Deep radio continuum imaging of the dwarf irregular galaxy IC 10: tracing star formation and magnetic fields
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Author
Heesen, V.
Rau, U.
Rupen, M. P.
Brinks, E.
Hunter, D. A.
Attention
2299/6483
Abstract
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.
Publication date
2011-09-20Published in
Astrophysical Journal LettersPublished version
https://doi.org/10.1088/2041-8205/739/1/L23Other links
http://hdl.handle.net/2299/6483Metadata
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