Untersuchung der Hochenergiegammastrahlung von aktiven galaktischen Kernen beobachtet mit GRO Abschlussbericht

The principal investigator pursued four cycle 4 Compton Observatory guest investigator programs that investigated the nature and the origin of the high energy gamma radiation of active galactic nuclei. As a result of two Compton Observatory key projects, simultaneous multiwavelength observations from radio to TeV frequencies of these objects were made available. These obsevations were modelled in detail using the existing theories on the origin of nonthermal radiation from these objects. Moreover, the Dermer-Schlickeiser-model for the inverse Compton radiation from gamma ray blazars was developed further and used as input for the multiwavelength modelling. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(84,4) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany); DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Bonn (Germany)DEGerman

Ursprung kosmischer Strahlung und Erzeugung galaktischer Gammastrahlung, beobachtet mit GRO Abschlussbericht

SIGLEAvailable from TIB Hannover: DtF QN1(21,37) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany); Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA) GmbH, Bonn (Germany)DEGerman

Radio obervations of the #gamma#-ray quasar 0528+134 Superluminal motion and an extreme scattering event

We report on multifrequency radio observations made with the Effelsberg 100-m telescope, the IRAM 30-m telescope and the Green Bank Interferometer between 1992 and 1994 and the #gamma#-ray quasar 0528+134. We present a new VLBI based map of 0528+134 at 22 GHz with sub-mas angular resolution observed in November 1992. At that time the source was in a phase of brightening at all of our observing frequencies above 3 GHz. The increase of brightness may be related to activity in the unresolved core component of the quasar. (orig.)Available from TIB Hannover: RN 9303(314) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

On the correlation between radio and gamma ray luminosities of active galactic nuclei

The possibility of a correlation between the radio (cm)- and #gamma#-ray luminosity of variable AGN seen by EGRET is investigated. We perform Monte-Carlo simulations of typical data sets and apply different correlation techniques (partial correlation analysis, #chi#"2-test applied on flux-flux relations) in view of a truncation bias caused by sensitivity limits of the surveys. For K-corrected flux densities, we find that with the lest squares method only a linear correlation can be recovered. Partial correlation analysis on the other side provides a robust tool to detect correlations even in flux-limited samples if intrinsic scatter does not exceed #propor to#40% of the original #gamma#-ray luminosity. However, if mean flux values of high variable sources are used we find the chance probability of high Spearman's correlation coefficient be significant underestimated. The analysis presented in this paper takes into account redshift bias and truncation effects simultaneously which was never considered in earlier papers. Applying this analysis to simultaneously observed radio- and #gamma#-ray data, no correlation is found. However, an artificial correlation appears when using the mean flux. This is probably due to the reduction of the dynamical range in the flux-flux relation. Furthermore, we show that comparing the emission in both spectral bands at a high activity state leads to no convincing correlation. In conclusion, we can not confirm a correlation between radio and #gamma#-rays luminosities of AGN which is claimed in previous works. (orig.)SIGLEAvailable from TIB Hannover: RN 9303(375) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman