نتایج جستجو برای: active galaxy

تعداد نتایج: 491329  

2000
B. T. Soifer

We present evidence for a significant overdensity of red galaxies, as much as a factor of 14 over comparable field samples, in the field of the z = 1.47 radio galaxy B3 0003+387. The colors and luminosities of the brightest red galaxies are consistent with their being at z > 0.8. The radio galaxy and one of the red galaxies are separated by 5 and show some evidence of a possible interaction. Ho...

2004
Dimitri Alexei Gadotti

In an effort to elevate to higher grounds our understanding on the impact of the formation and evolution of bars in the formation and evolution of galaxies, we have developed a diagnostic tool to distinguish between recently formed and evolved bars. Our method was applied in the study of a sample of 14 galaxies and revealed that, apparently, AGN activity tends to appear in galaxies which have y...

1996
Paul J. Wiita

A key argument in favor of orientation based unification schemes is the finding that among the most powerful 3CRR radio sources the (apparent) median linear size of quasars is smaller than that of radio galaxies, which supports the idea that quasars are a subset of radio galaxies, distinguished by being viewed at smaller angles to the line of sight. Recent measurements of radio sizes for a few ...

2002
Sylvain Veilleux

The recent results from a deep Fabry-Perot survey of nearby active and star-forming galaxies are presented. Line-emitting material is detected over two orders of magnitude in galactocentric radius, from the 100-pc scale of the active or starbursting nucleus out to several 10s of kpc, sometimes well beyond the optical confines of the host galaxies. The excitation and dynamical properties of the ...

2008
M. Ruszkowski A. Simionescu

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...

2008
R. J. Protheroe

We consider the implications of the recent determination of the universal infrared background for the propagation of photons up to 20 TeV from the active galaxy Markarian 501 as observed by HEGRA. At 20 TeV the mean free path for photon-photon collisions on the infrared background would be much shorter than the distance to Markarian 501, implying absorption factors of the order of exp(−10), or ...

1999
J. F. Gallimore

Active galaxies are thought to be both fueled and obscured by neutral gas removed from the host galaxy and funneled into a central accretion disk. We performed a VLA imaging survey of 21 cm absorption in Seyfert and starburst nuclei to study the neutral gas in the near-nuclear environment. With the exception of NGC 4151, the absorbing gas traces 100 pc scale, rotating disks aligned with the out...

1996
L. L. R. Williams G. F. Lewis

The proto-galaxy, cB58, was discovered in the CNOC survey of cluster redshifts. Absorption features reveal that this system is at a redshift of z = 2 : 72, implying an absolute magnitude of M v 26, and a star-formation rate of 4700M yr 1 , making it the most \active" star-forming galaxy. This proto-galaxy is observed to lie close (6 00) to a central cluster galaxy at z = 0 : 373. The X-ray prop...

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