Interstellar Scintillation and the Radio Counterpart of the Fast Radio Burst FRB150418

Abstract

Keane et al. (2016) have recently reported the discovery of a new fast radio burst, FRB150418, with a promising radio counterpart at 5.5 and 7.5 GHz -- a rapidly decaying source, falling from 200-300 $\mu$Jy to 100 $\mu$Jy on timescales of $\sim$6 d. This transient source may be associated with an elliptical galaxy at redshift $z=0.492$, providing the first firm spectroscopic redshift for a FRB and the ability to estimate the density of baryons in the intergalactic medium via the combination of known redshift and radio dispersion of the FRB. An alternative explanation, first suggested by Williams & Berger (2016b), is that the identified counterpart may instead be a compact AGN. The putative counterpart's variation may then instead be extrinsic, caused by refractive scintillation in the ionized interstellar medium of the Milky Way, which would invalidate the association with FRB150418. We examine this latter explanation in detail and show that the reported observations are consistent with scintillating radio emission from the core of a radio-loud active galactic nucleus (AGN) having a brightness temperature $T_{\mathrm{b}}\gtrsim 10^9\mathrm{K}$. Using numerical simulations of the expected scattering for the line of sight to FRB150418, we provide example images and light curves of such an AGN at 5.5 and 7.5 GHz. These results can be compared with continued radio monitoring to conclusively determine the importance of scintillation for the observed radio variability, and they show that scintillation is a critical consideration for continued searches for FRB counterparts at radio wavelengths.

arXiv comment6 pages, 3 figures, accepted for publication in ApJL

References in corpus (26)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• A bright millisecond radio burst of extragalactic origin
• Hot Accretion Flows Around Black Holes
• A Repeating Fast Radio Burst
• A Scheme to Unify Low-Power Accreting Black Holes - Jet-Dominated Accretion Flows and the Radio/X-Ray Correlation
• Fast Radio Burst Discovered in the Arecibo Pulsar ALFA Survey
• A model for fast extragalactic radio bursts
• Dense magnetized plasma associated with a fast radio burst
• Fast radio bursts: the last sign of supramassive neutron stars
• The 5th edition of the Roma-BZCAT. A short presentation
• Cosmological Fast Radio Bursts from Binary Neutron Star Mergers
• A Fast Radio Burst Host Galaxy
• A real-time fast radio burst: polarization detection and multiwavelength follow-up
• A possible connection between Fast Radio Bursts and Gamma-Ray Bursts
• On the origin of a highly-dispersed coherent radio burst
• Cosmological Fast Radio Bursts from Binary White Dwarf Mergers
• The Micro-Arcsecond Scintillation-Induced Variability (MASIV) Survey II: The First Four Epochs
• No precise localization for FRB 150418: claimed radio transient is AGN variability
• Theory and Simulations of Refractive Substructure in Resolved Scatter-Broadened Images
• mJIVE-20: a survey for compact mJy radio objects with the Very Long Baseline Array
• The VSOP 5-GHz AGN Survey: IV. The Angular Size/Brightness Temperature Distribution
• First-Epoch VLBA Imaging of Twenty New TeV Blazars
• The low-frequency radio catalog of flat spectrum sources
• Millimeter Radio Continuum Emissions as the Activity of Super Massive Black Holes in Nearby Early-Type Galaxies and Low-Luminosity Active Galactic Nuclei
• The Bologna complete sample of nearby radio sources: II -- phase referenced observations of faint nuclear sources
• EVN Observations of HESS J1943+213: Evidence for an Extreme TeV BL Lac Object

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