Bibcode
Hirzberger, J.; Bonet, J. A.; Vázquez, M.; Hanslmeier, A.; Sobotka, M.
Bibliographical reference
AG Abstract Services, vol. 15. Abstracts of Contributed Talks and Posters presented at the Annual Scientific Meeting of the Astronomische Gesellschaft, in Goettingen, 20-25 September 1999.
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1999
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Description
A comparative study of the statistical properties of granulation in
active and quiet regions is performed. The analysis is based on a
high-resolution time series of simultaneous white light (lambda5425
Å) and G-band (lambda 4308 Å) images obtained at the Swedish
Vacuum Solar Telescope, La Palma, Canary Islands. The G-band images have
been used to discern quiet and active regions in the field of view,
whereas the white-light images were taken to analyze the photometry,
size and time evolution of granules in regions of different magnetic
activity. Power spectra confirm that the granular size decreases with
increasing G-band brightness. Granules with diameters below 0''.8 are
systematically brighter in the abnormal granulation than in quiet
regions. These small and bright elements are embedded in a diffuse
background of approximately mean photospheric brightness covering all
the fields of abnormal granulation. The granular lifetime decreases with
increasing G-band brighness. The conclusions about the behaviour of the
granulation have been decontaminated of the influence of magnetic
elements (the so-called Bright Points), that have been separated using
criteria of size (d < 0''.5) and lifetime (T > 6 min). A
significant fraction of them are concentrated in regio ns of high G-band
activity, an emerging flux region, and the rest are mainly aligned
outlining a cellular pattern (the magnetic network formed by
supergranular motions).