By combining the C III λλ1906+1909 with the C II λ4267 line intensities it is possible to determine T(C++); this temperature is, in general, considerably smaller than T(O++), the temperature derived from the O III λ4363 to λ5007 intensity ratio. The authors study possible causes for this difference. They show that in the presence of spatial

The authors present two new methods to determine the electron temperature based on the He I line intensities. The temperatures derived from these methods are considerably smaller than those derived from the [O III] λλ4363, 5007 line intensities and imply the presence of large spatial temperature fluctuations in PNe. Considering the presence of

Bidimensional spectroscopy with good spatial and spectral resolution, sampling a particular emission line over the whole emitting area, is shown here to be the most suitable observational technique for understanding the kinematics of giant extragalactic H II regions (GEHRs). The TAURUS II Fabry-Perot spectrograph is an excellent instrument for this

We report the detection of the secondary star spectrum in the hard X-ray transient GRO J0422+32 during its lowest quiescent state. From the amplitude of the radial velocity curve we derive a mass function f(M)=0.85+/-0.30M_solar. We classify the companion star as type M2+/-2V which contributes 35+/-6 per cent of the total flux in the spectral range

We study the orbital properties of dumbbell galaxies which harbor twisted radio jets. Velocity and velocity dispersion profiles for four dumbbell pairs (3C66B, 3C75, 3C449, 0326+39) are presented. We analyze optical CCD images in search of isophote off-centering and large isophote twists. Combining the kinematic and isophotal information, we

IRAS 17423-1755 has been recognized as a new bipolar nebula during a multi-wavelength observational program of unidentified IRAS sources with far infrared colours similar to those of known planetary nebulae. B, V, R and Hα CCD images show a clearly marked bipolar structure with a total extension of ~11 arcsec. The spectrum of the core shows strong