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arXiv2026

XuYi Interferometer Observation Simulator

The XuYi Interferometer is the first Chinese long-baseline optical interferometer currently under development by the National Institute of Astronomical Optics and Technology (NIAOT) of the Chinese Academy of Sciences. In preparation for future scientific operations, we developed the XuYi Interferometer Observation Simulator (XIOS), a lightweight MATLAB-based software package designed to assist observers in planning interferometric observations. The simulator combines target observability calculations, interferometric baseline geometry, delay-line constraints, (u,v)-coverage prediction, and visibility estimation into a single graphical user interface. It incorporates astronomical routines from the MAAT toolbox and adopts visualization concepts inspired by ASPRO2. The software allows users to evaluate observing opportunities, predict interferometric performances, and generate realistic observing configurations before telescope operations. We present the architecture of the simulator, its principal modules, and representative simulation results obtained for the current three-telescope XuYi interferometric configuration operating in the near-infrared H band.

astro-ph.IM↗

arXiv2022

Application limit of the photocentre displacement to fundamental stellar parameters of fast rotators -- Illustration on the edge-on fast rotator Regulus

Differential Interferometry allows to obtain the differential visibility and phase, in addition to the spectrum. The differential phase contains important information about the structure and motion of stellar photosphere such as stellar spots and non-radial pulsations, and particularly the rotation. Thus, this interferometric observable strongly helps to constrain the stellar fundamental parameters of fast rotators. The spectro-astrometry mainly uses the photocentre displacements, which is a first approximation of the differential phase, and is applicable only for unresolved or marginally objects. We study here the sensitivity of relevant stellar parameters to the simulated photocentres using the SCIROCCO code: a semi-analytical algorithm dedicated to fast rotators, applied to two theoretical modeling stars based on Achernar and Regulus, in order to classify the importance of these parameters and their impact on the modeling. We compare our simulations with published VLTI/AMBER data. This current work sets the limits of application of photocentre displacements to fast rotators, and under which conditions we can use the photocentres and/or the differential phase, through a pre-established physical criterion. To validate our theoretical study, we apply our method of analysis on observed data of the edge-on fast rotator Regulus. For unresolved targets, with a visibility $V\sim 1$, the photocentre can constrain the main stellar fundamental parameters of fast rotators, whereas from marginally resolved objects ($0.8 \leq V < 1$), mainly the rotation axis position angle ($\rm PA_{\rm rot}$) can be directly deduced from the vectorial photocentre displacement, which is very important for young cluster studies.

astro-ph.SR↗