scholarly journals Radio broadband visualization of global three-dimensional magnetohydrodynamical simulations of spiral galaxies – I. Faraday rotation at 8 GHz

2018 ◽  
Vol 480 (1) ◽  
pp. 17-25 ◽  
Author(s):  
M Machida ◽  
T Akahori ◽  
K E Nakamura ◽  
H Nakanishi ◽  
M Haverkorn
Keyword(s):  
Faraday Rotation ◽  
Spiral Galaxies ◽  
Three Dimensional

scholarly journals Differences in Mass Distribution for Field and Cluster Spiral Galaxies

1987 ◽  
Vol 117 ◽  
pp. 66-66 ◽  
Author(s):  
David Burstein ◽  
Vera C. Rubin
Keyword(s):  
Mass Distribution ◽  
Classification Scheme ◽  
Spiral Galaxies ◽  
Three Dimensional ◽  
Rotation Curves ◽  
Mass Distributions ◽  
Distribution Form ◽  
Simple Classification ◽  
Observational Fact

Our group has now obtained rotation curves for 80 spiral galaxies, Hubble types Sa through Sd. As described in Rubin et al. (Ap. J. 289, 81; 1985), the forms of these rotation curves are similar for all Hubble types. Given this observational fact, we have chosen to analyze the mass distributions for these galaxies under the assumption that the mass distributions for all spirals can be described by the same three-dimensional form, here taken to be spherical for simplicity. The mass distribution forms for 71 of these galaxies can be placed into a simple classification scheme based on the curvature of mass distribution form in a log(radius) - log (integral mass) diagram. The three most common mass forms among this continuum are termed Types I, II and III, the forms of which are displayed below (see also the discussion by Rubin elsewhere in this Symposium).

A dynamical study of three-dimensional spiral galaxies

2001 ◽  
Vol 25 (2) ◽  
pp. 159-169
Author(s):  
Luo Xin-Lian ◽  
Long Min ◽  
Peng Qiu-he ◽  
Chou Chi-kang
Keyword(s):  
Spiral Galaxies ◽  
Three Dimensional ◽  
Dynamical Study

scholarly journals Using low-frequency pulsar observations to study the 3-D structure of the Galactic magnetic field

2017 ◽  
Vol 12 (S333) ◽  
pp. 151-156
Author(s):  
C. Sobey ◽  
Keyword(s):  
Magnetic Field ◽  
Faraday Rotation ◽  
Efficient Method ◽  
Galactic Halo ◽  
Three Dimensional ◽  
Low Frequency ◽  
Dimensional Structure ◽  
Galactic Magnetic Field ◽  
Fractional Bandwidth ◽  
Murchison Widefield Array

AbstractThe Galactic magnetic field (GMF) plays a role in many astrophysical processes and is a significant foreground to cosmological signals, such as the Epoch of Reionization (EoR), but is not yet well understood. Dispersion and Faraday rotation measurements (DMs and RMs, respectively) towards a large number of pulsars provide an efficient method to probe the three-dimensional structure of the GMF. Low-frequency polarisation observations with large fractional bandwidth can be used to measure precise DMs and RMs. This is demonstrated by a catalogue of RMs (corrected for ionospheric Faraday rotation) from the Low Frequency Array (LOFAR), with a growing complementary catalogue in the southern hemisphere from the Murchison Widefield Array (MWA). These data further our knowledge of the three-dimensional GMF, particularly towards the Galactic halo. Recently constructed or upgraded pathfinder and precursor telescopes, such as LOFAR and the MWA, have reinvigorated low-frequency science and represent progress towards the construction of the Square Kilometre Array (SKA), which will make significant advancements in studies of astrophysical magnetic fields in the future. A key science driver for the SKA-Low is to study the EoR, for which pulsar and polarisation data can provide valuable insights in terms of Galactic foreground conditions.

scholarly journals Large-Scale Galactic and Intergalactic Magnetic Fields

1990 ◽  
Vol 140 ◽  
pp. 90-94
Author(s):  
M. Fujimoto ◽  
T. Sawa
Keyword(s):  
Magnetic Fields ◽  
Radio Emission ◽  
Faraday Rotation ◽  
Large Scale ◽  
Spiral Galaxies ◽  
Radio Galaxies ◽  
Density Waves ◽  
Dynamo Theory ◽  
Spiral Density Waves

Large-scale axisymmetric and bisymmetric spiral (ASS and BSS) structures are found of magnetic fields in spiral galaxies by measuring the Faraday rotation of polarized radio emission. Dynamo theory is introduced to explain the field structures, and strong magnetogravitational interaction is suggested to occur between the BSS magnetic fields and spiral density waves. Up-to-date data about the rotation measures RM and redshifts z of QSOs and distant radio galaxies are given for discussing large-scale intergalactic magnetic fields.

Capabilities of next generation telescopes for cosmic magnetism

2018 ◽  
Vol 14 (A30) ◽  
pp. 311-314
Author(s):  
Jeroen M. Stil
Keyword(s):  
Faraday Rotation ◽  
Spiral Galaxies ◽  
Radio Telescopes ◽  
Next Generation ◽  
Rotation Measure

AbstractThe next generation of radio telescopes offer significant improvement in bandwidth and survey speed. We examine the ability to resolve Faraday thick objects in Faraday space as a function of survey parameters. The necessary combination of λmax and λmin to resolve objects with modest Faraday thick components requires one or two surveys with instantaneous bandwidth 300 MHz to 750 MHz offered by next generation telescopes. For spiral galaxies, bandwidths in excess of 1.5 GHz are required. Correction for Galactic Faraday rotation must account for common gradients of order 10 rad m−2 per degree. How effective a new rotation measure grid is in probing the foreground depends on off-axis polarization calibration.

scholarly journals Multiband Photometry of NGC 7479 and NGC 7606

1996 ◽  
Vol 157 ◽  
pp. 123-125
Author(s):  
A. M. Varela ◽  
J. A. L. Aguerri ◽  
M. Prieto ◽  
C. Muñoz-Tuñón
Keyword(s):  
Spiral Galaxies ◽  
Three Dimensional ◽  
Surface Photometry ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Isaac Newton ◽  
La Palma ◽  
Radial Profiles ◽  
Isaac Newton Telescope ◽  
Barred Spiral Galaxies

We present surface photometry in U BV RI passbands of the barred spiral galaxies NGC 7479 and NGC 7606, for which observations were obtained at the Cassegrain focus of the 2.5-m Isaac Newton Telescope at La Palma. Data are presented in the form of images and mean radial profiles from azimuthal fits of ellipses, giving the luminosity, ellipticities and position angles of the isophotes as functions of the galactocentric radii. Images in I-band are shown in Figure 1 of NGC 7479 (left) and NGC 7606 (right). These belong to a sample of galaxies with moderate circumnuclear starbursts. We are analyzing their structure to study the effects of departures from an axisymmetric potential for the dynamics of a galaxy. One objective of this study is to make a three-dimensional model of the bar and bulge using the method of photometric inversion. The sample consists of 27 spiral galaxies with and without a bar.

scholarly journals The integrated polarization of spiral galaxies

2008 ◽  
Vol 4 (S259) ◽  
pp. 543-544
Author(s):  
Jeroen M. Stil ◽  
Marita Krause ◽  
Lydia Mitchell ◽  
Rainer Beck ◽  
A. Russell Taylor
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Radio Emission ◽  
Faraday Rotation ◽  
Statistical Study ◽  
Spiral Galaxies ◽  
High Redshift ◽  
Cosmic Time ◽  
Disk Galaxies ◽  
Square Kilometre Array

AbstractWe present deep observations of polarized radio emission of distant spiral galaxies with the Effelsberg 100-m telescope† at 4.8 GHz. These cross scans with sensitivity of 50 μJy or better open the possibility of a statistical study of magnetic field properties and internal Faraday rotation as a function of inclination for a large sample of unresolved galaxies. The Square Kilometre Array (SKA) will be able to detect polarization of spiral galaxies to high redshift, probing the evolution of magnetic fields in disk galaxies over cosmic time.

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