General future asymptotically flat spacetimes

Moreschi, Osvaldo M.

doi:10.1088/0264-9381/4/5/010

Cited by 22 publications

(66 citation statements)

References 12 publications

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“…(12). We also define a spinor on M by ψ ABCD ω −1 Ψ ABCD , which we can extend continuously to I + .…”

Section: At Every Point Of Imentioning

confidence: 99%

“…These coordinates can be extended into a neighborhood of I + by taking ω as an additional coordinate along futuredirected null geodesics, where (u, θ, φ) labels the geodesics. Moreschi [12] showed that, up to irrelevant gauge freedom, the ω function is related to the luminosity distance r L by…”

Section: At Every Point Of Imentioning

confidence: 99%

“…Note that Eq. (C5b) is the standard formula for stellar aberration due to a boost, 12 because an observer detects photons moving into the future along past-directed null vectors. Put another way, an observer receiving null rays assigns a direction to a ray according to where it came from, rather than where it is going; an emitter assigns directions according to where the ray is going, rather than where it would have come from-this is the reason for the sign difference.…”

Section: Appendix A: Conventionsmentioning

confidence: 99%

“…Of course, rather than computing this angle to evaluate spinweighted functions, we can just use the right-hand side of 12 See, e.g., Eq. (1.3.5) of Ref.…”

Section: Appendix A: Conventionsmentioning

confidence: 99%

“…The allowed gauge transformations are symmetry transformations of this metric, which form a group known as the Bondi-Metzner-Sachs (BMS) group [9,10,12,[15][16][17][18]. This group simply extends the Poincaré group with generalized translations.…”

Section: Introductionmentioning

confidence: 99%

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Transformations of asymptotic gravitational-wave data

2016

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Gravitational-wave data is gauge dependent. While we can restrict the class of gauges in which such data may be expressed, there will still be an infinite-dimensional group of transformations allowed while remaining in this class, and almost as many different-though physically equivalent-waveforms as there are transformations. This paper presents a method for calculating the effects of the most important transformation group, the Bondi-Metzner-Sachs (BMS) group, consisting of rotations, boosts, and supertranslations (which include time and space translations as special cases). To a reasonable approximation, these transformations result in simple coupling between the modes in a spin-weighted spherical-harmonic decomposition of the waveform. It is shown that waveforms from simulated compact binaries in the publicly available SXS waveform catalog contain unmodeled effects due to displacement and drift of the center of mass, accounting for mode-mixing at typical levels of 1 %. However, these effects can be mitigated by measuring the average motion of the system's center of mass for a portion of the inspiral, and applying the opposite transformation to the waveform data. More generally, controlling the BMS transformations will be necessary to eliminate the gauge ambiguity inherent in gravitational-wave data for both numerical and analytical waveforms. Open-source code implementing BMS transformations of waveforms is included along with this paper in the supplemental materials.

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“…(12). We also define a spinor on M by ψ ABCD ω −1 Ψ ABCD , which we can extend continuously to I + .…”

Section: At Every Point Of Imentioning

confidence: 99%

Section: At Every Point Of Imentioning

confidence: 99%

Section: Appendix A: Conventionsmentioning

confidence: 99%

“…Of course, rather than computing this angle to evaluate spinweighted functions, we can just use the right-hand side of 12 See, e.g., Eq. (1.3.5) of Ref.…”

Section: Appendix A: Conventionsmentioning

confidence: 99%