Chirality of the gravitational-wave background and pulsar-timing arrays

Abstract

We describe the signatures of a circularly polarized gravitational-wave background on the timing residuals obtained with pulsar-timing arrays. Most generally, the circular polarization will depend on the gravitational-wave direction, and we describe this angular dependence in terms of spherical harmonics. While the amplitude of the monopole (the overall chirality of the gravitational-wave background) cannot be detected, measures of the anisotropy are theoretically conceivable. We provide expressions for the minimum-variance estimators for the circular-polarization anisotropy. We evaluate the smallest detectable signal as a function of the signal-to-noise ratio with which the isotropic GW signal is detected and the number of pulsars (assumed to be roughly uniformly spread throughout the sky) in the survey. We find that the overall dipole of the circular polarization and a few higher overall multipoles, are detectable in a survey with $\gtrsim 100$ pulsars if their amplitude is close to maximal and once the isotropic signal is established with a signal-to-noise ratio $\gtrsim 400$. Even if the anisotropy can be established, though, there will be limited information on its direction. Similar arguments apply to astrometric searches for gravitational waves.

arXiv comment7 pages, 2 figures

References in corpus (31)

• Gravitational Wave Experiments and Early Universe Cosmology
• European Pulsar Timing Array Limits On An Isotropic Stochastic Gravitational-Wave Background
• The Parkes Pulsar Timing Array Project
• Gravitational Wave Tests of General Relativity with Ground-Based Detectors and Pulsar Timing Arrays
• The International Pulsar Timing Array: First Data Release
• Gravitational Waves Probe the Coalescence Rate of Massive Black Hole Binaries
• The NANOGrav 11-year Data Set: Pulsar-timing Constraints On The Stochastic Gravitational-wave Background
• Gravitational waves from resolvable massive black hole binary systems and observations with Pulsar Timing Arrays
• Ultra-Low Frequency Gravitational Radiation from Massive Black Hole Binaries
• Optimal strategies for gravitational wave stochastic background searches in pulsar timing data
• The Parkes Pulsar Timing Array
• Measuring Statistical isotropy of the CMB anisotropy
• Cosmic Microwave Background Statistics for a Direction-Dependent Primordial Power Spectrum
• Characterising gravitational wave stochastic background anisotropy with Pulsar Timing Arrays
• Astrometric Effects of a Stochastic Gravitational Wave Background
• Detection of Anisotropies in the Gravitational-Wave Stochastic Background
• Mapping gravitational-wave backgrounds using methods from CMB analysis: Application to pulsar timing arrays
• An astrometric search method for individually resolvable gravitational wave sources with Gaia
• Single Sources in the Low-Frequency Gravitational Wave Sky: properties and time to detection by pulsar timing arrays
• Does a 'stochastic' background of gravitational waves exist in the pulsar timing band?
• Pulsar Timing Array Analysis for Black Hole Backgrounds
• Probing circular polarization in stochastic gravitational wave background with pulsar timing arrays
• Pulsar-timing arrays, astrometry, and gravitational waves
• Gravitational wave research using pulsar timing arrays
• Constraining the Polarization Content of Gravitational Waves with Astrometry
• Odd-Parity Bipolar Spherical Harmonics
• Astrometric Effects of Gravitational Wave Backgrounds with non-Einsteinian Polarizations
• Harmonic space analysis of pulsar timing array redshift maps
• Gravitational-Wave Detection and Astrophysics with Pulsar Timing Arrays
• Bipolar Harmonic encoding of CMB correlation patterns
• The Cosmic Microwave Background Bipolar Power Spectrum: Basic Formalism and Applications

Cited by in corpus (19)

• Axion-Gauge Dynamics During Inflation as the Origin of Pulsar Timing Array Signals and Primordial Black Holes
• Prospects for Future Binary Black Hole GW Studies in Light of PTA Measurements
• Nano-Hz gravitational wave signature from axion dark matter
• Measuring Parity Asymmetry of Gravitational Wave Backgrounds with a Heliocentric Detector Network in the mHz Band
• Pulsar-timing measurement of the circular polarization of the stochastic gravitational-wave background
• Gravitational Waves from an Axion-Dark Photon System: A Lattice Study
• Dissecting the Stochastic Gravitational Wave Background with Astrometry
• LiteBIRD Science Goals and Forecasts. A Case Study of the Origin of Primordial Gravitational Waves using Large-Scale CMB Polarization
• Pulsar Timing Array Harmonic Analysis and Source Angular Correlations
• Timing-residual power spectrum of a polarized stochastic gravitational-wave background in pulsar-timing-array observation
• Charting the Nanohertz Gravitational Wave Sky with Pulsar Timing Arrays
• Probing Parity Violation in the Stochastic Gravitational Wave Background with Astrometry
• Alternative LISA-TAIJI networks: Detectability of the Parity Violation in Stochastic Gravitational Wave Background
• Parity-violating primordial gravitational waves from null energy condition violation
• Chiral Gravitational Wave Background from Audible Axion via Nieh-Yan Term
• First astrometric constraints on parity-violation in the gravitational wave background
• Circularly Polarized Gravitational Wave Background Search with a Network of Space-borne Triangular Detectors
• Observation of polarized stochastic gravitational-wave background in pulsar-timing-array experiments
• Correlation analysis for isotropic stochastic gravitational wave backgrounds with maximally allowed polarization degrees