30 march 2006birmingham workshop1 the gaia mission a stereoscopic census of our galaxy
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30 March 2006 Birmingham workshop 2
Aims of the mission
• To observe the 6D phase-space map of our galaxy with sufficient accuracy to enable the first detailed reconstruction of its history– Positions and kinematics of objects to
distances of several tens of kpc need to be studied to enable this: parallaxes, proper motions and radial velocities required
– Classification of each object from photometry
30 March 2006 Birmingham workshop 3
How can this be done?
• One large survey of all 109 stars brighter than V=20, over 5 to 6 years, covering each object on average about 80 times, providing:– Astrometry, using the Hipparcos principle– Photometry, using dispersion spectra– Radial velocities, medium-resolution
spectrograph
30 March 2006 Birmingham workshop 4
The payload
• Telescope– 35-m focal length telescope with two
apertures, folded up in a 3m diameter satellite
• Focal plane– 0.5 square meter covered with 103 CCDs– Operating in TDI mode (Time-delayed
integration), following images passing over the CCDs
30 March 2006 Birmingham workshop 5
Scientific potential
• Solar system: census of smaller bodies
• Nearby stars: Detection of planets
• Star clusters: observational isochrones
• Galactic structure: history of the galaxy
• Distances globular clusters, LMC & SMC
• Fundamental physics: reference frames
30 March 2006 Birmingham workshop 11
The schedule
• Phase B2 has started
• Phase C will start end 2006
• Launch scheduled for end 2011
• Operations at L2
• Mission duration 5 to 6 years
• Final mission products around 2020
30 March 2006 Birmingham workshop 12Catalogue
Schedule
2000 2004 2008 2012 2016 2020
Acceptance
Technology Development
Design, Build, Test
Launch
Observations
Analysis
Early Data
Concept & Technology Study ESA SCI 2000(4)
Re-Assessment: Ariane Soyuz
To L2Start of
Phase B2
30 March 2006 Birmingham workshop 13
The data processing
• The Gaia Data Processing and Analysis Consortium is in the process of being created– Consists of 8, relatively independent,
coordination units, assigned to specific tasks– 3 data processing, 3 data analysis, and 2
support units– DPAC executive for coordination and planning
of activities
30 March 2006 Birmingham workshop 14
The size of the job
• We expect of order 1012 observations
• Calibration is in first instance towards an internally defined system
• Extensive iterations required in astrometry, photometry and radial velocities
• Processing requirements of order 100000 observations per second
30 March 2006 Birmingham workshop 15
UK involvement
• Photometric data processing– Software developments and implementation– Cambridge, Leicester, Edinburgh
• Radial velocity data processing– Software developments– MSSL
• Gaia Science Team– Floor van Leeuwen, IoA Cambridge– Mark Cropper, MSSL
• Industry: E2V will manufacture all CCDs