We investigate the relation between the radio (Fr) and optical (Fo) flux densities of a variety of classes of radio transients and variables, with the aim of analysing whether this information can be used, in the future, to classify such events. Using flux density values between 1 and 10 GHz and the optical bands V and R, we build a sample with a

Orientation studies have recently received considerable attention in the archaeological domain as a source of information that may shed light on a number of anthropological issues such as beliefs systems or landscape and territory apprehension by past cultures. This is especially important in those cultural contexts, such as the ‘megalithic’

Despite the fact that ancient writings indicate a clear necessity to orient Roman towns according to the path of the sun (Hyginus Gromatius, Constitutio, 1), Le Gall (1975) in an early work made clear that there was no clear preferred orientation pattern. However, Le Gall’s analysis was done by taking into consideration a sparse number of Roman

Generally, chemical peculiarity found for stars on the upper main sequence excludes delta Scuti type pulsation (e.g. Ap and Am stars), but for the group of lambda Bootis stars it is just the opposite. This makes them very interesting for asteroseismological investigations. The group of lambda Bootis type stars comprises late B- to early F-type

The chromospheric temperature rise to values above the photospheric temperature cannot be due to radiative energy transport alone. We will outline different possibilities for the additional energy transport in the solar atmosphere by processes that require (or exclude) the presence of magnetic fields. We will discuss which of them could be

We present new optical - near-IR spectroscopic and photometric observations of the newly discovered galactic microquasar LS 5039, which indicate a classification for the mass donor in the system of O6.5V((f)). Optical spectroscopy and photometry shows no variability over a timescale of years, and we find no evidence of modulation by, or emission