Probing the local interstellar medium with scintillometry of the bright pulsar B1133+16

TL;DR

This study analyzes 34 years of pulsar scintillation data to identify and characterize six scattering screens in the interstellar medium, revealing their locations, orientations, and velocities, including a nearby screen within 6 parsecs.

Contribution

It provides a detailed model of multiple scattering screens along the line of sight to PSR B1133+16, including precise distance measurements and associations with local interstellar structures.

Findings

Six scattering screens identified, persisting over decades.

One screen located approximately 5.5 parsecs from Earth.

Distant screen associated with the Local Bubble.

Abstract

The interstellar medium hosts a population of scattering screens, most of unknown origin. Scintillation studies of pulsars provides a sensitive tool for resolving these scattering screens and a means of measuring their properties. In this paper, we report our analysis of 34 years of Arecibo observations of PSR B1133+16, from which we have obtained high-quality dynamic spectra and their associated scintillation arcs, arising from the scattering screens located along the line of sight to the pulsar. We have identified six individual scattering screens that are responsible for the observed scintillation arcs, which persist for decades. Using the assumption that the scattering screens have not changed significantly in this time, we have modeled the variations in arc curvature throughout the Earth's orbit and extracted information about the placement, orientation, and velocity of five of the six screens, with the highest-precision distance measurement placing a screen at just $5.46^{+0.54}_{-0.59}$ pc from the Earth. We associate the more distant of these screens with an under-dense region of the Local Bubble.