Astronomical Databases and Virtual Observatories Surfing the Tsunami of Data

Transcription

1 Astronomical Databases and Virtual Observatories Surfing the Tsunami of Data 28th International School for Young Astronomers Instituto Nacional de Astronomía, Óptica y Electrónica Tonantzintla, México Rodolfo H. Barbá Universidad de La Serena Chile

2 Motivation We are living an age of very fast changes in the way to do Astronomy Astronomy is one of the prime sciences of the human being Astronomy goals through the centuries: Registering and recording of heaven events Developing of methodologies to keep and track such events SHARING During the information and the knowledge 20th century: international organization (IAU) Astronomy is one of the most international organised science. Nobody is owner of the heaven. 2

3 Motivation Astronomy now: The technology (computers, communications, etc.) is changing the way to access to the information. Observational facilities based in astronomical satellites, automated survey telescopes, and 4 8 meters class telescopes are available everywhere. The next decade are planned amazing facilities. The information gathered by these facilities (and their derived products) is organised in huge databases... 3

4 Motivation Astronomy now: and also, the services of such databases is being connected through computer grids virtual observational astronomy is coming now The observations are there, in fact, we don't need telescopes to do high-quality observational astronomy beyond the computer, software and internet connection, to use these observations and their products we need only... 4

5 Motivation We need... IMAGINATION and IDEAS 5

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8 Motivation For our countries with scarce resources: Opportunity to access to high quality material. We can do good observational astrophysics to relatively very low costs: free scientific software based on LINUX are available through Internet. Training young astronomer in the use of these observations as a experimental observatory to apply for observing time in international observatories (ground and space). Participating in the development of astronomical databases and grids. and more... 8

9 Goals to reach The goals to be reached in this 28th ISYA about the use of astronomical databases are: To understand how the different elements of an observing proposal (as astrophysical subjects) are related. To learn how the astronomical information is collected and organised on the Internet To get quick looks of several astronomical information systems (data centres, bibliographic severs, image servers, etc.) To learn which kind of information could be retrieved 9

10 Goals to reach To learn about the use of image and catalogue visualisation software To learn about some warnings in the use of catalogues and images Examples how to retrieve scientific observations from data servers Labs Ideas about how to access to these systems to do... The next future: basic concepts about astrophysical virtual observatories and datamining tools. 10

11 Bib. References The observing proposal References Science aims Dupl. Check Observing Proposal Antecedents Objects Image Servers Theor. Backg. Experimental Design Telescope Instrument Detector Processing & Analysis Methodology 11 Catalogues Nomenclature Coordinates Beam Others: Magnitudes Fluxes Ephemeris Proper motions

12 Data Centres They were the first institutions to systematically collect machine readable versions of astronomical catalogues. All Data Centres offer services (increasing continuously), and they are participating in the creation of virtual observatories. The access is free through Internet, using different technologies Some services offered: Images Catalogues Bibliographic resources Yellow pages 12

13 Data Centres There are two general purposes Data Centres: Resolved object populations in the MW and nearby galaxies: Extragalactic database 13

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16 Data Centres The increasing number of space missions have led to the creation of mission oriented data centres like: Hubble Space Telescope: STScI and ST ECF Infrared missions: IPAC High energy: NASA HEASARC Harvard and MPE ISO, IUE: VILSPA Multipurpose: CADC and many others 16

17 Data Centres Also several major goundbased observatories have established data centres to manage their past observations: European Southern Observatory: NRAO Very Large Array, Royal Greenwich Observatory on La Palma Gemini, CFHT: CADC Subaru (NAO JP): SMOKA Archive Facility NOAO (Cerro Tololo, Kitt Peak): Etc. etc. 17

18 Data Centres Many Sky Survey Projects are developed sophisticated Data Centres, and the list is growing incredibly fast: Two Micron All Sky Survey (2MASS): Sloan Digital Sky Survey (SDSS): Deep Near Infrared Survey of the Southern Sky (DENIS): Massive Compact Halo Objects (MACHO) OGLE, ASAS, Etc. etc., see 18

19 AstroWeb AstroWeb is a collection of astronomical & space science resources on Internet with relevant significance. It is maintained by the AstroWeb Consortium (distributed in several institution worldwide): CDS, strasbg.fr/astroweb.html MSSSO, NRAO, STScI, resources.html VILSPA, IoA Cambridge, AstroWeb looks like yellow pages and it is organised in specific items, actualised more or less periodically WARNING: it is uncompleted and some URL (links) could be out of date. 19

20 StarPages In CDS, André Heck (StarBriefs 2001, Dordretch: Kluwer Acad. Pub.) developed a series of astronomical services on Internet: the StarPages. They are part of Star*s Family resources on WWW), configuring the true astronomical pages. strasbg.fr/starpages.html StarWorlds: astronomy related organisations, institutions, associations, companies, and so on: about 6500 entries from more than 100 countries StarHeads: personal WWW pages of professional astronomers and related scientists: 6000 entries StarBits: abbreviations, acronyms, contractions, symbols, and so on: about 200,000 entries 20

21 AstroWeb vs StarPages AstroWeb or StarPages, which is better? Depends what you are finding. AstroWeb is free, and StarPages is expensive AstroWeb is a compilation of about 3000 URLs, compared with offered by StarPages StarPages offers specific information which is authenticated, regurlarly updated, homogenised, and systematically presents AstroWeb is presented as a long list for visual inspection StarPages is very useful for searching engines (like Google) AstrroWeb includes information of projects that not adjust in StarPages StarWorlds contains data of sites and institutions without presence on Internet 21

22 Object databases Object databases gather both bibliographic references and meansurement quantities on galactic and extragalactic objects. There are many with increasing specialisation and complexity. Three are the prime ones: SIMBAD, strasbg.fr NED, LEDA, Lyon Meudon Extragalactic Database SIMBAD is specialised in galactic objects, while NED and LEDA are specialised in extragalactic ones. All three involve the concept of an astronomical object-name resolver, which accept and return identifiers; it also permits retrieval of all objects within specific radius around coordinates. The nomenclature of astronomical sources of radiation outside the solar system is regulated by the IAU Commission 5 Task Group on Designations 22

23 Astronomical catalogues It should be in mind that object databases generally do not include the full information contained in CDS/NED catalogues. We consider astronomical catalogues as static, final compilations of data for a given set of cosmic objects. But (as we ll see the next week) now are appearing dynamic catalogues According to Jascheck (1989) they can be classified 1) Observational catalogues 2) Compilation catalogues 3) Critical compilation catalogues and bibliographical compilation catalogues In category (1) now are included a new generation of catalogues derived from very specific surveys: 2MASS, HDF, MACHO, etc. 23

24 Astronomical catalogues CDS maintain the most complete set of astronomical catalogues in the Astronomer's Bazaar, cdsweb.u strasbg.fr/cats.html 6060 catalogues available from CDS of which 5150 available on-line (as full ASCII or FITS tables) of which 4815 are also available through de VizieR browser VizieR is a powerful tool to search and retrieve information from catalogues A query in VizieR can be achieved: either in the traditional way of stepping through the following actions: 1.select one or a few catalogues to be queried 2.define your constraints (selection on columns) and the result layout 3. Get the results in a tabular form. Correlated data may be found. 4.Full Display of individual rows if wished; This traditional way accepts lists of constraints or targets saved in a file. or as a global search around a position on the sky addressed to all or to a subset of catalogues existing in VizieR 24

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29 Bibliographical services Astronomischer Jahresbericht was the first astronomical abstract service ( ) Astronomy & Astrophysics Abstracts - AAA ( ) Internet age: NASA's Astrophysics Data System Abstract and Paper Service - ADS (1993) Mirrors world-wide Access using web browsers and shell commands ADS provides sophisticated search facilities Access to scanned and electronic papers Links to references, object databases and other resources Refcode or Bibcode: 19-characters reference code unique for each paper, e.g. 2002ApJ S myads: notification service configurable by the user (through cookies) Internet age: e-prrint Services ArXiv including astro-ph, the most important preprint server for Astrophysics (since 4/1992), in Cornell Univ. linked to ADS and fully referenced Service integrated to myads 29

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37 Miscellaneous services NED hosts the LEVEL5 project. This is an on going and developing experimental service sponsored by NASA and the Carnegie Institution of Washington, in conjunction with NED The purpose of LEVEL5 is to bring together in a single gateway WEB site (where copyrights allow) "original" documents and reviews and/or electronic links to articles of current and lasting interest to cosmologists, particle physicists and extragalactic astronomers. 37

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42 Acknowledgements I am grateful to the ISYA organizers for the opportunity to give this lectures and for their financial support. The material presented in this talk is based on information collected from CDS, ADS, NED Data Centres and The New York Times. This talk was prepared using Open Office 2.0 running in a LINUX SuSe 9.3 box.