SIMTERFERE: An optical interferometry simulator for quantifying the coherent flux stability of VLTI/GRAVITY+. Reaching per mill stability: Application to exoplanet spectroscopy
Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Fakultät für Physik und Astronomie, Universität Heidelberg（海德堡大学物理与天文学学院）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理学研究所）；I. Physikalisches Institut, Universität zu Köln（科隆大学第一物理研究所）
J. R. Sauter, A. von Stauffenberg, G. Bourdarot, W. Brandner, F. Eisenhauer, L. Kreidberg, L. Labadie, S. Scheithauer, D. Trevascus, R. van Boekel
备注：
14 pages, 13 figures. Accepted for publication in Astronomy & Astrophysics (A&A)
The implementation of the GRAVITY+ Adaptive Optics (GPAO) system at VLTI enables unprecedented sensitivity and stability in optical interferometry. This allows high-precision characterization of directly imaged exoplanets at medium spectral resolution, providing a new pathway for studying planetary atmospheres. We aim to quantify and characterize the short- and long-term stability of GRAVITY+ through a consecutive seven-hour observation of the bright and stable star beta Pictoris, providing a benchmark for future exoplanet observations. We developed SIMTERFERE, a data-driven simulation tool that reproduces GRAVITY+ on-star observations using ancillary instrument and telemetry data. By comparing the simulations with the measured coherent fluxes, we traced the origins of systematic flux variations and assessed their impact on exoplanet contrast measurements. We find that the approximately 10% variations are dominated by throughput changes driven by variable fiber coupling, which depends on wavefront stability, atmospheric dispersion, and residual fiber offsets. These variations appear as smooth continuum changes across wavelength and can be effectively mitigated using second-order polynomial corrections. After removing these instrumental effects, the remaining approximately 1% variations are almost purely of telluric origin, which we can reliably correct down to the photon-noise limit (0.1% precision) using a contrast spectrum approach with linear airmass interpolation. The GRAVITY+ inferometric instrument is highly stable: low-order continuum and telluric variations can be corrected with high precision, making it uniquely capable of high-fidelity characterization of directly imaged exoplanets.
Asgard/NOTT: L-band nulling interferometry at the VLTI -- III. The mid-infrared integrated optics beam combiner for NOTT
I. Physikalisches Institut der Universität zu Köln（科隆大学第一物理研究所）；Department of Physics & Astronomy, University of California, Los Angeles（加州大学洛杉矶分校物理与天文学系）；Institute of Astronomy, KU Leuven（鲁汶大学天体物理研究所）
Towards an Extended VLTI: Turbulence Characterization for Kilometer-Scale Optical Links at Paranal
Aix Marseille Univ, CNRS, CNES, LAM（艾克斯马赛大学）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理研究所）；Pontificia Universidad Católica de Valparaíso（天主教瓦尔帕莱索大学）；DOTA, ONERA, Université Paris Saclay（巴黎萨克雷大学）；Apical Technologies（阿皮卡尔科技公司）；INAF - Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所）
The mid-infrared spectrum of $β$ Pictoris b. First VLTI/MATISSE interferometric observations of an exoplanet
Univ. Côte d'Azur, Observatoire de la Côte d'Azur（蔚蓝海岸大学，蔚蓝海岸天文台）；Univ. Grenoble Alpes（格勒诺布尔阿尔卑斯大学）；LESIA, Observatoire de Paris（天体物理与星际介质实验室，巴黎天文台）；European Southern Observatory（欧洲南方天文台）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Institute of Astronomy, Univ. of Cambridge（剑桥大学天文研究所）；Université Paris-Saclay（巴黎萨克雷大学）；Johns Hopkins Univ.（约翰斯·霍普金斯大学）；Space Telescope Science Institute（太空望远镜科学研究所）；Leiden Univ.（莱顿大学）；Univ. of Exeter（埃克塞特大学）；University of Amsterdam（阿姆斯特丹大学）；Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, HUN-REN（孔科利天文台，匈牙利研究与教育网络地球与天文学研究中心）；Aix Marseille Univ.（艾克斯-马赛大学）；Northwestern Univ.（西北大学）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）
VLTI/MATISSE observations of the hot dust around $β$ Pictoris: Observing faint objects with MATISSE
Univ. Grenoble Alpes, CNRS, IPAG（格勒诺布尔阿尔卑斯大学）；Univ. Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange（蔚蓝海岸大学，蔚蓝海岸天文台）；Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, HUN-REN（孔科利天文台，地球与天文学研究中心）；CSFK, MTA Centre of Excellence（匈牙利科学院天文学研究所，MTA卓越中心）；Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）
Pushing high angular resolution and high contrast observations on the VLTI from Y to L band with the Asgard instrumental suite: integration status and plans
