Postdoc I. Probing the magnetospheric accretion/ejection region of young stars with long baseline interferometry
The interaction region between the inner disk and the star where magnetospheric accretion takes place extends a few stellar radii above the stellar surface, amounting to less than 1 mas on the sky. Recent advance in long baseline interferometry, most notably thanks to the ESO VLTI/GRAVITY instrument, now enables to directly probe this region (e.g. Bouvier et al. 2020; Garcia-Lopez et al. 2020). IPAG has a unique expertise in high-angular resolution imaging, has contributed to the construction of GRAVITY and is co-I of the GRAVITY+ project, co-leads the GRAVITY YSO group for the exploitation of the GTO, and includes world-leading experts of interferometric techniques. The postdoctoral position aims at exploiting the spectro-astrometric capabilities of VLTI/GRAVITY to study the accretion/ejection process in young stellar objects. The work will involve interferometric data analysis, in close collaboration with local experts (K. Perraut). It will also include the exploitation of radiative transfer models of the star-disk interaction region being currently developed at IPAG, to compute interferometric quantities (visibilities, differential phases) on synthetic images to be directly confronted to observations. All these studies will be crucial to prepare for the future GRAVITY+ observations of YSOs. Experience in interferometric data analysis is required and expertise in numerical modeling is welcome.
Postdoc II. Innovative methods for time series analysis of the light curves of young stars.
Tremendous progress has been made in characterizing the photometric variability of young stars, thanks to continuous light curves provided by space missions (e.g. Kepler/K2, TESS, etc.). Of these, the so-called dippers (e.g., Cody et al. 2014) offer a direct window onto physical processes operating close to the star, including disk warps, dusty inner disk winds, and magnetospheric funnel flows. Up to now, the photometric time series have been submitted to conventional period-search algorithms (e.g., periodogram, wavelet transform). The goal of the proposed postdoctoral position is to go further in the analysis of the shape and temporal evolution of the light curves of young stars by applying innovative algorithms (e.g., DTW) and/or new approaches provided by AI. Applicants are expected to have a strong background in time-series analysis, including knowledge of innovative algorithms that may be relevant to the considered datasets. Experience in astronomical or physical time series is desirable but not mandatory.