Lorentz Center - WoW: the Week of WEAVE from 28 Nov 2016 through 2 Dec 2016
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    WoW: the Week of WEAVE
    from 28 Nov 2016 through 2 Dec 2016


WoW: the Week of WEAVE

November 28 December 2, @Snellius


The Week of Weave took place November 28 through December 2nd 2016 and thanks to the support of the Lorentz Center @Snellius. The week was divided into a first phase gathering the Galactic Archaeology team responsible for the WEAVE survey of our Galaxy as a complement to Gaia (WEAVE-GA), followed by a 1-day meeting of the WEAVE Survey Working Group.


A)    WEAVE Galactic Archaeology Surveys: (November 28 through December 1st).

Around 25 people were present throughout the meeting, gathering core WEAVE-GA team members, as well as different actors of the project (WEAVE Principal Investigator, Project Scientist, and leads of work-packages with direct impact on the WEAVE-GA survey planning such as data reduction systems, archiving, etc.). The meeting started with a full day in plenary session, with presentations of the different sub-surveys, science cases, and systems, while the three following days had a mixture of shorter plenary sessions or discussions, and ample time for discussions and hands-on work in smaller subgroups (making extensive use of the different Snellius working areas). At the end of each day we had a short summary of these splinter sessions as a plenary group.


As a result, we have made significant progress towards the expected goals of the meeting, that we outline below:


1) To complete the design and target selection of the WEAVE-GA survey in the light of Gaia DR1


The WEAVE surveys rely on the delicate task of designing and implementing a target selection as simple as possible (i.e. that can be reproduced easily and reliably in models) while aiming at efficiency (maximizing the number of targets of interest). This is mandatory to ensure that the obtained WEAVE-GA spectroscopic samples lead to sound interpretations when compared to models. This delicate task for GA relies on using various ancillary data for target selection: multi-colour photometric surveys (e.g. SDSS, Pan-STARRS, VPHAS, IPHAS) and for the first time in planning a spectroscopic survey, Gaia itself (photometric and astrometric Gaia measurements). The first Gaia data were released September 14th 2016, offering: i) stellar positions (α, δ) and G magnitudes for all stars with acceptable formal standard errors on positions; ii) the five-parameter astrometric solution - positions, parallaxes, and proper motions - for stars in common between the Tycho-2 Catalogue and Gaia. Although the WEAVE-GA surveys will need Gaia DR2 (five-parameter astrometric solutions for all stars in the Gaia limiting magnitude range), DR1 has allowed us to build up a much better understanding of what can be expected for DR2.


The meeting has allowed the various WEAVE-GA sub-surveys to be brought to a homogeneous level of readiness; the surveys definition were solidified to a much higher level of readiness (i.e. target selection functions solidified including the Gaia data). This would not have been achieved without the extensive discussions within and across the various sub-teams allowed by the format and length of the meeting@Snellius.


2) To ensure the proper degree of communication and discussions within the WEAVE-GA science team:

Beyond the target selection milestone outlined above, for good progress, regular face-to-face meetings of the WEAVE-GA steering group are mandatory in addition to the telecons held by the group every two weeks. The other on-going issues that will be discussed at the meeting within the group include:


i.              Discussions/actions of sub-surveys interfaces and communalities

ii.             Discussions/actions of the WEAVE-GA team with the WEAVE Core Processing System (CPS, data reduction) and Advanced Processing System (APS, classification and analysis) and the archive team (WAS).


The meeting has reached completely both these goals. With the second goal, we even went further than what we had set out to achieve, leading to a much tighter relation of the WEAVE-GA science team with the more project-driven activities of CPS/APS/WAS. On this chapter, one can note in particular: a change in the chart and responsibilities within the project to charge the science teams with a new role in quality assessment of the surveys and data; the goals of the next Operational Rehearsal planned within the project were also enlarged to best fulfil also the needs of the science teams in terms of simulated performances. Both these significant changes (improvements) in the interactions between science teams and the technical side of the project would not have been possible without the meeting @Snellius, and will benefit the project far beyond the Galactic Archaeology part of the science team.


B)    Survey Working Group Day (December 2nd)


The SWG day saw around 30 participants, with a handful of people also connected via Google Hangouts engaging in the first face-to-face meeting of the WEAVE SWG (Survey Working Group). The group, comprised of representatives from each of the seven Science Teams of the WEAVE survey and select members from the Project, will have a variety of responsibilities for the whole WEAVE survey. After an initial round-the-table introduction, the day began in earnest with a review of the responsibilities of the SWG, both in the short and long term. Discussion topics ranged from the best way to enable smooth communication within the group in the lead-up to the 5-year survey beginning in 2018 as well as during the survey proper, to details of interfaces that the SWG will have with various nodes of the WEAVE Project and Consortium. We ended the intense and productive day with a round-the-table session of questions, which allowed clarification of issues that had not been touched upon during the day, as well as highlighting topics for further discussion.


The scheduling of this one-day meeting as the final day of the Week of WEAVE meeting @Snellius was ideal, as discussions that had already occurred during the rest of the week helped consolidate real-time developments of some details of the running of the WEAVE survey, and already having familiarity of the facility enabled us to run the programme for the single day very efficiently.



Teresa Antoja, Noordwijk, the Netherlands

Giuseppina Battaglia, Santa Cruz de Tenerife, Spain

Vanessa Hill, Nice, France

Shoko Jin, Groningen, the Netherlands

Nicholas Walton, Cambridge, United Kingdom