ORCID Profile
0000-0002-1323-9788
Current Organisation
KU Leuven
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Publisher: American Astronomical Society
Date: 22-06-2015
Publisher: EDP Sciences
Date: 08-04-2016
Publisher: EDP Sciences
Date: 16-01-2015
Publisher: SPIE
Date: 03-01-2020
DOI: 10.1117/12.2541364
Publisher: EDP Sciences
Date: 06-2010
Publisher: SPIE
Date: 09-07-2018
DOI: 10.1117/12.2314426
Publisher: EDP Sciences
Date: 19-12-2016
Publisher: EDP Sciences
Date: 03-2023
DOI: 10.1051/0004-6361/202244351
Abstract: Context . NOTT (formerly Hi-5) is a new high-contrast L ′ band (3.5–4.0 µm) beam combiner for the VLTI designed with an ambitious aim to be sensitive to young giant exoplanets down to 5 mas separation around nearby stars. The performance of nulling interferometers in these wavelengths is affected both by fundamental noise from the background and contributions of instrumental noise. This motivates the development of end-to-end simulations to optimize these instruments. Aims . The aim of this study is to enable a performance evaluation of NOTT and inform the design of such instruments with current and future infrastructures in mind, taking into account the different sources of noise and their correlation. Methods . SCIFYsim is an end-to-end simulator for single-mode-filtered beam combiners, with an emphasis on nulling interferometers. We use it to compute a covariance matrix of the errors. We then use statistical detection tests based on likelihood ratios to compute compound detection limits for the instrument. Results . With the current assumptions as to the performance of the wavefront correction systems, the errors are dominated by correlated instrumental errors down to stars of magnitude 6–7 in the L band, beyond which thermal background from the telescopes and relay system becomes dominant. Conclusions . SCIFYsim is suited to anticipating some of the challenges of design, tuning, operation, and signal processing for integrated-optics beam combiners. The detection limits found for this early version of NOTT simulation with the unit telescopes are compatible with detections at contrasts up to 10 5 in the L band at separations of 5–80 mas around bright stars.
Publisher: EDP Sciences
Date: 02-2022
DOI: 10.1051/0004-6361/202142375
Abstract: Context. There is currently a niche for providing high-cadence, high resolution, time-series optical spectroscopy from space, which can be filled by using a low-cost cubesat mission. The Belgian-led ESA/KU Leuven CubeSpec mission is specifically designed to provide space-based, low-cost spectroscopy with specific capabilities that can be optimised for a particular science need. Approved as an ESA in-orbit demonstrator, the CubeSpec satellite’s primary science objective will be to focus on obtaining high-cadence, high resolution optical spectroscopic data to facilitate asteroseismology of pulsating massive stars. Aims. In this first paper, we aim to search for pulsating massive stars suitable for the CubeSpec mission, specifically β Cep stars, which typically require time-series spectroscopy to identify the geometry of their pulsation modes. Methods. Based on the science requirements needed to enable asteroseismology of massive stars with the capabilities of CubeSpec’s spectrograph, we combined a literature study for pulsation with the analysis of recent high-cadence time-series photometry from the Transiting Exoplanet Survey Satellite (TESS) mission to classify the variability for stars brighter than V ≤ 4 mag and between O9 and B3 in spectral type. Results. Among the 90 stars that meet our magnitude and spectral type requirements, we identified 23 promising β Cep stars with high- litude (non-)radial pulsation modes with frequencies below 7 d −1 . Using further constraints on projected rotational velocities, pulsation litudes, and the number of pulsation modes, we devised a prioritised target list for the CubeSpec mission according to its science requirements and the potential of the targets for asteroseismology. The full target catalogue further provides a modern TESS-based review of line profile and photometric variability properties among bright O9–B3 stars.
Publisher: SPIE
Date: 03-01-2020
DOI: 10.1117/12.2541317
No related grants have been discovered for Gert Raskin.