Gravitational wave signal from primordial magnetic fields in the Pulsar Timing Array frequency band

Abstract

The NANOGrav, Parkes, European, and International Pulsar Timing Array (PTA) Collaborations have reported evidence for a common-spectrum process that can potentially correspond to a stochastic gravitational wave background (SGWB) in the 1--100 nHz frequency range. We consider the scenario in which this signal is produced by magnetohydrodynamic (MHD) turbulence in the early Universe, induced by a nonhelical primordial magnetic field at the energy scale corresponding to the quark confinement phase transition. We perform MHD simulations to study the dynamical evolution of the magnetic field and compute the resulting SGWB. We show that the SGWB output from the simulations can be very well approximated by assuming that the magnetic anisotropic stress is constant in time, over a time interval related to the eddy turnover time. The analytical spectrum that we derive under this assumption features a change of slope at a frequency corresponding to the GW source duration that we confirm with the numerical simulations. We compare the SGWB signal with the PTA data to constrain the temperature scale at which the SGWB is sourced, as well as the amplitude and characteristic scale of the initial magnetic field. We find that the generation temperature is constrained to be in the 1--200 MeV range, the magnetic field amplitude must be $>1$\% of the radiation energy density at that time, and the magnetic field characteristic scale is constrained to be $>10$\% of the horizon scale. We show that the turbulent decay of this magnetic field will lead to a field at recombination that can help to alleviate the Hubble tension and can be tested by measurements in the voids of the Large Scale Structure with gamma-ray telescopes like the Cherenkov Telescope Array.

28 pages, 9 figures, 1 table, accepted for publication in Phys. Rev. D, files and code available in https://github.com/AlbertoRoper/GW_turbulence

References in corpus (56)

• The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
• Detecting gravitational waves from cosmological phase transitions with LISA: an update
• The Illustris simulation: the evolving population of black holes across cosmic time
• The stochastic gravitational-wave background from massive black hole binary systems: implications for observations with Pulsar Timing Arrays
• The International Pulsar Timing Array second data release: Search for an isotropic Gravitational Wave Background
• On the evidence for a common-spectrum process in the search for the nanohertz gravitational-wave background with the Parkes Pulsar Timing Array
• NANOGrav Hints to Primordial Black Holes as Dark Matter
• New Sensitivity Curves for Gravitational-Wave Signals from Cosmological Phase Transitions
• Cosmic String Interpretation of NANOGrav Pulsar Timing Data
• Common-red-signal analysis with 24-yr high-precision timing of the European Pulsar Timing Array: Inferences in the stochastic gravitational-wave background search
• Has NANOGrav found first evidence for cosmic strings?
• Did NANOGrav see a signal from primordial black hole formation?
• Implications of the NANOGrav results for inflation
• Relieving the Hubble tension with primordial magnetic fields
• Why reducing the cosmic sound horizon alone can not fully resolve the Hubble tension
• The Pencil Code, a modular MPI code for partial differential equations and particles: multipurpose and multiuser-maintained
• Solar-Mass Primordial Black Holes Explain NANOGrav Hint of Gravitational Waves
• From NANOGrav to LIGO with metastable cosmic strings
• Gravitational waves from first order cosmological phase transitions in the Sound Shell Model
• Primordial gravitational waves from NANOGrav: a broken power-law approach
• Nonhelical inverse transfer of a decaying turbulent magnetic field
• Gravitational Waves and Dark Radiation from Dark Phase Transition: Connecting NANOGrav Pulsar Timing Data and Hubble Tension
• Evolution of Primordial Magnetic Fields from Phase Transitions
• Progress on Cosmological Magnetic Fields
• Searching For Gravitational Waves From Cosmological Phase Transitions With The NANOGrav 12.5-year dataset
• Classes of hydrodynamic and magnetohydrodynamic turbulent decay
• Evolution of hydromagnetic turbulence from the electroweak phase transition
• Stochastic gravitational-wave background from metastable cosmic strings
• Observing Invisible Axions with Gravitational Waves
• Comparison of cosmic string and superstring models to NANOGrav 12.5-year results
• Gravitational Waves from Global Cosmic Strings and Cosmic Archaeology
• Whispers from the dark side: Confronting light new physics with NANOGrav data
• NANOGrav signal from MHD turbulence at QCD phase transition in the early universe
• Magnetic Fields from QCD Phase Transitions
• On the gravitational wave sources from the NANOGrav 12.5-yr data
• The turbulent chiral-magnetic cascade in the early universe
• Constraining the Solution to the Last Parsec Problem with Pulsar Timing
• Blue-tilted inflationary tensor spectrum and reheating in the light of NANOGrav results
• NANOGrav results and Dark First Order Phase Transitions
• Ultra-low frequency gravitational waves from cosmological and astrophysical processes
• Can we observe the QCD phase transition-generated gravitational waves through pulsar timing arrays?
• Induced gravitational waves as a cosmological probe of the sound speed during the QCD phase transition
• Is the NANOGrav signal a hint of dS decay during inflation?
• Large anisotropies of the stochastic gravitational wave background from cosmic domain walls
• NANOGrav Signal from First-Order Confinement/Deconfinement Phase Transition in Different QCD Matters
• Consistency of Planck, ACT and SPT constraints on magnetically assisted recombination and forecasts for future experiments
• Circular Polarization of Gravitational Waves from Early-Universe Helical Turbulence
• Cosmic Strings, Inflation, and Gravity Waves
• Primordial black holes and secondary gravitational waves from string inspired general no-scale supergravity
• Testing clockwork axion with gravitational waves
• Polarization of gravitational waves from helical MHD turbulent sources
• The scalar, vector, and tensor modes in gravitational wave turbulence simulations
• The turbulent stress spectrum in the inertial and subinertial ranges
• Sensitivity reach of gamma-ray measurements for strong cosmological magnetic fields
• Strongly Magnetized Hot QCD Matter and Stochastic Gravitational Wave Background
• Constraining models of Inflationary Magnetogenesis with NANOGrav

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