THE ENERGY, VELOCITY AND MAGNETIC FIELD STRUCTURE OF PROTOSTELLAR SOURCES IN POETS SURVEY

• Grant number: 25/12637-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2025
• End date: May 31, 2029
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Ciriaco Goddi
• Grantee: Elis Cristina Silva Sales
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 21/01183-8 - Astrophysical jets at the highest-angular resolution with very long baseline interferometry, AP.JP

Abstract

Outflows from high-mass young stellar objects (HMYSOs) are key components of high-mass star formation (HMSF), but the mechanisms responsible for launching and shaping these flows remain poorly constrained. Competing models - such as magneto-centrifugal disk winds, ionization-driven outflows, and radiation pressure - predict different morphologies, velocity structures, and magnetic field configurations. To test these models, this PhD project will investigate the physical and magnetic properties of jets from HMYSOs, using a multi-scale, multi-wavelength observational approach. Focusing on a sample of sources from the POETS survey, together with a few additional well-studied targets, the project will combine high-sensitivity Karl G. Jansky Very Large Array (VLA) observations, Very Long Baseline Interferometry (VLBI) of masers, and Atacama Large Millimeter/submillimeter Array (ALMA) spectral-line imaging. A primary goal is to build complete radio spectral energy distributions (SEDs) from S to Q band (2-45 GHz), allowing the separation of thermal and non-thermal components and the identification of synchrotron emission. Polarization measurements and Zeeman splitting of maser lines (\wat and CH$_3$OH) will be used to map magnetic field orientation and strength. VLBI proper motions of maser spots will trace the 3D kinematics near the jet base. Complementary ALMA observations of CO and SiO lines will probe molecular outflow structure and dynamics. By analyzing sources with existing high-resolution data and expanding to a larger sample, this project will provide new constraints on jet-launching mechanisms in massive protostars. The results will also serve as a pathfinder for future polarization surveys with next-generation instruments like the ngVLA and Square Kilometre Array (SKA). (AU)