Statistical analysis of the interplay between interstellar magnetic fields and filaments hostingPlanckGalactic cold clumps

AbstractWe discuss how measurements of linear polarisation of cluster background and embedded sources can be used to study cluster magnetic fields via Faraday rotation. We make forecasts for up-coming radio instruments on the basis of synthetic radio sky observations. Our mock polarised sky is modelled to agree with the sparse available data. By applying Bayesian statistical analysis methods, such as Markov Chain Monte Carlo and nested sampling techniques, we investigate which constraints can be placed on cluster magnetic field properties.

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Statistics on the relative orientation between magnetic fields and filaments hosting Planck Galactic Cold Clumps

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319003594 ◽

2018 ◽

Vol 14 (A30) ◽

pp. 104-104

Author(s):

D. Alina ◽

I. Ristorcelli ◽

L. Montier ◽

M. Juvela

Keyword(s):

Magnetic Field ◽

Statistical Analysis ◽

Magnetic Fields ◽

Column Density ◽

Evolutionary Process ◽

Bimodal Distribution ◽

Relative Orientation ◽

The Magnetic Field ◽

Preferential Alignment ◽

High Column

AbstractWe present a statistical analysis of the relative orientation between the plane-of-sky magnetic field and the filaments associated with the Galactic Cold Clumps. We separated polarization parameters components of the filaments and their background using thin optical medium assumption, the filaments were detected using the Rolling Hough Transform algorithm and we separated the clump and the filament contributions in our maps. We found that in high column density environments the magnetic fields inside the filaments and in the background are less likely to be aligned with each other. This suggests a decoupling between the inner and background magnetic fields at some stage of filamentsâ€™ evolution. A preferential alignment between the filaments and their inferred magnetic fields is observed in the whole selection if the clumpsâ€™ contribution is subtracted. Interestingly, a bimodal distribution of relative orientation is observed between the filamentary structures of the clumps and the filaments’ magnetic field. Similar results are seen in a subsample of nearby filaments. The relative orientation clearly shows a transition from parallel to no preferential and perpendicular alignment depending on the volume densities of both clumps and filaments. Our results confirm a strong interplay between the magnetic field and filamentary structures during their formation and evolutionary process.

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Statistical analysis of induced magnetic fields on oil-impregnated insulation pressboards

Electrical Engineering ◽

10.1007/s00202-020-01012-8 ◽

2020 ◽

Vol 102 (4) ◽

pp. 2095-2107

Author(s):

Fatih Atalar ◽

Cengiz Polat Uzunoğlu ◽

Serap Cekli ◽

Mukden Uğur

Keyword(s):

Statistical Analysis ◽

Magnetic Fields

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Statistical analysis of classification

Symposium - International Astronomical Union ◽

10.1017/s0074180900053420 ◽

1966 ◽

Vol 24 ◽

pp. 188-189

Author(s):

T. J. Deeming

Keyword(s):

Multivariate Analysis ◽

Statistical Analysis ◽

Classification Scheme ◽

Analytical Procedure ◽

Narrow Band ◽

Scientific Research ◽

Maximum Amount ◽

Amount Of Information

If we make a set of measurements, such as narrow-band or multicolour photo-electric measurements, which are designed to improve a scheme of classification, and in particular if they are designed to extend the number of dimensions of classification, i.e. the number of classification parameters, then some important problems of analytical procedure arise. First, it is important not to reproduce the errors of the classification scheme which we are trying to improve. Second, when trying to extend the number of dimensions of classification we have little or nothing with which to test the validity of the new parameters.Problems similar to these have occurred in other areas of scientific research (notably psychology and education) and the branch of Statistics called Multivariate Analysis has been developed to deal with them. The techniques of this subject are largely unknown to astronomers, but, if carefully applied, they should at the very least ensure that the astronomer gets the maximum amount of information out of his data and does not waste his time looking for information which is not there. More optimistically, these techniques are potentially capable of indicating the number of classification parameters necessary and giving specific formulas for computing them, as well as pinpointing those particular measurements which are most crucial for determining the classification parameters.

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Calculated Coronal Magnetic Fields and Their Comparison with the Coronal Structures as Observed during Five Solar Eclipses

International Astronomical Union Colloquium ◽

10.1017/s0252921100026038 ◽

1994 ◽

Vol 144 ◽

pp. 559-564

Author(s):

P. Ambrož ◽

J. Sýkora

Keyword(s):

Magnetic Field ◽

Solar Cycle ◽

Magnetic Fields ◽

Solar Corona ◽

Coronal Magnetic Field ◽

Coronal Magnetic Fields ◽

Solar Eclipses ◽

Coronal Structures

AbstractWe were successful in observing the solar corona during five solar eclipses (1973-1991). For the eclipse days the coronal magnetic field was calculated by extrapolation from the photosphere. Comparison of the observed and calculated coronal structures is carried out and some peculiarities of this comparison, related to the different phases of the solar cycle, are presented.

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Radio Measurements of Coronal Magnetic Fields

International Astronomical Union Colloquium ◽

10.1017/s0252921100024933 ◽

1994 ◽

Vol 144 ◽

pp. 21-28 ◽

Cited By ~ 4

Author(s):

G. B. Gelfreikh

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Solar Corona ◽

Active Regions ◽

High Sensitivity ◽

Coronal Magnetic Field ◽

Transverse Magnetic ◽

Radio Sources ◽

Radio Waves ◽

Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

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