Dissertation, University of Edinburgh. Accessed December 13, 2019. http://hdl.handle.net/1842/3502.

MLA Handbook (7^th Edition):

Rowe, Barnaby Thomas Peter. “Cosmological applications of weak gravitational flexion.” 2008. Web. 13 Dec 2019.

Vancouver:

Rowe BTP. Cosmological applications of weak gravitational flexion. [Internet] [Doctoral dissertation]. University of Edinburgh; 2008. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/1842/3502.

Council of Science Editors:

Rowe BTP. Cosmological applications of weak gravitational flexion. [Doctoral Dissertation]. University of Edinburgh; 2008. Available from: http://hdl.handle.net/1842/3502

Cornell University

17. Laszlo, Istvan. Probing The Dark Sector .

Degree: 2012, Cornell University

URL: http://hdl.handle.net/1813/31428

► Cosmology today is in a golden era, data is pouring in and exciting and challenging questions are being raised. We know that we live in… (more)

▼ Cosmology today is in a golden era, data is pouring in and exciting and challenging questions are being raised. We know that we live in an accelerating Universe populated largely by dark matter and dark energy, yet we have little information on the nature of either of these mysterious components. Theories abound and data is coming in with far greater quantity and precision than ever before and promises to enable distinguishing between these theories, however as we improve instruments we find ourselves plagued with how to effectively model signatures of the theories, and also how to truly interpret the data. Uncertainties in the nonlinear regime of theoretical predictions and in handling astrophysical systematics in observables are now emerging as leading issues that hinder constraining power. This thesis investigates the dark sector, considering first how one can approach the generation of correct nonlinear predictions for growth where gravity is modified (MG) in an attempt to explain the acceleration of the Universe. Next, we examine a possible Yukawa type self coupling of dark matter, motivated by the problems in small scale [LAMDA]CDM simulations of growth of structure, such as the cuspiness of halo density profiles and over production of small haloes. Finally, forecasts of constraining power for future surveys are made, in light of a key astrophysical systematic in weak lensing observations, namely the actual alignment of galaxies that form in the same halo which mixes in with the lensing signal in two ways, both generically summed up as Intrinsic Alignments(IA). We find that the standard approach of using fits developed in [LAMDA]CDM to generate nonlinear predicted matter power spectra for MG theories is valid, at least to mildly nonlinear scales. In the context of dark matter, there is no evidence against an interaction, yet also no preference for one. Finally for future survey forecasts, we find that previous forecasts were optimistic, and without a strong model for IA, additional probes will be required to compliment the weak lensing shear results and arrive at constraints similar to those derived from a survey in the absence of or with perfectly known IA contamination. Advisors/Committee Members: Wasserman, Ira M (committeeMember), Flanagan, Eanna E (committeeMember), Herter, Terry Lee (committeeMember).

Subjects/Keywords: Cosmology; Weak lensing; Dark Matter; Dark Energy; Intrinsic Alignments; Fisher matrix

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APA (6^th Edition):

Laszlo, I. (2012). Probing The Dark Sector . (Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/31428

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Laszlo, Istvan. “Probing The Dark Sector .” 2012. Thesis, Cornell University. Accessed December 13, 2019. http://hdl.handle.net/1813/31428.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Laszlo, Istvan. “Probing The Dark Sector .” 2012. Web. 13 Dec 2019.

Vancouver:

Laszlo I. Probing The Dark Sector . [Internet] [Thesis]. Cornell University; 2012. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/1813/31428.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Laszlo I. Probing The Dark Sector . [Thesis]. Cornell University; 2012. Available from: http://hdl.handle.net/1813/31428

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Sydney

18. Mahdi, Hareth Saad. Probing Galaxy Clusters in Non-standard Cosmologies with Gravitational Lensing .

Degree: 2015, University of Sydney

URL: http://hdl.handle.net/2123/14224

► What is the nature of the dark sector in the Universe? This is one of the most fundamental questions in modern cosmology. The so-called standard… (more)

▼ What is the nature of the dark sector in the Universe? This is one of the most fundamental questions in modern cosmology. The so-called standard model of cosmology (ΛCDM) fails to reproduce some observational data and thus exploring potential alternative cosmologies is of great importance for cosmology. In this research I probe two potential alternative cosmologies, ΛWDM and dynamical dark energy models, using both strong and weak gravitational lensing. Gravitational lensing is a powerful probe of the distribution of matter including dark matter. The mass of dark matter particles in the ΛWDM cosmologies is on the order of ∼ keV and the density fluctuations are suppressed on small scales. The evolving dark energy cosmologies assume that the role of dark energy is played by a dynamical scalar field rather than a cosmological constant with a constant energy density. The structures in non-standard cosmologies form and evolve differently from those in the ΛCDM model, and thus the internal properties and abundance of (sub)structures are not the same. Consequently, the strong and weak gravitational lensing which probe the matter distribution will differ. I find that both strong and weak lensing can probe for the presence of Warm Dark Matter. WDM clusters have slightly larger Einstein radii and lensing cross-sections than their CDM counterparts. The higher lensing efficiency in WDM cosmologies is a result of the physical size of dark matter haloes and their internal properties. WDM substructures are more extended than CDM ones, and hence they significantly alter the size of critical lines and caustics. The WDM substructures can also boost the cross-section for multiple images. In addition, they have a significant impact on the magnification distribution. Although the slope of the magnification distribution is the same for both WDM and CDM cosmologies, there is an excess in the magnification distribution of WDM model relative to that of the CDM one. In addition, the area of high magnification in the weak lensing regions of WDM models is larger than that of CDM ones. The matter in WDM cosmologies is more homogeneously distributed than their CDM counterparts, and hence there would be more matter in the beam. I also find that the impact of WDM on the weak lensing signature can be explored by means of the observed number density of galaxies as well as the reconstruction of shear and convergence. However, I find that the latter method is more reliable. Despite the difficulties with the method used to reconstruct the convergence, the spatial distributions of the reconstructed convergence in the WDM and CDM models show that the matter in the WDM cosmology is more homogeneously distributed than that in the CDM one. Strong lensing analyses in dynamical dark energy cosmologies showed that the Einstein radius and cross-section of φCDM clusters do not differ significantly from those of the ΛCDM counterparts. The φCDM clusters cannot reproduce the observations of 12 MACS clusters in the literature and thus the φCDM model cannot resolve…

Subjects/Keywords: Gravitational lensing; Dark matter; Dark energy; Galaxy clusters; Cosmology; Numerical simulations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mahdi, H. S. (2015). Probing Galaxy Clusters in Non-standard Cosmologies with Gravitational Lensing . (Thesis). University of Sydney. Retrieved from http://hdl.handle.net/2123/14224

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mahdi, Hareth Saad. “Probing Galaxy Clusters in Non-standard Cosmologies with Gravitational Lensing .” 2015. Thesis, University of Sydney. Accessed December 13, 2019. http://hdl.handle.net/2123/14224.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mahdi, Hareth Saad. “Probing Galaxy Clusters in Non-standard Cosmologies with Gravitational Lensing .” 2015. Web. 13 Dec 2019.

Vancouver:

Mahdi HS. Probing Galaxy Clusters in Non-standard Cosmologies with Gravitational Lensing . [Internet] [Thesis]. University of Sydney; 2015. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/2123/14224.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mahdi HS. Probing Galaxy Clusters in Non-standard Cosmologies with Gravitational Lensing . [Thesis]. University of Sydney; 2015. Available from: http://hdl.handle.net/2123/14224

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of the Western Cape

19. Cunnama, Daniel. Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama .

Degree: 2013, University of the Western Cape

URL: http://hdl.handle.net/11394/4042

► Numerical simulations play a crucial role in testing current cosmological models of the formation and evolution of the cosmic structure observed in the modern Universe.… (more)

▼ Numerical simulations play a crucial role in testing current cosmological models of the formation and evolution of the cosmic structure observed in the modern Universe. Simulations of the collapse of both baryonic and non-baryonic matter under the influence of gravity have yielded important results in our understanding of the large scale structure of the Universe. In addition to the underlying large scale structure, simulations which include gas dynamics can give us valuable insight into, and allow us to make testable predictions on, the nature and distribution of baryonic matter on a wide range of scales. In this work we give an overview of cosmological simulations and the methods employed in the solution of many body problems. We then present three projects focusing on scales ranging from individual galaxies to the cosmic web connecting clusters of galaxies thereby demonstrating the potential and diversity of numerical simulations in the fields of cosmology and astrophysics. We firstly investigate the environmental dependance of neutral hydrogen in the intergalactic medium by utilising high resolution cosmological hydrodynamic simulations in Chapter 3. We find that the extent of the neutral hydrogen radial profile is dependant on both the environment of the galaxy and its classification within the group ie. whether it is a central or satellite galaxy. We investigate whether this effect could arise from ram pressure forces exerted on the galaxies and find good agreement between galaxies experiencing high ram pressure forces and those with a low neutral hydrogen content. In Chapter 4 we investigate the velocity–shape alignment of clusters in a dark matter only simulation and the effect of such an alignment on measurements of the kinetic Sunyaev–Zeldovich (kSZ) effect. We find an alignment not only exists but can lead to an enhancement in the kSZ signal of up to 60% when the cluster is orientated along the line-of-sight. Finally we attempt to identify shocked gas in clusters and filaments using intermediate resolution cosmological hydrodynamic simulations in Chapter 5 with a view to predicting the synchrotron emission from these areas, something that may be detectable with the Square Kilometer Array.

Subjects/Keywords: Dark matter; dark energy; direct method; particle mesh codes

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Cunnama, D. (2013). Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama . (Thesis). University of the Western Cape. Retrieved from http://hdl.handle.net/11394/4042

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Cunnama, Daniel. “Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama .” 2013. Thesis, University of the Western Cape. Accessed December 13, 2019. http://hdl.handle.net/11394/4042.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Cunnama, Daniel. “Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama .” 2013. Web. 13 Dec 2019.

Vancouver:

Cunnama D. Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama . [Internet] [Thesis]. University of the Western Cape; 2013. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/11394/4042.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Cunnama D. Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama . [Thesis]. University of the Western Cape; 2013. Available from: http://hdl.handle.net/11394/4042

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of California – Irvine

20. Keeley, Ryan E. Cosmology and Astro-particle Physics: What is Dark Matter and What is Dark Energy?.

Degree: Physics, 2018, University of California – Irvine

URL: http://www.escholarship.org/uc/item/0vv986jn

► We model the expansion history of the Universe as a Gaussian process and find constraints on the dark energy density and its low-redshift evolution using… (more)

▼ We model the expansion history of the Universe as a Gaussian process and find constraints on the dark energy density and its low-redshift evolution using distances inferred from the Luminous Red Galaxy (LRG) and Lyman-alpha (Lyα) datasets of the Baryon Oscillation Spectroscopic Survey, supernova data from the Joint Light-curve Analysis (JLA) sample, Cosmic Microwave Background (CMB) data from the Planck satellite, and local measurement of the Hubble parameter from the Hubble Space Telescope (\mathsf H0). Our analysis shows that the CMB, LRG, Lyα, and JLA data are consistent with each other and with a ΛCDM cosmology, but the {\mathsf H0} data is inconsistent at moderate significance. Including the presence of dark radiation does not alleviate the {\mathsf H0} tension in our analysis. While some of these results have been noted previously, the strength here lies in that we do not assume a particular cosmological model. We calculate the growth of the gravitational potential in General Relativity corresponding to these general expansion histories and show that they are well-approximated by Ω_m^0.55 given the current precision. We assess the prospects for upcoming surveys to measure deviations from ΛCDM using this model-independent approach.We incorporate Milky Way dark matter halo profile uncertainties, as well as an accounting of diffuse gamma-ray emission uncertainties in dark matter annihilation models for the Galactic Center Extended gamma-ray excess (GCE) detected by the Fermi Gamma Ray Space Telescope. The range of particle annihilation rate and masses expand when including these unknowns. However, empirical determinations of the Milky Way halo's local density and density profile leave the signal region to be in considerable tension with dark matter annihilation searches from combined dwarf galaxy analyses. The GCE and dwarf tension can be alleviated if: one, the halo is extremely concentrated or strongly contracted; two, the dark matter annihilation signal differentiates between dwarfs and the Galactic Center; or, three, local stellar density measures are found to be significantly lower, like that from recent stellar counts, pushing up the local dark matter density.The Milky Way's Galactic Center harbors a gamma-ray excess that is a candidate signal of annihilating dark matter. Dwarf galaxies remain predominantly dark in their expected commensurate emission. We quantify the degree of consistency between these two observations through a joint likelihood analysis. In doing so I incorporate Milky Way dark matter halo profile uncertainties, as well as an accounting of diffuse gamma-ray emission uncertainties in dark matter annihilation models for the Galactic Center Extended gamma-ray excess (GCE) detected by the {\em Fermi Gamma-Ray Space Telescope}. The preferred range of annihilation rates and masses expands when including these unknowns. Even so, using two recent determinations of the Milky Way halo's local density leave the GCE preferred region of…

Subjects/Keywords: Physics; Astrophysics; Astro-Particle; Cosmolgy; Dark Energy; Dark Matter

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APA (6^th Edition):

Keeley, R. E. (2018). Cosmology and Astro-particle Physics: What is Dark Matter and What is Dark Energy?. (Thesis). University of California – Irvine. Retrieved from http://www.escholarship.org/uc/item/0vv986jn

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Keeley, Ryan E. “Cosmology and Astro-particle Physics: What is Dark Matter and What is Dark Energy?.” 2018. Thesis, University of California – Irvine. Accessed December 13, 2019. http://www.escholarship.org/uc/item/0vv986jn.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Keeley, Ryan E. “Cosmology and Astro-particle Physics: What is Dark Matter and What is Dark Energy?.” 2018. Web. 13 Dec 2019.

Vancouver:

Keeley RE. Cosmology and Astro-particle Physics: What is Dark Matter and What is Dark Energy?. [Internet] [Thesis]. University of California – Irvine; 2018. [cited 2019 Dec 13]. Available from: http://www.escholarship.org/uc/item/0vv986jn.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Keeley RE. Cosmology and Astro-particle Physics: What is Dark Matter and What is Dark Energy?. [Thesis]. University of California – Irvine; 2018. Available from: http://www.escholarship.org/uc/item/0vv986jn

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Drexel University

21. Pan, Danny C. Cosmic voids and void properties.

Degree: 2011, Drexel University

URL: http://hdl.handle.net/1860/3532

►

The cosmic energy budget of the standard model of cosmology ( CDM) dictates that 72% of the Universe is Dark Energy (undetected, unknown), 23% Dark… (more)

Subjects/Keywords: Physics; Astrophysics; Dark energy (Astronomy); Dark matter (Astronomy)

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APA (6^th Edition):

Pan, D. C. (2011). Cosmic voids and void properties. (Thesis). Drexel University. Retrieved from http://hdl.handle.net/1860/3532

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Pan, Danny C. “Cosmic voids and void properties.” 2011. Thesis, Drexel University. Accessed December 13, 2019. http://hdl.handle.net/1860/3532.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Pan, Danny C. “Cosmic voids and void properties.” 2011. Web. 13 Dec 2019.

Vancouver:

Pan DC. Cosmic voids and void properties. [Internet] [Thesis]. Drexel University; 2011. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/1860/3532.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Pan DC. Cosmic voids and void properties. [Thesis]. Drexel University; 2011. Available from: http://hdl.handle.net/1860/3532

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Western Australia

22. Beutler, Florian. Cosmology with the 6-degree field galaxy survey.

Degree: PhD, 2012, University of Western Australia

URL: http://repository.uwa.edu.au:80/R/?func=dbin-jump-full&object_id=34609&local_base=GEN01-INS01

►

[Truncated abstract] This thesis presents the analysis of the clustering of galaxies in the 6dF Galaxy Survey (6dFGS). At large separation scales the baryon acoustic… (more)

▼

[Truncated abstract] This thesis presents the analysis of the clustering of galaxies in the 6dF Galaxy Survey (6dFGS). At large separation scales the baryon acoustic oscillation (BAO) signal is detected which allows a measurement of the distance ratio, rs(zd)=DV (zeff) = 0:336±0:015 (4:5% precision), where rs(zd) is the sound horizon at the drag epoch zd and DV (zeff) is the absolute distance to the effective redshift of the survey, given by zeff = 0:106. The low effective redshift of 6dFGS makes it a competitive and independent alternative to Cepheids and low-z supernovae in constraining the Hubble constant. The value of the Hubble constant reported in this work is H0 = 67:0±3:2 km s¹ Mpc±¹ (4:8% precision) which depends only on the WMAP-7 calibration of the sound horizon and on the galaxy clustering in 6dFGS. Compared to earlier BAO studies at higher redshift, this analysis is less dependent on other cosmological parameters. This thesis also includes forecasts for the proposed TAIPAN all-southern-sky optical galaxy survey and the radio WALLABY survey. TAIPAN has the potential to constrain the Hubble constant with 3% precision using the BAO technique...

Subjects/Keywords: Cosmology; Dark energy; Hubble constant; General relativity

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APA (6^th Edition):

Beutler, F. (2012). Cosmology with the 6-degree field galaxy survey. (Doctoral Dissertation). University of Western Australia. Retrieved from http://repository.uwa.edu.au:80/R/?func=dbin-jump-full&object_id=34609&local_base=GEN01-INS01

Chicago Manual of Style (16^th Edition):

Beutler, Florian. “Cosmology with the 6-degree field galaxy survey.” 2012. Doctoral Dissertation, University of Western Australia. Accessed December 13, 2019. http://repository.uwa.edu.au:80/R/?func=dbin-jump-full&object_id=34609&local_base=GEN01-INS01.

MLA Handbook (7^th Edition):

Beutler, Florian. “Cosmology with the 6-degree field galaxy survey.” 2012. Web. 13 Dec 2019.

Vancouver:

Beutler F. Cosmology with the 6-degree field galaxy survey. [Internet] [Doctoral dissertation]. University of Western Australia; 2012. [cited 2019 Dec 13]. Available from: http://repository.uwa.edu.au:80/R/?func=dbin-jump-full&object_id=34609&local_base=GEN01-INS01.

Council of Science Editors:

Beutler F. Cosmology with the 6-degree field galaxy survey. [Doctoral Dissertation]. University of Western Australia; 2012. Available from: http://repository.uwa.edu.au:80/R/?func=dbin-jump-full&object_id=34609&local_base=GEN01-INS01

Penn State University

23. Kesavan, Aruna. Asymptotic structure of space-time with a positive cosmological constant.

Degree: PhD, Physics, 2016, Penn State University

URL: https://etda.libraries.psu.edu/catalog/f4752g72m

► In general relativity a satisfactory framework for describing isolated systems exists when the cosmological constant Λ is zero. The detailed analysis of the asymptotic structure… (more)

▼ In general relativity a satisfactory framework for describing isolated systems exists when the cosmological constant Λ is zero. The detailed analysis of the asymptotic structure of the gravitational field, which constitutes the framework of asymptotic flatness, lays the foundation for research in diverse areas in gravitational science. However, the framework is incomplete in two respects. First, asymptotic flatness provides well-defined expressions for physical observables such as energy and momentum as `charges' of asymptotic symmetries at null infinity, \scri⁺. But the asymptotic symmetry group, called the Bondi-Metzner-Sachs group is infinite-dimensional and a tensorial expression for the `charge' integral of an arbitrary BMS element is missing. We address this issue by providing a charge formula which is a 2-sphere integral over fields local to the 2-sphere and refers to no extraneous structure. The second, and more significant shortcoming is that observations have established that Λ is not zero but positive in our universe. Can the framework describing isolated systems and their gravitational radiation be extended to incorporate this fact? In this dissertation we show that, unfortunately, the standard framework does not extend from the Λ =0 case to the Λ >0 case in a physically useful manner. In particular, we do not have an invariant notion of gravitational waves in the non-linear regime, nor an analog of the Bondi `news tensor', nor positive energy theorems. In addition, we argue that the stronger boundary condition of conformal flatness of intrinsic metric on \scri⁺, which reduces the asymptotic symmetry group from \Diff to the de Sitter group, is insufficient to characterize gravitational fluxes and is physically unreasonable. To obtain guidance for the full non-linear theory with Λ > 0, linearized gravitational waves in de Sitter space-time are analyzed in detail. i) We show explicitly that conformal flatness of the boundary removes half the degrees of freedom of the gravitational field by hand and is not justified by physical considerations; ii) We obtain gauge invariant expressions of energy-momentum and angular momentum fluxes carried by gravitational waves in terms of fields defined at \scrip; iii) We demonstrate that the flux formulas reduce to the familiar ones in Minkowski space-time in spite of the fact that the limit Λ → 0 is discontinuous (since, in particular, \scrip changes its space-like character to null in the limit); iv) We obtain a generalization of Einstein's 1918 quadrupole formula for power emission by a linearized source to include a positive Λ; and, finally v) We show that, although energy of linearized gravitational waves can be arbitrarily negative in general, gravitational waves emitted by physically reasonable sources carry positive energy.

Subjects/Keywords: Asymptotics; Dark Energy; Gravitational Radiation; Cosmological Constant

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APA (6^th Edition):

Kesavan, A. (2016). Asymptotic structure of space-time with a positive cosmological constant. (Doctoral Dissertation). Penn State University. Retrieved from https://etda.libraries.psu.edu/catalog/f4752g72m

Chicago Manual of Style (16^th Edition):

Kesavan, Aruna. “Asymptotic structure of space-time with a positive cosmological constant.” 2016. Doctoral Dissertation, Penn State University. Accessed December 13, 2019. https://etda.libraries.psu.edu/catalog/f4752g72m.

MLA Handbook (7^th Edition):

Kesavan, Aruna. “Asymptotic structure of space-time with a positive cosmological constant.” 2016. Web. 13 Dec 2019.

Vancouver:

Kesavan A. Asymptotic structure of space-time with a positive cosmological constant. [Internet] [Doctoral dissertation]. Penn State University; 2016. [cited 2019 Dec 13]. Available from: https://etda.libraries.psu.edu/catalog/f4752g72m.

Council of Science Editors:

Kesavan A. Asymptotic structure of space-time with a positive cosmological constant. [Doctoral Dissertation]. Penn State University; 2016. Available from: https://etda.libraries.psu.edu/catalog/f4752g72m

University of Cambridge

24. Sakstein, Jeremy Aaron. Astrophysical tests of modified gravity .

Degree: 2014, University of Cambridge

URL: https://www.repository.cam.ac.uk/handle/1810/246265

► Einstein's theory of general relativity has been the accepted theory of gravity for nearly a century but how well have we really tested it? The… (more)

▼ Einstein's theory of general relativity has been the accepted theory of gravity for nearly a century but how well have we really tested it? The laws of gravity have been probed in our solar system to extremely high precision using several different tests and general relativity has passed each one with flying colours. Despite this, there are still some mysteries it cannot account for, one of which being the recently discovered acceleration of the universe and this has prompted a theoretical study of modified theories of gravity that can self-accelerate on large scales. Indeed, the next decade will be an exciting era where several satellites will probe the structure of gravity on cosmological scales and put these theoretical predictions to the test. Despite this, one must still worry about the behaviour of gravity on smaller scales and the vast majority of these theories are rendered cosmologically uninteresting when confronted with solar system tests of gravity. This has motivated the study of theories that differ from general relativity on large scales but include screening mechanisms which act to hide any modifications in our own solar system. This then presents the problem of being able to distinguish these theories from general relativity. In the last few years, astrophysical scales have emerged as a new and novel way of probing these theories. These scales encompass the mildly non-linear regime between galactic and cosmological scales where the astrophysical objects have not yet joined the Hubble flow. For this reason, the screening mechanism is active but not overly efficient and novel effects may be present. Furthermore, these tests do not require a large sample of galaxies and hence do not require dedicated surveys; instead they can piggyback on other experiments. This thesis explores a class of theories of screened modified gravity which are scalar-tensor theories where the field is conformally coupled to matter via the metric and includes chameleon and symmetron models as well as those that screen using the environment-dependent Damour-Polyakov effect. The thesis is split into two parts. The first is aimed at searching for new and novel astrophysical probes and using them to place new constraints on the model parameters. In particular, we derive the equations governing hydrodynamics in the presence of an external gravitational field that includes the modifications of general relativity. Using this, we derive the equations governing the equilibrium structure of stars and show that unscreened stars are brighter and hotter than their screened counterparts owing to the larger nuclear burning rate in the core needed to combat the additional inward force. These theories have the property that the laws of gravity are different in unscreened galaxies from our own. This means that the inferred distance to an unscreened galaxy using a stellar effect that depends on the law gravity will not agree with a measurement using a different method that is insensitive gravitational physics. We exploit this property by… Advisors/Committee Members: Davis, Anne-Christine (advisor).

Subjects/Keywords: Modified gravity; Dark energy; Cosmology; Astrophysics; Supersymmetry

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APA (6^th Edition):

Sakstein, J. A. (2014). Astrophysical tests of modified gravity . (Thesis). University of Cambridge. Retrieved from https://www.repository.cam.ac.uk/handle/1810/246265

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Sakstein, Jeremy Aaron. “Astrophysical tests of modified gravity .” 2014. Thesis, University of Cambridge. Accessed December 13, 2019. https://www.repository.cam.ac.uk/handle/1810/246265.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Sakstein, Jeremy Aaron. “Astrophysical tests of modified gravity .” 2014. Web. 13 Dec 2019.

Vancouver:

Sakstein JA. Astrophysical tests of modified gravity . [Internet] [Thesis]. University of Cambridge; 2014. [cited 2019 Dec 13]. Available from: https://www.repository.cam.ac.uk/handle/1810/246265.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sakstein JA. Astrophysical tests of modified gravity . [Thesis]. University of Cambridge; 2014. Available from: https://www.repository.cam.ac.uk/handle/1810/246265

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Illinois – Urbana-Champaign

25. Biswas, Rahul. Observational aspects of dark energy.

Degree: PhD, 0240, 2010, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/16936

► Our understanding of cosmology, supported by different forms of observation have led to a standard model of cosmology called the ΛCDM model. This model combines… (more)

▼ Our understanding of cosmology, supported by different forms of observation have led to a standard model of cosmology called the ΛCDM model. This model combines the idea of isotropy and homogeneity, with the presence of a cosmological constant and cold dark matter along with usual components. Additionally, it requires a special set of initial conditions, such as those that can be generated by inflation. The ΛCDM model is consistent with all current data and most model parameters are known to high accuracy by combining information from CMB experiments, Galaxy surveys, supernova surveys and measurements of the Hubble Constant. However, current data cannot discriminate between a cosmological constant and other dark energy or modified gravity models that also produce a late time acceleration. Similarly, it cannot distinguish between different models that could seed the primordial perturbations. Thus, the goal of future experiments is to distinguish between such models and thereby study the differences in the underlying physics. In this thesis, we discuss the observables for dark energy models with a time dependent equation of state, and methods of constraining cosmological parameters from current data as well forecasting constraints from future experiments. We apply these methods to forecast constraints on the dark energy with a time dependent equation of state for the LSST supernova survey, and to a combination of a CMB and supernovae survey similar to PLANCK and the Dark Energy Survey. We use examine parameter constraints in a cosmology with a time dependent equation of state by combining WMAP5, SDSS, SNe, HST data sets by comparing the power spectra. We carefully quantify the differences of these constraints to those obtained by using geometrical summaries for the same data sets. We find that (a) using summary parameters instead of the full data sets give parameter constraints that are similar, but with discernible differences, (b) due to degeneracies, the constraints on the standard parameters broaden significantly for the same data sets. In particular, we find that in the context of CPL dark energy, (i) a Harrison-Zeldovich spectrum cannot be ruled out at 2σ levels with our current data sets. and (ii) the SNe Ia, HST, and WMAP 5 data are not sufficient to constrain spatial curvature; we additionally require the SDSS DR4 data to achieve this. We then use large scale structure data that will be available in the future in a non-standard way to forecast the constraints on the dark energy equation of state. We argue that the shapes of cosmic voids, as measured in spectroscopic galaxy redshift surveys, constitute a promising new probe of dark energy (DE). We do this by forecasting constraints on the DE equation of state and its variation from current and future surveys and find that the promise of void shape measurements compares favorably to that of standard methods such as supernovae and cluster counts even for currently… Advisors/Committee Members: Wandelt, Benjamin D. (advisor), Lamb, Frederick K. (Committee Chair), Wandelt, Benjamin D. (committee member), Stack, John D. (committee member), Thaler, Jonathan J. (committee member).

Subjects/Keywords: Cosmology; Particle Physics; Dark Energy; Parameter Estimation

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APA (6^th Edition):

Biswas, R. (2010). Observational aspects of dark energy. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/16936

Chicago Manual of Style (16^th Edition):

Biswas, Rahul. “Observational aspects of dark energy.” 2010. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed December 13, 2019. http://hdl.handle.net/2142/16936.

MLA Handbook (7^th Edition):

Biswas, Rahul. “Observational aspects of dark energy.” 2010. Web. 13 Dec 2019.

Vancouver:

Biswas R. Observational aspects of dark energy. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2010. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/2142/16936.

Council of Science Editors:

Biswas R. Observational aspects of dark energy. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2010. Available from: http://hdl.handle.net/2142/16936

University of Minnesota

26. Barker, D'Ann. SuperCDMS Background Models for Low-Mass Dark Matter Searches.

Degree: PhD, Physics, 2018, University of Minnesota

URL: http://hdl.handle.net/11299/201081

► An abundance of astrophysical and cosmological evidence indicates the existence of a non-luminous, non-baryonic form of matter, called dark matter, that is approximately a quarter… (more)

▼ An abundance of astrophysical and cosmological evidence indicates the existence of a non-luminous, non-baryonic form of matter, called dark matter, that is approximately a quarter of all energy in the universe. One promising candidate for dark matter is the Weakly Interacting Massive Particle (WIMP) which interacts with baryonic matter at most on the scale of the weak force. The Cryogenic Dark Matter Search (CDMS) experiment aims to detect the nuclear recoils induced by the elastic scattering of WIMPs off of germanium nuclei. This is a rare signal and difficult to detect, especially the low-energy recoils that are produced by low-mass dark matter. The CDMS project operated at the Soudan Underground Laboratory from 2003 – 2015, with an upgrade to the SuperCDMS experiment in 2012. The germanium detectors were operated at 50~mK and able to measure both the ionization and athermal phonons produced in a particle interaction. Measuring two signals enables discrimination between electron recoil and nuclear recoil events. An alternative operating mode for the detectors is called the CDMS low ionization threshold experiment (CDMSlite), where a higher bias was applied to the detectors and only the phonon signal analyzed. This method increased sensitivity to low-mass dark matter interactions, but sacrificed discrimination capability. The CDMSlite spectrum had a large contribution from electron recoil background events. From the information gained during the first two CDMSlite Runs, a background model was developed for the third and final CDMSlite Run. Analytical descriptions were identified for those backgrounds that were theoretically known, e.g. tritium β-spectrum, and Geant simulations were used to understand and predict the low-energy spectra from other sources, e.g. Compton scattering. Multiple new models were developed for detectors operated in CDMSlite at Soudan. These include the analytical formula for Compton scattering, and empirical models for surface backgrounds from ²¹⁰Pb contamination of the germanium crystals and detector housing. In order to accurately describe the surface events, a new detector response function was developed that included information about the electric field and energy resolution of the detector. These models were essential to the implementation of a profile likelihood analysis of the CDMSlite Run 3 data, which improved on the sensitivity to dark matter over the Run 2 optimum interval analysis for WIMP masses above 2.5~GeV/c². This demonstrated a successful application of a likelihood analysis to the high-voltage operating mode, and the potential for these analyses in the future SuperCDMS SNOLAB experiment. For the SuperCDMS SNOLAB experiment, the change in background rates from radiogenic neutrons was considered as additional towers of detectors were added, and the feasibility of an active neutron veto as a potential upgrade for large payloads was studied. This veto could be constructed of plastic scintillator with layers of gadolinium resin, and would aid in reducing the nuclear…

Subjects/Keywords: backgrounds; CDMSlite; dark matter; low energy; SuperCDMS

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APA (6^th Edition):

Barker, D. (2018). SuperCDMS Background Models for Low-Mass Dark Matter Searches. (Doctoral Dissertation). University of Minnesota. Retrieved from http://hdl.handle.net/11299/201081

Chicago Manual of Style (16^th Edition):

Barker, D'Ann. “SuperCDMS Background Models for Low-Mass Dark Matter Searches.” 2018. Doctoral Dissertation, University of Minnesota. Accessed December 13, 2019. http://hdl.handle.net/11299/201081.

MLA Handbook (7^th Edition):

Barker, D'Ann. “SuperCDMS Background Models for Low-Mass Dark Matter Searches.” 2018. Web. 13 Dec 2019.

Vancouver:

Barker D. SuperCDMS Background Models for Low-Mass Dark Matter Searches. [Internet] [Doctoral dissertation]. University of Minnesota; 2018. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/11299/201081.

Council of Science Editors:

Barker D. SuperCDMS Background Models for Low-Mass Dark Matter Searches. [Doctoral Dissertation]. University of Minnesota; 2018. Available from: http://hdl.handle.net/11299/201081

University of Notre Dame

27. Brian T Hayden. Better Understanding Type Ia Supernovae With the Goal of Making Them More Reliable Distance Indicators</h1>.

Degree: PhD, Physics, 2013, University of Notre Dame

URL: https://curate.nd.edu/show/qj72p556m8h

► Type Ia supernovae have become fundamental tools for cosmology, but their progenitors, explosion mechanism, and dependence on environment remain key problems to be solved… (more)

▼ Type Ia supernovae have become fundamental tools for cosmology, but their progenitors, explosion mechanism, and dependence on environment remain key problems to be solved to improve their reliability as cosmological distance estimators. This thesis presents research into the nature of SN Ia explosions and their environments, and discusses ongoing efforts to understand systematic errors in SN Ia distance measurements. Using SDSS-II SNe, the 2-stretch fitting method was developed for SN Ia light curves. The 2-stretch method allows the rise and decline portions of the light curve to be fit separately, and as a result, I have discovered that SN Ia light curves with a normal decline rate show a large variation in rise times. This departure from the single stretch model also results in an average rise time of about 17.5 days, 2 days shorter than previously accepted results. While accurate measurements of the rise time do not significantly improve cosmological results, they do improve the estimate of 56-Ni yield, which is an important constraint in theoretical modeling of SN Ia explosions. Using the 2-stretch fitter, a search was conducted for shock interactions between the exploding white dwarf and a potential companion star in the single degenerate progenitor channel. No evidence was found for shocks in an SDSS-II sample of about 100 SNe, and simulations indicated that shocks above about 9% of peak SN flux are confidently ruled out. Comparing to theoretical models of single degenerate progenitors, this implies a lack of red giant companions and main sequence stars above 6 solar masses as common companions to SNe Ia. A statistical study of SN Ia Hubble residuals has focused on the effect of the SN environment, as multiple studies have shown a correlation between host galaxy mass and SN distances. The source of this mass correlation is unknown, but both metallicity and progenitor age are candidate explanations for the observed correlation. I have developed a method of testing the host galaxy correlation with SN Ia standardization that utilizes the host galaxy mass and star-formation rate to estimate the metallicity of the environment, and I have shown that the SN distances are strongly correlated with this metallicity estimate. This implies that the SN Ia correlation with host galaxy mass is tracing a correlation with the metallicity. Advisors/Committee Members: Peter Garnavich, Committee Chair, Mike Hildreth, Committee Member, Grant Mathews, Committee Member, Chris Howk, Committee Member.

Subjects/Keywords: cosmology; dark energy; Type Ia Supernovae

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APA (6^th Edition):

Hayden, B. T. (2013). Better Understanding Type Ia Supernovae With the Goal of Making Them More Reliable Distance Indicators</h1>. (Doctoral Dissertation). University of Notre Dame. Retrieved from https://curate.nd.edu/show/qj72p556m8h

Chicago Manual of Style (16^th Edition):

Hayden, Brian T. “Better Understanding Type Ia Supernovae With the Goal of Making Them More Reliable Distance Indicators</h1>.” 2013. Doctoral Dissertation, University of Notre Dame. Accessed December 13, 2019. https://curate.nd.edu/show/qj72p556m8h.

MLA Handbook (7^th Edition):

Hayden, Brian T. “Better Understanding Type Ia Supernovae With the Goal of Making Them More Reliable Distance Indicators</h1>.” 2013. Web. 13 Dec 2019.

Vancouver:

Hayden BT. Better Understanding Type Ia Supernovae With the Goal of Making Them More Reliable Distance Indicators</h1>. [Internet] [Doctoral dissertation]. University of Notre Dame; 2013. [cited 2019 Dec 13]. Available from: https://curate.nd.edu/show/qj72p556m8h.

Council of Science Editors:

Hayden BT. Better Understanding Type Ia Supernovae With the Goal of Making Them More Reliable Distance Indicators</h1>. [Doctoral Dissertation]. University of Notre Dame; 2013. Available from: https://curate.nd.edu/show/qj72p556m8h

University of Notre Dame

28. Jared W. Coughlin. Time-Dependent Dark Energy and the Flux Power Spectrum of the Lyman α Forest</h1>.

Degree: PhD, Physics, 2018, University of Notre Dame

URL: https://curate.nd.edu/show/tx31qf88w2b

► Dark energy is the as yet unidentified mechanism responsible for the accelerated expansion of the universe. Understanding this mechanism is one of the most… (more)

Subjects/Keywords: simulation; theory; Cosmology; Dark Energy; Physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Coughlin, J. W. (2018). Time-Dependent Dark Energy and the Flux Power Spectrum of the Lyman α Forest</h1>. (Doctoral Dissertation). University of Notre Dame. Retrieved from https://curate.nd.edu/show/tx31qf88w2b

Chicago Manual of Style (16^th Edition):

Coughlin, Jared W.. “Time-Dependent Dark Energy and the Flux Power Spectrum of the Lyman α Forest</h1>.” 2018. Doctoral Dissertation, University of Notre Dame. Accessed December 13, 2019. https://curate.nd.edu/show/tx31qf88w2b.

MLA Handbook (7^th Edition):

Coughlin, Jared W.. “Time-Dependent Dark Energy and the Flux Power Spectrum of the Lyman α Forest</h1>.” 2018. Web. 13 Dec 2019.

Vancouver:

Coughlin JW. Time-Dependent Dark Energy and the Flux Power Spectrum of the Lyman α Forest</h1>. [Internet] [Doctoral dissertation]. University of Notre Dame; 2018. [cited 2019 Dec 13]. Available from: https://curate.nd.edu/show/tx31qf88w2b.

Council of Science Editors:

Coughlin JW. Time-Dependent Dark Energy and the Flux Power Spectrum of the Lyman α Forest</h1>. [Doctoral Dissertation]. University of Notre Dame; 2018. Available from: https://curate.nd.edu/show/tx31qf88w2b

University of Sydney

29. Adermann, Eromanga. Shining a Light into the Dark: Cosmic Voids as Cosmological Probes of Evolving and Interacting Dark Sector Physics .

Degree: 2018, University of Sydney

URL: http://hdl.handle.net/2123/20013

► The dark sector of the Universe, which comprises dark matter and dark energy, presents one of the greatest unanswered questions in all of physics. Although… (more)

Subjects/Keywords: cosmology; large-scale structure; dark energy

Record Details Similar Records Cite « Share

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Adermann, E. (2018). Shining a Light into the Dark: Cosmic Voids as Cosmological Probes of Evolving and Interacting Dark Sector Physics . (Thesis). University of Sydney. Retrieved from http://hdl.handle.net/2123/20013

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Adermann, Eromanga. “Shining a Light into the Dark: Cosmic Voids as Cosmological Probes of Evolving and Interacting Dark Sector Physics .” 2018. Thesis, University of Sydney. Accessed December 13, 2019. http://hdl.handle.net/2123/20013.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Adermann, Eromanga. “Shining a Light into the Dark: Cosmic Voids as Cosmological Probes of Evolving and Interacting Dark Sector Physics .” 2018. Web. 13 Dec 2019.

Vancouver:

Adermann E. Shining a Light into the Dark: Cosmic Voids as Cosmological Probes of Evolving and Interacting Dark Sector Physics . [Internet] [Thesis]. University of Sydney; 2018. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/2123/20013.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Adermann E. Shining a Light into the Dark: Cosmic Voids as Cosmological Probes of Evolving and Interacting Dark Sector Physics . [Thesis]. University of Sydney; 2018. Available from: http://hdl.handle.net/2123/20013

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Sydney

30. Watts, Andrew. Large-Scale Structure Topology in Non-Standard Cosmologies .

Degree: 2018, University of Sydney

URL: http://hdl.handle.net/2123/18283

► On large scales the distribution of galaxies resembles a vast ‘cosmic web’ of clusters, walls, filaments and voids arranged in an interlocking network. The statistical… (more)

Subjects/Keywords: Cosmology; Dark Energy; Large-Scale Structure

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Watts, A. (2018). Large-Scale Structure Topology in Non-Standard Cosmologies . (Thesis). University of Sydney. Retrieved from http://hdl.handle.net/2123/18283

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Watts, Andrew. “Large-Scale Structure Topology in Non-Standard Cosmologies .” 2018. Thesis, University of Sydney. Accessed December 13, 2019. http://hdl.handle.net/2123/18283.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Watts, Andrew. “Large-Scale Structure Topology in Non-Standard Cosmologies .” 2018. Web. 13 Dec 2019.

Vancouver:

Watts A. Large-Scale Structure Topology in Non-Standard Cosmologies . [Internet] [Thesis]. University of Sydney; 2018. [cited 2019 Dec 13]. Available from: http://hdl.handle.net/2123/18283.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Watts A. Large-Scale Structure Topology in Non-Standard Cosmologies . [Thesis]. University of Sydney; 2018. Available from: http://hdl.handle.net/2123/18283

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Open Access Theses and Dissertations