8,913 research outputs found
Binary inspiral, gravitational radiation, and cosmology
Observations of binary inspiral in a single interferometric gravitational
wave detector can be cataloged according to signal-to-noise ratio and
chirp mass . The distribution of events in a catalog composed of
observations with greater than a threshold depends on the
Hubble expansion, deceleration parameter, and cosmological constant, as well as
the distribution of component masses in binary systems and evolutionary
effects. In this paper I find general expressions, valid in any homogeneous and
isotropic cosmological model, for the distribution with and of
cataloged events; I also evaluate these distributions explicitly for relevant
matter-dominated Friedmann-Robertson-Walker models and simple models of the
neutron star mass distribution. In matter dominated Friedmann-Robertson-Walker
cosmological models advanced LIGO detectors will observe binary neutron star
inspiral events with from distances not exceeding approximately
, corresponding to redshifts of (0.26) for
(), at an estimated rate of 1 per week. As the binary system mass
increases so does the distance it can be seen, up to a limit: in a matter
dominated Einstein-deSitter cosmological model with () that limit
is approximately (1.7) for binaries consisting of two
black holes. Cosmological tests based on catalogs of the
kind discussed here depend on the distribution of cataloged events with
and . The distributions found here will play a pivotal role in testing
cosmological models against our own universe and in constructing templates for
the detection of cosmological inspiraling binary neutron stars and black holes.Comment: REVTeX, 38 pages, 9 (encapsulated) postscript figures, uses epsf.st
The Cosmological Constant and Advanced Gravitational Wave Detectors
Interferometric gravitational wave detectors could measure the frequency
sweep of a binary inspiral [characterized by its chirp mass] to high accuracy.
The observed chirp mass is the intrinsic chirp mass of the binary source
multiplied by , where is the redshift of the source. Assuming a
non-zero cosmological constant, we compute the expected redshift distribution
of observed events for an advanced LIGO detector. We find that the redshift
distribution has a robust and sizable dependence on the cosmological constant;
the data from advanced LIGO detectors could provide an independent measurement
of the cosmological constant.Comment: 13 pages plus 5 figure, LaTeX. Revised and final version, to appear
in Phys. Rev.
Rotochemical Heating of Neutron Stars: Rigorous Formalism with Electrostatic Potential Perturbations
The electrostatic potential that keeps approximate charge neutrality in
neutron star matter is self-consistently introduced into the formalism for
rotochemical heating presented in a previous paper by Fernandez and
Reisenegger. Although the new formalism is more rigorous, we show that its
observable consequences are indistinguishable from those of the previous one,
leaving the conclusions of the previous paper unchanged.Comment: 14 pages, including 4 eps figures. Accepted for publication in The
Astrophysical Journa
Gravitational Waves from coalescing binaries: Estimation of parameters
The paper presents a statistical model which reproduces the results of Monte
Carlo simulations to estimate the parameters of the gravitational wave signal
from a coalesing binary system. The model however is quite general and would be
useful in other parameter estimation problems.Comment: LaTeX with RevTeX macros, 4 figure
A First Comparison of SLOPE and Other LIGO Burst Event Trigger Generators
A number of different methods have been proposed to identify unanticipated
burst sources of gravitational waves in data arising from LIGO and other
gravitational wave detectors. When confronted with such a wide variety of
methods one is moved to ask if they are all necessary, i.e. given detector data
that is assumed to have no gravitational wave signals present, do they
generally identify the same events with the same efficiency, or do they each
'see' different things in the detector? Here we consider three different
methods, which have been used within the LIGO Scientific Collaboration as part
of its search for unanticipated gravitational wave bursts. We find that each of
these three different methods developed for identifying candidate gravitational
wave burst sources are, in fact, attuned to significantly different features in
detector data, suggesting that they may provide largely independent lists of
candidate gravitational wave burst events.Comment: 10 Pages, 5 Figures, Presented at the 10th Gravitational Wave Data
Analysis Workshop (GWDAW-10), 14-17 December 2005 at the University of Texas,
Brownsvill
The R-Mode Oscillations in Relativistic Rotating Stars
The axial mode oscillations are examined for relativistic rotating stars with
uniform angular velocity. Using the slow rotation formalism and the Cowling
approximation, we have derived the equations governing the r-mode oscillations
up to the second order with respect to the rotation. In the lowest order, the
allowed range of the frequencies is determined, but corresponding spatial
function is arbitrary. The spatial function can be decomposed in non-barotropic
region by a set of functions associated with the differential equation of the
second-order corrections. The equation however becomes singular in barotropic
region, and a single function can be selected to describe the spatial
perturbation of the lowest order. The frame dragging effect among the
relativistic effects may be significant, as it results in rather broad spectrum
of the r-mode frequency unlike in the Newtonian first-order calculation.Comment: 19 pages, 4 figures, AAS LaTeX, Accepted for publication in The
Astrophysical Journa
Crustal Oscillations of Slowly Rotating Relativistic Stars
We study low-amplitude crustal oscillations of slowly rotating relativistic
stars consisting of a central fluid core and an outer thin solid crust. We
estimate the effect of rotation on the torsional toroidal modes and on the
interfacial and shear spheroidal modes. The results compared against the
Newtonian ones for wide range of neutron star models and equations of state.Comment: 15 page
Orbital evolution of a test particle around a black hole: higher-order corrections
We study the orbital evolution of a radiation-damped binary in the extreme
mass ratio limit, and the resulting waveforms, to one order beyond what can be
obtained using the conservation laws approach. The equations of motion are
solved perturbatively in the mass ratio (or the corresponding parameter in the
scalar field toy model), using the self force, for quasi-circular orbits around
a Schwarzschild black hole. This approach is applied for the scalar model.
Higher-order corrections yield a phase shift which, if included, may make
gravitational-wave astronomy potentially highly accurate.Comment: 4 pages, 3 Encapsulated PostScript figure
Templates for stellar mass black holes falling into supermassive black holes
The spin modulated gravitational wave signals, which we shall call smirches,
emitted by stellar mass black holes tumbling and inspiralling into massive
black holes have extremely complicated shapes. Tracking these signals with the
aid of pattern matching techniques, such as Wiener filtering, is likely to be
computationally an impossible exercise. In this article we propose using a
mixture of optimal and non-optimal methods to create a search hierarchy to ease
the computational burden. Furthermore, by employing the method of principal
components (also known as singular value decomposition) we explicitly
demonstrate that the effective dimensionality of the search parameter space of
smirches is likely to be just three or four, much smaller than what has
hitherto been thought to be about nine or ten. This result, based on a limited
study of the parameter space, should be confirmed by a more exhaustive study
over the parameter space as well as Monte-Carlo simulations to test the
predictions made in this paper.Comment: 12 pages, 4 Tables, 4th LISA symposium, submitted to CQ
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