Improved cosmological constraints on neutrino-producing decaying particles

1993 ◽  
Vol 48 (2) ◽  
pp. 562-566 ◽  
Author(s):  
Andrew A. de Laix ◽  
Robert J. Scherrer
Keyword(s):  
Cosmological Constraints

scholarly journals Redshift-space effects in voids and their impact on cosmological tests. Part I: the void size function

2020 ◽  
Vol 500 (1) ◽  
pp. 911-925
Author(s):  
Carlos M Correa ◽  
Dante J Paz ◽  
Ariel G Sánchez ◽  
Andrés N Ruiz ◽  
Nelson D Padilla ◽  
...  
Keyword(s):  
Theoretical Framework ◽  
Real Space ◽  
Global Dynamics ◽  
Void Size ◽  
Spherical Void ◽  
Cosmological Constraints ◽  
Redshift Surveys ◽  
Size Function ◽  
Expansion Effect ◽  
Space Effects

ABSTRACT Voids are promising cosmological probes. Nevertheless, every cosmological test based on voids must necessarily employ methods to identify them in redshift space. Therefore, redshift-space distortions (RSD) and the Alcock–Paczyński effect (AP) have an impact on the void identification process itself generating distortion patterns in observations. Using a spherical void finder, we developed a statistical and theoretical framework to describe physically the connection between the identification in real and redshift space. We found that redshift-space voids above the shot noise level have a unique real-space counterpart spanning the same region of space, they are systematically bigger and their centres are preferentially shifted along the line of sight. The expansion effect is a by-product of RSD induced by tracer dynamics at scales around the void radius, whereas the off-centring effect constitutes a different class of RSD induced at larger scales by the global dynamics of the whole region containing the void. The volume of voids is also altered by the fiducial cosmology assumed to measure distances, this is the AP change of volume. These three systematics have an impact on cosmological statistics. In this work, we focus on the void size function. We developed a theoretical framework to model these effects and tested it with a numerical simulation, recovering the statistical properties of the abundance of voids in real space. This description depends strongly on cosmology. Hence, we lay the foundations for improvements in current models of the abundance of voids in order to obtain unbiased cosmological constraints from redshift surveys.

Cosmological constraints on unstable heavy neutrinos

1984 ◽  
Vol 134 (3-4) ◽  
pp. 174-178 ◽  
Author(s):  
P. Binétruy ◽  
G. Girardi ◽  
P. Salati
Keyword(s):  
Cosmological Constraints

scholarly journals INTERACTION BETWEEN DARK ENERGY AND DARK MATTER: OBSERVATIONAL CONSTRAINTS FROM OHD, BAO, CMB AND SNe Ia

2013 ◽  
Vol 22 (14) ◽  
pp. 1350082 ◽  
Author(s):  
SHUO CAO ◽  
NAN LIANG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Observational Constraints ◽  
Coincidence Problem ◽  
Cosmological Constraints ◽  
Coincidence Index ◽  
Acceleration Of The Universe ◽  
Interaction Term ◽  
Negative Coupling ◽  
The Universe

In order to test if there is energy transfer between dark energy (DE) and dark matter (DM), we investigate cosmological constraints on two forms of nontrivial interaction between the DM sector and the sector responsible for the acceleration of the universe, in light of the newly revised observations including OHD, CMB, BAO and SNe Ia. More precisely, we find the same tendencies for both phenomenological forms of the interaction term Q = 3γHρ, i.e. the parameter γ to be a small number, |γ| ≈ 10-2. However, concerning the sign of the interaction parameter, we observe that γ > 0 when the interaction between dark sectors is proportional to the energy density of dust matter, whereas the negative coupling (γ < 0) is preferred by observations when the interaction term is proportional to DE density. We further discuss two possible explanations to this incompatibility and apply a quantitative criteria to judge the severity of the coincidence problem. Results suggest that the γm IDE model with a positive coupling may alleviate the coincidence problem, since its coincidence index C is smaller than that for the γd IDE model, the interacting quintessence and phantom models by four orders of magnitude.

Cosmological Constraints on Weyl's Vector Meson

1990 ◽  
Vol 14 (3) ◽  
pp. 373-378 ◽  
Author(s):  
Chao-guang Huang ◽  
Han-qing Zheng ◽  
Dan-di Wu
Keyword(s):  
Vector Meson ◽  
Cosmological Constraints

Gravitino dark matter and cosmological constraints

2009 ◽  
Author(s):  
Ki-Young Choi ◽  
Csaba Balazs ◽  
Fei Wang
Keyword(s):  
Dark Matter ◽  
Cosmological Constraints
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