"Blue Globular" star cluster NGC 1978 in the Large Magellanic Cloud

The populous blue star cluster NGC 1978 in the Large Magellanic Cloud, shown from a brief (60-second) blue-light exposure with an RCA CCD in the EFOSC system at the 3.6-meter telescope of the European Southern Observatory on Cerro La Silla, Chile. North is at the top and east to the left, for direct comparison with a chart or eyepiece view. The image uses a logarithmic intensity transformation to preserve information across a wide dynamic range. The field is 3.6x5.8 arcminutes.

This is one of the "blue globular" clusters which have long indicated that the Magellanic Clouds have had a more eventful recent history of star formation than has the Milky Way. The image was serendipitous - I needed to do an adjacent field for calibration, and it seemed a shame not to get an image of the cluster center. I use quotation marks arond "blue globular", because it remains far from clear that these objects are really rich enough and massive enough to evolve into true globular clusters - the same uncertainty that remains in dealing with the luminous stellar clusters often found by HST in starburst and merging galaxies. It is, however, clear that the observable part of the Milky Way has none of these, and that they are thus of intense interest for understanding possible modes of star formation.

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Last changes: September 1997