First results from a two-dimensional numerical study of the buoyant rise of twisted magnetic flux tubes in the solar convection zone are presented. We show in detail the process by which the transverse component of the field can suppress the splitting of the rising tube into two vortex filaments. For the suppression to be effective, the pitch angle

We use recent high-resolution infrared (IR; 1-20 μm) photometry to examine the origin of the IR emission in low-luminosity active galactic nuclei (LLAGN). The data are compared with published model fits that describe the spectral energy distribution (SED) of LLAGN in terms of an advection-dominated accretion flow, truncated thin accretion disk, and

The infrared sky quality is an important parameter to take into account for the evaluation of astronomical sites. The traditional idea of considering higher altitude sites as better for infrared astronomical observations than sites at lower altitudes is not in agreement with observational data. It has been shown that the observational infrared

From the analysis of low-order GOLF+MDI sectoral modes (l

The solar p-mode spectrum of very low l has already been measured with high accuracy for a sufficiently long period of time to permit the search for solar cycle variations. The longest one-site velocity observations for low l solar p-modes (Tenerife) has been used to measure the l = 1 mode splitting at the two extremes of the solar activity cycle