The wide-field, multiplexed, spectroscopic facility 
WEAVE
WEAVE is the new wide-field, massively multiplexed spectroscopic survey facility for the William Herschel Telescope. First light with LIFU has been in late 20221 , while full operation is planned to start in August 20232. WEAVE has a 2-degree field-of-view, a nearly 1000-multiplex fibre positioner, 20 individually deployable ‘mini’ integral field units (IFUs), and a single large IFU. The fibres feed a dual-beam spectrograph covering the wavelength range 366−959 nm at ∼ 5000, or two shorter ranges at ∼ 20 000. The WEAVE instrument is used for 70% of the time by the ‘WEAVE Survey’ for 5 to 7 years. A paper describing the instrument and the planned science is Jin, Trager, Dalton, et al. (2023)
The WEAVE Consortium covers both Galactic and extragalactic science and is organized in 8 individual surveys. In particular, the Galactic group intends to: (i) study our Galaxy’s origins by completing Gaia’s phase-space information, providing metallicities to its limiting magnitude for ∼3 million stars and detailed abundances for ∼ 1.5 million brighter field and open-cluster stars [WEAVE-Galactic Archaeology, comprising also the GA-Open Clusters sub-survey]; (ii) survey ∼ 0.4 million Galactic-plane OBA stars, young stellar objects and nearby gas to understand the evolution of young stars and their environments [SCIP]; (iii) perform an extensive spectral survey of white dwarfs [WD]. Within WEAVE-GA we are also involved in the study of local dwarf spheroidal galaxies, with special emphasis on the characterisation of the binary stars population by means of radial velocity time series.
INAF is part of the Consortium in many surveys. In particular, RSN2 researchers at OAS involved in WEAVE are3: Michele Bellazzini (GA); Angela Bragaglia (co-lead of the GA-Open Cluster survey); Ricardo Carrera (Survey Working Group, GA-OC); Gisella Clementini (RR Lyrae); Emanuele Dalessandro (GA-OC); Davide Massari (High-latitude, dwarf galaxies); Donatella Romano (GA, chemical evolution); Monica Tosi (GA). Involved at DIFA UniBO: A. Mucciarelli, A. Miglio, C. Nipoti
1 https://www.ing.iac.es/PR/press/weave_LIFU_first_light.html
2 Inauguration is 30 October 2023 (https://www.ing.iac.es/weave_inauguration/ )
3 Antonio Sollima was part of the Consortium
Figure 1 – Example of a configured MOS field