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Gaia Data Release 1: Pre-processing and source list creation

Fabricius, C and Bastian, U and Portell, J and Castañeda, J and Davidson, M and Hambly, NC and Clotet, M and Biermann, M and Mora, A and Busonero, D and Riva, A and Brown, AGA and Smart, R and Lammers, U and Torra, J and Drimmel, R and Gracia, G and Löffler, W and Spagna, A and Lindegren, L and Klioner, S and Andrei, A and Bach, N and Bramante, L and Brüsemeister, T and Busso, G and Carrasco, JM and Gai, M and Garralda, N and González-Vidal, JJ and Guerra, R and Hauser, M and Jordan, S and Jordi, C and Lenhardt, H and Mignard, F and Messineo, R and Mulone, A and Serraller, I and Stampa, U and Tanga, P and Van Elteren, A and Van Reeven, W and Voss, H and Abbas, U and Allasia, W and Altmann, M and Anton, S and Barache, C and Becciani, U and Berthier, J and Bianchi, L and Bombrun, A and Bouquillon, S and Bourda, G and Bucciarelli, B and Butkevich, A and Buzzi, R and Cancelliere, R and Carlucci, T and Charlot, P and Collins, R and Comoretto, G and Cross, N and Crosta, M and De Felice, F and Fienga, A and Figueras, F and Fraile, E and Geyer, R and Hernandez, J and Hobbs, D and Hofmann, W and Liao, S and Licata, E and Martino, M and McMillan, PJ and Michalik, D and Morbidelli, R and Parsons, P and Pecoraro, M and Ramos-Lerate, M and Sarasso, M and Siddiqui, H and Steele, IA and Steidelmüller, H and Taris, F and Vecchiato, A and Abreu, A and Anglada, E and Boudreault, S and Cropper, M and Holl, B and Cheek, N (2016) Gaia Data Release 1: Pre-processing and source list creation. Astronomy and Astrophysics, 595. ISSN 0004-6361

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Abstract

Context. The first data release from the Gaia mission contains accurate positions and magnitudes for more than a billion sources, and proper motions and parallaxes for the majority of the 2.5 million Hipparcos and Tycho-2 stars. Aims. We describe three essential elements of the initial data treatment leading to this catalogue: the image analysis, the construction of a source list, and the near real-time monitoring of the payload health. We also discuss some weak points that set limitations for the attainable precision at the present stage of the mission. Methods. Image parameters for point sources are derived from one-dimensional scans, using a maximum likelihood method, under the assumption of a line spread function constant in time, and a complete modelling of bias and background. These conditions are, however, not completely fulfilled. The Gaia source list is built starting from a large ground-based catalogue, but even so a significant number of new entries have been added, and a large number have been removed. The autonomous onboard star image detection will pick up many spurious images, especially around bright sources, and such unwanted detections must be identified. Another key step of the source list creation consists in arranging the more than 1010 individual detections in spatially isolated groups that can be analysed individually. Results. Complete software systems have been built for the Gaia initial data treatment, that manage approximately 50 million focal plane transits daily, giving transit times and fluxes for 500 million individual CCD images to the astrometric and photometric processing chains. The software also carries out a successful and detailed daily monitoring of Gaia health. © ESO, 2016.

Item Type: Article
Uncontrolled Keywords: 0201 Astronomical And Space Sciences
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: EDP Sciences
Date Deposited: 19 Jan 2017 11:19
Last Modified: 07 Sep 2017 12:51
DOI or Identification number: 10.1051/0004-6361/201628643
URI: http://researchonline.ljmu.ac.uk/id/eprint/5304

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