A dense plasma globule in the solar neighborhood

Abstract

The radio source J1819+3845 underwent a period of extreme interstellar scintillation between circa 1999 and 2007. The plasma structure responsible for this scintillation was determined to be just $1$-$3$pc from the solar system and to posses a density of $n_e\sim 10^2$cm${}^{-3}$ that is three orders of magnitude higher than the ambient interstellar density (de Bruyn & Macquart 2015). Here we present radio-polarimetric images of the field towards J1819+3845 at wavelengths of 0.2, 0.92 and 2m. We detect an elliptical plasma globule of approximate size $1^{\circ }\times \gtrsim 2^{\circ }$ (major-axis position angle of $\approx -40^{\circ }$), via its Faraday-rotation imprint ($\approx 15$radm${}^{-2}$) on the diffuse Galactic synchrotron emission. The extreme scintillation of J1819+3845 was most likely caused at the turbulent boundary of the globule (J1819+3845 is currently occulted by the globule). The origin and precise nature of the globule remain unknown. Our observations are the first time plasma structures that likely cause extreme scintillation have been directly imaged.

Accepted ApJL

References in corpus (8)

• The VLA Low-frequency Sky Survey
• The Micro-Arcsecond Scintillation-Induced Variability (MASIV) Survey II: The First Four Epochs
• Faraday tomography of the local interstellar medium with LOFAR: Galactic foregrounds towards IC342
• Initial LOFAR observations of Epoch of Reionization windows: II. Diffuse polarized emission in the ELAIS-N1 field
• Folded Fields as the Source of Extreme Radio-Wave Scattering in the Galactic Center
• Emergence and disappearance of micro-arcsecond structure in the scintillating quasar J1819+3845
• The intra-hour variable quasar J1819$+$3845: 13-year evolution, jet polarization structure and interstellar scattering screen properties
• The WENSS and Dwingeloo surveys and the Galactic magnetic field

Cited by in corpus (1)

• ASKAP observations of multiple rapid scintillators reveal a degrees-long plasma filament