DEEP RADIO CONTINUUM IMAGING OF THE DWARF IRREGULAR GALAXY IC 10: TRACING STAR FORMATION AND MAGNETIC FIELDS
- Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom)
- NRAO, P.V.D. Science Operations Center, National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801 (United States)
- Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)
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 {approx}50 pc. We find close agreement between radio continuum and H{alpha} 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.
- OSTI ID:
- 21565457
- Journal Information:
- Astrophysical Journal Letters, Vol. 739, Issue 1; Other Information: DOI: 10.1088/2041-8205/739/1/L23; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE ROLE OF THE MAGNETIC FIELD IN THE INTERSTELLAR MEDIUM OF THE POST-STARBURST DWARF IRREGULAR GALAXY NGC 1569
CALIBRATING EXTINCTION-FREE STAR FORMATION RATE DIAGNOSTICS WITH 33 GHz FREE-FREE EMISSION IN NGC 6946