The European Large Area ISO Survey - I. Goals, definition and observations
English
Oliver, Seb[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Rowan-Robinson, Michael[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Alexander, D. M.[SISSA, International School for Advanced Studies, Via Beirut 2-4, 34014 Trieste, Italy]
Almaini, O.[Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ]
Balcells, M.[Instituto de Astrofisica de Canarias, C/ Via Lactea, s/n, 38200 La Laguna, S/C de Tenerife, Spain]
Baker, A. C.[Dept of Physics & Astronomy, Cardiff University, PO Box 913, Cardiff CF24 3YB]
Barcons, X.[Instituto de Fúsica de Cantabria (Consejo Superior de Investigaciones Cientúficas - Universidad de Cantabria), 39005 Santander, Spain]
Bellas-Velidis, I.[National Observatory of Athens, Astronomical Institute, PO Box 20048, GR-11810, Greece]
Cabrera-Guerra, F.[Instituto de Astrofisica de Canarias, C/ Via Lactea, s/n, 38200 La Laguna, S/C de Tenerife, Spain]
Carballo, R.[Instituto de Fúsica de Cantabria (Consejo Superior de Investigaciones Cientúficas - Universidad de Cantabria), 39005 Santander, Spain; Departamento de Fúsica Moderna, Universidad de Cantabria, 39005 Santander, Spain]
Cesarsky, C. J.[CEA/SACLAY, 91191 Gif sur Yvette cedex, France]
Ciliegi, P.[Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy]
Clements, D. L.[Dept of Physics & Astronomy, Cardiff University, PO Box 913, Cardiff CF24 3YB5]
Crockett, H.[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Danese, L.[SISSA, International School for Advanced Studies, Via Beirut 2-4, 34014 Trieste, Italy]
Dapergolas, A.[National Observatory of Athens, Astronomical Institute, PO Box 20048, GR-11810, Greece]
Drolias, B.[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Eaton, N.[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Efstathiou, A.[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Egami, E.[Infrared Astronomy Group, 320-47 Downs Laboratory of Physics, California Institute of Technology, Pasadena, CA 91125, USA]
Elbaz, D.[CEA/SACLAY, 91191 Gif sur Yvette cedex, France]
Fadda, D.[CEA/SACLAY, 91191 Gif sur Yvette cedex, France]
Goldschmidt, P.[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Graham, M.[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Gonzalez-Serrano, J. I.[Instituto de Fúsica de Cantabria (Consejo Superior de Investigaciones Cientúficas-Universidad de Cantabria), 39005 Santander, Spain]
Gonzalez-Solares, E. A.[Instituto de Astrofisica de Canarias, C/ Via Lactea, s/n, 38200 La Laguna, S/C de Tenerife, Spain]
Granato, G. L.[Dipartimento di Astronomia, Universita'; di Padova, Vicolo Osservatorio 5, I-35122 Padova, Italy]
Gruppioni, C.[Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy]
Masegosa, J.[Instituto de AstrofÃsica de AndalucÃa, CSIC, Apartado 3004, E-18080 Granada, Spain]
Mattila, K.[Observatory, PO Box 14, Tahtitorninmaki, FIN-00014 University of Helsinki, Finland]
McMahon, R. G.[Institute of Astronomy, The Observatories, Madingley Road, Cambridge CB3 0HA]
Miley, G.[Leiden Observatory, PO Box 9513, NL-2300 RA Leiden, the Netherlands]
Missoulis, V.[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Mobasher, B.[Astrophysics Group, Blackett Laboratory, Imperial College of Science Technology & Medicine (ICSTM), Prince Consort Rd, London SW7 2BZ]
Morel, Thierry[Astrophysics Group, Imperial College of Science, Technology and Medicine, Blackett Laboratory, Prince Consort Road, London SW7 2BZ > > > >]
[en] We describe the European Large Area ISO Survey (ELAIS). ELAIS was the largest single Open Time project conducted by ISO, mapping an area of 12deg[SUP]2[/SUP] at 15μm with ISOCAM and at 90μm with ISOPHOT. Secondary surveys in other ISO bands were undertaken by the ELAIS team within the fields of the primary survey, with 6deg[SUP]2[/SUP] being covered at 6.7μm and 1deg[SUP]2[/SUP] at 175μm. This paper discusses the goals of the project and the techniques employed in its construction, as well as presenting details of the observations carried out, the data from which are now in the public domain. We outline the ELAIS `preliminary analysis' which led to the detection of over 1000 sources from the 15 and 90-μm surveys (the majority selected at 15μm with a flux limit of ~3mJy), to be fed into a ground-based follow-up campaign, as well as a programme of photometric observations of detected sources using both ISOCAM and ISOPHOT. We detail how the ELAIS survey complements other ISO surveys in terms of depth and areal coverage, and show that the extensive multi-wavelength coverage of the ELAIS fields resulting from our concerted and on-going follow-up programme has made these regions amongst the best studied areas of their size in the entire sky, and, therefore, natural targets for future surveys. This paper accompanies the release of extremely reliable subsets of the `preliminary analysis' products. Subsequent papers in this series will give further details of our data reduction techniques, reliability and completeness estimates and present the 15- and 90-μm number counts from the `preliminary analysis', while a further series of papers will discuss in detail the results from the ELAIS `final analysis', as well as from the follow-up programme.
