Polychronis Papaderos (Instituto de Astrofísica e Ciências do Espaço, CAUP, University of Porto)

FADO: a novel spectral population synthesis tool for the exploration of galaxy evolution by means of genetic optimization under self-consistency boundary conditions
When Jun 02, 2017 from 11:00 AM to 12:00 PM
What
  • Special Seminar
  • Colloquium
Where SH, Lecture hall
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Despite significant progress over the past decade, all current population spectral synthesis (PSS) codes suffer from two major deficiencies that limit their potential for gaining sharp insights into the star formation history (SFH) and chemical enrichment history (CEH) of star-forming (SF) galaxies, and potentially introduce substantial biases in studies of their physical properties (e.g., stellar mass, mass-weighted stellar age, specific SFR): i) the neglect of nebular continuum emission in spectral fits, consequently, ii) the lack of a mechanism that ensures consistency between the best-fitting SFH and the observed nebular emission characteristics (e.g., hydrogen Balmer-line luminosities and equivalent widths, shape of the continuum in the region around the Balmer and Paschen jump).

FADO (Fitting Analysis using Differential evolution Optimization; Gomes & Papaderos 2017, A&A, in press.; arXiv:1704.03922) is a conceptually novel, publicly available (www.spectralsynthesis.org) PSS code with the distinctive capability of permitting identification of the SFH and CEH that reproduce the observed nebular characteristics of a SF galaxy. This so far unique self-consistency concept allows us to significantly alleviate degeneracies in spectral synthesis, thereby opening a new avenue to the exploration of the assembly history of galaxies. FADO is the first PSS code employing genetic Differential Evolution Optimization. This, in conjunction with various other elements in its mathematical concept and numerical realization, results in key improvements with respect to computational efficiency and uniqueness of the best-fitting SFHs.