Comparisons of the Interstellar Magnetic Field Directions obtained from the IBEX Ribbon and Interstellar Polarization Measurements

Spatial variations in the configuration of the interstellar magnetic field (ISMF) near the Sun are constrained by differences in the directions of the interstellar magnetic field found from the Ribbon of emission of energetic neutral atoms (ENA) discovered by the Interstellar Boundary Explorer (IBEX) spacecraft, versus the ISMF direction found from the weak polarizations of starlight caused by magnetically aligned interstellar dust grains. The best fit to the interstellar polarization vectors occurs for a magnetic pole directed towards ecliptic longitude and latitude of about 263 deg, +37 deg, with uncertainties of about +/- 35 deg. Interstellar optical polarization data towards 30 nearby stars within 90 degrees of the heliosphere nose and within 40 pc of the Sun are used for this determination. The magnetic pole from the polarization data is approximately 33 degrees from the magnetic pole that is defined by the center of the arc of the ENA Ribbon. The similarity of the polarization and Ribbon directions for the local ISMF suggest that the local field is relatively coherent over scale sizes of tens of parsecs. The polarization ISMF vector direction corresponds to a pole towards the direction of 38 deg, 23 deg, in galactic longitude and latitude, and is approximately perpendicular to the vector flow of local ISM through the local standard of rest.