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Centro de Astrofísica da Universidade do Porto
Understanding star formation along interstellar filaments: prestellar core properties from HERSCHEL data

Pedro M. Palmeirim

Recent studies of nearby star-forming regions observed by the Herschel Space Observatory provided with an unprecedented view of the initial conditions of the early stages of star formation. In this seminar I will highlight some of the important results from the Herschel Gould Belt Survey and present a comprehensive study on interstellar dust Herschel observations of the most prominent star-forming filament located in the Taurus Molecular cloud. In this region, the Herschel images reveal the structure of the dense, star-forming filament B211/3 with unprecedented detail, along with the presence of striations perpendicular to the filament and generally oriented parallel to the magnetic field direction as traced by optical polarization vectors. The density structure of the B211/3 filament indicates that gravity is playing a dominant role, suggesting that the filament is gravitationally unstable to both radial contraction and fragmentation into cores. We further point out that the density and temperature structures of the B211/3 filament are consistent with a theoretical model of a cylindrical filament undergoing gravitational contraction. The analysis of these observations suggest that the B211/3 filament is radially contracting towards its long axis while at the same time accreting diffuse ambient gas, seemingly coupled with the magnetic field in the form of striations - consistent with existing kinematical constraints from previous CO observations. Using the Herschel dust emission maps of this field I reconstructed local volume density and dust temperature profiles for a sample of starless cores, using an inverse-Abel transform-based technique. The intrinsic radial dust temperature profiles allows us to disentangle the effect of temperature variations along the line of sight, which were previously limited to the radiative transfer calculations.

26 February 2015, 13:30

Centro de Astrofísica
Rua das Estrelas
4150-762 Porto

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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