Wide-field Imaging Spectroscopic Survey of Distant Clusters

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Wide-field Imaging Spectroscopic Survey of
Distant Clusters

• Masayuki Tanaka (ESO)

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Outline of this talk

• 1 PISCES project
• 2 Large-scale structures around distant
  clusters
• 3 Build-up of the red sequence at zlt1.3
• 4 Spectral Diagnostics
• 5 From the Cradle to the Grave
• 6 Summary

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Pisces   pahy-seez, pis-eez -n.   1. A
constellation in the equatorial region of the
Northern Hemisphere near Aries and Pegasus.
Also called Fishes. 2. a. The 12th sign of the
zodiac in astrology. Also called Fishes. b.
pl. Pisces One who is born under this sign.
3. A deep, wide-field survey of galaxy clusters
at 0.4ltzlt1.3.
1 PISCES project
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PISCES project (in AA abstract format)
Aims Methods Results Conclusions
Our goal is to quantify galaxy properties as
functions of environment, mass, and time and
understand how and when the environmental
dependence of galaxy properties is established.
We carry out a systematic, deep (M4),
wide-field (30x30), optical-nearIR imaging
spectroscopic survey of distant clusters.
Some of our recent results are presented in this
talk.
Our survey is not finished yet, so..we will see.
For details, see Kodama 2005 PASJ, 57, 309
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CL001616 at z0.55 BVRiz photometry 150 spec.
objects
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RXJ0152-13 at z0.83 VRizK photometry 200 spec.
objects
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RDCSJ0910 at z1.1 VRizK photometry some spec.
objects
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RDCSJ1252 at z1.24 VRizK photometry some spec.
objects
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Large-scale structure in the local Universe
2 Large-scale structures around distant
clusters
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Large-Scale Structures at z0.55
CL0016 at z0.55 (Tanaka MNRAS, 2007, 379,
1546)?
0.48ltzphotlt0.60
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cluster redshift
Large-Scale Structures at z0.55
3,600 objects
CL0016 at z0.55 (Tanaka MNRAS, 2007, 379,
1546)?
0.48ltzphotlt0.60
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red galaxies
Large-Scale Structures at z0.83
blue galaxies
RXJ0153 at z0.83 Tanaka 2006 MNRAS, 365, 1392
0.76ltzphotlt0.88
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spec. objects at 0.82ltzlt0.85
Large-Scale Structures at z0.83
z0.837
z0.844
z0.839
z0.844
z0.842
z0.782
z0.745
z0.835
RXJ0153 at z0.83
0.76ltzphotlt0.88
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Large-Scale Structures at z1.1
RDCSJ0910 at z1.1
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Large-Scale Structures at z1.2
RDCSJ1252 at z1.24 Tanaka 2007a MNRAS, 377, 1206
1.17ltzphotlt1.31
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Close-up views of the clumps
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galaxies come in two flavours...
red
blue
bright
faint
3 Build-up of the red sequence
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Colour-Magnitude Diagrams at zlt0.83
faint
bright
Tanaka 2005 MNRAS, 362, 268
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Colour-Magnitude Diagrams at z1.1 (preliminary!)
RDCSJ0910 at z1.1
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Colour-Magnitude Diagrams at z1.2
RDCSJ1252 at z1.24
18 20
22 24
Ks
18 20 22
24 26
Ks
Main Cluster Lidman et al. 2004 AA
Composite Group Tanaka et al. 2007a MNRAS
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Colour-Magnitude Diagrams at z1.2
1 The bright-end of the red sequence appears
first and the faint end appears later.
2 The build-up of the red sequence is
delayed in low-density environments.
Main Cluster Lidman et al. 2004 AA
Composite Clump Tanaka et al. 2007a MNRAS
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4 Spectral Diagnostics
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composite spectra of red galaxies at z0.8
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composite spectra of red galaxies at z0.5
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composite spectra of red galaxies at z0
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Spectral Diagnostics
Redshift Field
Group Cluster
z0.8

z0.5
z0
Red galaxies are consistent with passive
evolution no OII, no strong Hd
The strong Hd is suggestive of a sharp decline in
star formation rates.
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Fast Facts of Environmental Mechanisms
mechanisms
star formation effective env.

• galaxy-galaxy interactions ltlt1Gyr
  field/group
• harassment ?
  cluster
• ram-pressure stripping ltlt1Gyr
  cluster
• strangulation 1Gyr
  group/cluster

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Fast Facts of Environmental Mechanisms
mechanisms
star formation effective env.

• galaxy-galaxy interactions ltlt1Gyr
  field/group
• harassment ?
  cluster
• ram-pressure stripping ltlt1Gyr
  cluster
• strangulation 1Gyr
  group/cluster

For more detailed discussions, see Tanaka 2007
MNRAS, 379, 1546
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5 From the Cradle to the Grave
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Clusters at High/Low Redshifts
Proto-clusters at z5.7 can be traced by young,
forming galaxies (Ouchi '05).
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Galaxy clusters change their nature from the
cradle to the grave... Key question How
and when do they change?
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Key epoch redshift around 2
Probing z2 clusters would give us a hint for the
origin of the environmental dependence of galaxy
properties.
RDCSJ1252 cluster at z1.24 (Tanaka '07) Red
gals have already become the dominant population.
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Oktoberfest in Munich
6 Summary
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Summary

• Galaxies follow the 'environment-dependent
  down-sizing' evolution.
• Galaxy-galaxy interactions may be the driving
  process of this evolution.
• Probing clusters at z2 with next generation
  surveys would be interesting.

Environment
Mass