Observations of Starburst Galaxies


The search for TeV gamma-ray radiation from starburst galaxies (SBGs) has been conducted by the Whipple 10-m gamma-ray telescope from January 2001 to March 2003. The regions with high star formation rates (SFRs) observed in SBGs are frequently accompanied by high density clouds of interstellar matter (ISM). This seems to create nearly perfect conditions for generating diffuse gamma-ray radiation as high energy cosmic rays interact with the ISM. If the current paradigm that supernovae are the origin of high energy cosmic rays is valid, then star forming regions rich in type Ib/c, II supernovae may become the laboratories to test the hypothesis. Using the Whipple telescope we have conducted a survey of several plausible SBGs selected based on their distance, density of gas clouds, age of star forming regions, SFRs, and magnetic fields, as well as the presence of radio flux and X-ray point sources. We discuss the selection criteria based on gamma-ray flux estimates, as well as the results of a novel spectrum dependent analysis (to be reported during presentation) of SBG observations for which a total exposure of 10-30 hours per source have been accumulated.

In Proceedings, 28th International Cosmic Ray Conference