# The effect of HII regions on rotation measure of pulsars

Authors
Type
Published Article
Publication Date
Apr 03, 2003
Submission Date
Nov 15, 2002
Identifiers
DOI: 10.1051/0004-6361:20021702
arXiv ID: astro-ph/0211374
Source
arXiv
We have obtained new rotation measure for 11 pulsars observed with the Effelsberg 100-m radio telescope, in the direction of the Perseus arm. Using a combination of 34 published and the 11 newly measured pulsar rotation measures we study the magnetic field structure towards the Perseus arm. We find that two pulsars towards l$\sim$ 149$^{\circ}$ (Region 1) and four pulsars towards l$\sim113^{\circ}$ (Region 2) lie behind HII regions which seriously affects the pulsar rotation measures. The rotation measure of PSR J2337+6151 seem to be affected by its passage through the supernova remnant G114.3+0.3. For Region 1, we are able to constrain the random component of the magnetic field to $5.7\mu$G. For the large-scale component of the Galactic magnetic field we determine a field strength of $1.7\pm1.0\mu$G. This average field is constant on Galactic scales lying within the Galactic longitude range of $85^{\circ} <$ l $< 240^{\circ}$ and we find no evidence for large scale field reversal upto 5-6 kpc. We highlight the great importance to include the effects of foreground emission in any systematic study.