Regular magnetic fields in the dwarf irregular galaxy NGC 4449

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

10 pages, 7 figures, accepted for publication in A&A, ps-file with the full paper at: http://www.oa.uj.edu.pl/~chris/publ/9419

Scientific paper

We present a high-resolution VLA study of the total power and polarized radio continuum emission at 8.46 and 4.86 GHz of the irregular galaxy NGC 4449, known for its weak rotation and non-systematic gas motions. We found strong galaxy-scale regular magnetic fields, which is surprising because of a lack of ordered rotation required for the dynamo action. The strength of the regular field reaches 8 $\mu$G and that of the total field 14 $\mu$G, comparable to that of the total magnetic field strength in radio-bright spirals. The magnetic vectors in NGC 4449 form radial ``fans'' in the central region and fragments of a spiral pattern in the galaxy's outskirts. These structures are associated with large regions of systematic Faraday rotation, implying genuine galaxy-scale magnetic fields rather than random ones compressed and stretched by gas flows. The observed pattern of polarization B-vectors is similar to dynamo-type fields in normal spirals. Nonstandard, fast dynamo concepts are required to explain the observed field strengths, though it is unknown what kind of magnetic field geometry can be produced in slowly and chaotically rotating objects. The so far neglected role of magnetic fields for the dynamics and star formation in dwarf irregulars also needs to be revised.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Regular magnetic fields in the dwarf irregular galaxy NGC 4449 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 Regular magnetic fields in the dwarf irregular galaxy NGC 4449, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Regular magnetic fields in the dwarf irregular galaxy NGC 4449 will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-686224

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.