In this work, we study the physical and kinematical properties of the emission line region of the Seyfert 1.5 galaxy Mrk 817 using three sets of observations, among which are high-resolution spectra obtained with the Isaac Newton Telescope (INT) on the Canary Islands. We find that, in Mrk 817, the narrow and broad emission lines (NELs and BELs

New visible polarization data combined with existing IR and FIR polarization data are used to study how the magnetic field threading the filamentary molecular cloud GF 9 connects to larger structures in its general environment. When visible and NIR polarization data are combined, no evidence is found for a plateau in the polarization above

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We report the results of CCD V and R photometry of the RR Lyrae stars in M2. The periodicities of most variables are revised and new ephemerides are calculated. Light-curve decomposition of the RR Lyrae stars was carried out and the corresponding mean physical parameters [Fe/H] = -1.47, Teff = 6276K, logL = 1.63Lsolar and MV = 0.71 from nine RRab

Aims.We study the optical spectral properties of a sample of stars showing far infrared colours similar to those of well-known planetary nebulae. The large majority of them were unidentified sources or poorly known in the literature at the time when this spectroscopic survey started, some 15 years ago. Methods: .We present low-resolution optical