Release Images

Release No.: 2010-09
For Release: Sunday, July 11, 2010 - 8:00pm

Origin of Key Cosmic Explosions Still a Mystery

This Hubble image reveals the gigantic Pinwheel Galaxy (M101), one of the
best known examples of "grand design spirals," and its supergiant star-forming regions in unprecedented detail. Astronomers have searched galaxies like this in a hunt for the progenitors of Type Ia supernovae, but
their search has turned up mostly empty-handed.

NASA/ESA

In this negative image of the Pinwheel Galaxy (M101), red squares mark the positions of "super-soft" X-ray sources. The Pinwheel should contain hundreds of accreting white dwarfs on which nuclear fusion is occurring, which should produce prodigious X-rays. Yet we only detect a few dozen super-soft X-ray sources. This means that we must devise new methods to search for the elusive progenitors of Type Ia supernovae.

R. Di Stefano (CfA)