Is the UV Alignment Effect Present in Low Redshift Radio Galaxies?

1996 ◽  
pp. 234-235 ◽  
Author(s):  
Andrea Cimatti ◽  
Sperello Serego di Alighieri
Keyword(s):  
Radio Galaxies ◽  
Alignment Effect

scholarly journals Is the UV Alignment Effect Present in Low Redshift Radio Galaxies?

1996 ◽  
Vol 175 ◽  
pp. 234-235
Author(s):  
Andrea Cimatti ◽  
Sperello Di Serego Alighieri
Keyword(s):  
Rest Frame ◽  
Radio Galaxy ◽  
Selection Effect ◽  
Radio Galaxies ◽  
Emission Lines ◽  
Main Question ◽  
Strong Emission ◽  
Alignment Effect ◽  
Origin And Evolution ◽  
First Results

When a FRII radio galaxy at z > 0.7 is observed in the optical, its continuum appears extended and aligned with the radio axis. This phenomenon occurs actually when the optical bands start to sample the rest-frame UV, and it was called alignment effect (McCarthy et al. 1987). The UV continuum of high z radio galaxies shows also strong linear polarization due to scattering of anisotropic radiation escaping from the obscured quasar nucleus (di Serego Alighieri, Cimatti & Fosbury 1994). However, the observations of the UV continuum have been concentrated mostly on high z radio galaxies, leaving open a main question : is the alignment effect an evolutionary phenomenon present only at high z, or is it simply a selection effect due to the K-correction ? In order to investigate the origin and evolution of the UV alignment effect, we have started a ground-based imaging and polarimetric survey for studying the UV continuum in FR II radio galaxies with 0.1 < z < 0.5. Depending on the redshift, the filters U and B can be used to sample the UV continuum free from strong emission lines, and in the same rest-frame spectral region observed in radio galaxies at higher redshift. The survey is in progress and here we present only our first results.

scholarly journals The Emission Line Properties of the 3CR Radio Galaxies at Redshift One: Shocks, Evolution, and the Alignment Effect

1999 ◽  
Vol 194 ◽  
pp. 241-245
Author(s):  
Philip Best ◽  
Huub Röttgering ◽  
Malcolm Longair
Keyword(s):  
Emission Line ◽  
Radio Source ◽  
Velocity Structure ◽  
Radio Galaxies ◽  
Linear Size ◽  
Continuum Emission ◽  
Radio Sources ◽  
Powerful Radio ◽  
Alignment Effect ◽  
Optical Continuum

The results of a deep spectroscopic campaign on powerful radio galaxies with redshifts z ˜ 1, to investigate in detail their emission line gas properties, are presented. Both the 2-dimensional velocity structure of the [OII] 3727 emission line and the ionisation state of the gas are found to be strongly dependent upon the linear size (age) of the radio source in a manner indicative of the emission line properties of small (young) radio sources being dominated by the passage of the radio source shocks. The consequences of this evolution throughout the few x107 year lifetime of the radio source are discussed, particularly with relation to the alignment of the UV–optical continuum emission of these objects along their radio axis, the nature of which shows similar evolution.

Keck Spectropolarimetry of High z Radio Galaxies: Discerning the Components of the Alignment Effect

1997 ◽  
pp. 300-303
Author(s):  
Andrea Cimatti ◽  
Arjun Dey ◽  
Wil van Breugel ◽  
Robert Antonucci ◽  
Todd Hurt ◽  
...  
Keyword(s):  
Radio Galaxies ◽  
Alignment Effect

scholarly journals KECK Spectropolarimetry of High Redshift Radio Galaxies

1996 ◽  
Vol 175 ◽  
pp. 402-404
Author(s):  
A. Cimatti ◽  
A. Dey ◽  
W. Van BREUGEL ◽  
R. Antonucci ◽  
H. Spinrad
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Radio Galaxies ◽  
Unified Model ◽  
Powerful Radio ◽  
Imaging Spectrometer ◽  
Alignment Effect ◽  
Stellar Radiation ◽  
Resolution Imaging ◽  
To Come

High redshift radio galaxies (HzRGs) are observable up to cosmological distances competitive with the most distant quasars. However, before using them as probes of galaxy evolution, it is crucial to separate the stellar and non-stellar components. One of the most striking properties of HzRGs is the alignment of the UV continuum with the axis of the radio source (alignment effect; McCarthy et al. 1987). However, the relative importance of the stellar and non-stellar radiation to the alignment effect is still unknown, although a significant fraction is recognized to come from scattering of anisotropic radiation emitted by the obscured nucleus, as expected in the unified model of powerful radio sources (di Serego Alighieri, Cimatti & Fosbury 1994). Spectropolarimetry is the most powerful technique to observe at the same time different radiation components, but the 4m class telescopes can reach a sufficient S/N ratio only on the few brightest objects. Therefore, in order to investigate the origin of the alignment effect and to test the validity of the unified model of powerful radio-loud AGN, we have started a program of optical spectropolarimetry of HzRGs with the W.M. Keck 10m telescope equipped with the Low Resolution Imaging Spectrometer (LRIS) in polarimetric mode.

scholarly journals HSTand UKIRT imaging observations ofz∼ 1 6C radio galaxies - II. Galaxy morphologies and the alignment effect

2005 ◽  
Vol 359 (4) ◽  
pp. 1393-1414 ◽  
Author(s):  
K. J. Inskip ◽  
P. N. Best ◽  
M. S. Longair ◽  
H. J. A. Röttgering
Keyword(s):  
Radio Galaxies ◽  
Alignment Effect

6C radio galaxies at z∼1: the influence of radio power on the alignment effect

2003 ◽  
Vol 47 (4-5) ◽  
pp. 255-260
Author(s):  
Katherine J. Inskip ◽  
Philip N. Best ◽  
Malcolm S. Longair
Keyword(s):  
Radio Galaxies ◽  
Alignment Effect ◽  
Radio Power

3D Spectroscopy in Distant Radio Galaxies

2001 ◽  
Vol 1 ◽  
pp. 131-144
Author(s):  
B. Rocca-Volmerange
Keyword(s):  
Radio Galaxies
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