Zeeman Observations of the Magnetic Field in the Galactic Centre

1990 ◽  
pp. 383-384 ◽  
Author(s):  
U. J. Schwarz ◽  
J. Lasenby
Keyword(s):  
Magnetic Field ◽  
Galactic Centre ◽  
The Magnetic Field

OH Zeeman Determination of the Magnetic Field at the Galactic Centre

1990 ◽  
pp. 382-382
Author(s):  
N. E. B. Killeen ◽  
K. Y. Lo ◽  
R. J. Sault ◽  
R. M. Crutcher
Keyword(s):  
Magnetic Field ◽  
Galactic Centre ◽  
The Magnetic Field

Modelling the Galactic Centre Snake

1993 ◽  
Vol 10 (3) ◽  
pp. 233-235 ◽  
Author(s):  
Jennifer Nicholls ◽  
A.D. Gray
Keyword(s):  
Magnetic Field ◽  
Energy Spectrum ◽  
High Resolution ◽  
Particle Energy ◽  
Galactic Centre ◽  
High Resolution Imaging ◽  
Centre Region ◽  
Resolution Imaging ◽  
Thermal Sources ◽  
The Magnetic Field

AbstractHigh resolution imaging at radio frequencies has revealed several long, filamentary, non-thermal sources in the Galactic Centre region. One of these, known as the Snake, is unique in that it lies outside the Galactic Centre Lobe, and has two kinks along its length, one of which appears to be associated with a small, resolved source. For this work the Snake is assumed to be embedded in a region where both the magnetic field and the particle energy spectrum are uniform. The Snake is then modelled as an enhancement over the background of the particle energy spectrum. Some preliminary results from this model are presented here.

scholarly journals The Large-Scale Magnetic Field Structure Near the Galactic Centre

1990 ◽  
Vol 140 ◽  
pp. 369-372
Author(s):  
Wolfgang Reich
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Large Scale ◽  
Field Structure ◽  
Galactic Centre ◽  
Poloidal Magnetic Field ◽  
Magnetic Field Structure ◽  
Large Scale Magnetic Field ◽  
Centre Region ◽  
The Magnetic Field

High frequency polarization observations reveal the existence of a poloidal magnetic field structure in the Galactic Centre region on scales of about 200 pc. At lower frequencies large non–thermal spurs are seen tracing the magnetic field up to kpc distances from the Galactic Centre.

scholarly journals Zeeman Observations of the Magnetic Field in the Galactic Centre

1990 ◽  
Vol 140 ◽  
pp. 383-384
Author(s):  
U. J. Schwarz ◽  
J. Lasenby
Keyword(s):  
Magnetic Field ◽  
Zeeman Splitting ◽  
Galactic Centre ◽  
Direct Measurements ◽  
The Magnetic Field

Direct measurements of the magnetic field in the neutral ring at the Galactic centre were made by observing the Zeeman splitting in HI- absorption around ± 100 kms−1 and give a field of (–0.5mG ± 0.17mG); significantly less than inferred from IR polarisation observations (Werner et al., 1988).

scholarly journals A lower limit of 50 microgauss for the magnetic field near the Galactic Centre

Nature ◽  
2010 ◽  
Vol 463 (7277) ◽  
pp. 65-67 ◽  
Author(s):  
Roland M. Crocker ◽  
David I. Jones ◽  
Fulvio Melia ◽  
Jürgen Ott ◽  
Raymond J. Protheroe
Keyword(s):  
Magnetic Field ◽  
Lower Limit ◽  
Galactic Centre ◽  
The Magnetic Field

Observing the galactic magnetic field

1967 ◽  
Vol 31 ◽  
pp. 375-380
Author(s):  
H. C. van de Hulst
Keyword(s):  
Magnetic Field ◽  
Fair Agreement ◽  
Solar Neighbourhood ◽  
Galactic Magnetic Field ◽  
The Magnetic Field

Various methods of observing the galactic magnetic field are reviewed, and their results summarized. There is fair agreement about the direction of the magnetic field in the solar neighbourhood:l= 50° to 80°; the strength of the field in the disk is of the order of 10-5gauss.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

On the Configuration of the Magnetic Field of β CrB

1976 ◽  
Vol 32 ◽  
pp. 613-622
Author(s):  
I.A. Aslanov ◽  
Yu.S. Rustamov
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Radial Velocity ◽  
Magnetic Field Strength ◽  
Complex Shape ◽  
Rotation Period ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Secular Variations ◽  
The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

Materials for Electron Beam Information Storage

1969 ◽  
Vol 27 ◽  
pp. 152-153 ◽  
Author(s):  
D. E. Speliotis
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Recent Literature ◽  
Electron Beams ◽  
Information Storage ◽  
The Subject ◽  
The Magnetic Field

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.

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