 |
Figure 1: From top left to bottom right: a) the power spectrum from G-band observations, b) the power spectrum from Ca II H line observations, c) the phase shift between Ca II H and G-band (colour units are in radians), and d) the coherence spectrum between the two lines. |
| Open with DEXTER | |
In the text
![\begin{figure}
\par\includegraphics[width=12.5cm,clip]{9042fig2.ps}\end{figure}](/articles/aa/full/2008/13/aa9042-07/img17.gif) |
Figure 2: Cuts through the G-band (black line) and Ca II H (blue line) power spectra and their phase shift (red line) at different l values. The vertical dotted lines are plotted at f- and p-mode peak values of the G-band power spectrum. |
| Open with DEXTER | |
In the text
![\begin{figure}
\par\includegraphics[width=7cm,clip]{9042fig3.ps}\end{figure}](/articles/aa/full/2008/13/aa9042-07/img24.gif) |
Figure 3:
Power spectra and the phase cross-spectrum for a simple oscillation model (Sect. 3), which qualitatively represents the oscillation signals at two heights with different correlation background levels: in the photosphere (black curve) and in the chromosphere (blue curve). The red curve shows the phase shifted by  .
This cut is at no specific wave number, but reflects the general behavior of the p-mode peaks above and below the acoustic cut-off frequency. |
| Open with DEXTER | |
In the text