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Multi-filter galaxy surveys – Willliam Schoenel (UFRGS)
18 de abril de 2018: 12:30 - 13:30
The use of recent astronomical surveys and statistical techniques to answer questions about the composition of galaxies is shown by two different perspectives: the instruments needed to gather the data and the development of statistical tools to turn the observed data into physical properties of galaxies.
The first part is dedicated to describing the S-PLUS survey, a Local Universe survey, designed to study nearby galaxies in $12$ bands with an 80 cm telescope. Its design, installation, and commissioning are described as well how it is meant to map the sky autonomously every night. Then, we turn our attention to the data generated by these multi-band surveys, especially the ALHAMBRA and J-PAS surveys.
We show how the problem of the estimation of the photo-$z$ in the Universe is unfolded by the use of Bayesian statistics, where galaxies positions are described not by a single point estimator, but by a probability distribution function (PDF). Within the Bayesian photo-$z$ framework, we show a method for estimation of galaxy properties using the template-redshift PDFs given by photometric redshift codes as, for example, the BPZ code.