The Gaia archive is being designed and implemented by the DPAC Consortium.
The purpose of the archive is to maximize the scientific exploitation of the
Gaia data by the astronomical community. Thus, it is crucial to gather and
discuss with the community the features of the Gaia archive as much as
possible. It is especially important from the point of view of the GENIUS
project to gather the feedback and potential use cases for the archive. This
paper presents very briefly the general ideas behind the Gaia archive and
presents which tools are already provided to the community.Comment: Proceedings of the XXXVII Meeting of the Polish Astronomical Societ

Brown, Anthony G. A.

Hypki, Arkadiusz

English

arXiv

Hypki, A.P.

Brown, A.G.A.

Leiden University Scholary Publications

arXiv:1603.07347v1  [astro-ph.GA]  23 Mar 2016Gaia archiveArkadiusz Hypki1·2 and Anthony Brown11. Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, theNetherlands, ahypki@strw.leidenuniv.nl2. Nicolaus Copernicus Astronomical Center, Bartycka 18, 00–716 Warsaw, PolandThe Gaia archive is being designed and implemented by the DPAC Consortium.The purpose of the archive is to maximize the scientific exploitation of the Gaiadata by the astronomical community. Thus, it is crucial to gather and discuss withthe community the features of the Gaia archive as much as possible. It is especiallyimportant from the point of view of the GENIUS project to gather the feedbackand potential use cases for the archive. This paper presents very briefly the generalideas behind the Gaia archive and presents which tools are already provided to thecommunity.1 IntroductionGaia is an ambitious mission of ESA. Its goal is to chart a three-dimensional mapof the Galaxy (Lindegren et al., 2008). It will provide extraordinarily precise mea-surements for over one billion stars in the Milky Way including astrometry: stellarpositions, parallaxes, and proper motions; photometry: photometric magnitudes indifferent spectral bands and at each epoch; spectroscopy: radial velocities and as-trophysical parameters. Additionally, it will observe hundreds of thousands of solarsystem bodies, extragalactic sources, distant quasars and much more. Gaia will pro-vide unprecedented positional and radial velocity measurements with the accuraciesneeded to produce a stereoscopic and kinematic census of about one billion starsin our Galaxy and throughout the Local Group. This is by far the most advancedastrometric mission ever launched.The GENIUS project is an international effort to support ESA to design and de-velop the Gaia archive taking into account the needs of the user community and tomaximize the scientific return from the Gaia mission. The Gaia data processing, ofwhich final result will be the Gaia archive, is the responsibility of the DPAC con-sortium — a multinational European group of scientists and engineers. The designand implementation of this archive was opened by ESA to participation by the Eu-ropean community. GENIUS aims to significantly contribute to the development ofthe Gaia archive. It takes into account the input from the astronomical community,the interoperability with already existing and coming astronomical missions, and thecooperation with nanoJASMINE and JASMINE – the only other astrometric missionsunder development.The typical use cases of astronomical problems which researchers would like tosolve using Gaia archive were already gathered – long before the Gaia launch. How-ever, feedback from the researchers and discussion about already implemented toolsfor the Gaia archive is still very important. It helps to choose next goals and tweakthe current software developments plans in order to make the Gaia archive even moreuseful and more accessible for a broader range of users.pta.edu.pl/proc/2013nov3/123 PTA Proceedings ⋆Month 12, 2013 ⋆ vol. 123 ⋆ 51Arkadiusz Hypki, Anthony Brown2 Tools for the Gaia archiveThere is already available a number of tools which are connected to the Gaia archive,fully working and ready to serve real scientific data (currently Gaia archive containsonly measurements generated from a numerical model of the Milky Way).The main interface to access the Gaia archive is GACS – Gaia Archive CoreSystems1. It is a web portal which allows users to specify a query, run it withinthe European Space Astronomy Centre (ESAC) infrastructure and after completionview the results. The query language is called ADQL, which stands for AstronomicalDataset Query Language (Plante, 2007). It is an SQL-like language designed tosearch and join astronomical data sets, adopted as a standard and widely used acrossthe whole Virtual Observatory initiative2 – an international effort to make variousastronomical data sets and other resources accessible in a standardized way. TheGaia archive implements all needed protocols (TAP, SAMP) which makes it fullyaccessible from any VO compatible tool.Other interesting tools which are already connected to Gaia archive and allow toexploit the Gaia data are Topcat3 (Taylor, 2005) and Vaex4. Topcat is a graphicaltool which allows to view and edit a tabular data. It is especially designed to helpastronomers to analyse and manipulate the source catalogues. It has implemented allthe major formats and protocols widely used in astronomy, like FITS files, VOTableand thus it is seamlessly connected to the Gaia archive. Vaex is a graphical tool tovisualize and explore large tabular datasets. It handles tables with the number of rowsof the order 109 in seconds, thus it is suitable to explore the Gaia archive. Moreover,Vaex, also implements the VOTable protocol which makes it integrated with the Gaiaarchive out-of-the-box.Within the GENIUS project there are also designed and implemented tools ableto handle really huge datasets (∼ PBs of data) in order to compare them against thewhole or a large fraction of the Gaia archive. Simple bash/python scripts for dataanalysis of such huge datasets are not a reasonable solution here. There is a needto have a more advanced tool. One of such tools is the software called BEANS5. Itallows to query, aggregate and visualize huge data sets much easier and faster. It usesApache Cassandra6 as a database (one of the best solutions from emerging NoSQLtechnology movement), PigLatin7 as a scripting language to deal with distributed dataanalysis, and the library called D38 which is an example on how computer sciencesand art sciences can work together creating non-standard plots which at once arepowerful, interactive, clean and easy to read. The BEANS software is one of the firstattempts to adopt NoSQL data analysis techniques to astrophysics. It is written in avery general form, so it can be used in any field of research (economy, physics, biologyetc.), commercial companies or other open source projects. All the necessary codewhich connects BEANS with the GACS portal is already implemented as a plugin. Itallows to write an ADQL query which later one one can compare within BEANS withe.g. numerical simulations of Milky Way or globular star clusters. The first publicversion of the BEANS software, together with GACS plugin, is planned for release1http://gaia.esac.esa.int/archive/2http://www.ivoa.net/3http://www.star.bris.ac.uk/~mbt/topcat/4http://www.astro.rug.nl/~breddels/vaex/5http://beanscode.net6http://cassandra.apache.org7http://pig.apache.org8http://d3js.org52 ⋆ PTA Proceedings ⋆Month 12, 2013 ⋆ vol. 123 pta.edu.pl/proc/2013nov3/123Gaia archivein early 2016. Then, the software will be constantly improved taking into accountfeedback from users.The discussion on already existing features of the implemented software and pre-senting a new use case scenarios for the Gaia archive is still possible. The list of thecurrent use cases gathered in the community one can find in the document “Gaia dataaccess scenarios summary”9 (GAIA-C9-TN-LEI-AB-026). On the Gaia Research forEuropean Astronomy Training (GREAT) wiki pages10 one can find the informationon how to suggest more use cases.3 SummaryThe first public data release of Gaia data is planned for Summer 2016. In order tomaximize the scientific output of the Gaia mission it is crucial to put a lot of effort tocreate and implement a set of tools ready to allow scientists to analyze the Gaia data.That is the main goal of the GENIUS project – take the input from the communityand help to implement software which would support scientific research as much aspossible. The Gaia archive is accessible through the Virtual Observatory, which inthe recent years became a standard way to distribute astronomical catalogues. Thereis already a number of tools connected to the Gaia archive (Topcat, Vaex) and thereare even more tools to come (BEANS, GAVIP11). The first Gaia data are just aroundthe corner and it is crucial to provide to the community along the data the softwarewhich would allow to analyse the data easier.Acknowledgements. The research leading to these results has received funding from theEuropean Community’s Seventh Framework Programme (FP7-SPACE-2013-1) under grantagreement n. 606740.ReferencesLindegren, L., et al., The Gaia mission: science, organization and present status, inW. J. Jin, I. Platais, M. A. C. Perryman (eds.) IAU Symposium, IAU Symposium,volume 248, 217–223 (2008)Plante, R., Chapter 36: The Astronomical Dataset Query Language (ADQL), in M. J.Graham, M. J. Fitzpatrick, T. A. McGlynn (eds.) Astronomical Society of thePacific Conference Series, Astronomical Society of the Pacific Conference Series,volume 382, 381 (2007)Taylor, M. B., TOPCAT & STIL: Starlink Table/VOTable Processing Software, inP. Shopbell, M. Britton, R. Ebert (eds.) Astronomical Data Analysis Software andSystems XIV, Astronomical Society of the Pacific Conference Series, volume 347,29 (2005)9http://www.rssd.esa.int/doc_fetch.php?id=312540010http://great.ast.cam.ac.uk/Greatwiki/GaiaDataAccess/GdaScenariosFeedback11http://docs.gavip.science/#section2pta.edu.pl/proc/2013nov3/123 PTA Proceedings ⋆Month 12, 2013 ⋆ vol. 123 ⋆ 53

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