Radio wave scattering by circumgalactic cool gas clumps

Abstract

We consider the effects of radio-wave scattering by cool ionized clumps ($T\sim 10^4$K) in circumgalactic media (CGM). The existence of such clumps are inferred from intervening quasar absorption systems, but have long been something of a theoretical mystery. We consider the implications for compact radio sources of the `fog-like' two-phase model of the circumgalactic medium recently proposed by McCourt et al.(2018). In this model, the CGM consists of a diffuse coronal gas ($T\gtrsim 10^6$K) in pressure equilibrium with numerous $\lesssim 1$pc scale cool clumps or `cloudlets' formed by shattering in a cooling instability. The areal filling factor of the cloudlets is expected to exceed unity in $\gtrsim 10^{11.5}{M}_{\odot }$ haloes, and the ensuing radio-wave scattering is akin to that caused by turbulence in the Galactic warm ionized medium (WIM). If $30$per-cent of cosmic baryons are in the CGM, we show that for a cool-gas volume fraction of $f_{\mathrm{v}}\sim 10^{-3}$, sources at $z_{\mathrm{s}}\sim 1$ suffer angular broadening by $\sim 15\mu$as and temporal broadening by $\sim 1$ms at $\lambda =30$cm, due to scattering by the clumps in intervening CGM. The former prediction will be difficult to test (the angular broadening will suppress Galactic scintillation only for $<10\mu$Jy compact synchrotron sources). However the latter prediction, of temporal broadening of localized fast radio bursts, can constrain the size and mass fraction of cool ionized gas clumps as function of halo mass and redshift, and thus provides a test of the model proposed by McCourt et al.(2018).

arXiv commentIn press MNRAS

References in corpus (34)

• Planck 2015 results. XIII. Cosmological parameters
• The ATNF Pulsar Catalogue
• How Do Galaxies Get Their Gas?
• A bright millisecond radio burst of extragalactic origin
• The ATNF Pulsar Catalogue
• The Circumgalactic Medium
• A Repeating Fast Radio Burst
• The direct localization of a fast radio burst and its host
• The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102
• The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-Redshift Circumgalactic Medium
• Gaseous Galaxy Halos
• FRBCAT: The Fast Radio Burst Catalogue
• A cosmic web filament revealed in Lyman-alpha emission around a luminous high-redshift quasar
• Off-Axis Afterglow Emission from Jetted Gamma-Ray Bursts
• The Gaseous Environment of High-z Galaxies: Precision Measurements of Neutral Hydrogen in the Circumgalactic Medium of z ~ 2-3 Galaxies in the Keck Baryonic Structure Survey
• Ubiquitous giant Ly $\alpha$ nebulae around the brightest quasars at $z\sim 3.5$ revealed with MUSE
• Characterizing the Circumgalactic Medium of Nearby Galaxies with HST/COS and HST/STIS Absorption-Line Spectroscopy
• A Characteristic Scale for Cold Gas
• Field Galaxy Evolution Since Z~1 from a Sample of QSO Absorption-Selected Galaxies
• Quasar Quartet Embedded in Giant Nebula Reveals Rare Massive Structure in Distant Universe
• Do Hot Haloes Around Galaxies Contain the Missing Baryons?
• The Impact of Star Formation Feedback on the Circumgalactic Medium
• Metal-line absorption around $z\approx$2.4 star-forming galaxies in the Keck Baryonic Structure Survey
• Quasars Probing Quasars III: New Clues to Feedback, Quenching, and the Physics of Massive Galaxy Formation
• A Stellar Feedback Origin for Neutral Hydrogen in High-Redshift Quasar-Mass Halos
• Limits on Fast Radio Bursts at 145 MHz with ARTEMIS, a real-time software backend
• The impact of magnetic fields on thermal instability
• Quasars Probing Quasars VIII. The Physical Properties of the Cool Circumgalactic Medium Surrounding z ~ 2-3 Massive Galaxies Hosting Quasars
• The observed properties of Fast Radio Bursts
• Extremely Rapid Variations of Water Maser Emission from the Circinus Galaxy
• A Search for Fast Radio Bursts with the GBNCC Pulsar Survey
• Intergalactic Lyman continuum photon budget in the past 5 billion years
• A search for Fast Radio Bursts at low frequencies with Murchison Widefield Array high time resolution imaging
• The Vulture Survey I: Analyzing the Evolution of ${\MgII}$ Absorbers

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• Modeling Fast Radio Burst Dispersion and Scattering Properties in the First CHIME/FRB Catalog
• Interpreting the distributions of FRB observables
• Constraining Galaxy Haloes from the Dispersion and Scattering of Fast Radio Bursts and Pulsars
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• A bright, high rotation-measure FRB that skewers the M33 halo
• Constraining Primordial Black Holes using Fast Radio Burst Gravitational-Lens Interferometry with CHIME/FRB
• A measurement of circumgalactic gas around nearby galaxies using fast radio bursts
• Radio Scattering Horizons for Galactic and Extragalactic Transients
• A high baryon fraction in massive haloes at z~3
• Explaining the statistical properties of Fast Radio Bursts with suppressed low-frequency emission
• Fast Radio Burst Tomography of the Unseen Universe
• The ultra narrow FRB20191107B, and the origins of FRB scattering
• The dispersion measure and scattering of Fast Radio Bursts: contributions from multi-components, and clues for the intrinsic properties
• Refractive lensing of scintillating FRBs by sub-parsec cloudlets in the multi-phase CGM
• CGM cloud sizes from refractive FRB scattering
• Microphysics of Circumgalactic Turbulence Probed by Fast Radio Bursts and Quasars