scholarly journals THE OPTICALLY THICK HOMOGENEOUS SSC MODEL: APPLICATION TO RADIO GALAXY NGC 1275

2014 ◽  
Vol 28 ◽  
pp. 1460205
Author(s):  
PIOTR BANASIŃSKI ◽  
WLODEK BEDNAREK
Keyword(s):  
Synchrotron Radiation ◽  
Radio Galaxy ◽  
Active Galaxies ◽  
Emission Region ◽  
Model Application ◽  
Γ Rays ◽  
Γ Ray ◽  
Ngc 1275

We consider the Synchrotron Self-Compton (SSC) model for jets in active galaxies in which produced γ-ray photons can be absorbed in collisions with the synchrotron radiation already at the emission region. In terms of such modified SSC model, we argue that the higher emission stages should be characterised by γ-ray spectra extending to lower energies due to the efficient absorption of the highest energy γ-rays. As an example, we show that different emission stages of the nearby radio galaxy NGC 1275 could be explained by such scenario.

Young radio sources at high-energies and the γ-ray CSO PKS 1718–649

2018 ◽  
Vol 14 (S342) ◽  
pp. 176-179
Author(s):  
Giulia Migliori
Keyword(s):  
Radio Galaxy ◽  
Radio Galaxies ◽  
High Energy ◽  
Radio Sources ◽  
Host Galaxies ◽  
X Ray ◽  
High Energies ◽  
Γ Rays ◽  
Γ Ray ◽  
High Energy Emission

AbstractObservations at high-energies are important to define the first stages of the evolution of extragalactic radio sources and to characterize the interstellar medium of their host galaxies. In some of the X-ray-observed Compact Symmetric Objects (CSOs, among the youngest and most compact radio galaxies), we measured values of the total hydrogen column densities large enough to slow or prevent the radio source growth. The γ-ray window has the potential to constrain the non-thermal contribution of jets and lobes to the total high-energy emission. However, so far, young radio sources remain elusive in γ-rays, with only a handful of detections (or candidates) reported by Fermi. I present our γ-ray study of the CSO PKS 1718–649, and draw comparison with the restarted, γ-ray detected, radio galaxy 3C 84.

scholarly journals A strong radio brightening at the jet base of M87 during the elevated very-high-energy γ-ray state in 2012

2014 ◽  
Vol 10 (S313) ◽  
pp. 340-345
Author(s):  
K. Hada ◽  
M. Giroletti ◽  
M. Kino ◽  
G. Giovannini ◽  
F. D' Ammando ◽  
...  
Keyword(s):  
Radio Galaxy ◽  
High Energy ◽  
Jet Formation ◽  
Radio Monitoring ◽  
Linear Resolution ◽  
Very High Energy ◽  
Γ Rays ◽  
Γ Ray ◽  
Flux Increase ◽  
Very High

AbstractThe nearby radio galaxy M87 offers a unique opportunity for exploring the connection between γ-ray production and jet formation at an unprecedented linear resolution. However, the origin and location of the γ-rays in this source is still elusive. Based on previous radio/TeV correlation events, the unresolved jet base (radio core) and the peculiar knot HST-1 at >120 pc from the nucleus are proposed as candidate site(s) of γ-ray production. Here we report our intensive, high-resolution radio monitoring observations of the M87 jet with the VLBI Exploration of Radio Astrometry (VERA) and the European VLBI Network (EVN) from February 2011 to October 2012. During this period, an elevated level of the M87 flux is reported at TeV with VERITAS. We detected a remarkable flux increase in the radio core with VERA at 22/43 GHz coincident with the VHE activity. Meanwhile, HST-1 remained quiescent in terms of its flux density and structure at radio. These results strongly suggest that the TeV γ-ray activity in 2012 originates in the jet base within 0.03 pc (projected) from the central supermassive black hole.

scholarly journals Ultra-high-energy cosmic rays in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 432-433
Author(s):  
R. J. Protheroe
Keyword(s):  
Synchrotron Radiation ◽  
High Energy ◽  
Magellanic Clouds ◽  
Ultra High Energy ◽  
Microwave Background ◽  
X Ray ◽  
High Energy Cosmic Rays ◽  
Γ Rays ◽  
Γ Ray ◽  
X Ray Binaries

Ultra-high-energy (UHE) γ-rays have been detected from several X-ray binaries. UHE γ-rays from sources in the LMC will interact in the microwave background producing electrons which emit synchrotron radiation in the X-ray and γ-ray bands. This radiation might be observable.

scholarly journals THE γ-RAY EMISSION REGION IN THE FANAROFF-RILEY II RADIO GALAXY 3C 111

2012 ◽  
Vol 751 (1) ◽  
pp. L3 ◽  
Author(s):  
P. Grandi ◽  
E. Torresi ◽  
C. Stanghellini
Keyword(s):  
Radio Galaxy ◽  
Emission Region ◽  
Γ Ray

scholarly journals Molecular Clouds Observed by the EGRET Gamma-Ray Telescope

1997 ◽  
Vol 170 ◽  
pp. 22-24 ◽  
Author(s):  
Seth. W. Digel ◽  
Stanley D. Hunter ◽  
Reshmi Mukherjee ◽  
Eugéne J. de Geus ◽  
Isabelle A. Grenier ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Molecular Clouds ◽  
Gamma Ray ◽  
Angular Resolution ◽  
Cosmic Ray ◽  
High Energy ◽  
Background Rejection ◽  
Γ Rays ◽  
Γ Ray ◽  
Production Mechanisms

EGRET, the high-energy γ-ray telescope on the Compton Gamma-Ray Observatory, has the sensitivity, angular resolution, and background rejection necessary to study diffuse γ-ray emission from the interstellar medium (ISM). High-energy γ rays produced in cosmic-ray (CR) interactions in the ISM can be used to determine the CR density and calibrate the CO line as a tracer of molecular mass. Dominant production mechanisms for γ rays of energies ∼30 MeV–30 GeV are the decay of pions produced in collisions of CR protons with ambient matter and Bremsstrahlung scattering of CR electrons.

scholarly journals High Spin States in 193Hg

2020 ◽  
Vol 4 ◽  
pp. 170
Author(s):  
N. Fotiades ◽  
Et al.
Keyword(s):  
Excited States ◽  
High Spin ◽  
Normal Level ◽  
Beam Energy ◽  
Spin Structure ◽  
Spin States ◽  
Tandem Accelerator ◽  
High Spin States ◽  
Γ Rays ◽  
Γ Ray

The high-spin structure of 193Hg was investigated by in-beam γ-ray spectro­scopic techniques. The tandem accelerator at Daresbury Laboratory, U. K., was used to populate excited states of 193Hg through the reaction 150Nd(48Ca,5n)193Hg at a beam energy of 213 MeV and the EUROGAM detector array was used to de­ tect the γ-rays emitted by the deexciting nuclei. The normal level scheme has been further extended and a new band has been observed. In addition two new ΔI=1 structures of competing dipole and quadrupole transitions were found which will be discussed in detail.

scholarly journals X-Ray and GeV Gamma-Ray Variability of the Radio Galaxy NGC 1275

2018 ◽  
Vol 855 (2) ◽  
pp. 93 ◽  
Author(s):  
Yasushi Fukazawa ◽  
Kensei Shiki ◽  
Yasuyuki Tanaka ◽  
Ryosuke Itoh ◽  
Hiromitsu Takahashi ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Radio Galaxy ◽  
X Ray ◽  
Ngc 1275
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