Thermonuclear supernovae and cosmology⋆

Bright and homogeneous, thermonuclear, or type Ia, supernovae (SNeIa) are our best extragalactic distance indicators. Since the 60s, SNeIa have been used as cosmological tools, initially, to estimate the current expansion rate of the Universe, the Hubble constant. Decades ago SNeIa were discovered by chance, in many cases by amateurs. Advances in the instrumentation, techniques and new observational strategies allowed in the 80s to discover SNe in scheduled surveys. Moreover, through calibration relations, a high precision in extragalactic distance determinations was achieved, allowing SNIa observations to reveal the dynamics of the Universe. The Nobel prize in Physics in 2011 was awarded to the leaders of two independent teams “for the discovery of the accelerating expansion of the Universe through observations of distant supernovae”. This is a brief and incomplete story of SNeIa as cosmological tools. In the Madrasah of Granada (Spain), built in 1349 by the Nasrid monarch Yosuf the 1st, Astronomy was one of the disciplines included in the studies. On the Madrasah walls, a calligraphic decoration reads: “make study shine like stars”. It is a good motto for our 4th Azarquiel School of Astronomy.