Poster
Abstract :
A key issue of contemporary cosmology is
the problem of currently accelerating
expansion of the Universe. The nature of
this phenomenon is one of the most
outstanding problems of physics and
astronomy today. Its origin may be
attributed to either unknown exotic
material component with negative
pressure - so called Dark Energy (DE),
to infra red modification of gravity at
cosmological scale or requires to relax
the assumption of homogeneity of the
Universe. It should be pointed out that
the strength of modern cosmology (which
now enterd stage dubbed the era of
precision cosmology) lies in consistency
across independent pieces of evidence
rather than in single, crucial
experiment. We approach to this subject
from phenomenological point of view. In
this spirit we perform a cosmographic
analysis using several cosmological
probes such as Type Ia Supernovae
(Union2 compilation), data from Cosmic
Microwave Background (WMAP7), Baryon
Acoustic Oscillation (BAO) and strongly
gravitationally lensed systems (combined
data sets from SLACS and LSD surveys)
and Gamma Ray Bursts. These tests falls
into two distinct cathegories. The first
one makes use of the angular diameter
distance, and refers to the so called
standard rulers. Here we have strong
lensing systems, shift parameter R from
CMB and BAO scales. The second uses the
luminosity distance and then we deal
with standard (or rather standarizable)
candles. Here we deal with SN Ia and
GRB. The two distance concepts, although
theoretically related to each other, in
practice have different systematic
uncertainties and different parameter
degeneracies.Hence their joint analysis
is more restrictive in the parameter
space. We considered several
cosmological scenarios of dark energy,
widely discussed in current literature.
We also address the question which model
is the best with information-theoretic
criteria: the Akaike Criterion (AIC) and
Bayesian Information Criterion (BIC).
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