type Ic supernovae

I spent the day typesetting linear algebra for the paper with Tsalmantza and making sanity plots of the GALEX data with Schiminovich. Our photometry looks good; time to send it to some of our users for testing.

Maryam Modjaz (Berkeley) gave a great seminar about what you can learn about GRB and SN progenitors from studies of host environments. She showed one of the cleanest results I have ever seen about this: If you look at SNe type Ic-BL (broad-line), the ones associated with prompt GRBs are very much lower in local metallicity (oxygen-indicated) than those not associated with GRBs. The non-GRB SNe type Ic-BL are higher in metallicity and don't show evidence for afterglows at late times. This all shows that there are no orphan afterglows (all the low-metallicity SNe type Ic-BL have prompt GRB emission) and therefore that the GRBs cannot be highly beamed. Strange! Of course these SNe-associated GRBs tend to be lower in total luminosity from typical GRBs, and this might be relevant. How big a deal is it if we find that GRBs are not beamed?

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