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Data driven modelling of the distribution of young stars observed by the ESA Gaia mission
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Orientador(es)
Resumo(s)
The Gaia mission represents a significant milestone in the study of the three-dimensional structure
of the Milky Way and its properties, by providing astronomers with a massive catalog of unprecedented
quality and quantity of data, and which cannot be efficiently explored using traditional data analysis tools.
In this work, we use astrometry and photometry from Gaia DR3 to select a sample of young and bright
stars and map its spatio-kinematic distribution in the Galactic disk. We further improve on the sample
by studying the Gaia colour-magnitude diagrams and applying a linear regression model to remove
contaminating sources. Then, by employing a bivariate kernel density estimator, we produce density
maps for the sample that illustrate the spatial distribution of over- and under-dense regions on the Galactic
disk. The resulting map show resolved spiral structure features, including a diffuse Perseus arm toward
the third galactic quadrant, an extension of the Local Arm past the position of the Sun, and the indication
for the bifurcation in the Carina-Sagittarius arm, dividing the arm into two segments. To validate the
integrity of our results, we assessed the methods used to select and represent the sample, and determined
that no significant observational biases had been introduced. We proceeded to compare the spiral arms
revealed by our maps with the distribution of interstellar dust in our Galaxy and previous models from
the literature that use different tracers of spiral structure, and found further evidence to support the
bifurcation of the Carina-Sagittarius arm and the dying nature of Perseus on the third quadrant. Finally,
the kinematic maps for the sample demonstrate that the global pattern of the velocity fields of the young
stars shows no significant correlation with the spiral arm structure, except for the residuals of VΦ, which
aligns with the Local and Carina-Sagittarius arms.
Descrição
Tese de Mestrado, Engenharia Física, 2023, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
Missão Gaia Estrutura espiral Estrelas jovens e luminosas Mapas espaciais e cinemáticos Teses de Mestrado - 2023