Gaia Data Release 1
Principles of the photometric calibration of the G band
1 Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí Franquès 1, 08028 Barcelona, Spain
2 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
3 INAF–Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
4 INAF–Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monte Porzio Catone (Roma), Italy
5 INAF–Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
6 Sterrewacht Leiden, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
7 Department of Physics and Astronomy, Notre Dame University-Louaize, PO Box 72, Zouk Mikaël, Lebanon
8 ASI Science Data Center, via del Politecnico SNC, 00133 Roma, Italy
Corresponding author: J. M. Carrasco, e-mail: firstname.lastname@example.org
Received: 4 July 2016
Accepted: 30 October 2016
Context. Gaia is an ESA cornerstone mission launched on 19 December 2013 aiming to obtain the most complete and precise 3D map of our Galaxy by observing more than one billion sources. This paper is part of a series of documents explaining the data processing and its results for Gaia Data Release 1, focussing on the G band photometry.
Aims. This paper describes the calibration model of the Gaia photometric passband for Gaia Data Release 1.
Methods. The overall principle of splitting the process into internal and external calibrations is outlined. In the internal calibration, a self-consistent photometric system is generated. Then, the external calibration provides the link to the absolute photometric flux scales.
Results. The Gaia photometric calibration pipeline explained here was applied to the first data release with good results. Details are given of the various calibration elements including the mathematical formulation of the models used and of the extraction and preparation of the required input parameters (e.g. colour terms). The external calibration in this first release provides the absolute zero point and photometric transformations from the Gaia G passband to other common photometric systems.
Conclusions. This paper describes the photometric calibration implemented for the first Gaia data release and the instrumental effects taken into account. For this first release no aperture losses, radiation damage, and other second-order effects have not yet been implemented in the calibration.
Key words: instrumentation: photometers / space vehicles: instruments / techniques: photometric / surveys / Galaxy: general / catalogs
© ESO, 2016