Detailed photographic mappings are presented for 33 early-type E and S0 galaxies in the Virgo cluster which are brighter than 14 mag. The mappings are based on B-band CCD and large-field photographic material. Attention is given to the geometrical characteristics of the isophotes in order to establish whether a faint disk is present, and the

AX J1745.6-2901 is a low-mass X-ray binary with an accreting neutron star, showing clear evidence for highly ionized absorption. Strong ionized Fe Kα and Kβ absorption lines are always observed during the soft state, whereas they disappear during the hard state. We computed photoionization stability curves for the hard and the soft states, under

Using the photoionization code CLOUDY, we compute photoionization models for the giant extragalactic H II region NGC 2363 and compare them with optical observational data. We mainly focus on F(Hβ), Ne, EW(Hβ), and the ratios of I(λ5007), I(λ4363), I(λ3727), I(λ6300), I(λ6720), and I(λ4686) to I(Hβ). We discuss the variations of the emission spectra

We present results of photometry and photopolarimetry of the Wolf-Rayet eclipsing binary system HD 5980 in the Small Magellanic Cloud, which underwent an unexpected eruption during 1994, transforming its spectrum into a Luminous Blue Variable-like one. CCD photometry was performed during the post-outburst declining phase. Pre-outburst

This project presents the principal conclusions of a long series of infrared and visible observations of blazars taken from 1987-92. The data fall broadly into three classes: spectropolarimetry in the range 4000-9500A of a small sample of selected AGNs; polarimetry of a sample of a dozen blazars and some twenty low polarisation quasars (LPQs)

We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies were obtained by tracking the temporal modulations in the observations associated with the spots and magnetic features as the Sun rotates. We analyzed