Thesis defense: "Collapse scenarios in magnetized star-forming regions"

By: Carmen Juárez Rodríguez (Dept. Física Quàntica i Astrofísica)   
 
Date/Time: 26/06/2017, 16:00
 
Director: J. Miquel Girart, Aina Palau
 
Tutor: R. Estalella 
 
Place: Sala de Graus Eduard Fontseré 
 
 
 
Abstract:
Turbulence, magnetic fields and gravity driven flows are important for the formation of new stars. Although magnetic fields have been proven to be important in the formation of stars, only a few works have been done combining magnetic field and kinematic information. Such studies are important to analyze both gravity and gas dynamics and be able to compare them with the magnetic field. In this thesis we will combine dust polarization studies with kinematic analysis towards different star-forming regions. The aim of this thesis has been to study the physical properties of dense cores (at scales < 0.1 pc) from molecular line and dust emission, and to study the role of the magnetic field in their dynamic evolution. For this, we have used millimeter and submillimeter observational data. 
 
The studies have been performed towards 3 different star-forming regions. The pre-stellar core FeSt 1-457, located in an isolated and magnetized environment in the Pipe nebula. The high-mass star-forming region NGC6334V, in a more advanced evolutionary state and in an environment surrounded by other massive star-forming regions. And L1287, a lower-mass region but with similar characteristics to NGC6334V, with presence of high-velocity gas and several centimeter and infrared sources. 
 
The studies of the pre-stellar core FeSt1-457 and the massive region NGC6334V, show how the magnetic field has been overcome by gravity and is not enough to avoid the gravitational collapse. In addition, NGC6334V and the lower-mass region L1287 present very similar scenarios with the material converging from large scales (~0.1 pc) to the potential wells of both regions at smaller scales (~0.02 pc) through two dense gas flows separated by 2-3 km/s. In a similar scenario, FeSt1-457 is located just in the region where two dense gas structures, separated by 3 km/s, appear to converge.