Measuring cosmic structure with supernovae
I present a method which allows measurement of weak-lensing effects in the supernova Hubble diagram using observed SN magnitudes only. Such signal can be used as a novel measurement of growth of structure, independently from traditional methods. I then show that current data already allows a consistency check and the first measurement of both sigma_8 and gamma (the modified gravity growth-rate index) using SN magnitudes alone. Although these first results are imprecise, future surveys will make this new method competitive and valuable.