Central free-free-dominated 880 $\micron$ emission in II Zw 40

Abstract

The central star-forming region in a blue compact dwarf galaxy, II Zw 40, was observed in the 340 GHz ($880 \micron$) band at $\sim 5$ arcsec (250 pc) resolution with the Submillimetre Array (SMA). A source associated with the central star-forming complex was detected with a flux of $13.6\pm 2.0$ mJy. The structure is more extended than the beam in the east-west direction. The SMA 880 $\micron$ flux is analyzed by using theoretical models of radio spectral energy distribution along with centimetre interferometric measurements in the literature. We find (i) that the SMA 880 $\micron$ flux is dominated ($\sim 75$ per cent) by free-free emission from the central compact star-forming region, and (ii) that the contribution from dust emission to the SMA 880 $\micron$ flux is at most $4\pm 2.5$ mJy. We also utilize our models to derive the radio--FIR relation of the II Zw 40 centre, suggesting that free-free absorption at low frequencies ($ν\la$ several GHz; $λ\ga$ several cm) and spatial extent of dust affect the radio-FIR relation.

10 pages, 5 pages, accepted for publication in MNRAS

References in corpus (14)

• Dust Formation and Survival in Supernova Ejecta
• Metallicity Effects on Dust Properties in Starbursting Galaxies
• Rapid dust production in submillimeter galaxies at z>4?
• Exploring the infrared/radio correlation at high redshift
• Connecting Far-Infrared and Radio Morphologies of Disk Galaxies: Cosmic-Ray Electron Diffusion After Star Formation Episodes
• Cassiopeia A: dust factory revealed via submillimetre polarimetry
• Effects of grain size distribution on the interstellar dust mass growth
• A multi-resolution analysis of the radio-FIR correlation in the Large Magellanic Cloud
• Genesis and evolution of dust in galaxies in the early Universe I. Modeling dust evolution in starburst galaxies
• Integral field near-infrared spectroscopy of II Zw 40
• The FIR-Radio Relationship at High and Low Redshift
• Blue Compact Dwarf Galaxies with Spitzer: The Infrared/Radio Properties
• Time evolution of the radio continuum of young starbursts: The importance of synchrotron emission
• A VLBI Search for Radio Supernovae in Wolf Rayet Galaxies

Cited by in corpus (4)

• Physical Properties of II Zw 40's Super Star Cluster and Nebula: New Insights and Puzzles from UV Spectroscopy
• Dust emission in star-forming dwarf galaxies: General properties and the nature of the sub-mm excess
• First-generation Science Cases for Ground-based Terahertz Telescopes
• Properties of free-free, dust, and CO emissions in the starbursts of blue compact dwarf galaxies