Erratum: Gravitational Waves from Quasicircular Black-Hole Binaries in Dynamical Chern-Simons Gravity [Phys. Rev. Lett. 109, 251105 (2012)].

This corrects the article DOI: 10.1103/PhysRevLett.109.

Black Hole Spectroscopy with Coherent Mode Stacking.

The measurement of multiple ringdown modes in gravitational waves from binary black hole mergers will allow for testing the fundamental properties of black holes in general relativity and to constrain modified theories of gravity. To enhance the ability of Advanced LIGO/Virgo to perform such tasks, we propose a coherent mode stacking method to search for a chosen target mode within a collection of multiple merger events. We first rescale each signal so that the target mode in each of them has the same frequency and then sum the waveforms constructively.

Erratum: Gravitational Waves from Quasicircular Black-Hole Binaries in Dynamical Chern-Simons Gravity [Phys. Rev. Lett. 109, 251105 (2012)].

This corrects the article DOI: 10.1103/PhysRevLett.109.

Gravitation-Wave Emission in Shift-Symmetric Horndeski Theories.

Gravity theories beyond general relativity typically predict dipolar gravitational emission by compact-star binaries. This emission is sourced by "sensitivity" parameters depending on the stellar compactness. We introduce a general formalism to calculate these parameters, and show that in shift-symmetric Horndeski theories stellar sensitivities and dipolar radiation vanish, provided that the binary's dynamics is perturbative (i.

Strong binary pulsar constraints on Lorentz violation in gravity.

Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory of general relativity. One of these is Lorentz symmetry, which states that physical phenomena appear the same for all inertially moving observers. We study the effect of violations of Lorentz symmetry in the orbital evolution of binary pulsars and find that it induces a much more rapid decay of the binary's orbital period due to the emission of dipolar radiation.

I-Love-Q: unexpected universal relations for neutron stars and quark stars.

Neutron stars and quark stars are not only characterized by their mass and radius but also by how fast they spin, through their moment of inertia, and how much they can be deformed, through their Love number and quadrupole moment. These depend sensitively on the star's internal structure and thus on unknown nuclear physics. We find universal relations between the moment of inertia, the Love number, and the quadrupole moment that are independent of the neutron and quark star's internal structure.

Gravitational waves from quasicircular black-hole binaries in dynamical Chern-Simons gravity.

Dynamical Chern-Simons gravity cannot be strongly constrained with current experiments because it reduces to general relativity in the weak-field limit. This theory, however, introduces modifications in the nonlinear, dynamical regime, and thus it could be greatly constrained with gravitational waves from the late inspiral of black-hole binaries. We complete the first self-consistent calculation of such gravitational waves in this theory.

Torsion-bar antenna for low-frequency gravitational-wave observations.

We propose a novel type of gravitational-wave antenna, formed by two bar-shaped test masses and laser-interferometric sensors to monitor their differential angular fluctuations. This antenna has a fundamental sensitivity to low-frequency signals below 1 Hz, even with a ground-based configuration. In addition, it is possible to expand the observation band to a lower limit determined by the observation time, by using modulation and up-conversion of gravitational-wave signals by rotation of the antenna.