Transcript How different was the Universe at z=1?

How Different was the Universe
at z=1?
Christian Marinoni
Centre de Physique Théorique, Marseille
Université de Provence
Local properties:
Constraining galaxy structural parameters at z=1
Evolution is
Known
Simply gravitational!
t
Dark Matter
Observations
Evolution
?
Complex physics!
Sondages spectro-photometriques
de l’univers profond (VVDS,zCOSMOS)
- Constrain baryonic physics
- Disentangle Nature and Nurture scenarios
Not Dark Matter
Global Properties :
Constraining Cosmological parameters at z=1
- Galaxies (WL, Power spectrum, Age test…)
- Clusters of galaxies (SZ+X, Abundance, Baryon fraction…)
Pro: - Lots of objects
- Different degeneracies w/r to SN, CMB
Con: - None Independent from assumptions on physical
models, Galaxy-DM bias, simulation prescriptions
- Source evolution
Need for a purely geometrical approach with self consistent
treatment of evolution
Diagnostic that takes into account consistently source evolution and background
cosmology
Outline
• A new implementation strategy for the Angular
diameter test using high z galaxies
• Preliminary Results on Cosmology and Evolution of
Galaxy Structural Parameters
Marinoni, Saintonge, Le Fevre, et al. 2006 A&A submitted
Saintonge, Masters, Marinoni, et al. 2006 A&A submitted
Marinoni, Saintonge, Contini et al. 2006 A&A submitted
Metric constraints using the kinematics of high redshift
disc galaxies
• Direct geometrical test of
cosmology
• Independent of physics,
and simulations
(Tolman test)
D
(D,z,)
Standard Rod Selection
Method: V L=F(D)
Sample:
Deep “cone”
(2h Field: first-epoch data)
• ~7000 galaxies with
secure redshifts, IAB24
z=1.5
• Coverage:
0.7x0.7 sq. deg
(40x40 Mpc at z=1.5)
• Volume sampled:
2x106 Mpc3 (~CfA2)
(1/16th of final goal)
•Mean inter-galaxy
separation at z=0.8
<l>~4.3 Mpc (~2dF at z=0.1)
•Sampling rate: 1 over 3
galaxies down to I=24
z=0
Implementation Strategy:
Cosmos : major space
imaging survey:
2
590 orbits of ACS/HST
Standard Rod selection
Z=0.5
0<v(km/s)<100
0<v(km/s)<200
VLT
HST
Z=0.9
HR VVDS Spectroscopy
The angular diameter test : Evolutionary effects
- Modelling different redshift evolutions for the standard rod (galaxy discs)

 ( z )   ( D, d A ( z , ))  e( z )
o
Consider 3 different
evolutionary scenarios
- Late epoch evolution
- Linear evolution
- Early epoch evolution
Evolution Effects in the angular diameter test
- Is there a feature that may
be used to discriminate
the presence of evolution?
Yes
m
- Is there a particular
evolutionary scenario for
which the inferred values of
ΩΛ and w are minimally biased?
Yes! Linear e(z)
Evolution Effects: Bias in the ΩΛ – w plane
- Predictions using
a simulated sample
of 1000 standard
rods
Fiducial :
NO Evolution
- No flat prior
Retrieved
40% linear
evolution
in discs at z=1
Fiducial model still within 1σ also when strong linear evolution is present
Cosmology - Evolution Diagram at z=1
V~150km/s sample
Is it possible to infer
cosmological information
without a priori
knowing e(z) ?
Yes! One may derive a
mapping between
cosmological space
( m ,   )
and evolution space
(D, M )
Only imposing
ΔM(z)<0
i.e. that objects
were brighter
in the past
Evolution of Galaxy Structural Parameters
D(z), L(z), μ(z) up to z=1
Small Mass Galaxies
V~70 km/s
High Mass Galaxies
V~150 km/s
Evolution of Galaxy Structural Parameters
D(z), L(z), μ(z) up to z=1
- Baryonic discs hosted in both small and big DM halos
show insignificant size evolution up to z=1 (ΔD/D ~ 0.1±0.2)
- Over the same redshift range small rotators experienced a
strong luminosity evolution ΔMI ~ -1.2±0.3 while the luminosity
of large rotators is seen to remain constant over cosmic time
- We conclude that the corresponding strong/weak evolution
in galaxy surface brightness is entirely due to a strong/weak
luminosity evolution since z=1. This study thus rules out the
possibility that SB evolution of discs is caused by a significant
size evolution.
Conclusions
- Goal : use deep galaxy surveys in order to explore
at the same time both background Cosmological models
and sources evolution
- Strategy : use observationally measured and theoretically
justified correlation between size and rotational velocity
of galactic discs to select a set of high redshift standard rods
- Results : - If ΔM(z)<0 then Open and EdS cosmologies are
excluded
- Evolution of baryonic discs is independent of
halo mass at least up to z=1. Only galaxy emission
properties depend on mass (with small systems
experiencing the strongest luminosity evolution).
Prospects : Apply the method to a new (~100) HR sample taken
by the zCOSMOS survey (P.I. Lilly).
~40 High Resolution
VLT/VIMOS (spectra) + HUBBLE/COSMOS (images)
Are we selecting ….
  mo ( z)   ( z) |D 5 log  ( z)
  M (0)  5 log D(0)  25