Title: History of cosmic web of galaxies
1 History of cosmic web of galaxies
- Agnieszka Pollo
- Laboratoire d'Astrophysique de Marseille (LAM)
- Marseille, France
2Short History of the Universe (one of)
- Planck Era 10(-43) s. 10(-33) cm regions
homogeneous and isotropic. izotropowe,
T10(32)K. - Inflation. 10(-35) s after BB, T 10(27)
10(28)K, fast expansion. - Inflation ends. 10(-33 s), T 10(27)
10(28)K. Homogeneous regions from Planck era
have grown to 100 cm (gt 10(35) times). Tiny
nearly gaussian density fluctuations.
3Short History of the Universe
- Bariogenesis. 100,000,001 protons per 100,000,000
antiprotons (and 100,000,000 photons). - Till 100 s after BB Universe grows and cools
down, T 109K. Protons anihillate with
antiprotons, later e- and e. H i He are
created.
4Krótka historia Wszechswiata
- One month after BB processes which transform
radiation field into black body radiation become
slower than the velocity of expansion of the
Universe from now on there is a chance of some
informations being preserved in CMB 56 000 years
after BB matter density radiation density. T
9000 K. Inhomogeneities of (dark) matter start to
grow
5Short history of the Universe
- 380 000 after BB protons and electrons make
neutral H. T3000K. The Universe becomes
transparent - CMB may travel freely (last
scattering surface). Normal (barionic) matter
starts to accumulate on the dark matter
overdensities - 100-200 mln years after BB first stars shine and
re-ionize the Universe. First supernovae explode.
Galaxies and clusters form. - 4,6 bln years ago Sun shines.
- Today 13.7 bln years after BB. T2.725 K.
6After recombination (WMAP 3-years temperature map)
7 Large-scale structure in the local (zlt0.2)
Universe galaxies (Colless, Maddox, Peacock et
al.)
8The Large Scale Structure of the Universe
- Gravitational instability theory
- Density fluctuations (of dark matter) after
inflation, Gaussian (?) distribution - Matter gathers around these
- Galaxies, clusters, LSS form
- The smaller scale the more non-linear evolution
- Tests of the model
- Statistics
- Simulations
9From the observational side...
- The main source of our knowledge about the LSS of
the Universe are catalogs of galaxies (2D
positions only and 3D redshift surveys)
10 Redshift surveys may allow to investigate...
- The history of formation and evolution of
galaxies - Evolution of the LSS of the Universe and what
physical processes may determine it in different
epochs and timescales - Formation and evolution of different classes of
objects (e.g. AGNs) - Formation and evolution of clusters
11 Most of great calalogs today only local
Universe
- Local Universe a few big surveys, like
- SDSS
- 2dF
- gt 1M galaktyk do z 0.3
- Distribution and properties relatively easy to
examine - BUT no evolution
12 13 Which means practical problems
- Few objects (until recently not more than a
few1000 for 0.5ltzlt5) - Small volumes (-gtbig cosmic variance)
- Different selection criteria for different
measurements and related biases how to compare?
How to make a joint analysis?
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15Structure evolution we want to see the whole
movie, not only the last slide!
16Recent deep galaxy surveys
- Goalç to measure redshifts of gt 100 000 galaxies,
to analyse history of LSS and galaxies themselves - VVDS
- Deep-2
- ostatnio COSMOS
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19The origins build a redshift machine for the ESO
VLT targeted to deep, high-surface density galaxy
samples
- 1995 First ideas WFISNIRMOS
- 1996 Feasibility Study
- 1997 VIMOSNIRMOS contract
- VIisible Multi -Object Spectrograph
- Near InfraRed Multi -Object Spectrograph
20Whos Who in the the
Consortium
- Six main nodes Marseille, Bologna,
Haute-Provence, Milan, Naples, Toulouse - PIs O. Le Fevre G.Vettolani
- co-Is D. Maccagni (Milano), J.P. Picat
(Toulouse), D. Mancini (Naples) - Science Advisory Committee
- 50 people involved in the Hardware/Software
Team - 90 people involved in the Science Team for the
survey preparation and analysis - See web page, www.oamp.fr/virmos
21- Science drive the VIMOS-VLT Deep Survey (VVDS)
- 50 VIMOS guaranteed nights over 3 years on
ESO-VLT UT3 - 100,000 redshifts to IABlt22 over an area of 16
sq.deg., 0ltzlt1.3 in 5 fields - 50,000 redshifts to 22ltIABlt24 over an area of
1.5 sq.deg., 0ltzlt5 - 1000 redshifts to IAB26 over a 1x1 sq.arcmin
area using a Integral Field Spectroscopy unit
(6400 fibres) - Preparatory IMAGING
- UBVRIJK photometric surveys at CFHT, ESO, CTIO
- RADIO (VLA_at_1.4GHz, 80 mJy) X-ray (XMM, 1014
erg s-1 cm-2 for extended sources) coverage of
the F02 field (deep 1 sq.deg. area at RA02h) - X-ray (XMM) imaging to fx 10-15 erg s-1 cm-2
over F02
22VIMOS/NIRMOS layout
VLT Nasmith focus flattened separately into 4
channels, fed into 4 CCD cameras (7x8 arcmin
field of view each)
23A redshift machine gt 500 spectra in one shot
FOV 4x56 sq arcmin multiplexing 800 spectral
resolution 200 -5000 IFU 1'x 1', 6400 fibres
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25VVDS and structure evolution
- 2-point correlation function in redshift slices
- Clustering per color, luminosity, spectral types
- Bias evolution
- Clustering of particular types of objects (EROS,
starforming galaxies) as compared to general
population - Galaxy mergers how many close pairs in
different epochs? - redshift-space CF distortions -gt small-scale
galaxy dynamics - Clusters density Xray (XMM) and optical
(multi-colour, I-K, matched filter, photo-z,) - and many more...
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27First Epoch VVDS Data
- 11564 spectra from 17.5ltIABlt24, fields 0226-04
and CDFS, area 0.61 sq.deg. - 10518 galaxies with measured z, 8869 with
confidence level gt80 - 836 stars
- 85 AGNs
- 125 unidentified objects
- Field coverage 25 - 30
28First epoch VVDS-Deep survey VVDS-02 field
29First VVDS data
- 0ltzlt5
- 1065 galaxies zgt1.4
- Successful measurements on the redshift desert ,
i.e. 1.5ltzlt2.2 - Problems in 2.2ltzlt2.7 range (because of the
filter coverage)
30Distribution of secure redshifts (median 0.70)
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342-point correlation function
- Definition probability above random that we
find a pair of galaxies at a certain distance
from each other (spatial, angular) - In practice different estimators, e.g.
Landy-Szalay - Problems different densities of different parts
of the fields because of different number of
observation runs, bright stars, non-random choice
of objects for spectroscopy
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36Measuring the correlation function
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40Biases removal for the redshift-space correlation
function
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42Biases removal for the 2D redshift space
correlation function
43Biases removal for the projected (real space)
correlation function
44Evolution of the 2-point correlation function
from the first-epoch VVDS data
45Evolution of a comoving correlation length
46Comparison with DEEP-2
(astro-h/0409135)
47What theory says? Weinberg at al., 2004, LCDM
simulations clustering history of galaxies and
DM differs dramatically
48Similar informations may be extracted directly
from PDF
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50Red (old) galaxies and blue (recently star
forming) galaxies
- Now it is well known that red/early type galaxies
(elipticals, irregulars) are more clustered than
blue/late type (spiral) ones - How did it evolve? When did they segregate?
- When did galaxy types appear?
- Meneux et al., 2006, Cucciati et al. 2006
51Correlation length for different galaxy types and
colors
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53CF properties vs absolute luminosities
- w_p(r_p) in different luminosity ranges for small
and large z - Correlation length r_0
- slope gamma
- Non power-law fit!
- Different relative bias at different scales
54w_p in luminosity ranges
- VVDS-02, M_B
- 2 wide ranges corresponding to 3.5 bld years,
medians z0.4 and z0.9 - 7 luminosity ranges in each
55w_p(r_p) and the best (r_0, gamma)
56w_p(r_p) power-law fit
57r_0 VVDS vs SDSS and 2dF
58gamma VVDS vs SDSS i 2dF
59Relative bias at 1 Mpc scale
60No power law Argument for Halo Occupation
Distribution Models...
61...non-linear relative relative bias(with
rescpect to gal L)?
62Summary structure evolution in VVDS
- General populationç correlation length almost
constant between z0.5 and z2, in a survey
where the only selection criterion is luminosity
(IABlt24) - This effects may be understood as a
superposition of the evolution of structure
itself,evolution of bias and different dependence
of clustering on luminosity - Generaal population in a good agreement with
hydrodynamical simulations in a model with CMB
and big cosmological constant - Galaxies of early spectral types (eliptical and
early spirals) are more clustered than late
spirals and irregulars in all epochs - Red galaxies more correlated than blue ones
- But a tendency to reverse this relation at
z1.5?
63Summary structure evolution in VVDS
- For different absolute luminosities
- r_0 and gamma rise for LgtL for large z
- non power law fit of CF z -gt argument in favor
of HOD models? - Scale-dependent bias?
- Conclusions
- In the z0.9 Universe bright galaxies more
willingly were closer to other bright galaxies
than today - What happened to them? Did they merge? Did they
get fainter? - Bias not only evolving, but also non-linear?
- We have to develop models and theory
64First epoch VVDS results (selected)
- Survey description (Le Fevre et al. 2005)
- Two-point correlation function in z slices (Le
Fevre et al., 2005, Pollo et al., 2005, A A) - Evolution of LF and B luminosity density (Ilbert
et al. 2005, Tresse et al. 2005, Zucca et al.
2005) - Combined GALEX-VVDS evolution of UV LF and UV
luminosity density (Arnouts et al. 2005,
Schiminovich et al 2005) - Clustering of color-selected classes (Meneux et
al, 2006. AA, in press) - Clustering as a function of luminosity (Pollo et
al., 2006a, AA, in press, Pollo et al., 2006b,
in prep.) - Evolution of bias (Marinoni et al., 2005)
- Properties of K-selected galaxies in the
VVDS-Deep survey (Iovino et al., AA, in press)
65- Effective in isolating galaxies around z3
(U-dropouts) and z4 (B-dropouts) - Pioneered by Steidel Hamilton (1992)
- Spectroscopic confirmation only possible thanks
to the new generation of 10m-telescope
availability (Keck) - Selects strongly star-forming galaxies with
significant Lyman break
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68- Correlation length 3-5 h-1 Mpc, i.e. comparable
to todays normal galaxies!
69Lyman-break galaxies are strongly star-forming
objects, plausibly progenitors of todays
luminous cluster galaxies. Clearly, their
clustering is not representative of general
structure at z3. They are an illustrative
example of a highly biased population of LSS
tracers. Similar examples are provided by very
red galaxies selected using near-infrared bands
around z1 (R-K) and zgt2 (J-K) (e.g. works by
Cimatti et al. and Van Dokkum et al.). ? Need
for larger redshift surveys looking at the global
galaxy population. Two such projects underway
the DEEP2 survey at Keck (Davis et al) and the
VIMOS-VLT Deep Survey (VVDS)
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71Two-point correlation function from VVDS
first-epoch data per galaxy morphological types
example for one z slice
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73What we expect to find
742dFGRS Maximum likelihood fit of redshift-space
distortions
A more recent analysis of the 100,000 redshift
public release, with careful treatment of window
function aliases and error correlations finds
?0.16 (Tegmark, Hamilton Xu, 2002,
astro-ph/0111575)
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77The VIRMOS survey and the evolution of structure
- Two-point correlation function in z slices
- Clustering of color-selected classes
- Clustering of radio-loud vs. normal population
- Evolution of bias (i.e. the way light traces
mass) - Clustering of special classes (e.g. Extremely
Red Objects, strongly star-forming galaxies) vs.
general population - Merging history how many close pairs at
different redshifts? - Small-scale dynamics from redshift-space
distortions - Evolution of number density of galaxy clusters
X-ray selection (XMM survey over 2hrs field) vs.
optical selection (multi-colour, I-K, matched
filter, photo-z,) - and much more
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94- Effective in isolating galaxies around z3
(U-dropouts) and z4 (B-dropouts) - Pioneered by Steidel Hamilton (1992)
- Spectroscopic confirmation only possible thanks
to the new generation of 10m-telescope
availability (Keck) - Selects strongly star-forming galaxies with
significant Lyman break
95- Correlation length 3-5 h-1 Mpc, i.e. comparable
to todays normal galaxies!
96Lyman-break galaxies are strongly star-forming
objects, plausibly progenitors of todays
luminous cluster galaxies. Clearly, their
clustering is not representative of general
structure at z3. They are an illustrative
example of a highly biased population of LSS
tracers. Similar examples are provided by very
red galaxies selected using near-infrared bands
around z1 (R-K) and zgt2 (J-K) (e.g. works by
Cimatti et al. and Van Dokkum et al.). ? Need
for larger redshift surveys looking at the global
galaxy population. Two such projects underway
the DEEP2 survey at Keck (Davis et al) and the
VIMOS-VLT Deep Survey (VVDS)
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