Results 51 to 60 of about 512 (184)
AGN Obscuration and the Unified Model
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Unification Models of Active Galactic Nuclei postulate that all the observed differences between type 1 and type 2 objects are due to orientation effects with respect to the line of sight to the observer. The key ingredient of these models is the obscuring medium, historically envisaged as a toroidal structure on a parsec scale.
Stefano Bianchi +3 more
wiley +1 more source
A Practical Guide to the Massive Black Hole Cosmic History
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 I review our current understanding of massive black hole (MBH) formation and evolution along the cosmic history. After a brief introductory overview of the relevance of MBHs in the hierarchical structure formation paradigm, I discuss the main viable channels for seed BH formation at high redshift and for their subsequent mass growth and spin evolution.
A. Sesana, Francesco Shankar
wiley +1 more source
The Astrophysical JournalWe analyze a sample of ~113,000 galaxies ( z
Huynh Anh N. Le, Yongquan Xue
doaj +1 more source
Acta Polytechnica CTU Proceedings, 2014 Of the 271 sources in the 3rd EGRET catalogue, 131 were reported as unidentied, i.e. not associated with any particular class of point source in the sky.
Pieter J. Meintjes +3 more
doaj +1 more source
On X‐Ray Variability in Seyfert Galaxies [PDF]
The Astrophysical Journal, 1999 11 pages, 1 figure 1 table. LaTeX with encapsulated postscript. Accepted for publication in the Astrophysical Journal. Replaced first version to fix a printing problem caused by the figure.
Turner, T. J. +3 more
openaire +2 more sources
A Comparison of Star Formation Rates by Different Tracers in Nearby Galaxies
The Astrophysical Journal Supplement SeriesWe utilize a large sample of ∼113,000 galaxies ( z < 0.3) from the Sloan Digital Sky Survey with high-quality data to compare star formation rates (SFRs) across multiple diagnostic methods and examine their connection to the strength of active galactic ...
Huynh Anh N. Le +5 more
doaj +1 more source
HNC, HCN and CN in Seyfert galaxies [PDF]
Astronomy & Astrophysics, 2007 Accepted for publication in A&A. A selection of this paper will be presented as a poster in the FIR workshop 2007, held at Bad Honnef, Germany. High resolution figures in original paper.
Perez-Beaupuits, J. P. +2 more
openaire +3 more sources
Compact radio cores in Seyfert galaxies [PDF]
The Astrophysical Journal, 1994 We have observed a sample of 157 Seyfert galaxies with a 275 km baseline radio interferometer to search for compact, high brightness temperature radio emission from the active nucleus. We obtain the surprising result that compact radio cores are much more common in Seyfert 2 than in Seyfert 1 galaxies, which at first seems to be inconsistent with ...
Roy, A. L. +4 more
openaire +2 more sources
Extended Narrow-Line Region in Seyfert Galaxies
Frontiers in Astronomy and Space Sciences, 2017 We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different
Enrico Congiu +10 more
doaj +1 more source
Hidden starbursts in Seyfert 1 galaxies [PDF]
Monthly Notices of the Royal Astronomical Society, 2003 5 pages, 1 figure.
Rodriguez-Ardila, A., Viegas, S.
openaire +2 more sources