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Deep spectroscopic redshift surveys are a central tool to modern Astrophysics

Deep redshift surveys (z>0.3) have shaped our current understanding:

CFRS (1995) LBG surveys (Steidel et al. 1996+) DEEP/DEEP2 (2005+) VVDS (2005+)

Compare high redshift to low redshift spectroscopic surveys Knowledge of the sources: physical informations available Redshift information with ~100km/s accuracy enables to look

for 3D distribution A basis for robust selection for detailed follow-ups Important serendipitous capabilities

Understand galaxy formation and evolution

Understand LSS formation and evolution

Measure Cosmology parameters

600z

50000 z

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Deep spectroscopic surveys at ESO and elsewhere

10-15 years ago: CFHT-MOS, EFOSC, EMMI, OPTOPUS/MEFOS,

CFRS, 600z, z~1 ESP, 3000z, z~0.3

VVDS/VIMOS: created a new expertise in Europe Now at the VLT, several spectroscopic surveys

covering up to z~6 VIMOS: VVDS (50000z, up to z=5), zCOSMOS

(25000z, up to z=3), GOODS (7000z), UDF (5000z), VIPERS (100,000z, z~1)

FORS2: GMASS, UDF FLAMES/GIRAFFE, SINFONI: follow-ups

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VIMOS -VLT-UT3

A highly efficient high redshift machine in operations since 2002 on the VLT

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Multi-slit mode

Low res.

High re

s.

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Survey selection function: a key element

VVDS is magnitude limited, I-band (CFRS like) Probes to UV as z increase: a bias “easy” to work with Enables a complete census of the population probed Only other survey today with this selection: zCOSMOS

Most other surveys are color + magnitude/flux (+shape) selected

LBG, BM/BX, BzK, EROs LAE, H, …

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VIMOS VLT Deep Survey

Field IAB<22.5 WIDE 16+ deg²

IAB<24 DEEP 0.5deg²

IAB<24.75 Ultra-Deep 600 arcmin²

0226-04 ~14000 Public

1000

1000+03 ~5000 1400+05 ~11000

2217+00 ~15000 Public

CDFS ~1600 Public

Total ~31000 ~15500 ~1000

R~230, 5500-9300Å ~50000 spectra

50+ papers published so far

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Total VVDS N(z), 17.5≤IAB≤24.75

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Basic counts

Magnitude selection ismore complete than colorselection

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VVDS has complete samples in other bands

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Serendipitous power in VVDS

Slits: 1”x5-20”VVDS target

Photometrically invisible Lya emitter

Target spectrum

Serendipitous Lya @ 1216Å

• 1200 slits, 3.3 arcmin2, 3500-9500Å, 65000s

• 8000 slits, 22.2 arcmin2, 5500-9500 AA, 16000s

200 LAEs identified 2<z<6.5 (Cassata et al., in prep.)

DO IT ON WIDE !!!

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VVDS: enables follow-ups

Select galaxies from a large and unbiased sample before to study the physics of galaxy assembly

SINFONI obs. of VVDS galaxies 1<z<2Epinat et al., arXiv:0903.1216 (today)

merger

perturbed

perturbed

disc

MASSIV

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VVDS prepared/prepares the future z-surveys

VVDS heritage zCOSMOS VIPERS

New generation VIMOS surveys z>3 survey, proposed

New generation facilities, multi-slit JWST EELT EUCLID

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VVDS HighlightsPaper Year Citation Rate

Survey epoch 1 2005 170 2.8

CDFS 2004 161 2.2

Galex-VVDS 2005 142 2.4

Photoz 2007 138 2.9

LF global 2005 92 1.5

Galex LF 2005 89 1.0

LF type 2006 74 1.4

MF 2007 66 2.2

VLA 2003 58 0.9

Growth rate 2008 54 3.0

Color-density 2006 54 1.3

Mass assembly 2007 51 1.7

Clustering per type 2006 45 1.3

Bias 2005 39 0.8

• All works are great !• Attempt to look at the key papers, per citation

Some flops, strangely:Population census z~3, Nature, 2005 (33) LD, 2007 (30)- VVDS-SWIRE clustering, 2007 (3)