Abstract Details
| Name: Subhashis Roy Affiliation: NCRA-TIFR Conference ID: ASI2015_1031 Title : Equipartition magnetic fields in nearby spiral galaxies Abstract Type : Plenary Abstract : Magnetic fields play an important role in dynamics and energetics of interstellar medium and in star formation in galaxies. Assuming energy equipartition between magnetic fields and cosmic ray particles, we have determined magnetic fields in six nearby face-on spiral galaxies at sub-kpc spatial resolution. The mean magnetic field is found to be about 11 micro-Gauss. The field is strongest near the central regions with mean values of ~20 micro-Gauss and fall to 15 micro-Gauss in disc to 10 micro-Gauss in outer parts. The field strength in interarm regions are about 20% weaker than in arms. No significant variation of magnetic fields along arms are noted after correcting for the radial variation of magnetic fields. The energy density in the interstellar medium (turbulence) is found to be comparable to energy density in the magnetic fields within a factor of 2 at sub-kpc scales in the arms. Magnetic energy density is seen to dominate over the kinetic energy density of gas in the interarm regions and outer parts of the galaxies. |