Basic principles and data reduction strategy What Gaia will observe: the Gaia Simulator

• Basic principles and data reduction strategy

• What Gaia will observe: the Gaia Simulator (GUMS and GOG)

• Scientific challenges: some examples

• On ground spectroscopic surveys complementary to Gaia

For WHT

• For WHT

• FoV = 2o

• MOS + mIFU + LIFU

• R= 5k, ~1000 fibres

• V=20 (R=5k, SNR=10, 1h)

• R= 20k from grating change

• V=16 (R=20k, SNR=50, 1h)

•  = 0.37-1.00 μm

• Status:

• Concept Study, 01/2011, first Science Case completed 2/2012

• 03/2011 ASTRONET partners recommend North(WHT)+South(ESO) MOS

• 06/2011 UK, NL commit funding for WEAVE to PDR (expected 2013)

• 09/2011 IAC support construction of WEAVE

• 2016: Instrument First Light

Formation scenarios for Galactic stellar halo. In-situ or accreted?

• Formation scenarios for Galactic stellar halo. In-situ or accreted?

• Total mass of the Milky Way out to 200 kpc
• The shape of the Galactic gravitational potential within 50–100 kpc
• Lumpiness of the Galactic dark matter distribution within 20–50 kpc

• The dynamics of the Galactic disk & chemical labeling

• Configuration space and global phase-space constraints
• Local substructures in phase-space, resonances, and stochasticity
• Chemo-dynamical constraints

• Galactic open clusters

• Formation and disruption
• Tracers of chemical evolution of the disk

Provides:

• Provides:

• Epoch (transit) and combined (end-of-misssion) data
• True data, data as observed by Gaia and their errors

• Is based on:

• A model of the Gaia instruments
• Error models provided by the CUs (DPAC) (final Gaia data will be more complex)

• Has two main simulation modes :

• The GUMS universe model (integrated in GOG)
• An external list of sources provided by the user