2,167 research outputs found
On searches for gravitational waves from mini creation event by laser interferometric detectors
As an alternative view to the standard big bang cosmology the quasi-steady
state cosmology(QSSC) argues that the universe was not created in a single
great explosion; it neither had a beginning nor will it ever come to an end.
The creation of new matter in the universe is a regular feature occurring
through finite explosive events. Each creation event is called a mini-bang or,
a mini creation event(MCE). Gravitational waves are expected to be generated
due to any anisotropy present in this process of creation. Mini creation event
ejecting matter in two oppositely directed jets is thus a source of
gravitational waves which can in principle be detected by laser interferometric
detectors. In the present work we consider the gravitational waveforms
propagated by linear jets and then estimate the response of laser
interferometric detectors like LIGO and LISA
A Radical Departure from the ''steady State'' Concept in Cosmology
Radical departure from steady state theory in cosmolog
Interpretations of the Accelerating Universe
It is generally argued that the present cosmological observations support the
accelerating models of the universe, as driven by the cosmological constant or
`dark energy'. We argue here that an alternative model of the universe is
possible which explains the current observations of the universe. We
demonstrate this with a reinterpretation of the magnitude-redshift relation for
Type Ia supernovae, since this was the test that gave a spurt to the current
trend in favour of the cosmological constant.Comment: 12 pages including 2 figures, minor revision, references added, a
paragraph on the interpretation of the CMB anisotropy in the QSSC added in
conclusion, general results unchanged. To appear in the October 2002 issue of
the "Publications of the Astronmical Society of the Pacific
Modeling Repulsive Gravity with Creation
There is a growing interest in the cosmologists for theories with negative
energy scalar fields and creation, in order to model a repulsive gravity. The
classical steady state cosmology proposed by Bondi, Gold and Hoyle in 1948, was
the first such theory which used a negative kinetic energy creation field to
invoke creation of matter. We emphasize that creation plays very crucial role
in cosmology and provides a natural explanation to the various explosive
phenomena occurring in local (z<0.1) and extra galactic universe. We exemplify
this point of view by considering the resurrected version of this theory - the
quasi-steady state theory, which tries to relate creation events directly to
the large scale dynamics of the universe and supplies more natural explanations
of the observed phenomena. Although the theory predicts a decelerating universe
at the present era, it explains successfully the recent SNe Ia observations
(which require an accelerating universe in the standard cosmology), as we show
in this paper by performing a Bayesian analysis of the data.Comment: The paper uses an old SNeIa dataset. With the new improved data, for
example the updated gold sample (Riess et al, astro-ph/0611572), the fit
improves considerably (\chi^2/DoF=197/180 and a probability of
goodness-of-fit=18%
Inhomogeneities in the Microwave Background Radiation interpreted within the framework of the Quasi-Steady State Cosmology
We calculate the expected angular power spectrum of the temperature
fluctuations in the microwave background radiation (MBR) generated in the
quasi-steady state cosmology (QSSC). The paper begins with a brief description
of how the background is produced and thermalized in the QSSC. We then discuss
within the framework of a simple model, the likely sources of fluctuations in
the background due to astrophysical and cosmological causes. Power spectrum
peaks at , 180-220 and 600-900 are shown to be related in this
cosmology respectively to curvature effects at the last minimum of the scale
factor, clusters and groups of galaxies. The effect of clusters is shown to be
related to their distribution in space as indicated by a toy model of structure
formation in the QSSC. We derive and parameterize the angular power spectrum
using six parameters related to the sources of temperature fluctuations at
three characteristic scales. We are able to obtain a satisfactory fit to the
observational band power estimates of MBR temperature fluctuation spectrum.
Moreover, the values of `best fit' parameters are consistent with the range of
expected values.Comment: 27 pages, including 5 figures; to appear in Astrophys.
The luminosity-volume test and the local hypothesis of Quasars
It is shown that the luminosity-volume test for optically selected objects has an in-built bias towards increasing the average value of V/Vm above the Euclidean value of ½. A more satisfactory bias-free statistic is suggested in the form of In (V/Vm), The result of applying the test to a sample from the Bright Quasar Survey (BQS) shows that the local hypothesis of quasars is consistent with the data
Testing extra dimensions with boundaries using Newton's law modifications
Extra dimensions with boundaries are often used in the literature, to provide
phenomenological models that mimic the standard model. In this context, we
explore possible modifications to Newton's law due to the existence of an
extra-dimensional space, at the boundary of which the gravitational field obeys
Dirichlet, Neumann or mixed boundary conditions. We focus on two types of extra
space, namely, the disk and the interval. As we prove, in order to have a
consistent Newton's law modification (i.e., of the Yukawa-type), some of the
extra-dimensional spaces that have been used in the literature, must be ruled
out.Comment: Published version, title changed, 6 figure
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