자료유형  

 학위논문

Control Number  

0017164500

International Standard Book Number  

9798384044703

Dewey Decimal Classification Number  

523

Main Entry-Personal Name  

Esteves, Johnny H.

Publication, Distribution, etc. (Imprint  

[S.l.] : University of Michigan., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

161 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-03, Section: B.

General Note  

Advisor: Huterer, Dragan;Soares-Santos, Marcelle.

Dissertation Note  

Thesis (Ph.D.)--University of Michigan, 2024.

Summary, Etc.  

요약Galaxy clusters, which are predominantly composed of dark matter with only about 18% of their mass in baryonic form and a mere 2% in stars, serve as cosmological probes through their abundance across various mass and redshift ranges. The total mass of these systems is inferred via weak lensing, which distorts the light from background sources. This is done by calibrating scaling relations with observables such as galaxy richness, stellar mass, Sunyaev-Zeldovich signal, gas mass, and X-ray counts. The detection capabilities of large photometric surveys, like the Dark Energy Survey (DES) and the upcoming Legacy Survey of Space and Time (LSST), offer an unparalleled opportunity to study a wide array of systems, especially those of lower mass. However, accurately calibrating scaling relations with observables in the optical domain remains a significant challenge for leveraging these surveys for accurate cosmological constraints.In response, we present a novel mass-proxy, µ⋆, based on the probability-weighted stellar mass sum of cluster galaxies. Our methodology involves computing membership probabilities for all galaxies within clusters, not just the red-sequence ones. To achieve this, we developed and validated the Copacabana algorithm using simulations mimicking the photometric redshifts of both DES and LSST. Our findings indicate that the Copacabana µ⋆-mass relation has an average scatter of 0.20 dex, making it a competitive mass proxy for these surveys.Furthermore, we demonstrate that µ⋆ is robust against large-scale structure correlations. We study the optical selection bias, a major source of systematic uncertainties in current analyses, modeling it as a projection effect. Prior attempts to account for this bias employed ad-hoc corrections without considering physically motivated models. Our approach introduces a slight modification to the halo model, incorporating an additional halo density profile. We show that an effective Navarro-Frenk-White profile, accounting for contributions from secondary halos along the line-of-sight of the primary halo, provides a more accurate description than previous models.A novel forward method was proposed by the DES cluster working group for the upcoming DES cosmological results. This model encapsulates cluster cosmology observables, like number counts, in a single equation, incorporating all systematics. Despite the model's complexity, which requires computing integrals with multiple dimensions, we leveraged GPU acceleration along with optimized algorithms and some approximations to achieve evaluations in seconds-over 100 times faster than traditional CPU methods.We also studied the systematic effects of the LSST camera CCD sensors on PSF, photometry, and astrometry measurements. We offer detailed characterizations and corrections for gain variations and pixel area distortions. We show that sensor effects are within the stringent requirements of the project for the survey's ten-year lifespan.This work contributes towards future precision cosmology studies by improving elements of the analysis, overcoming some of the computational challenges, and mitigating instrumental sources of systematic uncertainties.

Subject Added Entry-Topical Term  

Astrophysics.

Subject Added Entry-Topical Term  

Physics.

Subject Added Entry-Topical Term  

Atmospheric sciences.

Index Term-Uncontrolled  

Galaxy cluster

Index Term-Uncontrolled  

Cosmology

Index Term-Uncontrolled  

Photometric surveys

Index Term-Uncontrolled  

Dark Energy Survey

Index Term-Uncontrolled  

Copacabana algorithm

Added Entry-Corporate Name  

University of Michigan Physics

Host Item Entry  

Dissertations Abstracts International. 86-03B.

Electronic Location and Access  

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Control Number  

joongbu:656746