[PDF] Precision Cosmology With Galaxy Cluster Surveys

Precision Cosmology with Galaxy Cluster Surveys PDF
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Publisher: Stanford University
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Precision Cosmology With Galaxy Cluster Surveys

by , release date 2011, Precision Cosmology With Galaxy Cluster Surveys Books available in PDF, EPUB, Mobi Format. Download Precision Cosmology With Galaxy Cluster Surveys books, The acceleration of the universe, which is often attributed to "dark energy, " has posed one of the main challenges to fundamental physics. Galaxy clusters provide one of the most sensitive probes of dark energy because their abundance reflects the growth rate of large-scale structure and the expansion rate of the universe. Several large galaxy cluster surveys will soon provide tremendous statistical power to constrain the properties of dark energy; however, the constraining power of these surveys will be determined by how well systematic errors are controlled. Of these systematic errors, the dominant one comes from inferring cluster masses using observable signals of clusters, the so-called "observable--mass distribution." This thesis focuses on extracting dark energy information from forthcoming large galaxy cluster surveys, including how we maximize the cosmological information, how we control important systematics, and how precisely we need to calibrate theoretical models. We study how multi-wavelength follow-up observations can improve cluster mass calibration in optical surveys. We also investigate the impact of theoretical uncertainties in calibrating the spatial distributions of galaxy clusters on dark energy constraints. In addition, we explore how the formation history of galaxy clusters impacts the self-calibration of cluster mass. In addition, we use N-body simulations to develop a new statistical sample of cluster-size halos in order to further understand the observable--mass distribution. We study the completeness of subhalos in our cluster sample by comparing them with the satellite galaxies in the Sloan Digital Sky Survey. We also study how subhalo selections impact the inferred correlation between formation time and optical mass tracers, including cluster richness and velocity dispersion.




[PDF] Precision Cosmology With Galaxy Cluster Surveys

Precision Cosmology with Galaxy Cluster Surveys PDF
Author: Hao-Yi Wu
Publisher:
ISBN:
Size: 50.39 MB
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Languages : en
Pages :
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Precision Cosmology With Galaxy Cluster Surveys

by Hao-Yi Wu, release date 2011, Precision Cosmology With Galaxy Cluster Surveys Books available in PDF, EPUB, Mobi Format. Download Precision Cosmology With Galaxy Cluster Surveys books, The acceleration of the universe, which is often attributed to "dark energy, " has posed one of the main challenges to fundamental physics. Galaxy clusters provide one of the most sensitive probes of dark energy because their abundance reflects the growth rate of large-scale structure and the expansion rate of the universe. Several large galaxy cluster surveys will soon provide tremendous statistical power to constrain the properties of dark energy; however, the constraining power of these surveys will be determined by how well systematic errors are controlled. Of these systematic errors, the dominant one comes from inferring cluster masses using observable signals of clusters, the so-called "observable--mass distribution." This thesis focuses on extracting dark energy information from forthcoming large galaxy cluster surveys, including how we maximize the cosmological information, how we control important systematics, and how precisely we need to calibrate theoretical models. We study how multi-wavelength follow-up observations can improve cluster mass calibration in optical surveys. We also investigate the impact of theoretical uncertainties in calibrating the spatial distributions of galaxy clusters on dark energy constraints. In addition, we explore how the formation history of galaxy clusters impacts the self-calibration of cluster mass. In addition, we use N-body simulations to develop a new statistical sample of cluster-size halos in order to further understand the observable--mass distribution. We study the completeness of subhalos in our cluster sample by comparing them with the satellite galaxies in the Sloan Digital Sky Survey. We also study how subhalo selections impact the inferred correlation between formation time and optical mass tracers, including cluster richness and velocity dispersion.




[PDF] Early Type Galaxies And Reliable Galaxy Cluster Selection

Early Type Galaxies And Reliable Galaxy Cluster Selection PDF
Author: Jeeseon Song
Publisher:
ISBN:
Size: 22.38 MB
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Languages : en
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Early Type Galaxies And Reliable Galaxy Cluster Selection

by Jeeseon Song, release date 2011, Early Type Galaxies And Reliable Galaxy Cluster Selection Books available in PDF, EPUB, Mobi Format. Download Early Type Galaxies And Reliable Galaxy Cluster Selection books, In an era of precision cosmology, clusters of galaxies are the natural consequences under the hierarchical scenario, within which clusters directly encapsulate the history of structure formation. Thus, determining the mass distribution of clusters as a function of redshift enables fundamental tests of this structure formation process. My projects have initially been motivated by an intellectual inquiry into how we can effectively and accurately analyze data from large cluster surveys, such as the South Pole Telescope (SPT), the Blanco Cosmology Survey (BCS) and the upcoming Dark Energy Survey (DES), which now extends to the galaxy formation and evolution studies. Through this thesis project followed by immediate extension of the thesis, I, therefore, aim to achieve three distinct, but highly inter-related main research goals: (1) creating mock catalogs that represent the universe well enough, (2) employing these mock catalogs to quantitatively characterize optical selection tools and then applying those well understood selection tools to large new surveys, and (3) exploring the underlying physics of galaxy population and property evolution over the cosmic time. Clusters of galaxies are an important laboratory for exploring galaxy formation and evolution. Automatic data analysis tools, such as cluster finding algorithms or mass and photometric redshift estimators, need to be tested prior to their use. We have launched a project to create realistic mock galaxy catalogs that will perform these tests accurately. This thesis project also includes development of tools to characterize clusters of galaxies, such as a red-sequence redshift estimator and an optical richness estimator. We also explore one of the candidates of contamination in cluster finding in sub-mm wavelength. The scientific goals to have been achieved are to build a realistic mock catalog on which several analysis tools are tested to better understand our ability to make accurate measurements; to develop an independent redshift and optical richness estimators with their applications to real clusters and to understand their systematics better to reduce the scatter; and to address a cautionary point in sub-mm cluster finding due to radio galaxies that are associated with clusters. These projects, in conjunction with each other, are demonstrated as crucial elements in constraining cosmological parameters to understand the evolution of the universe.




[PDF] 3k Sn S Clusters Hunting The Cosmological Parameters With Precision Cosmology

3K  SN s  Clusters  Hunting the Cosmological Parameters with Precision Cosmology PDF
Author: Domingos Barbosa
Publisher: Springer Science & Business Media
ISBN: 9401705593
Size: 48.30 MB
Format: PDF, ePub, Mobi
Category : Science
Languages : en
Pages : 218
View: 3952

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3k Sn S Clusters Hunting The Cosmological Parameters With Precision Cosmology

by Domingos Barbosa, release date 2013-11-11, 3k Sn S Clusters Hunting The Cosmological Parameters With Precision Cosmology Books available in PDF, EPUB, Mobi Format. Download 3k Sn S Clusters Hunting The Cosmological Parameters With Precision Cosmology books, A JENAM 2002 Workshop, Porto, Portugal, 3-5 September 2002




[PDF] Measuring The Growth Of Structure With Multi Wavelength Surveys Of Galaxy Clusters

Measuring the Growth of Structure with Multi wavelength Surveys of Galaxy Clusters PDF
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Publisher:
ISBN:
Size: 31.90 MB
Format: PDF, ePub, Docs
Category : Cosmology
Languages : en
Pages : 96
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Measuring The Growth Of Structure With Multi Wavelength Surveys Of Galaxy Clusters

by , release date 2008, Measuring The Growth Of Structure With Multi Wavelength Surveys Of Galaxy Clusters Books available in PDF, EPUB, Mobi Format. Download Measuring The Growth Of Structure With Multi Wavelength Surveys Of Galaxy Clusters books, Current and near-future galaxy cluster surveys at a variety of wavelengths are expected to provide a promising way to obtain precision measurements of the growth of structure over cosmic time. This in turn would serve as an important precision probe of cosmology. However, to realize the full potential of these surveys, systematic uncertainties arising from, for example, cluster mass estimates and sample selection must be well understood. This work follows several different approaches towards alleviating these uncertainties. Cluster sample selection is investigated in the context of arcminute-resolution millimeter-wavelength surveys such as the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). Large-area, realistic simulations of the microwave sky are constructed and cluster detection is simulated using a multi-frequency Wiener filter to separate the galaxy clusters, via their Sunyaev-Zel'dovich signal, from other contaminating microwave signals. Using this technique, an ACT-like survey can expect to obtain a cluster sample that is 90% complete and 85% pure above a mass of 3 x 10^14 Msun. Cluster mass uncertainties are explored by comparing X-ray and weak-lensing mass estimates for shear-selected galaxy clusters in the Deep Lens Survey (DLS) to study possible biases in using cluster baryons or weak-lensing shear as tracers of the cluster total mass. Results are presented for four galaxy clusters that comprise the top-ranked shear-selected system in the DLS, and for three of these clusters there is agreement between X-ray and weak-lensing mass estimates. For the fourth cluster, the X-ray mass estimate is higher than that from weak-lensing by 2-sigma, and X-ray images suggest this cluster may be undergoing a merger with a smaller cluster, which may be biasing the X-ray mass estimate high. The feasibility of measuring galaxy cluster peculiar velocities using an ACT-like instrument is also investigated. Such a possibility would allow one to measure structure growth via large-scale velocity fields and circumvent the uncertainties associated with measuring cluster masses. We show that such measurements are possible and yield statistical uncertainties of roughly 100 km/sec given either a temperature prior with 1-sigma errors of less than 2 keV or additional lower frequency millimeter-band observations.




[PDF] Weak Lensing By Galaxy Clusters

Weak Lensing by Galaxy Clusters PDF
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Publisher:
ISBN:
Size: 56.34 MB
Format: PDF, ePub, Docs
Category :
Languages : en
Pages : 249
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Weak Lensing By Galaxy Clusters

by , release date 2015, Weak Lensing By Galaxy Clusters Books available in PDF, EPUB, Mobi Format. Download Weak Lensing By Galaxy Clusters books, The story of the origin and evolution of our Universe is told, equivalently, by space-time itself and by the structures that grow inside of it. Clusters of galaxies are the frontier of bottom-up structure formation. They are the most massive objects to have collapsed at the present epoch. By that virtue, their abundance and structural parameters are highly sensitive to the composition and evolution of the Universe. The most common probe of cluster cosmology, abundance, uses samples of clusters selected by some observable. Applying a mass-observable relation (MOR), cosmological parameters can be constrained by comparing the sample to predicted cluster abundances as a function of observable and redshift. Arguably, however, cluster probes have not yet entered the era of per cent level precision cosmology. The primary reason for this is our imperfect understanding of the MORs. The overall normalization, the slope of mass vs. observable, the redshift evolution, and the degree and correlation of intrinsic scatters of observables at fixed mass have to be constrained for interpreting abundances correctly. Mass measurement of clusters by means of the differential deflection of light from background sources in their gravitational field, i.e. weak lensing, is a powerful approach for achieving this. This thesis presents new methods for and scientific results of weak lensing measurements of clusters of galaxies. The former include, on the data reduction side, (i) the correction of CCD images for non-linear effects due to the electric fields of accumulated charges (Chapter 2, Gruen et al. 2015a) and (ii) a method for masking artifact features in sets of overlapping images of the sky by comparison to the median image (Chapter 3, Gruen et al. 2014a). Also, (iii) I develop a method for the selection of background galaxy samples based on their color and apparent magnitude that includes a new correction for contamination with cluster member galaxies (Section 5.3.1). The main scientific results are the following. (i) For th! e Hubble Frontier Field cluster RXC J2248.7--4431 our lensing analysis constrains mass and concentration of the cluster halo and we confirm the large mass predicted by X-ray and Sunyaev-Zel'dovich (SZ) observations. The study of cluster members shows the relation of galaxy morphology to luminosity and environment (Chapter 4, Gruen et al. 2013). (ii) Our lensing mass measurements for 12 clusters are consistent with X-ray masses derived under the assumption of hydrostatic equilibrium of the intra-cluster gas. We confirm the MORs derived by the South Pole Telescope collaboration for the detection significance of the cluster SZ signal in their survey. We find discrepancies, however, with the Planck SZ MOR. We hypothesize that these are related either to a shallower slope of the MOR or a size, redshift or noise dependent bias in SZ signal extraction (Chapter 5, Gruen et al. 2014b). (iii) Finally, using a combination of simulations and theoretical models for the variation of cluster profiles at fixed mass, we find that the latter is a significant contribution to the uncertainty of cluster lensing mass measurements. A cosmic variance model, such as the one we develop, is necessary for MOR constraints to be accurate at the level required for future surveys (Chapter 6, Gruen et al. 2015b).




[PDF] Cosmology With The 6 Degree Field Galaxy Survey

Cosmology with the 6 degree Field Galaxy Survey PDF
Author: Florian Beutler
Publisher:
ISBN:
Size: 29.41 MB
Format: PDF, Docs
Category : Cosmology
Languages : en
Pages : 206
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Cosmology With The 6 Degree Field Galaxy Survey

by Florian Beutler, release date 2012, Cosmology With The 6 Degree Field Galaxy Survey Books available in PDF, EPUB, Mobi Format. Download Cosmology With The 6 Degree Field Galaxy Survey books, [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...




[PDF] The Effects Of Halo Assembly Bias On Self Calibration In Galaxy Cluster Surveys

The Effects of Halo Assembly Bias on Self Calibration in Galaxy Cluster Surveys PDF
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Size: 54.11 MB
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Languages : en
Pages : 12
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The Effects Of Halo Assembly Bias On Self Calibration In Galaxy Cluster Surveys

by , release date 2008, The Effects Of Halo Assembly Bias On Self Calibration In Galaxy Cluster Surveys Books available in PDF, EPUB, Mobi Format. Download The Effects Of Halo Assembly Bias On Self Calibration In Galaxy Cluster Surveys books, Self-calibration techniques for analyzing galaxy cluster counts utilize the abundance and the clustering amplitude of dark matter halos. These properties simultaneously constrain cosmological parameters and the cluster observable-mass relation. It was recently discovered that the clustering amplitude of halos depends not only on the halo mass, but also on various secondary variables, such as the halo formation time and the concentration; these dependences are collectively termed 'assembly bias'. Applying modified Fisher matrix formalism, we explore whether these secondary variables have a significant impact on the study of dark energy properties using the self-calibration technique in current (SDSS) and the near future (DES, SPT, and LSST) cluster surveys. The impact of the secondary dependence is determined by (1) the scatter in the observable-mass relation and (2) the correlation between observable and secondary variables. We find that for optical surveys, the secondary dependence does not significantly influence an SDSS-like survey; however, it may affect a DES-like survey (given the high scatter currently expected from optical clusters) and an LSST-like survey (even for low scatter values and low correlations). For an SZ survey such as SPT, the impact of secondary dependence is insignificant if the scatter is 20% or lower but can be enhanced by the potential high scatter values introduced by a highly-correlated background. Accurate modeling of the assembly bias is necessary for cluster self-calibration in the era of precision cosmology.




[PDF] Amiba 2001 High Z Clusters Missing Baryons And Cmb Polarization

AMiBA 2001   High z Clusters  Missing Baryons  and CMB Polarization PDF
Author: Lin-Wen Chen
Publisher:
ISBN:
Size: 14.85 MB
Format: PDF, Mobi
Category : Astronomy
Languages : en
Pages : 342
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Amiba 2001 High Z Clusters Missing Baryons And Cmb Polarization

by Lin-Wen Chen, release date 2002, Amiba 2001 High Z Clusters Missing Baryons And Cmb Polarization Books available in PDF, EPUB, Mobi Format. Download Amiba 2001 High Z Clusters Missing Baryons And Cmb Polarization books, Annotation Proceedings of a June 2001 workshop report on instrumentation for observing the Sunyaev-Zel'dovich (SZ) effect. Papers are grouped in sections on SZ surveys, optical surveys of galaxy clusters, ICM and IGM, cosmic microwave background polarization, and SZ machines and observation strategies. Some specific topics examined include X-ray properties of high redshift clusters, and 3D simulation of ultra light scalar field dark matter. There is no subject index. Annotation (c)2003 Book News, Inc., Portland, OR (booknews.com)




[PDF] Outskirts Of Galaxy Clusters Iau C195

Outskirts of Galaxy Clusters  IAU C195  PDF
Author: International Astronomical Union. Colloquium
Publisher: Cambridge University Press
ISBN: 9780521849081
Size: 46.74 MB
Format: PDF, ePub, Mobi
Category : Science
Languages : en
Pages : 560
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Outskirts Of Galaxy Clusters Iau C195

by International Astronomical Union. Colloquium, release date 2004-12-16, Outskirts Of Galaxy Clusters Iau C195 Books available in PDF, EPUB, Mobi Format. Download Outskirts Of Galaxy Clusters Iau C195 books, Proceedings of the International Astronomical Union Colloquium no. 195, held in Torino, Italy in 2004.