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The "standard" model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present --- as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-24 Jeppe Trøst Nielsen , Alberto Guffanti , Subir Sarkar

The High-Latitude Time-Domain Survey (HLTDS) for the Nancy Grace Roman Space Telescope (Roman) will discover thousands of high redshift Type Ia supernovae (SNeIa) to make generation-defining cosmological constraints on dark energy. To…

We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to trace the history of cosmic expansion over the last 10 billion years. These objects, which include 13 spectroscopically…

In this paper, we use a set of observational $H(z)$ data (OHD) to constrain the $\Lambda$CDM cosmology. This data set can be derived from the differential ages of the passively evolving galaxies. Meanwhile, the $\mathcal {A}$-parameter,…

Astrophysics · Physics 2014-11-18 Hui Lin , Cheng Hao , Xiao Wang , Qiang Yuan , Ze-Long Yi , Tong-Jie Zhang , Bao-Quan Wang

Modern machine learning will allow for simulation-based inference from reionization-era 21cm observations at the Square Kilometre Array. Our framework combines a convolutional summary network and a conditional invertible network through a…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-16 Benedikt Schosser , Caroline Heneka , Tilman Plehn

This paper introduces a new approach to reconstruct cosmological functions using artificial neural networks based on observational measurements with minimal theoretical and statistical assumptions. By using neural networks, we can generate…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-24 Isidro Gómez-Vargas , Ricardo Medel Esquivel , Ricardo García-Salcedo , J. Alberto Vázquez

We study the cosmic evolution of an interacting scalar field radiation model, in which a minimally coupled scalar field exchanges energy with the radiation sector through an exponential coupling. Extending previous formulations, a…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-01 Dorian Araya , Felipe Herrera , Nelson Videla

In the context of the discrepancies between the early and late universe, we emphasize the importance of independent measurements of the cosmic curvature in the late universe. We present an investigation of the model-independent measurement…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-26 Jing-Zhao Qi , Ping Meng , Jing-Fei Zhang , Xin Zhang

In this paper, we present a kinematic analysis of the Universe's expansion history using cosmography, with a particular emphasis on the jerk parameter $j_0$, which is equal to one in the standard $\Lambda$CDM scenario. We use distance…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-02 Gabriel Rodrigues , Rayff de Souza , Jailson Alcaniz

We use a new technique to extract the spectrum of a supernova from that of the contaminating background of its host galaxy, and apply it to the specific case of high-redshift Type Ia supernova (SN Ia) spectroscopy. The algorithm is based on…

Astrophysics · Physics 2007-05-23 S. Blondin , J. R. Walsh , B. Leibundgut , G. Sainton

Twenty years after the discovery that the expansion of the Universe is accelerating, a new finding is now challenging our understanding of the cosmos. Recent studies have shown that the Hubble constant, the speed of expansion measured…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-16 Michele Moresco

A detailed error analysis is carried out for the determination of the MSbar charm quark mass $\bar m_c(\bar m_c)$ from moments at order alpha_s^2 of the charm cross section in e^+e^- annihilation. To estimate the theoretical uncertainties…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. H. Hoang , M. Jamin

Type Ia supernovae (SNe~Ia) are central to studies of cosmic expansion, under the assumption that their absolute magnitude $M_B$ does not evolve with redshift. Even small drifts in brightness can bias cosmological parameters such as $H_0$…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-27 Akshay Rana

We compare four different methods that can be used to analyze the type Ia supernovae (SnIa) data, ie to use piecewise-constant functions in terms of: the dark energy equation of state $w(z)$, the deceleration parameter $q(z)$, the Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-24 Savvas Nesseris , Domenico Sapone

We use the latest compilation of observational H(z) measurements obtained with cosmic chronometers in the redshift range $0<z<2$ to place constraints on cosmological parameters. We consider the sample alone and in combination with other…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-15 Michele Moresco , Raul Jimenez , Licia Verde , Andrea Cimatti , Lucia Pozzetti , Claudia Maraston , Daniel Thomas

In this work, we reconstruct the H(z) based on observational Hubble data with Artificial Neural Network, then estimate the cosmological parameters and the Hubble constant. The training data we used are covariance matrix and mock H(z), which…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-23 Jie-feng Chen , Tong-Jie Zhang , Peng He , Tingting Zhang , Jie Zhang

We investigate the null tests of cosmic accelerated expansion by using the Baryon Acoustic Oscillation (BAO) data measured by the Dark Energy Spectroscopic Instrument (DESI) and reconstruct the dimensionless Hubble parameter $E(z)$ from the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-23 Xuchen Lu , Shengqing Gao , Yungui Gong

Recently, in [1] we developed a parametric reconstruction method to a homogeneous, isotropic and spatially flat Friedmann-Robertson-Walker (FRW) cosmological model filled of a fluid of dark energy (DE) with constant equation of state (EOS)…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-03 Freddy Cueva Solano , Ulises Nucamendi

Context: The cosmological concordance model ($\Lambda$CDM) matches the cosmological observations exceedingly well. This model has become the standard cosmological model with the evidence for an accelerated expansion provided by the type Ia…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-19 Isaac Tutusaus , Brahim Lamine , Arnaud Dupays , Alain Blanchard

We investigate the possibility of global cosmic rotation using a G\"odel-type rotating cosmological model, constrained through a cosmographic analysis of Type Ia supernovae (SNIa) from the Pantheon+ dataset. Employing a Taylor-expanded…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Anshul Verma , Pavan K. Aluri , David F. Mota , Yuri N. Obukhov
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