نتایج جستجو برای: agn
تعداد نتایج: 7335 فیلتر نتایج به سال:
We explore the cosmic evolution of radio detected star forming (SF) galaxies and active galactic nuclei (AGN), drawn from the VLA-COSMOS survey, out to z = 1.3. We present the 20 cm radio luminosity function for these populations, and find that SF galaxies evolve much more rapidly than low-power radio AGN. Our results imply that weak radio AGN (L1.4GHz . 5×1025 WHz) occur in the most massive ga...
I briefly describe a few important scientific issues that could be addressed effectively via the combination of data from JDEM and X-ray missions. The topics covered are largely focused on active galactic nuclei (AGN) and include (1) the selection of AGN via X-ray emission and optical variability, (2) nuclear outbursts in galaxies due to transient fueling of their supermassive black holes, (3) ...
Acute glomerulonephritis (AGN) is a common condition in childhood. Many children with AGN can be managed in the primary care setting. The diagnosis is usually made on the basis of urinary findings, especially the presence of red blood cell casts. One of the most important initial investigations is determining the complement C3 level; hypocomplementemia is most characteristic of post streptococc...
The widespread use of silver nanoparticles (AgN) in the articles of common use justifies the need to investigate their effects on the human body. Nanosilver toxicity of highly purified, stable, and well-characterized Ag sol toward human immune cells at various differentiation stages has been studied. Human promyelocytic leukemia cells (HL-60) were differentiated to granulocytes using dimethyl s...
For measurement of the AGN luminosity function and its evolution, X-ray selection samples all types of AGN and provides reduced obscuration bias in comparison with UV-excess or optical surveys. The apparent decline in optically-selected quasars above z ∼ 3 may be strongly affected by such a bias. The Chandra Multi–wavelength Project (ChaMP) is characterizing serendipitously detected X-ray sourc...
Many AGN exhibit a highly variable luminosity. Some AGN also show a pronounced time delay between variations seen in their optical continuum and in their emission lines. In effect, the emission lines are light echoes of the continuum. This light travel–time delay provides a characteristic radius of the region producing the emission lines. The cross correlation function (CCF) is the standard too...
Deep X-ray surveys provide the most efficient identification of Active Galactic Nuclei (AGN) activity. However, recent evidence has indicated that the current < 10 keV surveys do not detect the most heavily obscured AGNs. Here we explore whether the X-ray undetected AGN population can be identified within the ultra-deep Spitzer survey of the GOODS-N field using X-ray stacking techniques. We fin...
Feedback by active galactic nuclei (AGN) is frequently invoked to explain the cut-off of the galaxy luminosity function at the bright end and the absence of cooling flows in galaxy clusters. Meanwhile, there are recent observations of shock fronts around radioloud AGN. Using realistic 3D simulations of jets in a galaxy cluster, we address the question what fraction of the energy of active galac...
An analysis of radio and FIR emission in over 1500 IRAS selected galaxies produces a good linear correlation between radio and FIR luminosity, indicating that star formation in normal eld galaxies dominates the infrared luminosity in the local volume. Galaxies with clear radio-excess (deened as having at least 5 times larger radio ux over expected from FIR) are identiied as hosting a radio AGN,...
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