This paper explores the onset of thin-shell formation in interstellar shocks associated with supernova explosions. We outline a simple but useful scheme that indicates the time at which thin shell formation begins for supernova remnants (SNRs) evolving in a range of interstellar environments, extending the previous analytical models to arbitrary

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

Not Available

We present high quality long-slit spectra of the extended narrow line region (ENLR) near the nucleus of NGC 4151. We have used these data to map the spatial variations of the emission line intensities along three slit positions: one passing radially through the nucleus along the main NE-SW axis of the ENLR and two across this axis at offsets center

We present the results on the optical morphology and structure of 25 low-luminosity radio galaxies. The radial dependence of parameters like the surface brightness, ellipticity, center, and position angle of the isophotes is presented to study the properties of the galaxies. Results for individual objects are discussed. (1 data file).

Not Available