The cosmic equation of state
نویسندگان
چکیده
منابع مشابه
Measuring the Cosmic Equation of State with Counts of Galaxies.
The classical dN/dz test allows one to determine fundamental cosmological parameters from the evolution of the cosmic volume element. This test is applied by measuring the redshift distribution of a tracer whose evolution in number density is known. In the past, ordinary galaxies have been used for this; however, in the absence of a complete theory of galaxy formation, that method is fraught wi...
متن کاملGravitational lensing constraint on the cosmic equation of state
Recent redshift-distance measurements of Type Ia supernovae at cosmological distances suggest that two-third of the energy density of the universe is dominated by dark energy component with an effective negative pressure. This dark energy component is described by the equation of state px = wρx (w ≥ −1). We use gravitational lensing statistics to constrain the equation of state of this dark ene...
متن کاملReconstructing the cosmic equation of state from supernova distances.
Observations of high-redshift supernovae indicate that the Universe is accelerating. Here we present a model-independent method for estimating the form of the potential V(phi) of the scalar field driving this acceleration, and the associated equation of state w(phi). Our method is based on a versatile analytical form for the luminosity distance D(L), optimized to fit observed distances to dista...
متن کاملThe logarithmic equation of state for superconducting cosmic strings
This investigation follows up the suggestion that the equation of state for superconducting cosmic strings provided by Witten’s prototype biscalar field model can be well represented by an effective Lagrangian of simple logarithmic form depending on only 3 independent parameters. The numerical work described here confirms the validity of this approximation, and initiates the evaluation of the 3...
متن کاملConstraining the Dark Energy Equation of State with Cosmic Voids
Our universe is observed to be accelerating due to the dominant dark energy with negative pressure. The dark energy equation of state (w) holds a key to understanding the ultimate fate of the universe. The cosmic voids behave like bubbles in the universe so that their shapes must be quite sensitive to the background cosmology. Assuming a flat universe and using the priors on the matter density ...
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ژورنال
عنوان ژورنال: Astrophysics and Space Science
سال: 2014
ISSN: 0004-640X,1572-946X
DOI: 10.1007/s10509-014-2211-5