naoyuki tamura (university of durham) the universe at redshifts from 1 to 2 for early-type galaxies...
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Naoyuki Tamura(University of Durham)
The Universe at Redshifts from 1 to 2
for Early-Type Galaxies~ Unveiling “Build-up Era” with FMOS ~
Outline
Summary
Galaxy population at z < 1 and z > 2
To understand the histories ofearly-type galaxies …Does stellar population tell us all ?
What are expected at 1 < z < 2 ?
Revisit the starting point :
How can the strengths of Subaru/FMOS be exploited ?
Extremely Red ObjectsLimitation due to lack of spectrum
NGC 3923 : E4SFR
tEvolutions of CM relation & Fundamental Plane up to z ~ 1 look passive.
No active star formation is on-going at z=0. The bulk of stars seem to be old.
Stars in Elliptical Galaxies
Star formation Passiveevolutionstopped.
z > 2 ?
Ages at z = 0 from spectroscopy
[km/s] 100 200 300 [km/s]
60 100 180
Trager et al. (2000)
Caldwell et al. (2003)
Cluster Group
Field Virgo
Field
What does “age” tell us ?
“Galaxy formation history”
- when did a galaxy become an elliptical ?
“Star formation history”
- when did most of the stellar content form ??
Monolithic Collapse ScenarioStarburst
Gas rich
Hierarchical Merging ScenarioMajor mergerLuminosity
Function
Stellar Population
Luminosity Function of E/S0s at z < 1COMBO-17~ 2800 arcmin^2, R < 26 (5), ~ 25000 galaxies
~ 5000 galaxies on the red sequence at 0.2 < z < 1.2.
Rix et al. (2004)
GEMSHigh resolution imaging follow-up with ACS/HST
Most of them (~ 85 %) seem to be morphologically early-type.
Evolution of luminosity function
Luminosity Function of E/S0s at z < 1COMBO-
17
Bell et al. (2003)
About half of the local population were already in place at z ~ 1 ?
Luminosity Function of E/S0s at z < 1
Morphology
Spectroscopy
Multi-band photometry
Im et al. (2002): DEEP Groth Strip survey
Chen et al. (2003): Las Campanas IR survey
Pozzetti et al. (2003): K20 survey
Suggest a mild evolution up to z ~ 150 ~ 80 % were already in place at z
~ 1 ?
(HST/WFPC2 images)
Any “bona-fide” E/S0s at z > 2 ?
Radio galaxies
Rocca-Volmerange et al. (2004)
Pentericci et al. (2001)
(z = 2.3)
(z = 2.4)
Passive evolution prediction
(z = 10, M = 10 M )
f12
Any “bona-fide” E/S0s at z > 2 ?
Lyman Break GalaxiesSCUBA Galaxies
Red galaxies from FIRES
No clear Hubble sequence ?A population of passive E/S0s have not revealed
yet ?
Stellar mass ~ 10 M
J-K ~ 2 or redder
z = 2 ~ 3 (?)
z > 3
Strong clustering
<z> ~ 2.5 (1 < z < 4)SFR ~ 1000 M /yr
SFR ~ 1 - 100 M /yr
Starburst galaxies ?
10
Investigations are on-going ...
How can they be linked at z = 1 ~ 2 ? Star forming
galaxies Passive evolution phase
Luminosity function of passive galaxiesand its evolution at z = 1 ~ 2 A number of post-starburst galaxies ?
Half or more of the local population show up in this epoch ?
Consumption ?
Distant clusters are revealed ?
Through redshift survey …
somehowEnvironmental effect ?
Extremely Red Objects (EROs)
Good candidates for passive ellipticals at z > 1.
Heterogeneity Although the colour criterion seems to
work for isolating passive ellipticals …
Luminosity function of EROs has been studied.Our understandings of EROs have
been limited due to lack of spectra.
R-K > 5 / I-K > 4
(Cimatti et al. 2003; Yan et al. 2004)
Smith et al. (2002)
Smail et al. (2002)
Mannucci et al. (2002)
Colour criterion to classify EROs Cimatti et al.
(2003)
Miyazaki et al. (2002)
Caputi et al. (2004)
Evolution of ERO LF at z > 1 ?
Extremely Red Objects (EROs)
Good candidates for passive ellipticals at z > 1.
Heterogeneous Although the colour criterion seems to
work for isolating passive ellipticals …
Luminosity function of EROs has been studied.
Photo-z : z ~ 0.3 at z ~ 1.5
Our understandings of EROs have been limited due to lack of spectra.
Too coarse to investigate evolution at 1 < z < 2 ?
R-K > 5 / I-K > 4
(Cimatti et al. 2003; Yan et al. 2004)
What we need to do are :To perform deep spectroscopic
observations and to get quality data.
Redshift
ClassificationAbsorption line
To collect a large number of galaxies at z > 1 from a large survey area.
Good statistics Cosmic variance
The other word of FMOS (1)Wide spectral coverage in the NIRSpectral features in the rest frame optical
are available for galaxies at z > 1.
Combination with UKIDSS-DXS
Optimal for redshift survey.
(& Subaru/Suprime-Cam)
Allows us to efficiently pick up candidates for galaxies at z > 1 with colour information.
Luminosity can be derived with the aid of redshift.
The other word of FMOS (2)Wide field & high multiplicity
30’
FMOS-FOV / 400 fibres
~ 200 fibres will be available for objects in one exposure.
Better statisticsLonger integration
Highly efficient !
Simulated Spectrum
H = 20.5 mag
Old stellar population (3.0 Gyr age) at z = 1.5
8 hr integration (1 hr x 8) & 5 pix. binning
4000 A
G-band
H
Mgb
Gemini Deep Deep Survey
4 x 30 arcmin^2 fieldNod & shuffle technique
Gemini Multi-Object Spectrograph
> 30 hr integration per field
Fibre Multi-Object SpectrographFOV ~ 700
arcmin^2200/200 fibres for object/sky(+ Double beam switching obs. ?)??? hr integration per
FOV
???????????????? Survey
Simulated Spectrum
H = 22.0 mag
Old stellar population (3.0 Gyr age) at z = 1.5
100 hr integration (1 hr x 100) & 5 pix. binning
4000 A
G-band
H
MgbNaD
Summary
Luminosity function of passive galaxies Evolution of LF between z = 1
and 2.A number of post-starburst galaxies ?
To understand history of early-type galaxyLuminosity
FunctionStellar Population
Bridging two epochs ? z <
12 < z
Need to look at absorption lines
Star forming galaxiesPassive evolution
Wide field & high multiplicity can beexploited for deep observation.
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