UVa Astronomy News Picture Archive

October 2007

Picture of the Month
The most intense episodes of star formation in the local universe result in the formation of "super star clusters". Super star clusters are the most massive and dense of all stellar clusters and are consistent with being young analogues of ancient globular clusters. The formation and evolution of local super star clusters represents an extreme mode of star formation that was prevalent in the early universe and continues to have a major impact on the evolution of galaxies.

Radio imaging with the Very Large Array captures newborn super star clusters in the local starburst galaxy NGC 4449. These massive clusters contain tens to hundreds of thousands of stars. The young stars produce hot ionized gas which is detectable at radio wavelengths, shown in blue here. An image from the Hubble Space Telescope shows the visible starlight in yellow.

NGC 4449 was observed at 3.6 cm with the Very Large Array in the C configuration. This image (blue) has a circular beam with a resolution of 1.3 arcsec. The optical image (yellow) was obtained with the Advanced Camera for Surveys aboard the Hubble Space Telescope through the F550M filter centered at 5581 Angstroms.

This image was created by UVa graduate student Amy Reines, and placed second in the Third NRAO/AUI Image contest.

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