Evidence of an interaction between jets and intra-cluster magnetic layer

2020 ◽  
Author(s):  
James Chibueze ◽  
Haruka Sakemi ◽  
Takumi Ohmura ◽  
Mami Machida ◽  
Hiroki Akamatsu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Radio Galaxy ◽  
Dense Plasma ◽  
Contact Discontinuity ◽  
Magnetic Layer ◽  
Galaxy Cluster ◽  
Cosmic Ray ◽  
Relativistic Electrons ◽  
Cluster Member

Abstract Galaxy clusters are known to harbor magnetic field, however, the extent of the influence of the intra-cluster magnetic field on the cluster member galaxies remains an unresolved question. Intra-cluster magnetic field can be observed as density contact discontinuity formed by cool and dense plasma running into hot ambient plasma, and this exist in the central region of a merging galaxy cluster Abell 3376. Here we report on unambiguous evidence of an interaction between the relativistic electrons and intra-cluster magnetic fields from MeerKAT observations of a radio galaxy MRC0600-399, having bent jets. Contrary to typical bent jets, the jet shows a 90 degrees bend at the contact discontinuity and the collimated jet further extends over 100 kpc from the bend point. The spectral index flattens downstream of the bend point, indicating cosmic-ray re-acceleration. High-resolution numerical simulations reveal that the ordered magnetic field along the discontinuity, at which the intra-cluster magnetic field can be compressed and amplified, plays a significant role to the change in the direction of the jet propagation. The overall morphology of the bent jet bears remarkable similarities with the simulations, which greatly strengthens our understanding of the interaction between relativistic electrons and intra-cluster magnetic field.

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 Oblique Shocks in Extragalactic Jets

1990 ◽  
Vol 140 ◽  
pp. 437-437
Author(s):  
D. Fraix-Burnet
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Shock Front ◽  
Shock Acceleration ◽  
Relativistic Electrons ◽  
Optical Polarization ◽  
Diffusive Shock Acceleration ◽  
Extragalactic Jets ◽  
The Magnetic Field ◽  
Oblique Shocks

In the framework of the diffusive shock acceleration of relativistic electrons in extragalactic jets, we show that it is possible to derive the speed of the jet. For this purpose, we transform continuity relations through an oblique shock front into the reference frame of the observer. We apply these calculations to knot A of the M87 jet. Measuring the deviation of the fluid through the shock front from high-resolution radio maps and the deviation of the magnetic field from optical polarization maps (Fraix-Burnet et al., 1989), we derive speeds of about 0.01 c (Fraix-Burnet and Biermann, in preparation). The compression ratio is most probably 4 and the magnetic field is nearly parallel to the shock front both upstream and downstream.

scholarly journals Particle acceleration and magnetic field amplification in massive young stellar object jets

2021 ◽  
Author(s):  
Anabella T Araudo ◽  
Marco Padovani ◽  
Alexandre Marcowith
Keyword(s):  
Magnetic Field ◽  
Cosmic Ray ◽  
Maximum Energy ◽  
Shock Acceleration ◽  
Relativistic Electrons ◽  
Diffusive Shock Acceleration ◽  
Field Amplification ◽  
Protostellar Jets ◽  
Γ Rays ◽  
The Magnetic Field

Abstract Synchrotron radio emission from non-relativistic jets powered by massive protostars has been reported, indicating the presence of relativistic electrons and magnetic fields of strength ∼0.3 −5 mG. We study diffusive shock acceleration and magnetic field amplification in protostellar jets with speeds between 300 and 1500 km s−1. We show that the magnetic field in the synchrotron emitter can be amplified by the non-resonant hybrid (Bell) instability excited by the cosmic-ray streaming. By combining the synchrotron data with basic theory of Bell instability we estimate the magnetic field in the synchrotron emitter and the maximum energy of protons. Protons can achieve maximum energies in the range 0.04 − 0.65 TeV and emit γ rays in their interaction with matter fields. We predict detectable levels of γ rays in IRAS 16547-5247 and IRAS 16848-4603. The γ ray flux can be significantly enhanced by the gas mixing due to Rayleigh-Taylor instability. The detection of this radiation by the Fermi satellite in the GeV domain and the forthcoming Cherenkov Telescope Array at higher energies may open a new window to study the formation of massive stars, as well as diffusive acceleration and magnetic field amplification in shocks with velocities of about 1000 km s−1.

scholarly journals Acceleration and Evolution of Cosmic Ray Electrons During Radio-Galaxy-Cluster-Shock Encounters

2017 ◽  
Author(s):  
Thomas Jones ◽  
B. J. O'Neill ◽  
C. Nolting ◽  
P. J. Mendygral
Keyword(s):  
Radio Galaxy ◽  
Galaxy Cluster ◽  
Cosmic Ray

Imaging of ferroelectric domain walls by electron holography

1992 ◽  
Vol 50 (1) ◽  
pp. 246-247
Author(s):  
Xiao Zhang
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Domain Walls ◽  
Ferroelectric Domain ◽  
Object Wave ◽  
Electron Holography ◽  
High Resolution Imaging ◽  
Quantitative Measurements ◽  
Resolution Imaging ◽  
Electron Microscopes

Electron holography has recently been available to modern electron microscopy labs with the development of field emission electron microscopes. The unique advantage of recording both amplitude and phase of the object wave makes electron holography a effective tool to study electron optical phase objects. The visibility of the phase shifts of the object wave makes it possible to directly image the distributions of an electric or a magnetic field at high resolution. This work presents preliminary results of first high resolution imaging of ferroelectric domain walls by electron holography in BaTiO3 and quantitative measurements of electrostatic field distribution across domain walls.

A Super-High-Resolution HVEM (H-1500) Newly Installed in NIRIM

1990 ◽  
Vol 48 (1) ◽  
pp. 142-143
Author(s):  
S. Horiuchi ◽  
Y. Matsui
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Chromatic Aberration ◽  
Inorganic Materials ◽  
Electron Gun ◽  
Resolving Power ◽  
National Budget ◽  
Voltage Electron ◽  
Specimen Holder ◽  
The Magnetic Field

A new high-voltage electron microscope (H-1500) specially aiming at super-high-resolution (1.0 Å point-to-point resolution) is now installed in National Institute for Research in Inorganic Materials ( NIRIM ), in collaboration with Hitachi Ltd. The national budget of about 1 billion yen including that for a new building has been spent for the construction in the last two years (1988-1989). Here we introduce some essential characteristics of the microscope.(1) According to the analysis on the magnetic field in an electron lens, based on the finite-element-method, the spherical as well as chromatic aberration coefficients ( Cs and Cc ). which enables us to reach the resolving power of 1.0Å. have been estimated as a function of the accelerating As a result of the calculaton. it was noted that more than 1250 kV is needed even when we apply the highest level of the technology and materials available at present. On the other hand, we must consider the protection against the leakage of X-ray. We have then decided to set the conventional accelerating voltage at 1300 kV. However. the maximum accessible voltage is 1500 kV, which is practically important to realize higher voltage stabillity. At 1300 kV it is expected that Cs= 1.7 mm and Cc=3.4 mm with the attachment of the specimen holder, which tilts bi-axially in an angle of 35° ( Fig.1 ). In order to minimize the value of Cc a small tank is additionally placed inside the generator tank, which must serve to seal the magnetic field around the acceleration tube. An electron gun with LaB6 tip is used.

High Resolution Current Imaging by Direct Magnetic Field Sensing

2003 ◽  
Author(s):  
S.I. Woods ◽  
Nesco M. Lettsome ◽  
A.B. Cawthorne ◽  
L.A. Knauss ◽  
R.H. Koch
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Spatial Resolution ◽  
Great Promise ◽  
Magnetoresistive Sensor ◽  
Magnetic Sensitivity ◽  
Current Lines ◽  
Scanning Squid ◽  
Scanning Fiber ◽  
Ferromagnetic Probe

Abstract Two types of magnetic microscopes have been investigated for use in high resolution current mapping. The scanning fiber/SQUID microscope uses a SQUID sensor coupled to a nanoscale ferromagnetic probe, and the GMR microscope employs a nanoscale giant magnetoresistive sensor. Initial scans demonstrate that these microscopes can resolve current lines less than 10 µm apart with edge resolution of 1 µm. These types of microscopes are compared with the performance of a standard scanning SQUID microscope and with each other with respect to spatial resolution and magnetic sensitivity. Both microscopes show great promise for identifying current defects in die level devices.

scholarly journals Can the Local Bubble explain the radio background?

2021 ◽  
Vol 502 (2) ◽  
pp. 2807-2814
Author(s):  
Martin G H Krause ◽  
Martin J Hardcastle
Keyword(s):  
Magnetic Field ◽  
Energy Density ◽  
Radio Emission ◽  
Magnetic Energy ◽  
Cosmic Ray ◽  
Observational Constraints ◽  
Local Bubble ◽  
Magnetic Energy Density ◽  
Magnetic Field Model ◽  
Radio Background

ABSTRACT The ARCADE 2 balloon bolometer along with a number of other instruments have detected what appears to be a radio synchrotron background at frequencies below about 3 GHz. Neither extragalactic radio sources nor diffuse Galactic emission can currently account for this finding. We use the locally measured cosmic ray electron population, demodulated for effects of the Solar wind, and other observational constraints combined with a turbulent magnetic field model to predict the radio synchrotron emission for the Local Bubble. We find that the spectral index of the modelled radio emission is roughly consistent with the radio background. Our model can approximately reproduce the observed antenna temperatures for a mean magnetic field strength B between 3 and 5 nT. We argue that this would not violate observational constraints from pulsar measurements. However, the curvature in the predicted spectrum would mean that other, so far unknown sources would have to contribute below 100 MHz. Also, the magnetic energy density would then dominate over thermal and cosmic ray electron energy density, likely causing an inverse magnetic cascade with large variations of the radio emission in different sky directions as well as high polarization. We argue that this disagrees with several observations and thus that the magnetic field is probably much lower, quite possibly limited by equipartition with the energy density in relativistic or thermal particles (B = 0.2−0.6 nT). In the latter case, we predict a contribution of the Local Bubble to the unexplained radio background at most at the per cent level.

High resolution, single shot emittance measurement of relativistic electrons from laser-driven accelerator

2011 ◽  
Author(s):  
G. G. Manahan ◽  
E. Brunetti ◽  
R. P. Shanks ◽  
M. R. Islam ◽  
B. Ersfeld ◽  
...  
Keyword(s):  
High Resolution ◽  
Relativistic Electrons ◽  
Single Shot ◽  
Resolution Single ◽  
Emittance Measurement
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