摘要:

©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291835

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291836

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We report on the status of the five resonant-mass detectors of gravitational waves operating today in Australia, Italy and USA. These bar detectors are in continuous observational mode with burst sensitivityh≃4×10−19,or, in spectral units,2×10−22&hthinsp;Hz−1/2over bandwidths of about 1 Hz, with a duty cycle mainly limited by cryogenic operations. The strongest potential sources of GW bursts in our Galaxy and in the local group are today monitored by such instruments. With the formation of the IGEC (International Gravitational Event Collaboration), the activity on bar detectors passed a phase transition: from the occasional exchange of data between two groups to the systematic exchange of data between all the groups, following an agreed protocol. In addition to the search for impulsive events, the data collected are being used to detect periodic waves over long time periods, to give new upper limits for the stochastic background of cosmological origin, and to study possible correlations with gamma ray bursts. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291837

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

This paper is a brief review of the topic of binary systems as sources of gravitational-wave emission for both LIGO and LISA. In particular I review the current estimates of the associated Galactic event rates and their implications for expected detection rates. I discuss the estimates for (i) the coalescence of close binaries containing neutron stars or black holes, (ii) white dwarfs going through accretion-induced collapse into neutron stars, and (iii) detached but close binaries containing two white dwarfs. The relevant uncertainties and robustness of the estimates are addressed along with ways of obtaining conservative upper limits. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291838

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Symmetry-breaking rotational instabilities may play a significant role in the dynamics of rapidly rotating compact objects. During the growth of such global non-axisymmetric instabilities, the external spacetime undergoes dynamical changes in response to the changing shape of the object and gravitational radiation is emitted. Using a three-dimensional Smoothed Particle Hydrodynamics code, the numerically generated gravitational wave signals of two pre-supernova stellar cores undergoing a dynamical instability will be compared. The first model assumes a purely Newtonian gravitational field, while the second model incorporates the General Relativistic “back reaction” into the hydrodynamical equations. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291839

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Since the last Amaldi meeting in 1997 we have learned that ther-modes of rapidly rotating neutron stars are unstable to gravitational radiation reaction in astrophysically realistic conditions. Newborn neutron stars rotating more rapidly than about 100 Hz may spin down to that frequency during up to one year after the supernova that gives them birth, emitting gravitational waves which might be detectable by the enhanced LIGO interferometers at a distance which includes several supernovae per year. A cosmological background of these events may be detectable by advanced LIGO. The spins (about 300 Hz) of neutron stars in low-mass x-ray binaries may also be due to ther-mode instability (under different conditions), and some of these systems in our galaxy may also produce detectable gravitational waves—see the review by G. Ushomirsky in this volume. Much work is in progress on developing our understanding ofr-mode astrophysics to refine the early, optimistic estimates of the delectability of the gravitational waves. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291840

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We summarize the observations of the spin periods of rapidly accreting neutron stars. If gravitational radiation is responsible for balancing the accretion torque at the observed spin frequencies of ≈300 Hz, then the brightest of these systems make excellent gravitational wave sources for LIGO-II and beyond. We review the recent theoretical progress on two mechanisms for gravitational wave emission: mass quadrupole radiation from deformed neutron star crusts and current quadrupole radiation fromr-mode pulsations in neutron star cores. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291841

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Space-based gravitational-wave interferometers such as LISA will be sensitive to the inspiral of stellar mass compact objects into black holes with masses in the range of roughly105solar masses to (a few)107solar masses. During the last year of inspiral, the compact body spends several hundred thousand orbits spiraling from several Schwarzschild radii to the last stable orbit. The gravitational waves emitted from these orbits probe the strong-field region of the black hole spacetime and can make possible high precision tests and measurements of the black hole’s properties. Measuring such waves will require a good theoretical understanding of the waves’ properties, which in turn requires a good understanding of strong-field radiation reaction and of properties of the black hole’s astrophysical environment which could complicate wave-form generation. In these proceedings, I review estimates of the rate at which such inspirals occur in the universe, and discuss what is being done and what must be done further in order to calculate the inspiral waveform. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291842

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291843

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We overview the recently proposed mode-sum regularization prescription (MSRP) for the calculation of the local radiation-reaction forces, which are crucial for the orbital evolution of binaries. We then describe some new results which were obtained using MSRP, and discuss their importance for gravitational-wave astronomy. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1291844

出版商:AIP    

年代:1900

数据来源: AIP