Letter to the Editor
Dependence of the photospheric vertical flow characteristics on the granule dimension *
F. Berrilli 1,
A. Florio 2,
G. Consolini 3,
B. Bavassano 3,
C. Briand 4,
R. Bruno 3,
B. Caccin 1,
V. Carbone 5,
G. Ceppatelli 4,
A. Egidi 1,
I. Ermolli 2,
G. Mainella 3 and
E. Pietropaolo 6
Received 8 January 1999 / Accepted 26 February 1999
The first high spectral resolution and white-light images obtained at the THEMIS telescope with the Italian Panoramic Monochromator (IPM), are analyzed to study intensity and velocity fluctuations in the photosphere of the sun. Monochromatic images, in two spectral ranges around 538.03 nm (C I line) and 557.61 nm (Fe I line), are used to characterize the vertical structure of the photosphere. Granulation cells and granules are obtained by segmentation of white-light images using suitable finding algorithms.
We observe the height dependence of velocity vs. intensity fluctuations, and we found a dependence of velocity and intensity on granule dimension. Our results show that granules increase their intensity with dimension in the lower solar photosphere. In the higher photosphere, on the contrary, the intensity decreases with the dimension.
Key words: Sun: photosphere Sun: granulation techniques: image processing
Send offprint requests to: F. Berrilli (firstname.lastname@example.org)
This article contains no SIMBAD objects.
© European Southern Observatory (ESO) 1999
Online publication: March 18, 1999