Details

Autor(en) / Beteiligte

• Martínez-Sansigre, Alejo
• Marleau, Francine R
• Fadda, Dario
• Willott, Chris J
• Rawlings, Steve
• Lacy, Mark
• Simpson, Chris
• Jarvis, Matt J

Titel

The obscuration by dust of most of the growth of supermassive black holes

Ist Teil von

• Nature, 2005-08, Vol.436 (7051), p.666-669

Ort / Verlag

London: Nature Publishing

Erscheinungsjahr

2005

Link zum Volltext

Quelle

EBSCOhost Psychology and Behavioral Sciences Collection

Beschreibungen/Notizen

• Supermassive black holes underwent periods of exponential growth during which we see them as quasars in the distant Universe. The summed emission from these quasars generates the cosmic X-ray background, the spectrum of which has been used to argue that most black-hole growth is obscured. There are clear examples of obscured black-hole growth in the form of 'type-2' quasars, but their numbers are fewer than expected from modelling of the X-ray background. Here we report the direct detection of a population of distant type-2 quasars, which is at least comparable in size to the well-known unobscured type-1 population. We selected objects that have mid-infrared and radio emissions characteristic of quasars, but which are faint at near-infrared and optical wavelengths. We conclude that this population is responsible for most of the black-hole growth in the young Universe and that, throughout cosmic history, black-hole growth occurs in the dusty, gas-rich centres of active galaxies.