scholarly journals 24 synoptic maps 1974-1982 (ascending phase of cycle XXI) of 323 prominence average magnetic fields measured by the Hanle effect

2013 ◽  
Vol 8 (S300) ◽  
pp. 397-400
Author(s):  
Véronique Bommier

AbstractThe poster was made of 323 average prominence magnetic fields reported on 24 synoptic maps. The paper first resumes the methods for the field derivation, and the different results of the whole program of these second generation Hanle effect observations. From their conclusions, it was possible to derive a unique field vector for each of the 323 prominences. The maps put in evidence a large scale structure of the prominence magnetic field, probably distorted by the differential rotation, which leads to a systematically small angle (on the order of 30°) between the field vector and the prominence long axis.

2010 ◽  
Vol 2010 ◽  
pp. 1-19 ◽  
Author(s):  
Dai G. Yamazaki ◽  
Kiyotomo Ichiki ◽  
Toshitaka Kajino ◽  
Grant J. Mathews

Magnetic fields are everywhere in nature, and they play an important role in every astronomical environment which involves the formation of plasma and currents. It is natural therefore to suppose that magnetic fields could be present in the turbulent high-temperature environment of the big bang. Such a primordial magnetic field (PMF) would be expected to manifest itself in the cosmic microwave background (CMB) temperature and polarization anisotropies, and also in the formation of large-scale structure. In this paper, we summarize the theoretical framework which we have developed to calculate the PMF power spectrum to high precision. Using this formulation, we summarize calculations of the effects of a PMF which take accurate quantitative account of the time evolution of the cutoff scale. We review the constructed numerical program, which is without approximation, and an improvement over the approach used in a number of previous works for studying the effect of the PMF on the cosmological perturbations. We demonstrate how the PMF is an important cosmological physical process on small scales. We also summarize the current constraints on the PMF amplitudeBλand the power spectral indexnBwhich have been deduced from the available CMB observational data by using our computational framework.


1990 ◽  
Vol 140 ◽  
pp. 301-303
Author(s):  
J. M. Moran

Zeeman splitting in the spectra of molecular masers that arise in the envelopes of newly formed stars (called interstellar masers) offers a method of estimating the magnetic field in these dense regions (106–1011 cm−3). The magnetic field strengths in regions of OH and H2O masers scale as the square root of the density when compared to the density and field of the ambient interstellar medium. The direction of the field in OH masers may help trace the large scale structure of the magnetic field in the Galactic spiral arms.


2010 ◽  
Author(s):  
Dai G. Yamazaki ◽  
Kiyotomo Ichiki ◽  
Toshitaka Kajino ◽  
Grant. J. Mathews ◽  
Isao Tanihara ◽  
...  

2006 ◽  
Vol 642 (1) ◽  
pp. L1-L4 ◽  
Author(s):  
Mikhail V. Medvedev ◽  
Luis O. Silva ◽  
Marc Kamionkowski

2006 ◽  
Vol 637 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Yongzhong Xu ◽  
Philipp P. Kronberg ◽  
Salman Habib ◽  
Quentin W. Dufton

2012 ◽  
Vol 8 (S294) ◽  
pp. 213-224 ◽  
Author(s):  
JinLin Han

AbstractMagnetic fields in our Galaxy and nearby galaxies have been revealed by starlight polarization, polarized emission from dust grains and clouds at millimeter and submillimeter wavelength, the Zeeman effect of spectral lines or maser lines from clouds or clumps, diffuse radio synchrotron emission from relativistic electrons in interstellar magnetic fields, and the Faraday rotation of background radio sources as well as pulsars for our Milky Way. It is easy to get a global structure for magnetic fields in nearby galaxies, while we have observed many details of magnetic fields in our Milky Way, especially by using pulsar rotation measure data. In general, magnetic fields in spiral galaxies probably have a large-scale structure. The fields follow the spiral arms with or without the field direction reversals. In the halo of spiral galaxies magnetic fields exist and probably also have a large-scale structure as toroidal and poloidal fields, but seem to be slightly weaker than those in the disk. In the central region of some galaxies, poloidal fields have been detected as vertical components. Magnetic field directions in galaxies seem to have been preserved during cloud formation and star formation, from large-scale diffuse interstellar medium to molecular clouds and then to the cloud cores in star formation regions or clumps for the maser spots. Magnetic fields in galaxies are passive to dynamics.


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