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Observational Cosmology

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lightbulbAbout this topic
Observational Cosmology is the branch of astronomy that studies the universe's large-scale structure, evolution, and dynamics through the analysis of astronomical observations. It focuses on measuring cosmic phenomena, such as the cosmic microwave background radiation, galaxy distributions, and supernovae, to understand the universe's origins, composition, and fate.
lightbulbAbout this topic
Observational Cosmology is the branch of astronomy that studies the universe's large-scale structure, evolution, and dynamics through the analysis of astronomical observations. It focuses on measuring cosmic phenomena, such as the cosmic microwave background radiation, galaxy distributions, and supernovae, to understand the universe's origins, composition, and fate.

Key research themes

1. How can multiple cosmological probes be combined and extended to enhance our understanding of cosmic acceleration and cosmological parameters?

This research theme focuses on the development, evaluation, and integration of traditional and novel cosmological probes—such as Cosmic Microwave Background (CMB), Type Ia Supernovae (SNe Ia), Baryon Acoustic Oscillations (BAO), strong gravitational lensing systems, cosmic chronometers, large-scale structure, and weak lensing—to better constrain the expansion history of the Universe, dark energy properties, and fundamental cosmological parameters. It also examines the interplay of these probes in mitigating systematics and breaking degeneracies inherent in individual methods, given the emerging tensions and anomalies at percent-level precision in modern cosmology.

Key finding: This 2022 review systematically documents how standard probes like CMB, SNe Ia, and BAO remain foundational yet insufficient alone due to parameter degeneracies and systematics. It highlights the critical need to expand the... Read more
Key finding: By utilizing a comprehensive sample of 143 strong gravitational lensing systems in conjunction with over 30 observational Hubble parameter data points from cosmic chronometers, this 2021 study demonstrates that strong-lensing... Read more
Key finding: Using the relative entropy (Kullback-Leibler divergence) as a rigorous information-theoretic metric, this 2016 paper quantifies and ranks the constraining power of cosmological probes updated from WMAP9 priors. It finds that... Read more
Key finding: This 2022 work explores modified gravity effects arising from semi-classical quantum fluctuations incorporated into teleparallel gravity, leading to non-minimal gravity-matter couplings. Confronting these models with... Read more
Key finding: This 2022 study articulates the conceptual framework of measuring the cosmological redshift drift in real time as a direct probe of cosmic acceleration, independent of integrated distance measurements. It elucidates how... Read more

2. What are the major theoretical and observational challenges confronting the standard ΛCDM cosmological model, and how might alternative frameworks address these issues?

This theme evaluates the foundational assumptions, internal inconsistencies, and observational tensions in the concordance ΛCDM cosmology, including the physical origin and nature of dark energy and dark matter, the inflationary paradigm inconsistencies, cosmic horizon problems, Big Bang nucleosynthesis contradictions, the cosmic entropy evolution paradox, Hubble parameter tensions, and formation timeline discrepancies of large-scale structure. It further examines systematically proposed alternatives from modifications of gravity, quantum cosmology perspectives, and epistemological critiques aiming to develop physically well-motivated, empirically consistent cosmological frameworks.

Key finding: This 2022 critical review rigorously dissects eight fundamental failures of the ΛCDM model rooted in both theoretical and observational grounds, including inconsistencies with slow-roll inflation potentials, unexplained... Read more
Key finding: This 2017 paper adopts an epistemological framework distinguishing phenomenological and well-founded scientific tenets, challenging speculative constructs such as cosmic inflation, Λ (dark energy), and exotic dark matter as... Read more
Key finding: This work rigorously defines multiple cosmological background solutions (Global, Averaged, Phenomenological) and formalizes the concept of cosmological backreaction as the non-coincidence among these descriptions. It... Read more
Key finding: The 2024 paper proposes a modified redshift model anchored in the spatial distribution of luminous matter that explains late-time cosmic acceleration without invoking dark energy. By reconciling observables such as light... Read more

3. How can gravitational-wave observations, especially from space-based detectors, be used as novel cosmological probes to address early Universe physics and cosmic expansion?

This theme investigates the emerging role of precision gravitational-wave astronomy, particularly utilizing future facilities like the Laser Interferometer Space Antenna (LISA), as a transformative cosmological probe. It includes the use of gravitational-wave standard sirens for measuring the expansion rate, constraining modified gravity theories, and directly detecting stochastic gravitational-wave backgrounds generated from early Universe phenomena such as first-order phase transitions, cosmic strings, and inflationary scenarios. These observations promise to provide novel, independent constraints that complement electromagnetic probes and extend cosmological insight to unexplored epochs and physics regimes.

Key finding: This comprehensive review from the early 2020s details how LISA's planned multi-year space-based gravitational-wave measurements across the mHz band will enable precise cosmological investigations including direct measurement... Read more

All papers in Observational Cosmology

The Hubble Tension refers to the persistent discrepancy between early-universe estimates of the Hubble constant and local-universe measurements obtained through distance-ladder techniques. Current determinations include the Planck... more
[Dark Energy Series-Paper 1] We derive the dark energy equation of state from the Pin⁺ framework, which identifies the time direction as a topological invariant of the Pin⁺ bundle. The Pin⁻ bordism group vanishes in 4D (Ω₄Pin⁻ = 0),... more
We use hydrodynamic simulations to examine how the baryonic components of galaxies are assembled, focusing on the relative importance of mergers and smooth accretion in the formation of $L * systems. In our primary simulation, which... more
CGenome is an interdisciplinary framework that explores hierarchy, emergence, structural memory, and large-scale cosmic organization. The work investigates whether common organizational principles may underlie the evolution of complex... more
CGenome (Cosmic Genome Framework) is a conceptual and interdisciplinary framework that explores the possibility that hierarchical organization, structural memory, information persistence, and large-scale cosmic evolution may be connected... more
The Hermes gravity relation predicts galaxy rotation curves from observed baryonic structure and a galaxy-age term with no per-galaxy free parameters. Previous work evaluated Hermes on a 133-galaxy age-verified subset of the SPARC... more
CGenome is a purely phenomenological observational framework that represents astrophysical systems as structured vectors in a 20-dimensional feature space. The framework does not introduce new physical laws, modify gravity, or assume... more
This work presents a phenomenological observational framework designed to test whether cumulative radiative history contains statistically meaningful predictive information about dynamical-offset observables in black-hole systems. The... more
Quantum-Informational Metric Genesis Cosmology (QIMG Cosmology) and its associated thermalisation framework propose a layered transition from pre-FRW informational initial conditions to a physically realised hot early universe. In the... more
We present a phenomenological Effective Field Theory (EFT) framework for late-time cosmology inspired by a brane-stability condition in a higher-dimensional bulk. The framework does not attempt to derive cosmology from a specified... more
現代物理学における根本的な課題、すなわち階層構造問題、宇宙定数問題(ダークエネルギー密度)、CP対称性の破れ問題、そして大統一理論(GUT)によって予測される観測不可能な陽子崩壊に対処するため、本論文では「量子化フラクタル方程式(QFE)」の枠組みの中で包括的な幾何学的解決策を提示する。

ファイル
The Concentric Orbital Cosmological Model (COCM) is an effective extension of ΛCDM that introduces a fixed oscillatory modulation in the Hubble parameter H(z), characterised by a frequency ωz = 11.1991, a period Tn = 2.861 Gyr, and an... more
Phase 11 collects the cosmic-scale observational signatures of the Unified Loop Framework. Earlier phases established the framework's architecture: the figure-8 atomic primitive with its black-hole-mode and white-hole-mode lobes (Phases... more
This episode presents, for the first time in its complete form, the fundamental equation of the Primary Network, as derived from RTS and VG. It is a short, elegant equation, whose simplicity contrasts with the depth of its implications.... more
Let us take a look at another rare book of old, one that our generation hardly knows exists. This hard-to-find treatise should be read as a grand theophysical architecture of reality in which the author Ponton does not divide the cosmos... more
This paper proposes a cosmological origin model distinct from the standard Big Bang singularity. In this framework, the observable universe originated as a shockwave collapse event within a pre-existing, equilibrium ocean of... more
In this work, we introduced a generalized concept of Caputo fractional derivatives, specifically the Caputo fractional delta derivative (Fr∆D) and Caputo fractional delta Dini derivative (Fr∆DiD) of order α ∈ (0, 1), on an arbitrary time... more
This paper develops how the known physical fields emerge from the decoherent substrate within the Aetherium cosmological framework. Building on the coherence–decoherence dynamics established in earlier work, it shows how gauge fields,... more
Aetherium theory proposes that physical systems evolve through structured coherence fields rather than through isolated particle interactions. This paper develops the first numerical framework for modeling those coherence dynamics... more
This paper introduces the Inversion Exchange Model (MIO), which conceptualizes the Universe as a closed, two-layer system of interacting manifolds: our observable layer and a hidden inversion sector. Within the MIO paradigm, Dark Energy... more
We demonstrate that General Relativity emerges from two axioms applied to a three-dimensional cubic lattice: fields E and χ defined at each node, and the 19-point isotropic stencil leapfrog update governing their evolution (GOV-01 and... more
Neptune was observed in Ancient Babylonia, Mycenaean Greece, early Rome, and Kyivan Rus'
In this paper we implement an improved (error-sensitive) Richardson-Lucy deconvolution algorithm on the measured angular power spectrum from the Wilkinson Microwave Anisotropy Probe (WMAP) 3 year data to determine the primordial power... more
We calculate the expected angular power spectrum of the temperature fluctuations in the microwave background radiation (MBR) generated in the quasi-steady state cosmology (QSSC). The paper begins with a brief description of how the... more
Observational cosmology has indeed made very rapid progress in recent years. The ability to quantify the universe has largely improved due to observational constraints coming from structure formation. The transition to precision cosmology... more
Einstein's theory of gravitation that governs the geometry of space-time, coupled with spectacular advance in cosmological observations, promises to deliver a 'standard model' of cosmology in the near future. However, local geometry of... more
We use weighted mean and median statistics techniques to combine individual cosmic microwave background (CMB) anisotropy detections and determine binned, multipolespace, CMB anisotropy power spectra. The resultant power spectra are... more
We develop a conservative higher-dimensional effective framework in which part of the apparent dark sector may arise from Weyl curvature projected onto our observable brane from adjacent matter-bearing branes in a compactified... more
This note extracts only the cosmology-facing claims from the author-supplied manuscript Discrete Invariants in Holographic Quantum Gravity: Emergent Structure at N ≈ 302 and compares them with the DESI Data Release 2 (DR2) dark-energy... more
Quantum field theory in curved spacetime has been remarkably fruitful. It can be used to explain how the large-scale structure of the universe and the anisotropies of the cosmic background radiation that we observe today first arose.... more
We introduce the notion of the cosmic numbers of a cosmological model, and discuss how they can be used to naturally classify models according to their ability to solve some of the problems of the standard cosmological model.
The standard cosmological model ΛCDM represents one of the most successful frameworks in modern physics: it accounts for the CMB power spectrum, BAO scale, Big Bang nucleosynthesis, large-scale structure, and the accelerated expansion of... more
We test a periodic oscillatory parametrisation of the Hubble expansion rate, derived from the physical framework of the Concentric Orbital Cosmological Model (COCM; Vázquez González 2026a,d), against DESI DR1+CC (n = 24) and DESI DR2+CC... more
This paper proposes a cosmological framework where the expansion of the universe is intrinsically linked to local density and the growth of event horizons. We challenge the standard dark energy dogma by introducing the concept of... more
Part V of the BigSnap research program. This document develops the observational falsification infrastructure for the BigSnap framework, establishing the Euclid DR1 forecast, the f(z)/D(z) separation analysis, and the pre-specified... more
We develop the Unified N-Mode-Field Membrane Theory (NMFMT) as a candidate mode-parametric variational framework for organizing and testing cross-domain dynamical structures. The central idea is that many physical and engineered systems... more
We present a unified dissipative framework linking cosmological observations to nuclear binding energies through a viscosity parameter η = 0.4182%. Calibration using Pantheon+ data (N = 1590) yields χ²/N = 0.901, comparable to ΛCDM. The... more
This paper assumes familiarity with the two previous Light Mechanics papers and extends their geometric framework to a closed conformal cosmology based on a logarithmic dilation field. Using Einstein's field equations, the conservation of... more
Modern cosmology operates under conditions of finite data, covariance uncertainty, and incomplete models. We present a unified framework in which statistical bias is not a correction but an intrinsic structural feature of physical... more
The empirical detection of gravitational waves proves the physical reality of space. And the physical reality of space makes it possible to demonstrate, with a very brief and simple argument, that special relativity is a formally... more
Professor David Tytler, Chair A precise determination of the light-element abundances produced during the epoch of Big Bang Nucleosynthesis (BBN) is an important probe of the early universe. The Deuterium-Hydrogen abundance ratio (D/H) is... more
This paper presents two complementary analyses of MAAT v1.2.1: a baseline observable prediction run and a systematic two-parameter stability scan. MAAT v1.2.1 introduces a conceptual clarification relative to v1.0. Structural respect R... more
The 21cm line of neutral hydrogen is a powerful probe of the high-redshift universe. In the standard ΛCDM model, the 21cm power spectrum is assumed isotropic-the cosmic expansion and the speed of light are direction-independent. In XLG... more
Standard cosmology interprets the cosmic microwave background (CMB) as the cooling remnant of a primordial singularity, necessitating inflation, dark matter, and dark energy to reconcile observations. This article proposes an alternative... more
MAAT v0.10 introduced an observable layer that converts stable structural-selection trajectories into expansion, equation-of-state, density-fraction, and growth-proxy quantities. This paper formulates MAAT v0.11 as a projection-observable... more
This paper presents the first direct confrontation of the MAAT projection observable with standard cosmological data. Building on previous work, the projection Critical Coherence Index (C_proj) is interpreted as a structural observable... more
The standard model of cosmology has a problem. When astronomers measure how clumped together matter is in the universe today, they get a lower number than what the Big Bang predicts. Two different measurements of the same universe... more
Polar ring galaxies are rare systems with two planes of stars and gas at nearly right angles, making them natural experiments for testing the shape of the gravitational field. When published models fit the dark matter in these systems,... more
The EP framework makes a specific prediction: the gravitational pull of a galaxy is not fixed. It fades as the galaxy ages. Younger galaxies should have more of it than their visible stars can explain. Older galaxies should have less. If... more
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