Deep radio continuum imaging of the dwarf irregular galaxy IC 10: tracing star formation and magnetic fields
Rupen, M. P.
Hunter, D. A.
We exploit the vastly increased sensitivity of the Expanded Very Large Array to study the radio continuum and polarization properties of the post-starburst, dwarf irregular galaxy IC 10 at 6 cm, at a linear resolution of similar to 50 pc. We find close agreement between radio continuum and Ha emission, from the brightest H II regions to the weaker emission in the disk. A quantitative analysis shows a strictly linear correlation, where the thermal component contributes 50% to the total radio emission, the remainder being due to a non-thermal component with a surprisingly steep radio spectral index of between -0.7 and -1.0 suggesting substantial radiation losses of the cosmic-ray electrons. We confirm and clearly resolve polarized emission at the 10%-20% level associated with a non-thermal superbubble, where the ordered magnetic field is possibly enhanced due to the compression of the expanding bubble. A fraction of the cosmic-ray electrons has likely escaped because the measured radio emission is a factor of three lower than what is suggested by the H alpha-inferred star formation rate.
Published inAstrophysical Journal Letters
RelationsSchool of Physics, Astronomy and Mathematics
MetadataShow full item record
Showing items related by title, author, creator and subject.
The H alpha galaxy survey. I. The galaxy sample, H alpha narrow-band observations and star formation parameters for 334 galaxies James, P.A.; Shane, N.S.; Beckman, J.E.; Cardwell, A.; Collins, C.A.; Etherton, J.; de Jong, R.S.; Fathi, K.; Knapen, J.; Peletier, R.F.; Percival, S.M.; Pollacco, D.L.; Seigar, M.S.; Stedman, S. (2004)We discuss the selection and observations of a large sample of nearby galaxies, which we are using to quantify the star formation activity in the local Universe. The sample consists of 334 galaxies across all Hubble types ...
Galaxy evolution in Abell 85. I: Cluster substructure and environmental effects on the blue galaxy population Bravo-Alfaro, H.; Caretta, C.A.; Lobo, C.; Durret, F.; Scott, T.C. (2009)
Knapen, J.; Perez-Ramirez, D.; Laine, S. (2002-12)