Supernova Cosmology: Thirty Years of Watching Stars Blow Up

Data: 
21/06/2017 - 14:00 - 15:00
Local: 
Auditório IAG, Bloco G

Supernova Cosmology: Thirty Years of Watching Stars Blow Up

Nicholas B. Suntzeff

Texas A&M University


Starting in 1986, Mark Phillips, Mario Hamuy, and I began the study of the properties of nearby supernovae, and were the first to produce a light curve based on CCD data. With Jose Maza, in 1989, we began the concentrated study of nearby supernovae called the Calan/Tololo Survey, which led to discoveries including the establishment of Type Ia supernovae as standardizable candles, the deeper understanding of reddening and temperature effects in light curves and spectra, and with the HST calibration of distances to nearby host galaxies of these SNe, the modern value of the Hubble constant based on the quiet Hubble flow defined by supernovae. In 1994, Brian Schmidt and I founded the High-Z Supernova Team utilizing the Calán/Tololo results and MLCS techniques developed by Riess et al. The image subtraction software was developed by Schmidt and later Tonry. These techniques underlie the discovery by both the HZT and the Supernova Cosmology Project of Saul Perlmutter et al (who developed independent software) of the apparent accelerated expansion of the Universe. All these discoveries rest on the rickety photometric system astronomers have organically developed over the last 70 years. With the improvement in the fundamental calibration system led by HST astronomers, and a reanalysis of astronomical photometric techniques by Stubbs and Tonry, we now see the results of supernova cosmology are limited by the systematic errors in how we do photometry. We founded the Carnegie Supernova Project to create a new and precisely calibrated set of nearby supernovae to dig into these systematic effects and to anchor the acceleration results. In this talk, I will present the background of supernova cosmology and reveal the strengths and pitfalls of this field.