The obscured universe
نویسندگان
چکیده
منابع مشابه
The obscured γ-ray and UHECR universe
Auger results on clustering of > ∼ 60 EeV ultra-high energy cosmic ray (UHECR) ions and the interpretation of the γ-ray spectra of TeV blazars are connected by effects from the extragalactic background light (EBL). The EBL acts as an obscuring medium for γ rays and a reprocessing medium for UHECR ions and protons, causing the GZK cutoff. The study of the physics underlying the coincidence betwe...
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Deep X-ray surveys have shown that the cosmic X-ray background (XRB) is largely due to accretion onto supermassive black holes, integrated over cosmic time. However, the characteristic hard spectrum of the XRB can only be explained if most AGN spectra are heavily absorbed. The absorbed AGN will suffer severe extinction and therefore, unlike classical QSOs, will not be prominent at optical wavel...
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We present the results of a Spitzer search for obscured AGN in the Chandra Deep Field-North, using both radio-excess and mid-infrared power-law selection. AGN selected via the former technique tend to lie at z ∼ 1, have SEDs dominated by the 1.6 μm stellar bump, and have Seyfert-like X-ray luminosities (when detected in the X-ray). In contrast, the IRAC (3.6-8.0 μm) power-law selected AGN lie a...
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Most of the local active galactic nucleus (AGN) population is obscured and much of the Xray background originates in obscured AGNs. The contribution of obscured accretion to the growth of massive black holes is discussed here. The recent identification of significant samples of the X-ray sources that dominate the X-ray background intensity has shown a redshift peak at 0.7–0.8, rather than the r...
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ژورنال
عنوان ژورنال: Journal of Physics: Conference Series
سال: 2008
ISSN: 1742-6596
DOI: 10.1088/1742-6596/120/6/062006