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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)