scholarly journals Observations of Three Radio Galaxies with The Einstein X-Ray Observatory

1980 ◽  
Vol 5 ◽  
pp. 695-697
Author(s):  
E. D. Feigelson ◽  
E. J. Schreier
Keyword(s):  
Radio Galaxies ◽  
X Ray ◽  
Cygnus A ◽  
Early Results ◽  
Radio Lobe ◽  
Extended Radio ◽  
Double Radio Source ◽  
Parent Galaxy ◽  
Detailed Presentation ◽  
Centaurus A

We would like to present early results from the EINSTEIN X-ray Observatory on three radio galaxies: Centaurus A, NGC 315 = DW0055+30, and Cygnus A = 3C405. We hope to demonstrate that imaging X-ray astronomy can provide important insights into the physics and environment of radio galaxies and their extended radio components.NGC 5128, the parent galaxy of the double-double radio source Centaurus A, is the nearest radio galaxy, providing the best testing ground for high resolution X-ray studies. The X-ray morphology has proved to be rich and varied. We detect four distinct components to the X-ray emission: (1) the strong, compact nucleus detected by earlier satellites; (2) extended emission around the nucleus; (3) emission from the inner radio lobes; and (4) a unique X-ray jet between the nucleus and the NE radio lobe. A detailed presentation of these observations can be found in Schreier et al. (1979).

Einstein observations of the X-ray structure of Centaurus A - Evidence for the radio-lobe energy source

1979 ◽  
Vol 234 ◽  
pp. L39 ◽  
Author(s):  
E. J. Schreier ◽  
E. Feigelson ◽  
J. Delvaille ◽  
R. Giacconi ◽  
J. Grindlay ◽  
...  
Keyword(s):  
Energy Source ◽  
X Ray ◽  
Radio Lobe ◽  
Centaurus A

scholarly journals THE JET HEATED X-RAY FILAMENT IN THE CENTAURUS A NORTHERN MIDDLE RADIO LOBE

2009 ◽  
Vol 698 (2) ◽  
pp. 2036-2047 ◽  
Author(s):  
R. P. Kraft ◽  
W. R. Forman ◽  
M. J. Hardcastle ◽  
M. Birkinshaw ◽  
J. H. Croston ◽  
...  
Keyword(s):  
X Ray ◽  
Radio Lobe ◽  
Centaurus A

scholarly journals High-Energy Cosmic Rays from Radio Galaxies

2019 ◽  
Vol 210 ◽  
pp. 04001
Author(s):  
Björn Eichmann
Keyword(s):  
Chemical Composition ◽  
Cosmic Rays ◽  
Radio Galaxies ◽  
High Energy ◽  
High Energy Cosmic Rays ◽  
Cygnus A ◽  
Strong Source ◽  
Average Contribution ◽  
Centaurus A

A detailed investigation of radio galaxies has recently stressed these sources as the possible origin of the cosmic rays observed above 3 EeV. Here, the relevance of this model at energies below 3 EeV is investigated. It is shown that the average contribution of radio galaxies can accurately explain the observed CR flux between the second knee and the ankle in the case of a strong source evolution. However, the model cannot provide the increasing heaviness and variance at energies ≲ 1 EeV of the observed chemical composition. In addition, it is exposed that the resulting variance of the chemical composition at Earth shows also at higher energies a clear disagreement with the observations, indicating that the compositional contributions by Centaurus A and Cygnus A need to be less different.

scholarly journals Non-thermal emission in lobes of radio galaxies – III. 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236

2019 ◽  
Vol 491 (4) ◽  
pp. 5740-5746 ◽  
Author(s):  
Massimo Persic ◽  
Yoel Rephaeli
Keyword(s):  
Thermal Emission ◽  
Radio Galaxies ◽  
Spectral Energy ◽  
Large Area ◽  
Microwave Background ◽  
Extragalactic Background Light ◽  
X Ray ◽  
Radiation Fields ◽  
Cygnus A ◽  
Γ Ray

ABSTRACT Recent analyses of the broad spectral energy distributions (SEDs) of extensive lobes of local radio galaxies have confirmed the leptonic origin of their Fermi/Large Area Telescope γ-ray emission, significantly constraining the level of hadronic contribution. SEDs of distant (DL > 125 Mpc) radio-galaxy lobes are currently limited to the radio and X-ray bands, hence give no information on the presence of non-thermal (NT) protons but are adequate to describe the properties of NT electrons. Modelling lobe radio and X-ray emission in 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236, we fully determine the properties of intralobe NT electrons and estimate the level of the related γ-ray emission from Compton scattering of the electrons off the superposed cosmic microwave background, extragalactic background light, and source-specific radiation fields.

scholarly journals Radio morphology–accretion mode link in Fanaroff–Riley type II low-excitation radio galaxies

2020 ◽  
Vol 493 (3) ◽  
pp. 4355-4366 ◽  
Author(s):  
D Macconi ◽  
E Torresi ◽  
P Grandi ◽  
B Boccardi ◽  
C Vignali
Keyword(s):  
Accretion Rate ◽  
Control Sample ◽  
Radio Galaxies ◽  
Optical Data ◽  
Type Ii ◽  
Nuclear Excitation ◽  
Complete Sample ◽  
X Ray ◽  
Extended Radio ◽  
Accretion Rates

ABSTRACT Fanaroff–Riley type II (FR II) low-excitation radio galaxies (LERGs) are characterized by weak nuclear excitation on parsec-scales and properties typical of powerful FR IIs (defined as high-excitation radio galaxies, hereafter HERGs/BLRGs) on kiloparsec-scales. Since a link between the accretion properties and the power of the produced jets is expected both from theory and observations, their nature is still debated. In this work, we investigate the X-ray properties of a complete sample of 19 FR II-LERGs belonging to the 3CR catalogue, exploiting Chandra and XMM–Newton archival data. We also analyse 32 FR II-HERGs/BLRGs with Chandra data as a control sample. We compared FR II-LERG and FR II-HERG/BLRG X-ray properties and optical data available in literature to obtain a wide outlook of their behaviour. The low accretion rate estimates for FR II-LERGs, from both X-ray and optical bands, allow us to firmly reject the hypothesis as they are the highly obscured counterpart of powerful FR II-HERGs/BLRGs. Therefore, at least two hypothesis can be invoked to explain the FR II-LERG nature: (i) they are evolving from classical FR IIs because of the depletion of accreting cold gas in the nuclear region, while the extended radio emission is the heritage of a past efficiently accreting activity; and (ii) they are an intrinsically distinct class of objects with respect to classical FR Is/FR IIs. Surprisingly, in this direction, a correlation between accretion rates and environmental richness is found in our sample. The richer the environment is, the more inefficient is the accretion. In this framework, the FR II-LERGs are intermediate between FR Is and FR II-HERGs/BLRGs both in terms of accretion rate and environment.

scholarly journals Radio and X-Ray Structure of Centaurus A

1982 ◽  
Vol 97 ◽  
pp. 107-114
Author(s):  
Eric D. Feigelson
Keyword(s):  
Radio Galaxy ◽  
Hii Regions ◽  
X Rays ◽  
Active Nucleus ◽  
Very Large Array ◽  
X Ray ◽  
Radio Lobe ◽  
Inverse Compton ◽  
Centaurus A

Recent studies of the nearby radio galaxy Centaurus A with the Very Large Array and the Einstein X-Ray Observatory reveal complex radio and X-ray structures. A prominent one-sided jet comprised of resolved knots located 0.2–6 kpc from the nucleus is seen in both radio and X-rays. The X-ray emission is probably synchrotron, requiring in situ reacceleration up to Γ ≃ 107. Inverse Compton emission is not a likely explanation though a thermal model in which the nucleus ejects dense 105M0 clouds cannot be excluded. An elongated X-ray region is also found near the “middle” radio lobe and optical HII regions ∼ 30 kpc NE of the nucleus. Conditions around the active nucleus, the absence of X-rays from the inner radio lobes, and X-ray evidence for a hot interstellar medium are briefly discussed.

Observations of compact radio nuclei in Cygnus A, Centaurus A, and other extended radio sources

1975 ◽  
Vol 197 ◽  
pp. L113 ◽  
Author(s):  
K. I. Kellermann ◽  
B. G. Clark ◽  
A. E. Niell ◽  
D. B. Shaffer
Keyword(s):  
Radio Sources ◽  
Cygnus A ◽  
Extended Radio ◽  
Centaurus A

scholarly journals X‐Ray Emission from the Hot Interstellar Medium and Southwest Radio Lobe of the Nearby Radio Galaxy Centaurus A

2003 ◽  
Vol 592 (1) ◽  
pp. 129-146 ◽  
Author(s):  
R. P. Kraft ◽  
S. E. Vazquez ◽  
W. R. Forman ◽  
C. Jones ◽  
S. S. Murray ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Radio Galaxy ◽  
X Ray ◽  
Radio Lobe ◽  
Centaurus A

scholarly journals Interaction of Cygnus A with its environment

2014 ◽  
Vol 10 (S313) ◽  
pp. 236-241
Author(s):  
Paul E. J. Nulsen ◽  
Andrew J. Young ◽  
Ralph P. Kraft ◽  
Brian R. McNamara ◽  
Michael W. Wise
Keyword(s):  
Energy Flow ◽  
Radio Galaxy ◽  
Galaxy Cluster ◽  
Solar Mass ◽  
X Ray ◽  
Radio Jets ◽  
Cygnus A ◽  
Radio Lobe ◽  
Massive Galaxy ◽  
Powerful Radio Galaxy

AbstractCygnus A, the nearest truly powerful radio galaxy, resides at the centre of a massive galaxy cluster. Chandra X-ray observations reveal its cocoon shocks, radio lobe cavities and an X-ray jet, which are discussed here. It is argued that X-ray emission from the outer regions of the cocoon shocks is nonthermal. The X-ray jets are best interpreted as synchrotron emission, suggesting that they, rather than the radio jets, are the path of energy flow from the nucleus to the hotspots. In that case, a model shows that the jet flow is non-relativistic and carries in excess of one solar mass per year.

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