Thesis

Star formation in the most massive star clusters in the Galaxy with cutting edge, multi-wavelength observations

• Call:

  IDPASC Portugal - PHD Programme 2016

• Academic Year:

  2016 / 2017

• Domain:

  Astrophysics

• Supervisor:

  Paulo Garcia

• Co-Supervisor:

  Joana Ascenso

• Institution:

  Universidade do Porto

• Host Institution:

  CENTRA - Centro Multidisciplinar de Astrofisica

• Abstract:

  Star formation across the Universe occurs mainly in massive stellar clusters forming at the densest and coldest regions of giant molecular clouds. This mode of star formation has a significant impact on a wide range of scales, from local effects on the evolution of protoplanetary disks and local ISM, to global effects that affect the populations and evolution of galaxies. Yet, we know very little on why the clustered mode is the one favoured by nature, and on how the star formation process develops and is regulated over the relevant timescales. Two factors contribute to this: a) there are too few comprehensive observational studies of massive stellar clusters, and b) theory and simulations are difficult to undertake due to the large dynamic range of the physical variables envolved (density, size) and because radiative feedback in a highly structured ISM is very challenging to model. The most fruitful way to make progress in the field is to characterise consistently a statistically significant sample of massive clusters using observational data from instruments on world-class observatories, to be able to constrain the properties of the emerging stellar clusters in the context of their molecular clouds. This PhD thesis proposes to advance the current state-of-the-art by combining a survey of deep, high-resolution, near-infrared and infrared observations of massive young stellar clusters (ages 1-5 Myr) with ancillary ESA Herschel, Planck and sub-milimiter data, ensuring the characterisation of the young stellar population as well as the properties of the molecular clouds from which the clusters formed. This approach enables a global and detailed understanding of massive star forming regions in the Galaxy resulting in a robust study of all the properties that are critical to guide and constrain our understanding of clustered star formation: cluster ages and age spreads, initial stellar mass function, protoplanetary disk evolution in massive clusters, impact of early supernovae, cluster and gas dynamical state, and cluster dispersal into the galactic field. Ultimately, the foreseen characterization of the most massive clusters in the Galaxy will provide crucial constraints to the impending generation of theoretical and numerical models. Technically, besides handling multi-wavelength data, the student will use adaptive-optics data in depth, acquiring essential expertise for the new and upcoming generations of telescopes and instruments. This is a considerable added value to this project since all world-class observatories, such as ESO’s VLT and all the foreseen extremely large telescopes, will have adaptive-optics assisted instruments as default starting in the near future. The applicant will also collect and analyse cutting-edge observations from one of the newest VLT instruments, the Multi Unit Spectroscopic Explorer (MUSE), combining the characterisation of stellar spectral energy distributions with visible line emission diagnostics of the stellar cluster population and associated ionized gas, adding important skills of spectral analysis to his or her experience. The applicant should have an interest in observational astronomy, ideally with scripting/ programming and statistics skills. The applicant should be available for observing runs in leading edge observatories and missions with collaborating institutions (CENTRA and João Alves lab at University of Vienna).