The Dispersion of Fast Radio Bursts from a Structured Intergalactic Medium at Redshifts z < 1.5

Abstract

We analyze the sources of free electrons that produce the large dispersion measures, DM $\approx 300-1600$ (in units cm${}^{-3}$ pc), observed toward fast radio bursts (FRBs). Individual galaxies typically produce DM $\sim 25-60$ cm${}^{-3}$ pc from ionized gas in their disk, disk-halo interface, and circumgalactic medium. Toward an FRB source at redshift $z$, a homogeneous IGM containing a fraction $f_{\mathrm{IGM}}$ of cosmological baryons will produce DM $=(935{\mathrm{cm}}^{-3}\mathrm{pc})f_{\mathrm{IGM}}{h}_{70}^{-1}I(z)$, where $I(z)=(2/3{\Omega }_m)[\{{\Omega }_m(1+z{)}^3+{\Omega }_{\Lambda }{\}}^{1/2}-1]$. A structured IGM of photoionized Ly-alpha absorbers in the cosmic web produces similar dispersion, modeled from the observed distribution, $f_b(N,z)$, of H I (Lya-forest) absorbers in column density and redshift with ionization corrections and scaling relations from cosmological simulations. An analytic formula for DM($z$) applied to observed FRB dispersions suggests that $z_{\mathrm{FRB}}\approx 0.2-1.5$ for an IGM containing a significant baryon fraction, $f_{\mathrm{IGM}}=0.6\pm 0.1$. Future surveys of the statistical distribution, DM($z)$, of FRBs identified with specific galaxies and redshifts, can be used to calibrate the IGM baryon fraction and distribution of Ly-alpha absorbers. Fluctuations in DM at the level $\pm 10$ cm${}^{-3}$ pc will arise from filaments and voids in the cosmic web.

8 pages, 2 figures, submitted to Astrophysical Journal

References in corpus (12)

• A bright millisecond radio burst of extragalactic origin
• A New Electron Density Model for Estimation of Pulsar and FRB Distances
• The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102
• The Search for the Missing Baryons at Low Redshift
• The Vertical Structure of Warm Ionised Gas in the Milky Way
• The Low-z Intergalactic Medium. III. HI and Metal Absorbers at z<0.4
• Do Hot Haloes Around Galaxies Contain the Missing Baryons?
• The detection of an extremely bright fast radio burst in a phased array feed survey
• The COS/UVES Absorption Survey of the Magellanic Stream. III: Ionization, Total Mass, and Inflow Rate onto the Milky Way
• The primordial deuterium abundance of the most metal-poor damped Lyman-alpha system
• An Ultraviolet Survey of Low-Redshift Partial Lyman-Limit Systems with the HST Cosmic Origins Spectrograph
• Discovery of Galactic OIV and OV X-ray absorption due to transition temperature gas in the PKS 2155-304 spectrum

Cited by in corpus (25)

• A fast radio burst localised to a massive galaxy
• The Evolution of the Baryons Associated with Galaxies Averaged over Cosmic Time and Space
• The prevalence of repeating fast radio bursts
• Baryon Cycles in the Biggest Galaxies
• The host galaxy and persistent radio counterpart of FRB 20201124A
• Fast Radio Bursts and cosmological tests
• Implications of a rapidly varying FRB in a globular cluster of M81
• The BINGO Project I: Baryon Acoustic Oscillations from Integrated Neutral Gas Observations
• Redshift Estimation and Constraints on Intergalactic and Interstellar Media from Dispersion and Scattering of Fast Radio Bursts
• Cosmology-insensitive estimate of IGM baryon mass fraction from five localized fast radio bursts
• Constraining the Cosmic Baryon Distribution with Fast Radio Burst Foreground Mapping
• The dispersion measure and scattering of FRBs: Contributions from the intergalactic medium, foreground halos, and hosts
• Fast Radio Burst Dispersion Measure Distribution as a Probe of Helium Reionization
• EAGLE-Auriga: effects of different subgrid models on the baryon cycle around Milky Way-mass galaxies
• Fast Radio Burst Tomography of the Unseen Universe
• Using realistic host galaxy metallicities to improve the GRB X-ray equivalent total hydrogen column density and constrain the intergalactic medium density
• Physical Conditions of Five O VI Absorption Systems Towards PG $1522+101$
• Reinvestigation of Fast Radio Burst Host Galaxy and Event Rate Density
• Conformally-rescaled Schwarzschild metrics do not predict flat galaxy rotation curves
• Constraining the Hubble constant with scattering in host galaxies of fast radio bursts
• Probing the physical properties of the intergalactic medium using blazars
• Baryonic Post-Processing of N-body Simulations, with Application to Fast Radio Bursts
• Probing the parameters of the intergalactic medium using quasars
• Probing the physical properties of the IGM using SRG/eROSITA spectra from blazars
• Constraining the Milky Way's Dispersion Measure Using FRB and X-ray Data