COMPARISON OF 2 FITTING METHODS FOR RING DIAGRAM ANALYSIS OF VERY HIGH L-SOLAR OSCILLATIONS

A new method of fitting tridimensional power spectra of solar oscillat ions is described and compared with a previous one whose use has been more common. The new method fits the parameters of the Lorentzian prof iles in a bidimensional k-omega diagram constructed from an azimuthal average of the tridimensional one. The horizontal velocities are then determined keeping these parameters fixed, greatly reducing the comput ation time. Both methods are compared for two radial orders (n = 3, 4) of a tridimensional power spectrum obtained for a region of about 15 degrees square around solar disk center. The images used in this work correspond to a 3 day set of 1080 x 1080 pixel intensity images obtain ed at the Observatorio del Teide on 1994 November 8-10 with the Taiwan ese Oscillation Network (TON) instrument. The results of the fitted ve locities agree within the estimated errors for the two methods. The re duction of the computing time obtained with the new method makes it co nvenient for the ring diagram analysis.