Photospheric oscillations. IV. An accurate omega -spectrum at low values of k.
Abstract
Two spatiotemporal (k - omega) power spectra of the solar five-minute oscillation are calculated with a resolution of 0.3 mHz for an 8.5-ft and a 36-in. aperture, respectively. The two spectra are found to appear almost identical except in the low-frequency range, where differences arise due to large amounts of atmospheric noise. An average omega-spectrum is determined from the two power spectra and is compared with a previously computed power spectrum. It is concluded that for wavenumbers (k) not exceeding 0.0001 per km, the dependence of the unresolved omega-spectrum on wavenumber is fairly weak and that the average of the two spatiotemporal power spectra can be regarded as a good estimate of the unresolved omega-spectrum for any wavenumber bandwidth in the range from 0 to 0.0001 per km.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1977
- Bibcode:
- 1977A&A....60..151F
- Keywords:
-
- Oscillations;
- Photosphere;
- Power Spectra;
- Solar Atmosphere;
- Bandwidth;
- Frequency Response;
- Solar Spectra;
- Solar Physics