We monitored the light variations of 58 weak-line T Tauri stars in Taurus, recently discovered in the X-ray wavelength range during the ROSAT All-Sky Survey. We derive photometric periods for 18 stars, all but one being ascribed to rotational modulation by stellar spots. The exception is a 37.6d period assigned to the orbital motion of a new pre

We have studied the signal received by a distant observer from a pulsar orbiting a stellar black hole. The binary system has a non-eccentric orbit and the most favourable configuration (edge-on) for observing the influence of the black hole on the signal emitted by the pulsar. In particular, the influence of the spin of the black hole on the

As part of a long term effort to understand pre-main sequence Li burning, we have obtained high resolution spectroscopic observations of 14 late type stars (G0-M1) in the young open cluster IC 4665. Most of the stars have Hα filled-in and LiI absorption, as expected for their young age. From the equivalent widths of Hα emission excess (obtained

We present high-resolution images of three BL Lac objects (0814+425, 1823+568, 2254+074) taken with the WFPC-2 camera on Hubble Space Telescope (HST) as part of a study of BL Lacs from a complete radio-selected sample. In two cases we clearly detect the host galaxies while the third BL Lac (0814+425) is unresolved. The host galaxy of 2254+074 is a

From 2-D spectroscopy of the [O III] λλ 4959,5007 and [S III] λ 9069 lines we have studied the ionized gas-velocity field in the central regions of NGC 1068. The existence of a strong bipolar outflow of ionized gas is confirmed. The origin of this outflow, which is probably related to the active nucleus, is about 1.4″ NE of the optical nucleus

IAUC 6558 available at Central Bureau for Astronomical Telegrams.