scholarly journals Observations of magnetic fields in intracluster medium

2012 ◽  
Vol 10 (H16) ◽  
pp. 404-405
Author(s):  
Federica Govoni
Keyword(s):  
Magnetic Fields ◽  
Galaxy Clusters ◽  
Intracluster Medium ◽  
Radio Observations ◽  
New Techniques ◽  
New Radio

AbstractThe presence of μG-level magnetic fields associated with the intracluster medium of galaxy clusters is now widely acknowledged. Our knowledge of their properties has greatly improved in the recent years thanks to both new radio observations and the developments of new techniques to interpret data.

scholarly journals Magnetism Science with the Square Kilometre Array

Galaxies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 53
Author(s):  
George Heald ◽  
Sui Mao ◽  
Valentina Vacca ◽  
Takuya Akahori ◽  
Ancor Damas-Segovia ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Large Scale ◽  
Galactic Nuclei ◽  
Dark Matter Annihilation ◽  
New Techniques ◽  
Square Kilometre Array ◽  
New Radio ◽  
Recent Developments ◽  
Using Data ◽  
The Impact

The Square Kilometre Array (SKA) will answer fundamental questions about the origin, evolution, properties, and influence of magnetic fields throughout the Universe. Magnetic fields can illuminate and influence phenomena as diverse as star formation, galactic dynamics, fast radio bursts, active galactic nuclei, large-scale structure, and dark matter annihilation. Preparations for the SKA are swiftly continuing worldwide, and the community is making tremendous observational progress in the field of cosmic magnetism using data from a powerful international suite of SKA pathfinder and precursor telescopes. In this contribution, we revisit community plans for magnetism research using the SKA, in light of these recent rapid developments. We focus in particular on the impact that new radio telescope instrumentation is generating, thus advancing our understanding of key SKA magnetism science areas, as well as the new techniques that are required for processing and interpreting the data. We discuss these recent developments in the context of the ultimate scientific goals for the SKA era.

scholarly journals Polarization of radio relics in galaxy clusters

2019 ◽  
Vol 490 (3) ◽  
pp. 3987-4006 ◽  
Author(s):  
D Wittor ◽  
M Hoeft ◽  
F Vazza ◽  
M Brüggen ◽  
P Domínguez-Fernández
Keyword(s):  
High Resolution ◽  
Magnetic Fields ◽  
Galaxy Clusters ◽  
Thermal Emission ◽  
Cosmic Ray ◽  
Degree Of Polarization ◽  
Small Scale ◽  
Radio Observations ◽  
Cosmological Simulations ◽  
Polarized Emission

ABSTRACT Radio emission in the form of giant radio relics is observed at the periphery of galaxy clusters. This non-thermal emission is an important tracer for cosmic ray electrons and intracluster magnetic fields. One striking observational feature of these objects is their high degree of polarization, which provides information on the magnetic fields at the relics’ positions. In this contribution, we test if state-of-the-art high resolution cosmological simulations are able to reproduce the polarization features of radio relics. Therefore, we present a new analysis of high-resolution cosmological simulations to study the polarization properties of radio relics in detail. In order to compare our results with current and future radio observations, we create mock radio observations of the diffuse polarized emission from a massive galaxy cluster using six different projections, for different observing frequencies and for different telescopes. Our simulations suggest that, due to the effect of Faraday rotation, it is extremely difficult to relate the morphology of the polarized emission for observing frequencies below 1.4 GHz to the real magnetic field structure in relics. We can reproduce the observed degree of polarization and also several small-scale structures observed in real radio relics, but further work would be needed to reproduce some large-scale spectacular features as observed in real radio relics, such as the ‘Sausage’ and ‘Toothbrush’ relics.

Magnetic Fields of Sunspots Based on Combined Optical and Radio Observations

1996 ◽  
pp. 333-343
Author(s):  
V. E. Abramov-Maksimov ◽  
G. F. Vyalshin ◽  
G. B. Gelfreikh ◽  
V. I. Shatilov
Keyword(s):  
Magnetic Fields ◽  
Radio Observations

scholarly journals Cluster Physics & Evolution

2015 ◽  
Vol 11 (A29B) ◽  
pp. 70-78
Author(s):  
Daisuke Nagai ◽  
Monique Arnaud ◽  
Sarthak Dasadia ◽  
Michael McDonald ◽  
Ikuyuki Mitsuishi ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Statistical Power ◽  
Scaling Relations ◽  
Intracluster Medium ◽  
Physical Processes ◽  
X Ray ◽  
Cosmological Constraints ◽  
Recent Advances

AbstractRecent advances in X-ray and microwave observations have provided unprecedented insights into the structure and evolution of the hot X-ray emitting plasma from their cores to the virialization region in outskirts of galaxy clusters. Recent Sunyaev-Zel'dovich (SZ) surveys (ACT, Planck, SPT) have provided new cluster catalogs, significantly expanding coverage of the mass-redshift plane, whileChandraandXMM-NewtonX-ray follow-up programs have improved our understanding of cluster physics and evolution as well as the surveys themselves. However, the current cluster-based cosmological constraints are still limited by uncertainties in cluster astrophysics. In order to exploit the statistical power of the current and upcoming X-ray and microwave cluster surveys, it is critical to improve our understanding of the structure and evolution of the hot X-ray emitting intracluster medium (ICM). In this session, we discussed recent advances in observations and simulations of galaxy clusters, with highlights on (i) the evolution of ICM profiles and scaling relations, (ii) physical processes operating in the outskirts of galaxy clusters, and (iii) impact of mergers on the ICM structure in groups and clusters.

scholarly journals Optical and Radio Observations of Large Scale Magnetic Fields on the Sun

1971 ◽  
Vol 43 ◽  
pp. 609-615 ◽  
Author(s):  
G. Daigne ◽  
M. F. Lantos-Jarry ◽  
M. Pick
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Interplanetary Medium ◽  
Coronal Magnetic Field ◽  
The Sun ◽  
Radio Observations ◽  
Active Centers ◽  
Field Patterns

It is possible to deduce information concerning large scale coronal magnetic field patterns from the knowledge of the location of radioburst sources.As the method concerns active centers responsible for corpuscular emission, the knowledge of these structures may have important implications in the understanding of corpuscular propagation in the corona and in the interplanetary medium.

scholarly journals Decaying turbulence and magnetic fields in galaxy clusters

2019 ◽  
Vol 488 (3) ◽  
pp. 3439-3445 ◽  
Author(s):  
Sharanya Sur
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Galaxy Clusters ◽  
Power Law ◽  
Dynamo Action ◽  
Wide Range ◽  
Major Merger ◽  
Decaying Turbulence ◽  
Field Decay ◽  
The Magnetic Field

Abstract We explore the decay of turbulence and magnetic fields generated by fluctuation dynamo action in the context of galaxy clusters where such a decaying phase can occur in the aftermath of a major merger event. Using idealized numerical simulations that start from a kinetically dominated regime we focus on the decay of the steady state rms velocity and the magnetic field for a wide range of conditions that include varying the compressibility of the flow, the forcing wavenumber, and the magnetic Prandtl number. Irrespective of the compressibility of the flow, both the rms velocity and the rms magnetic field decay as a power law in time. In the subsonic case we find that the exponent of the power law is consistent with the −3/5 scaling reported in previous studies. However, in the transonic regime both the rms velocity and the magnetic field initially undergo rapid decay with an ≈t−1.1 scaling with time. This is followed by a phase of slow decay where the decay of the rms velocity exhibits an ≈−3/5 scaling in time, while the rms magnetic field scales as ≈−5/7. Furthermore, analysis of the Faraday rotation measure (RM) reveals that the Faraday RM also decays as a power law in time ≈t−5/7; steeper than the ∼t−2/5 scaling obtained in previous simulations of magnetic field decay in subsonic turbulence. Apart from galaxy clusters, our work can have potential implications in the study of magnetic fields in elliptical galaxies.

scholarly journals Connecting magnetic fields from sub-galactic scale to clusters of galaxies and beyond with cosmological MHD simulations

2015 ◽  
Vol 11 (A29B) ◽  
pp. 699-699
Author(s):  
Klaus Dolag ◽  
Alexander M. Beck ◽  
Alexander Arth
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Heat Transport ◽  
Galaxy Clusters ◽  
Large Scale ◽  
High Redshift ◽  
Galactic Halos ◽  
Rotation Measure ◽  
The Magnetic Field ◽  
Good Agreement

AbstractUsing the MHD version of Gadget3 (Stasyszyn, Dolag & Beck 2013) and a model for the seeding of magnetic fields by supernovae (SN), we performed simulations of the evolution of the magnetic fields in galaxy clusters and study their effects on the heat transport within the intra cluster medium (ICM). This mechanism – where SN explosions during the assembly of galaxies provide magnetic seed fields – has been shown to reproduce the magnetic field in Milky Way-like galactic halos (Beck et al. 2013). The build up of the magnetic field at redshifts before z = 5 and the accordingly predicted rotation measure evolution are also in good agreement with current observations. Such magnetic fields present at high redshift are then transported out of the forming protogalaxies into the large-scale structure and pollute the ICM (in a similar fashion to metals transport). Here, complex velocity patterns, driven by the formation process of cosmic structures are further amplifying and distributing the magnetic fields. In galaxy clusters, the magnetic fields therefore get amplified to the observed μG level and produce the observed amplitude of rotation measures of several hundreds of rad/m2. We also demonstrate that heat conduction in such turbulent fields on average is equivalent to a suppression factor around 1/20th of the classical Spitzer value and in contrast to classical, isotropic heat transport leads to temperature structures within the ICM compatible with observations (Arth et al. 2014).

scholarly journals SNR G320.4-01.2 and PSR B1509-58: new radio observations of a complex interacting system

1999 ◽  
Vol 305 (3) ◽  
pp. 724-736 ◽  
Author(s):  
B. M. Gaensler ◽  
K. T. S. Brazier ◽  
R. N. Manchester ◽  
S. Johnston ◽  
A. J. Green
Keyword(s):  
Radio Observations ◽  
New Radio
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