Ultra-compact nuclear rings (UCNRs) are ring-shaped star-forming regions around galactic nuclei that range in radius from a few to 200 pc. Only a handful are known in the literature, but thanks to the high resolution of HST, we are now able to study their frequency and properties in detail. We have discovered UCNRs in three nearby galaxies. In NGC

It is well known that the temperature structure of ionized interstellar gas departs considerably from homogeneity. This is detected in the form of ``temperature fluctuations'' characterized by a parameter represented as t2. In this paper we present the formalism to check whether these small deviations from the equilibrium temperature are also

Data collected recently by the helioseismic experiments aboard the SOHO spacecraft have allowed the detection of low degree p-modes with increasingly lower order n. In particular, the GOLF experiment is currently able to unambiguously identify low degree modes with frequencies as low as 1.3 mHz. The detection of p-modes with very low frequency ({i

A new version of the cute-SCIDAR instrument, which employs the generalised SCIntillation Detection And Ranging technique to obtain detailed atmospheric turbulence profiles with height, has been designed, developed and tested by the Instituto de Astrofísica de Canarias. The instrument was developed to match the requirements of the ESO VLT Auxiliary

AB Dor, Speedy Mic, and Rst 137B are in their early post-T Tauri evolutionary phase ( ~107 K toward the saturated-supersaturated boundary but a decline beyond this among supersaturated stars. The coronal Fe abundances of the stellar sample are inversely correlated with LX/Lbol, declining slowly with rising LX/Lbol, but with a much more sharp

The recent finding that the integrated galactic initial stellar mass function, comprising all newly formed stars in all young star clusters, has, through its dependence on the star formation rate, a steeper slope in the high mass regime than the underlying canonical initial mass function of each star cluster individually offers new insights into