The WEAVE-TwiLight-Survey: Expanding WEAVE's Reach to Bright and Low-Surface-Density Targets with a Novel Observing Mode

作者：Thomas Hajnik, N. A. Walton, G. D’Ago, P. Bonifacio, Gavin Dalton, Lilian Domínguez-Palmero, E. Gafton, Irwin, Mike J., Sergio Picó, David Terrett, Anke Arentsen, Rubén Sánchez-Janssen, David S. Aguado, J. A. L. Aguerri, Carlos Allende Prieto, M. Balcells, Chris Benn, A. Bragaglia, E. Caffau, Esperanza Carrasco, R. Carrera, S. Desidera, B. T. Gänsicke, Sarah Hughes, Shoko Jin, Ian Lewis, Alireza Molaeinezhad, D. N. A. Murphy, Ellen Schallig, S. C. Trager, A. Vallenari · 发表于：arXiv (Cornell University) · 年份：2025 · DOI：10.48550/arxiv.2511.21184 · 研究领域：Stellar, planetary, and galactic studies、Astronomy and Astrophysical Research、Astrophysics and Star Formation Studies

Current-day multi-object spectroscopic surveys are often limited in their ability to observe bright stars due to their low surface densities, resulting in increased observational overheads and reduced efficiency. Addressing this, we have developed a novel observing mode for WEAVE (William Herschel Telescope Enhanced Area Velocity Explorer) that enables efficient observations of low-surface-density target fields without incurring additional overheads from calibration exposures. As a pilot for the new mode, we introduce the WEAVE-TwiLight-Survey (WTLS), focusing on bright exoplanet-host stars and their immediate surroundings on the sky. High observational efficiency is achieved by superimposing multiple low-target-density fields and allocating the optical fibres in this configuration. We use a heuristic method to define fields relative to a central guide star, which serves as a reference for their superposition. Suitable guide fibres for each merged configuration are selected using a custom algorithm. Test observations have been carried out, demonstrating the feasibility of the new observing mode. We show that merged field configurations can be observed with WEAVE using the proposed method. The approach minimizes calibration times and opens twilight hours to WEAVE's operational schedule. WTLS is built upon the new observing mode and sourced from the ESA PLATO long-duration-phase fields. This survey will result in a homogeneous catalogue of approximately 6300 bright stars, inclu...