**title** Asp Conference Series, Vol. **volume**, **publication Year** **editors** Obscured Accretion and Black Holes
نویسنده
چکیده
The evidence for obscured AGN and in particular for obscured quasars is discussed. The spectrum and source modelling of the X-ray Background suggests that most massive black holes grow by obscured accretion. A possible major growth phase which is Compton thick is explored and shown to be difficult to detect directly with current instruments .
منابع مشابه
**full Title** Asp Conference Series, Vol. **volume**, **year of Publication** **names of Editors** Stellar Jets
With a goal of understanding the conditions under which jets might be produced in novae and related objects, I consider the conditions under which jets are produced from other classes of accreting compact objects. I give an overview of accretion disk spectral states, including a discussion of in which states these jets are seen. I highlight the differences between neutron stars and black holes,...
متن کامل**full Title** Asp Conference Series, Vol. **volume**, **year of Publication** **names of Editors** High-redshift Obscured Quasars
Using mid-infrared and radio criteria, we select a sample of candidate z ∼ 2 obscured quasars. Optical spectroscopy confirms about half of these as type-2 quasars, and modelling the population suggests 50-80% of the quasars are obscured. We find some flat radio spectrum type-2 quasars, and tentative evidence for obscuration unrelated to the torus. Using a similar sample, we also find evidence f...
متن کامل**title** Asp Conference Series, Vol. **volume***, **year of Publication** **names of Editors**
The properties of radio loud active galaxies (radiogalaxies, BL Lac objects and radio loud quasar) at low and high redshift are briefly reviewed and compared. The recently derived empirical relations between central black hole mass and host properties allow one to explore the demographics of massive black hole in active galaxies. It is shown that all classes of active galaxies considered exhibi...
متن کامل**title** Asp Conference Series, Vol. **volume**, **publication Year** **editors** Chandra and Rxte Observations of X-ray Novae
We discuss new observations of X-ray novae with Chandra which provide strong evidence that black holes have event horizons. The evidence is based on the finding that black hole X-ray novae in quiescence are approximately 100 times fainter than equivalent neutron star X-ray novae. The advection-dominated accretion flow model provides a natural explanation for this difference. RXTE observations o...
متن کامل**full Title** Asp Conference Series, Vol. **volume**, **year of Publication** **names of Editors** Stellar Processes near Agn
Precise mechanisms by which Active Galactic Nuclei (AGN) receive their gaseous fuel is still a mystery. Here I draw attention to the extra ordinary star formation event that took place in the central ∼ 0.5 parsec of our Galaxy. The most reliable explanation of the event seems to be that two somewhat massive nearly co-eval gaseous disks failed to accrete on Sgr A * , the super-massive black hole...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2001