45 research outputs found
Sun wonder! Non-trivial concepts through day-time astronomy experiments with self-constructed equipment
No full textOur Sun is visible during school hours, as long as the sky is relatively cloudless. Equipment that we can easily construct ourselves can be used to conduct simple observations and make measurements related to the Sun, from which insights into the world of astronomy, the workings of the Sun, pin-hole cameras and imaging, can emerge. A few examples of these activities are described here, with pointers to external text and video resources
What are Black Holes?
No full textIn the very hearts of galaxies, like our Milky Way, lurk giant black holes that sometimes evolve into monstrous powerhouses of light. How do we know that they exist? How are they born? How do they grow? Are they important in the ‘big picture’
Daytime Astronomy with Self-constructed Equipment
No full textHow do we introduce students to astronomy when regular school hours are nearly always during the day? Can students explore the sky without the expensive equipment that modern astronomers use? What can students learn from daytime astronomy and self-constructed equipment
Extrapolating SMBH correlations down the mass scale: the case for IMBHs in globular clusters
No full text
Gaseous outflows in Seyferts and unification: the case of Mrk 533
No full textWe present our recent results from the observation of the O VI \u3bb \u3bb1032,1038 emission doublet in Seyfert galaxies of type 2 with the FUV spectrograph on the FUSE satellite. These observations are part of our investigation to contrast the properties of the OVI emission line and the absorbing outflows in a sample of rigorously matched Seyfert 1s and 2s, in the framework of the Unified Scheme. The OVI emission line is an excellent diagnostic of the outflowing hot gas at temperatures of 3c10\u2076K. In the Unified Scheme, Seyferts of type 2 are those whose central regions are obscured by the ubiquitous dusty torus. We interpret our results in this framework.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.htmlPeer reviewed: YesNRC publication: Ye
Seyfert Galaxies: Nuclear Radio Structure And Unification
No full textA radio study of a carefully selected sample of 20 Seyfert galaxies that are matched in orientation-independent parameters, which are measures of intrinsic active galactic nucleus power and host galaxy properties, is presented to test the predictions of the unified scheme hypothesis. Our sample sources have core flux densities greater than 8 mJy at 5 GHz on arcsec scales due to the feasibility requirements. These simultaneous parsec-scale and kiloparsec-scale radio observations reveal (1) that Seyfert 1 and Seyfert 2 galaxies have an equal tendency to show compact radio structures on milliarcsecond scales, (2) the distributions of parsec-scale and kiloparsec-scale radio luminosities are similar for both Seyfert 1 and Seyfert 2 galaxies, (3) there is no evidence for relativistic beaming in Seyfert galaxies, (4) similar distributions of source spectral indices in spite of the fact that Seyferts show nuclear radio flux density variations, and (5) the distributions of the projected linear size for Seyfert 1 and Seyfert 2 galaxies are not significantly different as would be expected in the unified scheme. The latter could be mainly due to a relatively large spread in the intrinsic sizes. We also find that a starburst alone cannot power these radio sources. Finally, an analysis of the kiloparsec-scale radio properties of the CfA Seyfert galaxy sample shows results consistent with the predictions of the unified scheme
