Context. Ground-based imaging and imaging spectropolarimetric data are often subjected to post-facto reconstruction techniques to improve the spatial resolution. Aims: We test the effects of reconstruction techniques on two-dimensional data to determine the best approach to improve our data. Methods: We obtained an 1-h time-series of

Evolved stars observed within the Penn State - Torun Center for Astronomy Planet Search (PTPS) conducted with the Hobby-Eberly Telescope are supposed to present various effects of activity. In addition to chromospheric activity and/or pulsations one may expect spots temporarily appearing on their surfaces and rotating with stars that mimic

It is now established that thermal disc emission and non-thermal jet emission can both play a role at optical/infrared (OIR) wavelengths in X-ray transients. The spectra of the jet and disc components differ, as do their dependence on mass accretion properties. Here we demonstrate that the OIR colour-magnitude diagrams (CMDs) of the evolution of

All Galactic black hole binaries with low mass donor stars are transient X-ray sources; we expect most of the X-ray transients observed in external galaxies to be black hole binaries also. Obtaining period estimates for extra-galactic transients is challenging, but the resulting period distribution is an important tool for modeling the evolution

Context. Observations have shown that inner discs and rings (IDs and IRs) are not preferably found in barred galaxies, which indicates that their formation may differ from that described by the traditional bar-origin scenario in many cases. In contrast, the role of minor mergers in producing these inner components (ICs), while often invoked, is

We recently discovered an unresolved radio source coincident with the ultraluminous X-ray source (ULX) IC 342 X-1. The radio emission and hard X-ray spectrum of the source suggest that it is a compact object accreting in the X-ray hard/radio loud state. This enables use of the fundamental plane relation, found valid for stellar to supermassive