OH zeeman magnetic field detections toward five supernova remnants using the VLA

C. L. Brogan, D. A. Frail, W. M. Goss, T. H. Troland

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


We have observed the OH (1720 MHz) line in five galactic SNRs with the VLA to measure their magnetic field strengths using the Zeeman effect. We detected all 12 of the bright (Sv > 200 mJy) OH (1720 MHz) masers previously detected by Frail et al. and Green et al. and measured significant magnetic fields (i.e., > 3 σ) in 10 of them. Assuming that the "thermal" Zeeman equation can be used to estimate \B\ for OH masers, our estimated fields range from 0.2 to 2 mG. These magnetic field strengths are consistent with the hypothesis that ambient molecular cloud magnetic fields are compressed via the SNR shock to the observed values. Magnetic fields of this magnitude exert a considerable influence on the properties of the cloud with the magnetic pressures (10-7-10-9 ergs cm-3) exceeding the pressure in the ISM or even the thermal pressure of the hot gas interior to the remnant. This study brings the number of galactic SNRs with OH (1720 MHz) Zeeman detections to 10.

Original languageEnglish
Pages (from-to)875-890
Number of pages16
JournalAstrophysical Journal
Issue number2 PART 1
StatePublished - Jul 10 2000


  • ISM: clouds
  • Masers
  • Polarization
  • Radio lines: ISM

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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