Bayesian reconstruction of primordial perturbations from induced gravitational waves

Abstract

The formation of primordial black holes or other dark matter relics from amplified density fluctuations in the early universe may also generate scalar-induced gravitational waves (GW), carrying vital information about the primordial power spectrum and the early expansion history of our universe. We present a Bayesian approach aimed at reconstructing both the shape of the scalar power spectrum and the universe's equation of state from GW observations, using interpolating splines to flexibly capture features in the GW data. The optimal number of spline nodes is chosen via Bayesian evidence, aiming at balancing complexity of the model and the fidelity of the reconstruction. We test our method using both representative mock data and recent Pulsar Timing Array measurements, demonstrating that it can accurately reconstruct the curvature power spectrum as well as the underlying equation of state, if different from radiation.

34 pages, 15 figures. V3: version accepted PRD

References in corpus (31)

• The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background
• Bayes in the sky: Bayesian inference and model selection in cosmology
• The NANOGrav 15-year Data Set: Search for Signals from New Physics
• Gravitational Wave Spectrum Induced by Primordial Scalar Perturbations
• The cosmological gravitational wave background from primordial density perturbations
• PolyChord: nested sampling for cosmology
• The recent gravitational wave observation by pulsar timing arrays and primordial black holes: the importance of non-gaussianities
• Inflation and Primordial Black Holes
• Nested sampling for physical scientists
• Induced gravitational waves as a probe of thermal history of the universe
• Observable Spectra of Induced Gravitational Waves from Inflation
• Cosmological Background Interpretation of Pulsar Timing Array Data
• Probing the equation of state of the early Universe with pulsar timing arrays
• Limits on scalar-induced gravitational waves from the stochastic background by pulsar timing array observations
• Implications for the non-Gaussianity of curvature perturbation from pulsar timing arrays
• Probing Primordial Features with the Stochastic Gravitational Wave Background
• The Need For Speed: Rapid Refitting Techniques for Bayesian Spectral Characterization of the Gravitational Wave Background Using PTAs
• Thermal History of the Early Universe and Primordial Gravitational Waves from Induced Scalar Perturbations
• Implications of Pulsar Timing Array Data for Scalar-Induced Gravitational Waves and Primordial Black Holes: Primordial Non-Gaussianity $f_{\mathrm{NL}}$ Considered
• Gravitational waves from first-order phase transitions in LISA: reconstruction pipeline and physics interpretation
• Scalar induced gravitational waves in light of Pulsar Timing Array data
• Gravitational waves from dark matter isocurvature
• Stochastic gravitational wave background reconstruction for a non-equilateral and unequal-noise LISA constellation
• Induced Gravitational Wave interpretation of PTA data: a complete study for general equation of state
• Simultaneously probing the sound speed and equation of state of the early Universe with pulsar timing arrays
• Model-independent reconstruction of the primordial curvature power spectrum from PTA data
• Expansion history-dependent oscillations in the scalar-induced gravitational wave background
• Gravitational waves induced by scalar-tensor mixing
• Primordial Black Holes from CDM Isocurvature Perturbations
• Primordial black holes and induced gravitational waves from logarithmic non-Gaussianity
• Can we distinguish the adiabatic fluctuations and isocurvature fluctuations with pulsar timing arrays?

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