Magnetic fields in nearby normal galaxies: Energy equipartition
  We present maps of total magnetic field using 'equipartition' assumptions for
five nearby normal galaxies at sub-kpc spatial resolution. The mean magnetic
field is found to be ~11 \mu G. The field is strongest near the central regions
where mean values are ~20--25 \mu G and falls to ~15 \mu G in disk and ~10 \mu
G in the outer parts. There is little variation in the field strength between
arm and interarm regions, such that, in the interarms, the field is < 20
percent weaker than in the arms. There is no indication of variation in
magnetic field as one moves along arm or interarm after correcting for the
radial variation of magnetic field. We also studied the energy densities in
gaseous and ionized phases of the interstellar medium and compared to the
energy density in the magnetic field. The energy density in the magnetic field
was found to be similar to that of the gas within a factor of <2 at sub-kpc
scales in the arms, and thus magnetic field plays an important role in pressure
balance of the interstellar medium. Magnetic field energy density is seen to
dominate over the kinetic energy density of gas in the interarm regions and
outer parts of the galaxies and thereby helps in maintaining the large scale
ordered fields seen in those regions.
