Abstracts » Zoology and wildlife conservation

Dark matter versus magnetism

Article Abstract:

A recent study suggests that magnetic effects alone may explain the observed rotational velocity of gas orbiting in spiral galaxies and may obviate positing dark matter as part of a gravitational explanation of the phenomena. The accepted view is challenged by the contention that very small magnetic forces far from a galaxy's center may strongly affect gas dynamics. The configuration and requisite forces of such a field are deduced for the Andromeda galaxy. However, neither observations of Faraday rotation nor synchrotron emission conclusively establish the presence of these forces.

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Lumpy haloes spin faster

Article Abstract:

Research published in Monthly Notices of the Royal Astronomical Society indicates that, due to an unexpectedly powerful interaction with the galactic disk, dark haloes could have a rapidly spinning central bulge. The researchers argue that both a disk and a bar could be able to cause the halo to spin more rapidly. If this is the case, the bar will not be significantly slowed by the halo. The disk and halo could be effectively coupled by inhomogeneities in the halo. These inhomogeneities gravitationally focus the orbits of stars and gas in the disk.

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Magnetic fields as an alternative explanation for the rotation curves of spiral galaxies

Article Abstract:

Magnetic effects alone may explain the observed rotational velocity of gas orbiting in spiral galaxies and may obviate positing dark matter as part of a gravitational explanation of the phenomena. The accepted view is challenged by the contention that very small magnetic forces far from a galaxy's center may strongly affect gas dynamics. The configuration and requisite forces are deduced for the Andromeda galaxy. Observed synchrotron emission is consistent with these deductions.

Spiral galaxies

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