The Intensity Profile of the Solar Supergranulation

Abstract

We have measured the average radial (cell center to network boundary) profile of the continuum intensity contrast associated with supergranular flows using data from the Precision Solar Photometric Telescope (PSPT) at the Mauna Loa Solar Observatory (MLSO). After removing the contribution of the network flux elements by the application of masks based on Ca II K intensity and averaging over more than 10^5 supergranular cells, we find a ~ 0.1% decrease in red and blue continuum intensity from the supergranular cell centers outward, corresponding to a ~ 1.0 K decrease in brightness temperature across the cells. The radial intensity profile may be caused either by the thermal signal associated with the supergranular flows or a variation in the packing density of unresolved magnetic flux elements. These are not unambiguously distinguished by the observations, and we raise the possibility that the network magnetic fields play an active role in supergranular scale selection by enhancing the radiative cooling of the deep photosphere at the cell boundaries.

Accepted to ApJ

References in corpus (6)

• The intensity contrast of solar granulation: comparing Hinode SP results with MHD simulations
• Hinode Observations of Magnetic Elements in Internetwork Areas
• Latitudinal variation of the solar photospheric intensity
• Solar supergranulation revealed by granule tracking
• Photometric properties of resolved and unresolved magnetic elements
• Realistic Simulation of Local Solar Supergranulation

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• The Quest to Understand Supergranulation and Large-Scale Convection in the Sun
• Magnetic pattern at supergranulation scale: the Void Size Distribution
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• Brightness Fluctuation Spectra of Sun-Like Stars. I. The Mid-Frequency Continuum
• Plasma flows and sound-speed perturbations in the average supergranule
• Texture of average solar photospheric flows and the donut-like pattern