Discovery of a strong spiral magnetic field crossing the inner pseudoring of NGC 4736

Details Discovery of a strong spiral magnetic field crossing the inner pseudoring of NGC 4736 Discovery of a strong spiral magnetic field crossing the inner pseudoring of NGC 4736

2008-03-04

arxiv.org/abs/0803.0555v1

Astronomy and Astrophysics

Astrophysics

Accepted for publication in the Astrophysical Journal Letters, 5 pages, 5 color figures

Scientific paper

10.1086/587958

We report the discovery of a coherent magnetic spiral structure within the nearby ringed Sab galaxy NGC 4736. High sensitivity radio polarimetric data obtained with the VLA at 8.46GHz and 4.86GHz show a distinct ring of total radio emission precisely corresponding to the bright inner pseudoring visible in other wavelengths. However, unlike the total radio emission, the polarized radio emission reveals a clear pattern of ordered magnetic field of spiral shape, emerging from the galactic centre. The magnetic vectors do not follow the tightly-wrapped spiral arms that characterize the inner pseudoring, but instead cross the ring with a constant and large pitch angle of about 35deg. The ordered field is thus not local adjusted to the pattern of star-formation activity, unlike what is usually observed in grand-design spirals. The observed asymmetric distribution of Faraday rotation suggests the possible action of a large-scale MHD dynamo. The strong magnetic total and regular field within the ring (up to 30microG and 13microG, respectively) indicates that a highly efficient process of magnetic field amplification is under way, probably related to secular evolutionary processes in the galaxy.

Affiliated with

Also associated with

No associations

Rating

Discovery of a strong spiral magnetic field crossing the inner pseudoring of NGC 4736 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Discovery of a strong spiral magnetic field crossing the inner pseudoring of NGC 4736, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Discovery of a strong spiral magnetic field crossing the inner pseudoring of NGC 4736 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-160424