2 Postdoc positions at KU Leuven, Belgium: massive binaries & stellar winds

The project

Throughout the Universe, the dynamics and chemical evolution of spiral galaxies like our Milky Way are largely controlled by the lives and deaths of stars with masses many times that of the Sun. The evolution of these massive stars, in turn, is highly regulated by their multiplicity and by the mass and angular momentum exchanged through binary interaction, and by the huge amounts of mass expelled from their surfaces by means of powerful starlight-driven wind outflows. These fundamental properties critically determine how these massive stars live and die and control the nature and properties of the compact remnants – neutron stars and black holes – that are left behind. In close binaries, these compact objects may merge, producing intense bursts of gravitational waves (GW) that can be detected by current interferometers. In this broad context, various large observational, theoretical and instrumental projects have been undertaken at KU Leuven to obtain new constraints on the evolution of gravitational wave progenitors and to pave the way towards even more sensitive GW observations by future ground-based and spaceborne GW interferometers.

Led by 4 academic members of the Institute of Astronomy at KU Leuven (Decin, Sana, Sundqvist, de Koter), the MAESTRO project aims to fundamentally improve our understanding of the driving mechanism of massive star winds, both hot and cool by bridging the theoretical, computational, and observational KU Leuven’s expertise in the field of stellar winds. Members of MAESTRO team are heavily involved in the (XSH)ULLYSES collaboration, aiming at further our understanding of hot star winds through the analysis of a large representative sample of UV-optical spectroscopy of massive stars at different metallicity environments.

The ERC-CoG MULTIPLES project (PI: Sana) aims at constraining the multiplicity properties of massive stars across their entire life cycle, as well as to investigate the origin of close massive binaries and to characterize the nature and frequency of post-interaction products in populations of massive stars through multi-techniques observations of massive stars. This specific call will focus on optical spectroscopy acquire through various facilities as well as on a possible kick off of the Magellanic Clouds MultiEpoch 4MOST public survey (proposal submitted), which aims at obtaining systematic multiplicity statistics of intermediate- and high-mass stars in the Magellanic Clouds.

The Vacancies

Through an ERC-CoG and other fundings, the KU Leuven Institute of Astrophysics is advertising 4 PhD and 2 Postdoc positions. The selected candidates will join the broad KU Leuven’s effort to unravel the physics and evolution of gravitational wave progenitors as part of an international network of collaborators. The funding for these 6 positions is already secured, but more positions may be available depending on the interest and quality of the applicants, and on the results of upcoming funding applications. Only the postdoctoral positions are descred here.

The winds of hot massive stars through quantitative UV-optical spectroscopy (1 PhD and 1 PD): The selected PD and PhD candidates will join the effort of the MAESTRO team (Decin, Sundqvist, Sana, de Koter) in the analysis and interpretation of high-quality UV and optical observations collected in the framework of the (XSH)-ULLYSES project to characterize atmospheric and wind properties of massive stars in different metallicity environments. The selected candidates will pay particular attention to the surface abundances and the geometrical and dynamical wind properties of these stars using state-of-the-art retrieval methods currently developed at KU Leuven and Amsterdam. The final goal will be to study the morphology and mass-loss evolution of their winds. Theoretically inclined candidates with interest in developing atmosphere models and/or retrieval methods are welcome to apply as well.

The multiplicity of massive stars (1 PhD and 1 PD): The selected candidates will join the team of Prof Sana on spectroscopic analysis of population of massive stars in the framework of the ERC-CoG MULTIPLES project. Tasks encompass among other: collect, reduce and/or organize multi-wavelength datasets covering hot massive stars across range of metallicity environments, develop, use and/or adapt the necessary quantitative techniques to analyze and interpret large amount of spectroscopic data, retrieve the underlaying properties of populations of single and binary stars and to unravel their evolutionary history, including strong involvement in the 4MOST Magellanic Clouds Multiplicity Campaign (if approved). Theoretically or computationally inclined candidates with interest in binary evolution, retrieval methods and/or statistical analysis of large samples are welcome to apply as well.

The Host Institute

The Institute of Astronomy (IoA) of Leuven University in Belgium is a young and vibrant research group of some 80 scientists, engineers, and administrative staff (fys.kuleuven.be/ster), including 6 full-time and 3 part-time professors. The institute is an expertise center in stellar physics and is active in several international consortia and collaborations, involving telescopes at observatories worldwide and in space. Members of IoA have access to parallel computing facilities at Leuven University. The IoA is responsible for the organization of the 2-year Master in Astronomy & Astrophysics of the Faculty of Science and owns the 1.2m Mercator telescope at Roque de los Muchachos, La Palma Observatory, Canary Islands. The institute has a long tradition in instrumental, observational, and theoretical studies of stellar evolution.

Requirements and Instructions to Apply

PhD applicants must hold a M.Sc. degree in physics, astrophysics or mathematics or else own an equivalent diploma. The degree must be dated at the latest one month before the position can be taken up. For PhD students. Expertise in astrophysics is an asset but not a requirement. Similarly, prior expertise in stellar evolution, stellar winds, binaries and/or instrumentation is an asset but not a requirement.

Post-doc applicants must hold a PhD in astrophysics, or an equivalent diploma. The ideal candidates will have a strong observational and data analysis background, including expertise relevant for the projects they are applying to. This encompass but is not limited to spectroscopic analysis of massive single and/or binary stars, spectral disentangling, atmosphere analysis and/or expertise with relevant codes such as CMFGEN, FASTWIND, POWR, or equivalent codes. Prior-experience with UV, optical and/or IR observations and facilities such as the HST, ESO/VLT (Xshooter, Uves, Sphere, Muse, KMOS, …), or JWST, or similar facilities, or relevant modelling or theoretical background will be viewed positively by the selection committee. Proficiency in English is required. The application package should include:

• a curriculum vitae, with a publication list if relevant.
• a statement of interest (max. 2 pages);
• a summary of the research experience (max. 3 pages text and up to 2 pages of figures)

Applicants must also provide the names and contact details of two reference persons who would be prepared to send confidential recommendation letters should they be requested to do so. The selection committee will send out requests for such letters for those applicants on the short-list after an initial ranking. The short-listed applicants will be invited for an interview (to be hold through videoconference or in presence depending on the geographical constraints and sanitary conditions). The selection committee will start reviewing the application on April 04, 2021 and will continue until positions are filled.

How to apply: Applications should be sent through the KU Leuven job portal at the latest by April 04, 2021 following the instructions thereby (in case of slightly different instructions, those of the Job Portal supersede the ones described iher). Links to access the KU Leuven job portal as well as other PhD and/or PD offers can be found at https://fys.kuleuven.be/ster/vacancies .

Further information on the positions and on the projects may be obtained by contacting Prof. Hugues Sana, by email ([email protected]) or phone (+32-16-37.43.61), or any other promotor of these projects (jon.sundqvist /  leen.decin @ kuleuven.be, [email protected]).

Member of minorities and underrepresented groups are strongly encouraged to apply.