Bibcode
Sánchez-Gil, M. C.; Alfaro, Emilio J.; Cerviño, M.; Pérez, Enrique; Bland-Hawthorn, Joss; Jones, D. Heath
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 483, Issue 2, p.2641-2670
Fecha de publicación:
2
2019
Número de citas
2
Número de citas referidas
2
Descripción
One of the fundamental goals of modern astrophysics is to estimate the
physical parameters of galaxies. We present a hierarchical Bayesian
model to compute age maps from images in the H α line (taken with
Taurus tunable filter, TTF), ultraviolet band (GALEX far UV, FUV), and
infrared bands (Spitzer 24, 70, and 160 μm). We present the burst
ages for young stellar populations in a sample of nearby and nearly
face-on galaxies. The H α to FUV flux ratio is a good relative
indicator of the very recent star formation history (SFH). As a nascent
star-forming region evolves, the H α line emission declines
earlier than the UV continuum, leading to a decrease in the H
α/FUV ratio. Using star-forming galaxy models, sampled with a
probabilistic formalism, and allowing for a variable fraction of
ionizing photons in the clusters, we obtain the corresponding
theoretical ratio H α/FUV to compare with our observed flux
ratios, and thus to estimate the ages of the observed regions. We take
into account the mean uncertainties and the interrelationships between
parameters when computing H α/FUV. We propose a Bayesian
hierarchical model where a joint probability distribution is defined to
determine the parameters (age, metallicity, IMF) from the observed data
(the observed flux ratios H α/FUV). The joint distribution of the
parameters is described through independent and identically distributed
(i.i.d.) random variables generated through MCMC (Markov Chain Monte
Carlo) techniques.