* Astronomy

Title: Extended Emission by Dust in the Dwarf Galaxy UGC 10445
Authors: J. L. Hinz, K. Misselt, M. J. Rieke, G. H. Rieke, P. S. Smith, M. Blaylock, K. D. Gordon (U. Arizona)

Researchers present Spitzer Space Telescope images of the isolated dwarf galaxy UGC 10445. The galaxy is detected at all photometric bands (3.6-160um) as well as in the Multiband Imaging Photometer for Spitzer (MIPS) spectral energy distribution mode (55-95um).
They derive a star formation rate of 0.25 solar masses per year based on H-alpha and infrared flux densities. There is over 10^6 solar masses of cold dust (T~18K) in the galaxy, represented by 160um emission, that extends to a larger radius than the ultraviolet (UV), optical and near-infrared light. Such extended emission has been seen previously only in dwarf galaxies in cluster environments.
The researchers suggest the source of heating for this dust is UV light originating in star forming complexes. To produce the large quantity of dust requires a higher rate of star formation in the past than is observed currently.

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