SEPARATION OF THE INTERSTELLAR BOUNDARY EXPLORER RIBBON FROM GLOBALLY DISTRIBUTED ENERGETIC NEUTRAL ATOM FLUX

Journal Article · Sun Apr 10 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/731/1/56· OSTI ID:21574747

Schwadron, N A; Kucharek, H; Moebius, E ^[1]

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1. Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)

The Interstellar Boundary Explorer (IBEX) observes a remarkable feature, the IBEX ribbon, which has energetic neutral atom (ENA) flux over a narrow region {approx}20{sup 0} wide, a factor of 2-3 higher than the more globally distributed ENA flux. Here, we separate ENA emissions in the ribbon from the distributed flux by applying a transparency mask over the ribbon and regions of high emissions, and then solve for the distributed flux using an interpolation scheme. Our analysis shows that the energy spectrum and spatial distribution of the ribbon are distinct from the surrounding globally distributed flux. The ribbon energy spectrum shows a knee between {approx}1 and 4 keV, and the angular distribution is approximately independent of energy. In contrast, the distributed flux does not show a clear knee and more closely conforms to a power law over much of the sky. Consistent with previous analyses, the slope of the power law steepens from the nose to tail, suggesting a weaker termination shock toward the tail as compared to the nose. The knee in the energy spectrum of the ribbon suggests that its source plasma population is generated via a distinct physical process. Both the slope in the energy distribution of the distributed flux and the knee in the energy distribution of the ribbon are ordered by latitude. The heliotail may be identified in maps of globally distributed flux as a broad region of low flux centered {approx}44{sup 0}W of the interstellar downwind direction, suggesting heliotail deflection by the interstellar magnetic field.

• OSTI ID: 21574747
• Journal Information: Astrophysical Journal, Vol. 731, Issue 1; Other Information: DOI: 10.1088/0004-637X/731/1/56; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
EMISSION
ENERGY SPECTRA
HELIOSPHERE
MAGNETOHYDRODYNAMICS
PLASMA
SHOCK WAVES
SOLAR WIND
SPATIAL DISTRIBUTION
ATMOSPHERES
DISTRIBUTION
FLUID MECHANICS
HYDRODYNAMICS
MECHANICS
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SPECTRA
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR WINDS