Kinematics/Dynamics  Chemistry/dust  Stellar populations  Searches for z ~ 6-7 « Hot » scientific researches at VLT in cosmology Mass Galaxy formation/gas accretion Star formation/enrichment Ages, history Beyond the reionisation epochs  At increasing redshifts To be improved by:  higher spectral resolution (3000 < R < 15000)  3D spectroscopy in the near IR (high z)

R>1000 spectroscopy for: - extinction ( Balmer lines corrected for stellar absorption) - SFRs -gas chemistry -proper analysis of stellar populations Galaxy spectroscopy pre-requisites (Liang et al, 2003a, A&A submitted)

Spectral resolution Assuming low read-out noise CCDs and that OH sky lines dominate at > 0.7  m Low resolution: should be > 1000 (extinction, SFRs, gas abundances) Medium resolution : ~ (dynamics, stellar populations) Much better detection of emission/absorption lines at R ~ few 1000 Recently illustrated by: Steidel (2004): several 100 spectra 1.4 < z < 2.6 (DEIMOS R=5000) ~ 10/arcmin 2, 5 times more than LBGs VIMOS survey, I=24 (R=250): very few objects at z > Based on ISAAC ETC

Estimating extinctions and SFRs at z ~1 (Flores et al, 2003, A&A in press) FORS2/ISAAC: 16 ISO galaxies, 0.4< z <1, R=1250 to extinction corrected H  SFRs are close to mid-IR estimates (Elbaz et al, 2002) for SFR < 150 M O /yr (i.e. below ULIRGs)  Double check on SFR estimates

3D to test the merging hypothesis

Galaxy populations: what do we know ? Redshift/ # objects z < 1.3 Several 10000s 1.3 < z < 2.6 z desert ? but Steidel.. z= LBGs SCUBA’s z > 6 2 QSOs, 3 galaxies ?? Epoch ofFormation of disks ? ???Ellipticals forming? Reionisation First stars ? Extinction/ SFR Still uncertain but SIRTF/VLT Unknown ?? Largely model dependent unknown Stellar mass/ Metal Uncertain Few measures Very uncert. ?? Very uncert. 5 measures ? ??? ?? Mass/ Dynamics TF uncertain FP for E’s ? none Small  ’s ? ??

Image quality requirements Distant galaxies are small and low surface brightness sources! 3D spectroscopy at R> « FWHM » arcsec (8 m) or 0.06 « FWHM » arcsec ( 30m) 0.02 « FWHM » arcsec ( 100m)  need to concentrate the light! IJK ISAAC, Ks=28, van Dokkum et al 

FWHM Microlenses  AO sharpens the PSF  FWHM decreases.  Gain in angular resolution. Spatial resolution  Increase of the fraction of light into a sub-aperture.  More object, less sky.  Increase of the spectral S/N

 Integration of DM and pupil relay optics in an « adaptive button »  µ-DM required.  Problem : no optical feedback from DM to WFS.  Critical point : servo loop, to be studied.  sky coverage is essential  Several independent AO systems in a wide field. IFUs WFS FALCON AO system

 10 Cosmological fields (b  45°), 100 objects/field  Tomographic reconstruction of on-axis phase (F Assemat et al, 2003)  Fraction of light in a 0.25 square aperture increased by at least a factor 2 in J band (1.25 µm) and H band (1.65 µm).  FWHM < 0.2 arcsec  sky coverage of 50% (GS with V<16, S/N=10)  allow to reach ~ 0.06 arcsec (FWHM) on a 30m, 0.02 arcsec on a 100m  Requirements : µ-DMs with actuators for 8m, 15 times more for 30 m (but density conserved), very sensitive WFS with a high number of apertures. Performances based on simulations

multi-object 3D spectroscopy at R>> 1000 (AO does not need to correct all the field, just the scientific targets!) - Small fields severely affected by cosmic variance (e.g. HDF-N & S, ~ 6 arcmin 2 ) - Galaxy correlation scales 4-9 Mpc (z=0 to z=4, LBGs)   =9 to 20 arcmin a minimum also # density of LBGs, LIRGs, sub-mm, Ellipticals : 0.01 to few / arcmin 2 Which field of view for galaxy spectroscopy ?

z= 1000 (WMAP): accurate physics & cosmological parameters z= 0: first detailed star formation histories (Local Group) detailed dynamics (FP) and galaxy properties z= 1 to > 6: ELTs + (3D spectroscopy, R>>1000 and fov=10 arcmin):  the only way to understand the physics of the galaxy formation Discussion