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Understanding star-formation along filaments and the impact of HII regions

Pedro M. Palmeirim

In this seminar I will present the highlights of my previous research work, focusing mostly on Herschel submilimeter data.
During the first part of the seminar I will discuss the importance of the role of filamentary structures in the star-formation process. In particular, I will present the comprehensive study on interstellar dust Herschel observations of the most prominent star-forming filament located in the B211/3 region of the Taurus Molecular cloud.
I will also present a method we developed to take into account the problem of dust temperature variations along the line-of-sight that affects the optically thin dust emission in the Herschel data, allowing to reconstruct local volume density and dust temperature profiles of prestellar cores, which were previously limited to the radiative transfer calculations.
In a second part, I will discuss the impact of HII regions on the star-formation process by presenting a comprehensive statistical analysis of ~100 000 star-forming objects at different evolutionary stages (from prestellar objects to more evolved YSOs), detected in both Hi-GAL and GLIMPSE surveys, and located in the vicinity of 1360 HII ionizing bubbles throughout the Inner Galactic Plane. Surface density maps reveal for the first time a clear evolutionary gradient, where more evolved star-forming sources are found close to the center of the bubbles, and newly formed prestellar and protostellar clumps are found at the edges of the bubbles. We estimate that nearly 1/4 of stars may be formed in these environments and argue for the possibility of acceleration of the star-formation process cause by the feedback of the (HII) bubbles.

2017 January 11, 13:30

Centro de Astrofísica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto

Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia