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The Build-up of the Red Sequence at z<1.3
Masayuki Tanaka (ESO, not STScI)
+
Taddy Kodama (NAOJ)
galaxies come in two flavours...red
blue
bright faint
Conclusion
• The bright end of the red sequence appears first and it extends to fainter mags., and the build-up of the red sequence is ‘delayed’ in low density environments.
• Galaxy-galaxy interactions may be a primary driver of this build-up.E
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Outline of this talk
0 – Introduction
1 – PISCES project
2 – Large-scale structures around distant clusters
3 – Build-up of the red sequence at z<1.3
4 – Spectral Diagnostics
5 – Summary
large-scale structure in the local
universe
0 – Introduction
outline
0 – introduction
1 – pisces prject
2 – large-scale structures in the distant
universe
3 – the build-up of the colour-magnitude
relation
4 – spectral diagnostics
5 – summary
Galaxies in low-density
environments...
NGC5668
Galaxies in high-density
environments...
Coma
cluster
Clusters at higher redshifts
CL0016 at z=0.55 taken with WFPC2 on
HST
?
?
?
?
?
Clusters at higher redshifts
CL0016 at z=0.55 taken with WFPC2 on
HST
Cluster outskirts and surrounding
clumps/filaments remain unexplored.
Also, faint galaxies at high redshifts have not
been extensively examined yet.
We carried out a wide and deep cluster
survey.
1 – PISCES projectoutline
1 – pisces project
2 – large-scale structures around distant
clusters
3 – the build-up of the red sequence
4 – spectral diagnostics
5 – summary
Pi·sces [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 0.4<z<1.3.
PISCES project (in A&A abstract format)
For details, see Kodama+ 2005 PASJ, 57, 309
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 (~M*+4), wide-field (30’x30’),
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.
ACS/
HST
CL0016+16 at z=0.55
BVRiz photometry + 150 spec. objects
RXJ1716 at z=0.81
VRizK, H photometry + AKARI IR photometry
RXJ0152-13 at z=0.83
VRizK photometry + 200 spec. objects
RDCSJ0910 at z=1.1
VRizK photometry + some spec. objects
RDCSJ1252 at z=1.24
VRizK photometry + some spec. objects
2 – Large-scale structures
around distant clusters
outline
1 – pisces project
2 – large-scale structures around distant
clusters
3 – the build-up of the red sequence
4 – spectral diagnostics
5 – summary
Large-scale structure in the local Universe
~70,700 objects~3,600 objects
0.48<zphot<0.60
Large-Scale Structures at z=0.55
CL0016 at z=0.55 (Tanaka+ MNRAS, 2007, 379, 1546)
~3,600 objects
0.48<zphot<0.60
Large-Scale Structures at z=0.55cluster redshift
CL0016 at z=0.55 (Tanaka+ MNRAS, 2007, 379, 1546)
Large-Scale Structures at z=0.83
RXJ0153 at z=0.83Tanaka+ 2006 MNRAS, 365, 13920.76<zphot<0.88
red galaxies
blue galaxies
Redshift distribution of spec. galaxies
0.76<zphot<0.88
cluster redshift
RXJ0153 at z=0.83Tanaka+ 2006 MNRAS, 365, 1392
RXJ0153 at z=0.83
Large-Scale Structures at z=0.83
z=0.844
z=0.842
z=0.745z=0.782
z=0.835
z=0.837
z=0.839
z=0.844
spec. objects at
0.82<z<0.85
0.76<zphot<0.88
Large-Scale Structures at z=1.1
RDCSJ0910 at z=1.1
RDCSJ1252 at z=1.24
Tanaka+ 2007a MNRAS, 377, 1206
Large-Scale Structures at z=1.2
1.17<zphot<1.31
Close-up views of the clumps
3 – Build-up of the red sequenceoutline
1 – pisces project
2 – large-scale structures around distant
clusters
3 – the build-up of the red sequence
4 – spectral diagnostics
5 – summary
galaxies come in two flavours...red
blue
bright faint
Cluster / Group / Field Environments
For details of the definition, refer to Tanaka+2005 MNRAS
Colour-Magnitude Diagrams at z<0.83
blue
red
faintbright
Tanaka+ 2005 MNRAS, 362, 268
Evolution of Fraction of red galaxies
Color-Magnitude Diagrams at z=0.81
RXJ1716 cluster surrounding field
Koyama et al. 2007 MNRAS submitted.
Colour-Magnitude Diagrams at z=1.1 (preliminary!)
RDCSJ0910 at z=1.1
Colour-Magnitude Diagrams at z=1.2
Main Cluster
Lidman et al. 2004 A&A
Composite Group
Tanaka et al. 2007a MNRAS
18 20 22 24 26
Ks
18 20 22 24
Ks
RDCSJ1252 at z=1.24
Colour-Magnitude Diagrams at z=1.2
Main Cluster
Lidman et al. 2004 A&A
Composite Clump
Tanaka et al. 2007a MNRAS
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.
4 – Spectral Diagnosticsoutline
1 – pisces project
2 – large-scale structures around distant
clusters
3 – the build-up of the red sequence
4 – spectral diagnostics
5 – summary
z=1.24
z=1.1
z=0.83
z=0.81
z=0.55
z=0
: RDCSJ1252
: RDCSJ0910
: RXJ0152
: RXJ1716
: CL0016
: Sloan Survey
composite spectra of red galaxies at z~0.8
composite spectra of red galaxies at z~0.5
composite spectra of red galaxies at z=0
Spectral Diagnostics
...for details see Tanaka+07 MNRAS, 379, 1546
Spectral Diagnostics
Redshift Field Group Cluster z~0.8
z~0.5
z~0
No clear CMR CMR at bright end Tight CMR
CMR at bright end Tight CMR Tight CMR
Red galaxies are consistent with passive evolution
no [OII], no strong Hd
EW[OII]=14A EW[OII]=4A No [OII]
EW[OII]=4A No [OII] No [OII]
No strong Hd Strong Hd No strong Hd
Strong Hd No strong Hd No strong Hd
The strong Hd is suggestive of a sharp decline in star formation rates.
Fast Facts of Environmental Mechanisms
galaxy-galaxy interactions <<1Gyr field/group
harassment ? cluster
ram-pressure stripping <<1Gyr cluster
strangulation ~1Gyr group/cluster
mechanisms star formation effective env.
Fast Facts of Environmental Mechanisms
galaxy-galaxy interactions <<1Gyr field/group
harassment ? cluster
ram-pressure stripping <<1Gyr cluster
strangulation ~1Gyr group/cluster
mechanisms star formation effective env.
For more detailed discussions, see Tanaka+ 2007 MNRAS, 379, 1546
5 – Summaryoutline
1 – pisces project
2 – large-scale structures around distant
clusters
3 – the build-up of the red sequence
4 – spectral diagnostics
5 – summary
Ein Prosit, ein Prosit der Gemütlichkeit!
Ein Prosit, ein Prosit der Gemütlichkeit!
Summary
Galaxies follow the 'environment-dependent down-sizing' evolution.
Galaxy-galaxy interactions may be the driving process of this
evolution.E
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