From the analysis of the 13-color photometry and spectroscopy of
HD 184279 (V 1294 Aql), we have found that for the last 10 years, this atar presents a pseudo period of 5.0 years both in light and radial velocity. There is a phase difference of 0.148 P (8.9 months) between the maximum of light and the minimum of radial velocity. The magnitude of the star changes by 0.4 mag. and the radial velocity shows a range ef 185 km/sec. A comparison with theoretical models give ua an Teff.<=28, 700 K with log.g<=4.0 in agreement with spectroscopic determinations.
The atar is reaching the maximum of light and some of their shell features are decreasing, a probable indication that the atar may return to a quiesent stage on its evolution, or it will continue the cyclic behaviour that has characterize it for the last 10 years. Its observation in UV and IR wavelenghts should be very important to measure the wind that may be present in the well developed shell surrounding the atar.
The Ondřejov 2-meter Telescope is used either in the Cassegrain or in the coudé focus; the primary focus is not used. The primary goal is the spectroscopy. Nowadays, the Cassegrain focus is equipped with the fiber-fed echelle spectrograph HEROS owned by the Landessternwarte Heidelberg-Konigstuhl. The coudé focus is equipped with the slit spectrograph. Usually, the slit coudé spectrograph is being used in winter due to the lower sensitivity to the weather condition (seeing).
Seyfert galaxies with linear nuclear radio structures have been studied with long-slit spectroscopy. Very extended, narrow [OIll] emission is detected in several of the objects, highly elongated along the radio source axis. This Extended Narrow Line Region would be consistent with interstellar gas that is photoionized by collimated energetic radiation from the nucleus. Within the Narrow Line Region detailed correspondences between [Olll] emission features and individual radio components have been found in a number of Seyfert galaxies. Velocities and positions of these [OIll] features suggest that they may be produced when ambient gas has been compressed by an outmoving radio component, subsequently cools down behind the bow shock and then is photoionized by the nuclear continuum source.
The spectroscopic monitoring programs carried out by the Spectroscopy Group of the German "Vereinigung der Sternfreunde" are reviewed in light of current research. Potential benefits for the professional community in collaborating and obtain long-term monitoring data otherwise unaccessible due to telescope time restrictions are summarized. The contribution highlights results on specific objects of wide interest, such as the well investigated Be stars ≥ Tauri or the S Doradus type variable P Cygni.
The progress in the investigation of Be stars during the past decade was enabled mainly thanks to high-resolution echelle spectrographs. Such instruments made possible to carry out multi-line studies of line profile variations and to search for correlations between photospheric and circumstellar phenomena. The Heros team was one of the most active in this field during the last decade. Here we summarize the most important achievements reached by the group.
A numerical-analytical model has been developed to investigate the effect of the coverage density of metallic nanoparticles on the interplay between Raman gain and attenuation of guided mode in SERSactive optical fibers. The model was applied to different types of SERS-active fibers: a single-mode suspended-core photonic crystal fiber with silver nanoparticles immobilized on the walls of cladding channels and multi-mode unclad sapphire fiber with silver nanoparticles on its outer cylindrical surface. The predicted Raman intensity curves as functions of nanoparticle coverage density, covered fiber length and excited modes are in a good agreement with the published experimental results for the contrasting types of SERS-active fibers. and Numericko-analytický model byl vyvinut pro vyšetření vlivu hustoty pokrytí kovových nanočástic na souhru Ramanova zesílení a útlumu vedeného vidu v SERS-aktivních optických vláknech. Tento model byl aplikován na dva odlišné typy SERS-aktivních vláken: na jednovidové fotonické krystalové vlákno typu ''suspended-core'' se stříbrnými nanočásticemi immobilizovaných na stěnách plášťových kanálů a na mnohovidové bezplášťové safírové vlákno se stříbrnými nanočásticemi na jeho válcovém povrchu. Předpovězené křivky Ramanovy intenzity jako funkce hustoty pokrytí nanočástic, délky vlákna pokryté nanočásticemi a excitovaných vidů jsou v dobré shodě s publikovanými experimentálními výsledky pro uvedené kontrastní typy SERS-aktivních vláken.