scholarly journals Radio Source Heating in the ICM: The Example of Cygnus A

2008 ◽  
pp. 101-108 ◽  
Author(s):  
E. Belsole ◽  
A.C. Fabian
Keyword(s):  
Radio Source ◽  
Cygnus A

The Hydrogen-Line Red Shift of Radio Source Cygnus a.

1956 ◽  
Vol 123 ◽  
pp. 172 ◽  
Author(s):  
A. E. Lilley ◽  
E. F. McClain
Keyword(s):  
Radio Source ◽  
Red Shift ◽  
Hydrogen Line ◽  
Cygnus A

scholarly journals The Impact of the Early Stages of Radio Source Evolution on the ISM of the Host Galaxies

2003 ◽  
Vol 20 (1) ◽  
pp. 129-133 ◽  
Author(s):  
R. Morganti ◽  
C. N. Tadhunter ◽  
T. A. Oosterloo ◽  
J. Holt ◽  
A. Tzioumis ◽  
...  
Keyword(s):  
Radio Source ◽  
Radio Galaxy ◽  
Optical Emission ◽  
The Other ◽  
Emission Lines ◽  
Radio Sources ◽  
Host Galaxies ◽  
Cygnus A ◽  
Intermediate Size ◽  
The Impact

AbstractThe study of both neutral and ionised gas in young radio sources is providing key information on the effect the radio plasma has on the ISM of these objects. We present results obtained for the compact radio sources PKS 1549–79, 4C 12.50 and PKS 1814–63 and for the intermediate-size radio galaxy 3C 459. At least in the first two, low ionisation optical emission lines and HI absorption appear to be associated with the extended, but relatively quiescent, dusty cocoon surrounding the nucleus. The [OIII] lines are, on the other hand, mostly associated with the region of interaction between the radio plasma and the ISM, indicating a fast outflow from the centre. A case of fast outflow (up to ∼1000 km s-1) is also observed in HI in the radio source 4C 12.50. As the radio source evolves, any obscuring material along the radio axis is swept aside until, eventually, cavities (of the same kind as observed e.g. in Cygnus A) are hollowed out on either side of the nucleus. We may witness this phase in the evolution of a radio source in the radio galaxy 3C 459.

scholarly journals Interferometric observation of Cygnus-А discrete radiosource scintillations at Irkutsk Incoherent Scatter radar

2016 ◽  
Vol 2 (1) ◽  
pp. 34-43
Author(s):  
Мария Глоба ◽  
Mariia Globa ◽  
Роман Васильев ◽  
Roman Vasilyev ◽  
Дмитрий Кушнарев ◽  
...  
Keyword(s):  
Radio Source ◽  
Angular Size ◽  
Brightness Distribution ◽  
Statistical Characteristics ◽  
Cosmic Radio ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
Cygnus A ◽  
Scatter Radar ◽  
Interferometric Observation

We propose a new method for analyzing data from the Irkutsk Incoherent Scatter Radar. The method allows us to accomplish interferometric observation of discrete cosmic radio source characteristics. In this study, we analyze ionospheric scintillations of the radio source Cygnus-A. Observations were made in 2013 during regular radar sessions within 5–15 days for different seasons; the effective time of observation was 15–30 minutes per day. For interferometric analysis, the properties of correlation (coherence) coefficient of two independent recording channels were used. The statistical analysis of data from the independent channels allows us to construct two-dimensional histograms of radio source brightness distribution with a period of 18 s and to determine parameters (the maximum position and the histogram width) representing position and angular size of the radio source for each histogram. It is shown that the change of statistical characteristics does not correlate with fluctuations in power (scintillations) of the signal induced by radio wave propagation through ionospheric irregularities.

scholarly journals Measurements of Interstellar Scattering in the Cygnus Region

1988 ◽  
Vol 129 ◽  
pp. 303-304
Author(s):  
S. Spangler ◽  
A. Fey ◽  
R. Mutel
Keyword(s):  
Radio Source ◽  
Spectral Index ◽  
High Quality ◽  
Visibility Function ◽  
Cygnus A ◽  
Interstellar Scattering

We report progress on a study of interstellar scattering in the direction of the constellation Cygnus. A high quality, 1663 MHz VLBI image has been obtained of the radio source 2013+370, whose structure at this frequency is dominated by scattering. The visibility function indicates that the spectral index of the interstellar density irregularities is between 3.7 and 4.0, with the higher value being somewhat more likely. Another project consists of multifrequency observations of eight sources in this region. Pronounced changes in the scattering are observed for sources separated by only a few degrees.

scholarly journals Hot spots in Cygnus A; A mosaiced map at 86 GHz

1991 ◽  
Vol 131 ◽  
pp. 276-280
Author(s):  
M.C.H. Wright ◽  
R.J. Sault
Keyword(s):  
Radio Source ◽  
Hot Spots ◽  
Software Package ◽  
Radio Galaxy ◽  
Aperture Synthesis ◽  
Cygnus A ◽  
Radio Lobe ◽  
Multichannel Images ◽  
Multiple Field

AbstractWe describe a new software package, MIRIAD, for making multichannel images of multiple-field aperture synthesis observations. As an example of the use of the new software we present a map of the radio galaxy Cygnus A. We used the BIMA array to map Cygnus A at 86 GHz with 2.28 × 3.06 arcsec resolution in 3 fields centered on the central radio source and the radio hot spots in each radio lobe. The 3 fields were combined and deconvolved to find the positions and flux densities of the radio source components.

scholarly journals Magnetic Fields in Cooling Flow Clusters

1990 ◽  
Vol 140 ◽  
pp. 463-468 ◽  
Author(s):  
R. A. Perley
Keyword(s):  
Magnetic Field ◽  
Radio Source ◽  
Radio Galaxies ◽  
Line Of Sight ◽  
Cooling Flow ◽  
Cygnus A ◽  
Cd Galaxies ◽  
The Magnetic Field ◽  
Very High ◽  
Number Of Cells

Faraday rotation measurements of the luminous radio galaxies 3C295, Cygnus A, and Hydra A, all of which are associated with cD galaxies located in massive cooling flow clusters, show very high rotation measures – typically a few thousand radm−2, exceeding 20,000 radm−2 for 3C295. The RMs vary over large ranges and with different scales. The RMs are both positive and negative, implying reversals of the magnetic field – the variations cannot be due to density changes alone. The RMs originate in magnetized cluster gas, but it is unclear what fraction is due to a coccoon surrounding the radio source. If from the cluster as a whole, the magnetic field is , where N is the number of cells along the line of sight. A good case can be made for an enhanced magnetic field localized at or near the surface of the radio source, accounting for a significant fraction of the observed RM.

Gas Dynamics of Galaxy Collisions

1958 ◽  
Vol 8 ◽  
pp. 1074-1076
Author(s):  
M. P. Savedoff
Keyword(s):  
Interstellar Medium ◽  
Radio Source ◽  
Gas Dynamics ◽  
Close Contact ◽  
Type Systems ◽  
Low Density ◽  
Late Type ◽  
Face To Face ◽  
Cygnus A ◽  
Galaxy Collisions

When two galaxies collide at extremely high velocities, Baade and Spitzer note that negligible stellar effects are anticipated but that the interstellar medium is violently affected. Recently the radio source Cygnus A has been identified with what appears to be two colliding galaxies. Baade and Minkowski describe the optical nebula as two … “late-type systems, judging by low density gradients of the two disks. Spatially they are oriented face to face, they are slightly decentered, and we look upon them at an angle not far from 45°.” “ … the two systems must be in close contact because of the strong signs of tidal distortion which the nuclei show.” The lines are noted as diffuse.

Radio Source Surveys: Mergers at High Redshifts?

1999 ◽  
Vol 186 ◽  
pp. 321-328
Author(s):  
Patrick J. McCarthy
Keyword(s):  
Radio Source ◽  
Empirical Evidence ◽  
Radio Galaxies ◽  
Morphological Evidence ◽  
Radio Sources ◽  
Cygnus A ◽  
Visible Wavelengths

The early study of radio sources at visible wavelengths and the first empirical evidence that galaxies can have strong dynamical interactions are closely intertwined. Baade & Minkowski's (1954) model of Cygnus A as a pair of galaxies in collision, while now believed to be incorrect, presaged the merger-driven picture for the generation of radio sources (e.g. Heckman et al. 1986) by some 30 years. Morphological evidence for an association between mergers and radio loud AGN is seen in both the nearest radio galaxies (e.g. Cen A; Schweizer 1986) and in the most powerful sources at z ~ 0.1 - 0.3 (Stockton & Mackenty 1983; Hutchings et al. 1988; Heckman et al. 1986).

Fine Structure of the Radio Source Cygnus A

1966 ◽  
Vol 17 (20) ◽  
pp. 1061-1062 ◽  
Author(s):  
C. M. Wade
Keyword(s):  
Fine Structure ◽  
Radio Source ◽  
Cygnus A
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