Aberration of gravitational waveforms by peculiar velocity
arXiv:2211.14183 · doi:10.1093/mnras/stad1907
Abstract
One key prediction of General Relativity is that gravitational waves are emitted with a pure spin-2 polarisation. Any extra polarisation mode, spin-1 or spin-0, is consequently considered a smoking gun for deviations from General Relativity. In this paper, we show that the velocity of merging binaries with respect to the observer gives rise to spin-1 polarisation in the observer frame even in the context of General Relativity. These are pure projection effects, proportional to the plus and cross polarisations in the source frame, hence they do not correspond to new degrees of freedom. We demonstrate that the spin-1 modes can always be rewritten as pure spin-2 modes coming from an aberrated direction. Since gravitational waves are not isotropically emitted around binary systems, this aberration modifies the apparent orientation of the binary system with respect to the observer: the system appears slightly rotated due to the source velocity. Fortunately, this bias does not propagate to other parameters of the system (and therefore does not spoil tests of General Relativity), since the impact of the velocity can be fully reabsorbed into new orientation angles.
arXiv comment14 pages, 4 figures; v2: the discussion of differences with respect to previous literature has been extended, references added
References in corpus (35)
- Observation of Gravitational Waves from a Binary Black Hole Merger
- GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs
- GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run
- Massive Gravity
- Tests of General Relativity with the Binary Black Hole Signals from the LIGO-Virgo Catalog GWTC-1
- Tests of General Relativity with Binary Black Holes from the second LIGO-Virgo Gravitational-Wave Transient Catalog
- Dipole Anisotropy in the COBE DMR First-Year Sky Maps
- The basics of gravitational wave theory
- Planck 2013 results. XXVII. Doppler boosting of the CMB: Eppur si muove
- The Dipole Observed in the COBE DMR Four-Year Data
- Transformations of asymptotic gravitational-wave data
- Peculiar velocity effects in high-resolution microwave background experiments
- Velocity correction for Hubble constant measurements from standard sirens
- Detectable environmental effects in GW190521-like black-hole binaries with LISA
- The effect of matter structure on the gravitational waveform
- The peculiar acceleration of stellar-origin black hole binaries: measurement and biases with LISA
- Cosmology and modified gravitational wave propagation from binary black hole population models
- The Signature of Proper Motion in the Microwave Sky
- Measuring our peculiar velocity on the CMB with high-multipole off-diagonal correlations
- Current and future constraints on cosmology and modified gravitational wave friction from binary black holes
- Detecting the Beaming Effect of Gravitational Waves
- Transformation of the multipolar components of gravitational radiation under rotations and boosts
- Bayesian estimation of our local motion from the Planck-2018 CMB temperature map
- Excitation of gravitational wave modes by a center-of-mass velocity of the source
- Statistical Isotropy violation of CMB polarization sky due to Lorentz boost
- Exciting modes due to the aberration of gravitational waves: Measurability for extreme-mass-ratio inspirals
- New operator approach to the CMB aberration kernels in harmonic space
- Modified gravitational wave propagation and the binary neutron star mass function
- Post-Newtonian templates for gravitational waves from compact binary inspirals
- Detection and estimation of the cosmic dipole with the Einstein Telescope and Cosmic Explorer
- Are we living near the center of a local void?
- Radiative transport of relativistic species in cosmology
- A Generalized Doppler and Aberration Kernel for Frequency-Dependent Cosmological Observables
- Distortion of Gravitational-wave Signals by Astrophysical Environments
- Statistical effects of the observer's peculiar velocity on source number counts