Radio-Infrared Supernebulae in II Zw 40
Abstract
We report subarcsecond-resolution VLA and Keck mid-infrared imaging of the dwarf starburst galaxy II Zw 40. II Zw 40 contains a bright, compact thermal radio and infrared source with all the characteristics of a collection of dense HII regions ionized by at least 14,000 O stars. The supernebula is revealed to be multiple sources within an envelope of weaker emission. The radio emission is dominated by free-free emission at 2cm, and the spectrum of this emission appears to be rising. This suggests that the free-free emission is optically thick at 2cm, and that the individual HII regions are ~1pc in size. This complex of "supernebulae" dominates the total infrared luminosity of II Zw 40, although the radio source is less than ~150pc in diameter. Multiple super star clusters appear to be forming here, the much larger analogues of large Galactic HII region complexes.
Cite
@article{arxiv.astro-ph/0208077,
title = {Radio-Infrared Supernebulae in II Zw 40},
author = {S. C. Beck and J. L. Turner and L. E. Langland-Shula and D. S. Meier and L. P. Crosthwaite and V. Gorjian},
journal= {arXiv preprint arXiv:astro-ph/0208077},
year = {2009}
}
Comments
Accepted for publication in The Astronomical Journal (~November 2002), 26 pages and 4 JPEG figures