English
Related papers

Related papers: Five parameters are all you need (in $\Lambda$CDM)

200 papers

The average rate of emission of ionizing radiation per unit volume (or emissivity) in the universe can be calculated as the ratio of the intensity of the ionizing background to the mean free path of ionizing photons. The intensity of the…

Astrophysics · Physics 2009-11-07 Jordi Miralda-Escude

Using a semi-analytical model developed by Choudhury & Ferrara (2005) we study the observational constraints on reionization via a principal component analysis (PCA). Assuming that reionization at z>6 is primarily driven by stellar sources,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Sourav Mitra , T. Roy Choudhury , Andrea Ferrara

The incorporation of radiative transfer effects into cosmological hydrodynamical simulations is essential for understanding how the intergalactic medium (IGM) makes the transition from a neutral medium to one that is almost fully ionized.…

Astrophysics · Physics 2009-11-06 Aaron Sokasian , Tom Abel , Lars E. Hernquist

A new parametrization of the Hubble parameter is proposed to explore the issue of the cosmological landscape. The constraints on model parameters are derived through the Markov Chain Monte Carlo (MCMC) method by employing a comprehensive…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-06 L. Sudharani , Kazuharu Bamba , N. S. Kavya , V. Venkatesha

Over the next decade, improvements in cosmological parameter constraints will be driven by surveys of large-scale structure. Its inherent non-linearity suggests that significant information will be embedded in higher correlations beyond the…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-19 Joyce Byun , Alexander Eggemeier , Donough Regan , David Seery , Robert E. Smith

Recent results of ground-based telescopes, giving high-quality measurements of the CMB temperature power spectrum on small scales motivate the need for an accurate model of foregrounds, which dominate the primary signal at these multipoles.…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-06 Adélie Gorce , Marian Douspis , Laura Salvati

Recently, the mean free path of ionizing photons in the $z = 6$ intergalactic medium (IGM) was measured to be very short, presenting a challenge to existing reionization models. At face value, the measurement can be interpreted as evidence…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-07 Christopher Cain , Anson D'Aloisio , Vid Irsic , Nakul Gangolli , Sanya Dhami

A parametric reconstruction of the jerk parameter, the third order derivative of the scale factor expressed in a dimensionless way, has been discussed. Observational constraints on the model parameters have been obtained by Maximum…

General Relativity and Quantum Cosmology · Physics 2016-03-23 Ankan Mukherjee , Narayan Banerjee

Presently, we are facing a 3$\sigma$ tension in the most basic cosmological parameter -- the Hubble constant $H_0$. This tension arises when fitting the Lambda-cold-dark-matter model ($\Lambda$CDM) to the high-precision…

General Physics · Physics 2017-10-18 Steffen Hahn , Ralf Hofmann

The Thomson optical depth from reionization is a limiting factor in measuring the amplitude of primordial fluctuations, and hence in measuring physics that affects the low-redshift amplitude, such as the neutrino masses. Current constraints…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-05 P. Daniel Meerburg , Joel Meyers , Kendrick M. Smith , Alexander van Engelen

We present constraints on cosmological and star formation parameters based on combining observations of the Wilkinson Microwave Anisotropy Probe (WMAP) and high-redshift quasars from the Sloan Digital Sky Survey (SDSS). We use a…

Astrophysics · Physics 2009-11-07 Weihsueh A. Chiu , Xiaohui Fan , Jeremiah P. Ostriker

We use the photon flux and absorption tracer algorithm presented in Katz et al.~2018, to characterise the contribution of haloes of different mass and stars of different age and metallicity to the reionization of the Universe. We employ a…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-05 Harley Katz , Taysun Kimm , Martin G. Haehnelt , Debora Sijacki , Joakim Rosdahl , Jeremy Blaizot

The $\rm\Lambda$CDM cosmological model is remarkable: with just 6 parameters it describes the evolution of the Universe from a very early time when all structures were quantum fluctuations on subatomic scales to the present, and it is…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-07 Michael S. Turner

We present model-marginalized limits on the six standard $\Lambda$CDM cosmological parameters ($\Omega_{\rm c} h^2$, $\Omega_{\rm b} h^2$, $\theta_{\rm MC}$, $\tau_{\rm reio}$, $n_s$ and $A_s$), as well as on selected derived quantities…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-29 Stefano Gariazzo , William Giarè , Olga Mena , Eleonora Di Valentino

The annihilation or decay of Dark Matter (DM) particles could affect the thermal history of the universe and leave an observable signature in Cosmic Microwave Background (CMB) anisotropies. We update constraints on the annihilation rate of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Gaelle Giesen , Julien Lesgourgues , Benjamin Audren , Yacine Ali-Haïmoud

Recent observations have set the first constraints on the epoch of reionization (EoR), corresponding to the formation epoch of the first luminous objects. Studies of Gunn-Peterson (GP) absorption, and related phenomena, suggest a…

Astrophysics · Physics 2008-11-26 Xiaohui Fan , C. L. Carilli , B. Keating

Accurate cosmological parameter estimates using polarization data of the cosmic microwave background (CMB) put stringent requirements on map calibration, as highlighted in the recent results from the Planck satellite. In this paper, we…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-21 Silvia Galli , W. L. Kimmy Wu , Karim Benabed , François Bouchet , Thomas M. Crawford , Eric Hivon

Driven by the CMB temperature-redshift ($T$-$z$) relation as demanded by deconfining SU(2) Yang-Mills thermodynamics, an according cosmological model is proposed and analysed. This model -- SU(2)$_\CMB$ -- exhibits a dark sector,…

General Physics · Physics 2018-12-13 Steffen Hahn , Ralf Hofmann , Daniel Kramer

We simulate a variety of optical systematics for Taurus, a balloon-borne cosmic microwave background (CMB) polarisation experiment, to assess their impact on large-scale E-mode polarisation measurements and constraints of the optical depth…

The density contrast of the Universe, parametrized in terms of the matter power spectrum and its variance, can amplify the signal of the free-free process in the plasma. The damping of fluctuations on scales smaller than the DM particle…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Tiziana Trombetti , Carlo Burigana
‹ Prev 1 8 9 10 Next ›