36 research outputs found
Limit on Continuous Neutrino Emission from Neutron Stars
The timing data of the binary pulsar PSR1913+16, are used to establish an
upper limit on the rate of continuous neutrino emission from neutron stars.
Neutrino emission from each of the neutron stars of the binary system,
increases the star binding energy and thus translates to a decrease in their
masses. This in turn implies an increase with time of the binary period. Using
the pulsar data we obtain an upper limit on the allowed rate of mass reduction
: , where is the total mass of
the binary. This constrains exotic nuclear equations of state that predict
continuous neutrino emissions. The limit applies also to other channels of
energy loss, e.g. axion emission. Continued timing measurements of additional
binary pulsars, should yield a stronger limit in the future.Comment: 5 pages, Added a section on energy transport in the neutron star,
JHEP publishe
Interpretation of Binary Pulsar Observations
The nature, dynamics and evolution of the three known radio pulsar binaries are discussed. The system containing 1913+16 appears to comprise two ~1.4 M⊙ components, and to undergo orbital decay as predicted by general relativity. It is proposed that 1913+16 has a neutron star companion and that 0655+64 and 0820+02 have white dwarf companions which should be observable optically
Isolated and dynamical horizons and their applications
Over the past three decades, black holes have played an important role in
quantum gravity, mathematical physics, numerical relativity and gravitational
wave phenomenology. However, conceptual settings and mathematical models used
to discuss them have varied considerably from one area to another. Over the
last five years a new, quasi-local framework was introduced to analyze diverse
facets of black holes in a unified manner. In this framework, evolving black
holes are modeled by dynamical horizons and black holes in equilibrium by
isolated horizons. We review basic properties of these horizons and summarize
applications to mathematical physics, numerical relativity and quantum gravity.
This paradigm has led to significant generalizations of several results in
black hole physics. Specifically, it has introduced a more physical setting for
black hole thermodynamics and for black hole entropy calculations in quantum
gravity; suggested a phenomenological model for hairy black holes; provided
novel techniques to extract physics from numerical simulations; and led to new
laws governing the dynamics of black holes in exact general relativity.Comment: 77 pages, 12 figures. Typos and references correcte
An increased estimate of the merger rate of double neutron stars from observations of a highly relativistic system
The merger of close binary systems containing two neutron stars should
produce a burst of gravitational waves, as predicted by the theory of general
relativity. A reliable estimate of the double-neutron-star merger rate in the
Galaxy is crucial in order to predict whether current gravity wave detectors
will be successful in detecting such bursts. Present estimates of this rate are
rather low, because we know of only a few double-neutron-star binaries with
merger times less than the age of the Universe. Here we report the discovery of
a 22-ms pulsar, PSR J0737-3039, which is a member of a highly relativistic
double-neutron-star binary with an orbital period of 2.4 hours. This system
will merge in about 85 Myr, a time much shorter than for any other known
neutron-star binary. Together with the relatively low radio luminosity of PSR
J0737-3039, this timescale implies an order-of-magnitude increase in the
predicted merger rate for double-neutron-star systems in our Galaxy (and in the
rest of the Universe).Comment: 6 pages, 2 figure
Binary and Millisecond Pulsars at the New Millennium
We review the properties and applications of binary and millisecond pulsars.
Our knowledge of these exciting objects has greatly increased in recent years,
mainly due to successful surveys which have brought the known pulsar population
to over 1300. There are now 56 binary and millisecond pulsars in the Galactic
disk and a further 47 in globular clusters. This review is concerned primarily
with the results and spin-offs from these surveys which are of particular
interest to the relativity community.Comment: 59 pages, 26 figures, 5 tables. Accepted for publication in Living
Reviews in Relativity (http://www.livingreviews.org
Stationary Black Holes: Uniqueness and Beyond
The spectrum of known black-hole solutions to the stationary Einstein
equations has been steadily increasing, sometimes in unexpected ways. In
particular, it has turned out that not all black-hole-equilibrium
configurations are characterized by their mass, angular momentum and global
charges. Moreover, the high degree of symmetry displayed by vacuum and
electro-vacuum black-hole spacetimes ceases to exist in self-gravitating
non-linear field theories. This text aims to review some developments in the
subject and to discuss them in light of the uniqueness theorem for the
Einstein-Maxwell system.Comment: Major update of the original version by Markus Heusler from 1998.
Piotr T. Chru\'sciel and Jo\~ao Lopes Costa succeeded to this review's
authorship. Significantly restructured and updated all sections; changes are
too numerous to be usefully described here. The number of references
increased from 186 to 32
Exploring new physics frontiers through numerical relativity
The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology
Binary and Millisecond Pulsars
We review the main properties, demographics and applications of binary and
millisecond radio pulsars. Our knowledge of these exciting objects has greatly
increased in recent years, mainly due to successful surveys which have brought
the known pulsar population to over 1700. There are now 80 binary and
millisecond pulsars associated with the disk of our Galaxy, and a further 103
pulsars in 24 of the Galactic globular clusters. Recent highlights have been
the discovery of the first ever double pulsar system and a recent flurry of
discoveries in globular clusters, in particular Terzan 5.Comment: 77 pages, 30 figures, available on-line at
http://www.livingreviews.org/lrr-2005-