We have used high-resolution spectra of the Ca II H resonance line in late-type dwarfs, obtained with high S:N ratios, over a period of four years to widen our understanding of the dynamical behavior of the Ca II emission cores. All of the stars dealt with in this article, which are chromospherically active, show variability both in core emission

Results of CCD photometry of the three low-luminosity radio galaxies which contain jets at the kpc scale: B2 0836 + 29, B2 2116 + 26, and B2 2236 + 35 are presented and discussed. The photometric properties of the galaxies are examined by analyzing the radial variations of surface brightness, ellipticity, major axis position angle, and isophote

High resolution spectrophotometry of the black hole system V404 Cyg during quiescence, performed during 1990 and 1991, is discussed. In addition to a 6.5d orbital modulation, there is strong evidence of a 0.24d periodicity in both the H alpha emission radial velocities and the continuum flux. The relative phasing between the photometric and

The influence of the upper layers of a star on p-mode frequencies can be described asymptotically by means of a phase function, which depends essentially only on the frequency of the mode. The extent to which the phase function may provide information about the superficial layers of a star is investigated. In particular, a linear relation between

Spectroscopy and mapping of the type I postmain-sequence source CRL 618, taken with the 45-m antenna of the Nobeyama Radio Observatory and the 12-m NRAO facility at Kitty Peak, are presented. It is shown that the exterior constant velocity envelope has a typical aspect ratio of about 0.8, extends over a range not less than 70 arcsec, and has an

Long-slit spectroscopy of the extended gas in the Seyfert galaxy NGC 3516 reveals considerable substructure in the narrow emission lines with several kinematically distinct components visible in H-alpha and N II lambda 6583. The velocity measurements cover almost all of the 3 kpc scale, Z-shaped emission-line structure seen in narrow-band images