A mechanism for X-ray production in Sco X-1

1969 ◽  
Vol 313 (1514) ◽  
pp. 395-402 ◽  
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Magnetoactive Plasma ◽  
Cosmic Ray ◽  
Field Energy ◽  
Close Collaboration ◽  
Ionized Gas ◽  
X Ray ◽  
Magnetic Field Energy ◽  
Cosmic Ray Acceleration

In this brief talk I should like to present a summary of some recent results on the mechanism of X -ray production in extars, with special emphasis on Sco X-1. These results are an outcome of a close collaboration between Professor S. Olbert of M.I.T. and me. As mentioned by Professor Burbidge earlier today, we hypothesize that galactic X-ray sources are in fact entities wherein ‘frozen in’, compressed magnetic field rapidly relaxes by transferring magnetic field energy to ultrarelativistic (u.r.) electrons. Consider a volume of space filled with magnetoactive plasma. For reasons elaborated on elsewhere (Manley & Olbert 1968, 1969) we do not expect the ionized gas to be homogeneous. Rather we expect it to consist of an aggregate of long thin plasmoids acting almost independently of one another. We now postulate the presence of random Alfvén waves (m.h.d. noise) propagating back and forth, along the plasmoids, and inquire into the possibility of charged particle acceleration by interaction with these noisy plasmoids. This is akin to the cosmic ray acceleration mechanism proposed by Fermi, who however, considered only interactions with large, approximately spherical plasmoids.

scholarly journals Radio and X-ray connection in radio mini-halos: Implications for hadronic models

2020 ◽  
Vol 640 ◽  
pp. A37 ◽  
Author(s):  
A. Ignesti ◽  
G. Brunetti ◽  
M. Gitti ◽  
S. Giacintucci
Keyword(s):  
Magnetic Field ◽  
Large Fraction ◽  
Cosmic Ray ◽  
Physical Parameters ◽  
Model Parameters ◽  
Relativistic Electrons ◽  
X Rays ◽  
X Ray ◽  
Hadronic Model ◽  
Radio Halos

Context. A large fraction of cool-core clusters are known to host diffuse, steep-spectrum radio sources, called radio mini-halos, in their cores. Mini-halos reveal the presence of relativistic particles on scales of hundreds of kiloparsecs, beyond the scales directly influenced by the central active galactic nucleus (AGN), but the nature of the mechanism that produces such a population of radio-emitting, relativistic electrons is still debated. It is also unclear to what extent the AGN plays a role in the formation of mini-halos by providing the seeds of the relativistic population. Aims. In this work we explore the connection between thermal and non-thermal components of the intra-cluster medium in a sample of radio mini-halos and we study the implications within the framework of a hadronic model for the origin of the emitting electrons. Methods. For the first time, we studied the thermal and non-thermal connection by carrying out a point-to-point comparison of the radio and the X-ray surface brightness in a sample of radio mini-halos. We extended the method generally applied to giant radio halos by considering the effects of a grid randomly generated through a Monte Carlo chain. Then we used the radio and X-ray correlation to constrain the physical parameters of a hadronic model and we compared the model predictions with current observations. Results. Contrary to what is generally reported in the literature for giant radio halos, we find that the mini-halos in our sample have super-linear scaling between radio and X-rays, which suggests a peaked distribution of relativistic electrons and magnetic field. We explore the consequences of our findings on models of mini-halos. We use the four mini-halos in the sample that have a roundish brightness distribution to constrain model parameters in the case of a hadronic origin of the mini-halos. Specifically, we focus on a model where cosmic rays are injected by the central AGN and they generate secondaries in the intra-cluster medium, and we assume that the role of turbulent re-acceleration is negligible. This simple model allows us to constrain the AGN cosmic ray luminosity in the range ∼1044−46 erg s−1 and the central magnetic field in the range 10–40 μG. The resulting γ-ray fluxes calculated assuming these model parameters do not violate the upper limits on γ-ray diffuse emission set by the Fermi-LAT telescope. Further studies are now required to explore the consistency of these large magnetic fields with Faraday rotation studies and to study the interplay between the secondary electrons and the intra-cluster medium turbulence.

scholarly journals Magnetic Fields & Ionized Gas in Elliptical Galaxy Halos

1990 ◽  
Vol 140 ◽  
pp. 459-462
Author(s):  
Richard G. Strom
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Elliptical Galaxy ◽  
Radio Sources ◽  
Early Type ◽  
Ionized Gas ◽  
X Ray ◽  
Galaxy Halos ◽  
Field Strengths

Faraday depolarization estimates of thermal densities within the components of double radio sources agree well with estimates from X-ray observations of hot halos around early-type galaxies, provided magnetic field strengths are close to their equipartition values. Internal Faraday dispersion is the main cause of the depolarization observed.

scholarly journals Finite size scaling in the solar wind magnetic field energy density as seen by WIND

2002 ◽  
Vol 29 (10) ◽  
pp. 86-1-86-4 ◽  
Author(s):  
B. Hnat ◽  
S. C. Chapman ◽  
G. Rowlands ◽  
N. W. Watkins ◽  
W. M. Farrell
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Energy Density ◽  
Finite Size ◽  
Field Energy ◽  
Finite Size Scaling ◽  
Size Scaling ◽  
Magnetic Field Energy ◽  
Solar Wind Magnetic Field ◽  
Field Energy Density

scholarly journals A shear-mode magnetoelectric heterostructure for harvesting external magnetic field energy

2017 ◽  
Vol 59 ◽  
pp. 012027
Author(s):  
Wei He ◽  
Jitao Zhang ◽  
Yueran Lu ◽  
Aichao Yang ◽  
Chiwen Qu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Field Energy ◽  
Shear Mode ◽  
Magnetic Field Energy

scholarly journals The Formation of Discontinuities in Gas Flows in the ISM and its Relation to the Galactic Synchrotron Radio Emission

1990 ◽  
Vol 140 ◽  
pp. 159-162
Author(s):  
V.G. Berman ◽  
L.S. Marochnik ◽  
Yu.N. Mishurov ◽  
A.A. Suchkov
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Radio Emission ◽  
Large Scale ◽  
Field Energy ◽  
Gas Flows ◽  
Interstellar Gas ◽  
Gas Density ◽  
Magnetic Field Energy ◽  
Wide Range

We show that large–scale motions of the interstellar gas, such as those associated with galactic density waves, easily develop, over a wide range of scales, shocks and discontinuities which are expected to generate turbulence. The latter is supposed to evoke diffusion of magnetic fields and cosmic rays on scales down to a few parsecs. We suggest that these processes may be of major importance in discussions of interconnections between the observed radio emission of the disks of spiral galaxies and the gas density distribution within them. In particular, we predict that the density of cosmic rays and magnetic field energy must be much less contrasted (on scales of ~1 pc and up to the scales of galactic shocks) than the gas density, hence the synchrotron radio emission is not as contrasted as is predicted under the hypothesis of a fully frozen-in magnetic field.

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