Gaia data in the CDS portal. Sébastien Derriere, Mark Allen, Thomas Boch & CDS team Observatoire de Strasbourg, France

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1 Gaia data in the CDS portal Sébastien Derriere, Mark Allen, Thomas Boch & CDS team Observatoire de Strasbourg, France Gaia Data Access Workshop, Heidelberg 19 Jun 2018

2 Centre de Données astronomique de Strasbourg hosted at the Observatoire astronomique de Strasbourg, Université de Strasbourg

3 since 1972 Collect useful data on objects in electronic form Improve them by critical evaluation and combination Distribute the results to the international community Conduct research using the data

4 Status Supported as a French Research Infrastructure (via CNRS/INSU), plus international partners serving global community ~30 staff: Scientists, Software Engineers, Documentalists, Admin Heavily used, VO-compliant, evolving fast Certification - Data Seal of Approval

5 Astronomy Publishing and Reference services must evolve because science is constantly changing Era of big surveys (but also detailed individual studies) Multi-wavelength astronomy, Time Domain astronomy, multi-messenger astronomy coming.

6 Interconnected science Multi-wavelength, multi-messenger messengers: photons,, grav. waves, VHE using multiple instruments/telescopes combining data from multiple sources More open and collaborative using tools and services that fit the purpose distributed teams/collaborations/projects

7 CDS services Astronomical Objects : IDs, bibliography, measurements Catalogue Service : Catalogues, published tables, observation logs, surveys, associated data Visualisation and integration : images, catalogues, archives, VO portal, all-sky capabilities X-Match : Catalogue cross-match Portal: Integration of services

8 Making information useable Add value - by homogeneous description of heterogeneous data Standardisation Metadata Formats, conventions, VO protocols Encodes a level of meaning to the data Connections - literature, archives, tools y t i l i b a r e p o r e Int

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10 SIMBAD Database of astronomical objects extracted and curated from the literature Object types, coordinates, crossidentifications, citations, basic data 9.5 million objects, 27 million identifiers, 17 million citation links

11 SIMBAD well known via the object name resolver Sombrero widely used: ~ queries/day in 2017

12 VizieR Catalogues, published tables, observation logs, surveys, associated data Heterogeneous tables described by standardised metadata Curated by professional documentalists Cooperation with major journals Added value - interoperability, usability, services (e.g. X-Match, visualisation, complex queries)

13 Simple query interface

14 Advanced query interface

15 Query interface for single table

16 Query result

17 VizieR: Multiple Interfaces Vizier web page, Aladin interface, CDS Portal, direct URL queries, Topcat interface, DS9, VO TAP, VO Cone Search, VizQuery

18 Photometry in catalogues

19 strasbg.fr/vizier/sed/

20 ~18,000 catalogues, containing 38,000 tables ~1200 new catalogues per year total of ~26 billion rows ~300,000 queries per day (working to decrease this by making queries smarter )

21 Vizier associated data Science ready data associated with a journal publication Catalogues/tables Time-series Spectra Images evolving very quickly with data publication efforts

22 CDS X-Match Positional 2 table cross-match epoch and proper motion taken into account where possible cross-match done in J ,000 VizieR cats, & SIMBAD, & upload Fast big catalogue matching: SDSS vs. 2MASS in 10 minutes Web interface HTTP API

23 Aladin

24 Aladin Lite

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26 Access to data via Aladin

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28 ESA sky - built on Aladin Lite

29 Recent developments Hierarchical representation of large image surveys, catalogues and cubes - a structuring development at CDS Coverage maps open up new possibilities for manipulating surveys and catalogues new interactions between images, cubes and catalogues

30 HiPS Hierarchical Progressive Surveys Multi-resolution HEALPix data structure for Images Catalogues 3-dimensional data cubes Conserves scientific data properties alongside visualisation considerations (FITS & png/jpeg) Mechanisms for links to original data Implemented for ~300 data sets and growing

31 HEALPix* 12 quadrilateral pixels 2x2 division at each level Equal area Iso-latitude Nested index scheme encodes inheritance Libraries Gorski et al *

32 HiPS Tiles and Pixels

33 Tiles WMAP - PLANCK HFI - IRAS - NVSS - SCUBA - DSS - SDSS - CFHTLS - HST ACS

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35 Use an archive as a survey HiPS of the WFPC2 HST archive images (filter by filter)

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37 Fermi EGRET XMM INTEGRAL RASS GALEX DSS SDSS CFHTLS HST 2MASS PanSTARRS ULTRAVISTA WISE ALLWISE DIRBE IRIS GLIMPSE360 SPITZER AKARI SCUBA BGPS WMAP DECaPS PLANCK NVSS CHIPASS SUMSS DWINGELOO HASLAM408 VLSSR WENSS SHS SHASSA VTSS DECaLS GASS CGPS GALFA CALIFA MUSE HARP/JCMT Gaia GUMS SIMBAD GOODS PHAT Gaia DR1 Gaia DR2

38 Survey/image outlines MOC: Multi-Order Coverage maps IVOA Recommendation

39 Comparing coverage of 100s of large data sets Intersection/union/complement trivial Catalogue coverage - ~18000 (Vizier) Queries based on coverage and catalogues - e.g. Veron quasars in HST, XMM and SDSS images

40 Hierarchical views of Catalogues Same idea: HiPS Catalogue. Important when dealing with/visualizing 106, 107, catalogues Allows zooming into large or deep catalogue HiPS catalogues - provide progenitor links to HiPS images Hierarchy can be defined in different ways brightness, parallax, local density e.g. SIMBAD progressive Survey (hierarchy based on size of object and number of citations)

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42 Links CDS: Hierarchical Progressive Surveys - Fernique et al. 2015, A&A 578, HiPS on CDS web pages: Aladin Aladin Lite HiPS generation tools:

43 CDS : partner data center

44 Gaia DR2 at CDS Ingestion in the CDS services Catalogue description ReadMe + byte-by-byte Description of columns : range of values, unit, UCD Indexation : columns + column combinations HiPS generation Deployment in VizieR (+TAP), X-Match, Aladin Visualization of light curves Ingestion in SIMBAD (being done) Full interoperability within the CDS framework and the VO

45 Coordinates at CDS Gaia DR2 coordinates are at epoch J Most catalogues are in J2000 The CDS X-match uses coordinates computed at epoch J2000.0! Uploaded data should be J Be careful when cross-matching two catalogues

46 Gaia DR2 Released April 25 12:00 Contents : 20 tables gaia2 : 1.6 billion rows 9575 Cepheid time series, RR Lyrae and other time series! Solar system objects...

47 Gaia DR2 access VizieR TAP VizieR Cross-match service Command-line Aladin Aladin Desktop Aladin Lite HiPS catalogue

48 Gaia DR2 in VizieR Catalogue I/345

49 Gaia DR2 in VizieR Catalogue I/345 Query by position + constraint on fields Cone Search interface Light curves visualization

50 Gaia DR2 in TAP VizieR Gaia DR2 tables available in TAP VizieR Web interface: TAP endpoint: Also from TOPCAT, Aladin...

51 Gaia DR2 in X-match service Fast positional crossidentification of Gaia sources with any VizieR table with positions (or user-uploaded table) Web interface: HTTP API astroquery Topcat (Python)

52 Gaia DR2 in Aladin Dedicated form to access Gaia DR2 data Visialization of proper motions

53 Other products HiPS progressive catalogue Color flux map

54 Thank you! And now, it's your turn to use Gaia DR2 1) In Aladin Lite 2) In VizieR 3) From the CDS X-match service 4) From Aladin Desktop 5) From TOPCAT 6) With TAP queries See you later for the CDS tutorial