نتایج جستجو برای: radio galaxies

تعداد نتایج: 141170  

2008
E. J. Murphy G. Helou A. Chung J. H. Howell

We present a study on the effects of the intracluster medium (ICM) on the interstellar medium (ISM) of 10 Virgo cluster galaxies using Spitzer far-infrared (FIR) and VLA radio continuum imaging. Relying on the FIR-radio correlation within normal galaxies, we use our infrared data to create model radio maps which we compare to the observed radio images. For 6 of our sample galaxies we find regio...

2001
P. N. Best

Deep and high resolution radio observations of the Hubble Deep Field and flanking fields have shown the presence of two distant edge-darkened FR I radio galaxies, allowing for the first time an estimate of their high redshift space density. If it is assumed that the space density of FR I radio galaxies at z>1 is similar to that found in the local universe, then the chance of finding two FR I ra...

2009
Pietro M. Reviglio David J. Helfand

In this third of a series of papers concerning active galaxies in the FIRST and Sloan Digital Sky Surveys, we analyze the spectroscopic and radio properties of a sample of narrow-line Active Galactic Nuclei (AGN), broad-line Seyfert I galaxies, and Quasars in the local universe in order to investigate the dependence of their activity on the mass, spin and accretion rates of the supermassive bla...

2008
Massimo Della Valle Paolo Padovani Filippo Mannucci Massimo Turatto

An analysis of SNIa events in early type galaxies from the Cappellaro et al. (1999) database provides conclusive evidence that the rate of type Ia Supernovae (SNe) in radio-loud galaxies is about 4 times higher than the rate measured in radio-quiet galaxies, i.e. SNIa-rate(radio− loud galaxies) = 0.43 −0.14h 2 75 SNu as compared to SNIa-rate(radio− quiet galaxies) = 0.11 −0.03h 2 75 SNu. The ac...

1998
G. Gavazzi A. Boselli

Using new extensive radio continuum surveys at 1.4 GHz (FIRST and NVSS), we derive the distribution of the radio/optical and radio/NIR luminosity (RLF) of late-type (Sa-Irr) galaxies (mp < 15.7) in 5 nearby clusters of galaxies: A262, Cancer, A1367, Coma and Virgo. With the aim of discussing possible environmental dependences of the radio properties, we compare these results with those obtained...

2008
Myung Gyoon Lee

In this paper, we collect radio and X-ray observations for most Fanaroff-Riley I (FRI) radio galaxies in the Zirbel-Baum radio galaxy sample, and investigate the distribution of the radio-to-X-ray effective spectral index, αrx, to test the unified scheme of BL Lac objects and FRI radio galaxies. It is found that the range of αrx for FRI radio galaxies is almost the same as that for BL Lac objec...

2000
Yoshiaki Taniguchi

We report on large-scale, regular morphological patterns found in the radio jet of the nearby radio galaxy NGC 6251. Investigating morphological properties of this radio jet from the nucleus to a radial distance of ∼ 300 arcsec (≈ 140 kpc) mapped at 1662 MHz and 4885 MHz by Perley, Bridle, & Willis, we find three chains, each of which consists of five radio knots. We also find that eight radio ...

1997
L. Saripalli

We present high resolution radio observations of the nuclear radio emission in a sample of eight radio galaxies having Megaparsec sizes, using the European VLBI network at 18 cm. At a resolution of 25 mas we detect all the giant radio galaxies from our sample. Among themDA 240 and 1331−099 were imaged for an extended period. These observations reveal a twin-jet structure for DA 240 and one-side...

1997
J A Peacock

This review discusses three ways in which radio galaxies and other high-redshift objects can give us information on the nature and statistics of cosmological inhomogeneities, and how they have evolved between high redshift and the present: (1) The present-day spatial distribution and clustering of radio galaxies; (2) The evolution of radio-galaxy clustering and biased clustering at high redshif...

2006
Pietro Reviglio David J. Helfand

Analysis of the frequency and physical properties of galaxies with starformation and AGN activity in different environments in the local universe is a cornerstone for understanding structure formation and galaxy evolution. We have built a new multiwavelength catalog for galaxies in a complete redshift survey (the 15R Survey), gathering information on their Hα, R-band, radio, far-infrared, and X...

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