Cosmology with Large Telescopes: an ESO-centric view Catherine - - PowerPoint PPT Presentation

Cosmology with Large Telescopes:

an ESO-centric view Catherine Cesarsky ESO Venice, August 2007

The Very Large Telescope (VLT)

The ALMA Project (2012)

GMT TMT

ELTs: the world scene

• 2 US projects

– Giant Magellan Telescope (21-m)

• Carnegie & US Universities

– Thirty Meter Telescope

• Caltech, U. of Calif., Canada

E-ELT

• 42m baseline

diameter

• Innovative

5-mirror design

• Excellent image quality
• Reconfigurable: multiple foci

F/15+F/16 F/16 gravity invariant Coude

Axis 1’ 2’ 3’ 4’ 5’

50 mas

E-ELT

Stiff mechanics

FE models and analysis

Cross Altitude: 2.1 Hz Altitude locked rotor: 2.5 Hz

85008 elements 27106 nodes

E-ELT

Powerful built-in AO

• M4+M5:

GLAO, LTAO

• Plus post-focal AO:

ExAO, MCAO, MOAO, …

M4 (adaptive) M5 (tip-tilt)

WAVEFRONT ABERRATION

Optical design laser friendly

AO mirror

• ptions

E-ELT

Instrumentation friendly

Nasmyth: Coude:

MCAO module Codex

Part 1:Fundamental Cosmology

• Spectroscopy of distant supernovae
• Ly forest:
• small scale coherence length of the

mass distribution

• variation of physical constants
• dynamic measurement of the

acceleration of the Universe

• Age of the oldest stars

Supernova evidence for acceleration

Riess et al. 2004

ESSENCE

• World-wide collaboration

to find and characterise SNe Ia with 0.2 < z < 0.8

• Search with CTIO 4m

Blanco telescope

• Spectroscopy with VLT,

Gemini, Keck, Magellan

• Goal: Measure distances

to 200 SNe Ia with an

• verall accuracy of 5%

determine to 10%

• verall

SNLS – The SuperNova Legacy Survey

• World-wide

collaboration to find and characterise SNe Ia with 0.2 < z < 0.8

• Search with CFHT 4m

telescope

• Spectroscopy with

VLT, Gemini, Keck, Magellan

• Goal: Measure

distances to 1000 SNe Ia with an overall accuracy of 5%

determine to 7%

• verall

First cosmology results published

• SNLS

– Astier et al. 2006 – 71 distant SNe Ia – various papers describing spectroscopy (Lidman et

• al. 2006, Hook et al. 2006), rise time (Conley et al.

2006) and individual SNe (Howell et al. 2006)

• ESSENCE

– Wood-Vasey et al. 2007 – 60 distant SNe Ia – Miknaitis et al. 2007 – description of the survey – Davis et al. 2007 – comparison to exotic dark energy proposals – spectroscopy (Matheson et al. 2005, Blondin et al. 2006)

Time variable w?

Wood-Vasey et al. 2007

w=w0+wa (1-a) Distance module versus z Residuals for (-1, 0.27, 0.73) universe

High-z SNe with ELTs: What type of AO?

• Use a low-z reference galaxy image shifted to higher z:

– angular scale changes – surface brightness changes (+ crude galaxy evolution model)

• “Supernova” = point source with approx 80% of galaxy flux
• Convolve with different AO PSFs

Simulations for a 42m telescope H band on axis, z=1.65

LTAO Few arcsec MCAO (~ 2’ FOV) GLAO (~5’ FOV) No AO

PSFs from Le Louarn et al.

High-z Supernovae with ELT

• ELT ideal for high-z

spectroscopy

– redshifts and types – detailed test of evolution

• 42m ELT with AO could

reach

– z=1.7 (no OH suppression) – or z~4 with OH suppression – using AO

GRBs could also be used for similar purposes

Statistical Comparison of high and low-z spectral features –Garavini et al.(2007)

Combined analysis of Lyman forest matter power spectrum, weak lensing and CMB

Lesgourgues et al.2007 (VHS; Viel et al.2006) Conclusion: Sigma 8 (co-moving rms of density fluctuations in sphere of radius 8/h Mpc) slightly higher than with WMAP alone

Cosmic structure at small scales

Observations of distant QSO pairs can be used to measure the structure of the intergalactic H I and to derive the cosmological parameters. Present results fit with the concordance model. Lyman -forests of two pairs of QSOs observed with UVES; separations: ~ 1’. z ~ 2.6 and 2.1; (B mag : 18.8-20.5) (d’Odorico et al. 2006)

With the 2nd generation VLT instrument X-shooter , higher SNR to fainter magnitudes will make possible to increase significantly the QSO pair sample

(2008)

Alcock-Paczynski test using the X-shooter

(2nd generation VLT spectrograph)

The transverse distance scale, which is sensitive to the vacuum energy ( ?) can be determined through the 3-D correlation of Ly forests of neighboring QSO spectra .An accuracy of 10 % on can be achieved analyzing 13 (/1’) QSO pairs with separation < (McDonald 2003). Given the current counts on QSO pairs (left plot) and the performance prediction

• n the X-shooter the measurement becomes possible with ~140 hr exposure time (

120 faint QSOs)

2 < z < 3 z < 0.1 < 3’ < +15°

# of QSO pairs (V mag of the faintest one) Expected SNR with Xshooter

Variability of Physical Constants from QSO Absortion Line Spectra

In many models the cosmological evolution of dark energy is accompanied by variations of the fine-structure constant and of the electron/proton mass ratio . These variations could be used to trace the evolution with z of the equation of state parameter w

From accurate measurements of the absorption line centers in QSO metal absorption lines From Molecular Rotational vs. Vibrational modes

• f H2 molecules

Measurement of a possible variability of fundamental constants: upper limits of from Keck (HIRES) and VLT (UVES) spectra of QSO

Murphy et al.- fig1 (2004), Chand et al -fig2- (2004)., Levshakov et al (2007) Very accurate measurements of lines centers of different ion transitions in QSO absorption systems. Status: detection at the limit of accuracy, possibly still biased by systematic errors. Contradictory results from different data sets or the application of different methods.

Fig.2 Fig.1

e.g. Variation of µ = mp/me

Ivanchik et al. (2005, A&A, 440, 45), see also

Reinhold et al. (2006), Murphy et al (2006) and many more…..

K 1 ) 1 (

i i i

• µ

µ

• +

+ =

• abs

lab

• bs

z

Laboratory Observations

Coefficients K have been calculated (Varshalovich and Potekhin 1995) The wavelength of electron-vibro- rotational lines depend on the reduced mass of the molecule

Profiles of lines selected

Q0347-383 Q0405-443

UVES: 20 hours per line of sight Absorptions free of blending and Narrow lines

Correlation between (z-< z>)/(1+<z>) and K?

• Systematics ? -> Need for more laboratory wavelength measurements
• Increase the number of lines of sight WITH the same absorption lines
• Increase S/N ratio

High-Precision Spectrographs at ELTs (e.g. CODEX @ 42m) will be able to increase the accuracy by 2 orders of magnitude (better S/N, special calibration techniques) and give much more significant constraints

Simulated data set as state-of-art (upper panels) and with CODEX at ELT , for a given DE model , lower panels (Martins, 2006) Reconstruction of equation of state and band of uncertainty (grey area): dashed line corresponding to input to simulations, solid line reconstruction’s best fit. (Martins, 2006)

Cosmic Dynamics Experiment

Measuring (z):

• Allows us to watch, in real-time,

the Universe changing its expansion rate.

• Most direct and model-

independent route to the expansion history.

• First non-geometric measurement
• f the global RW metric.
• Independent confirmation and

quantification of accelerated expansion.

De- or acceleration of the universal expansion rate causes a small change in observed redshifts as a function of time:

z &

v &

Solid lines: Dashed lines: in cm/s

Cosmic Dynamics Experiment

Measuring the redshift drift requires:

• E-ELT
• High resolution, extremely stable spectrograph
• ~15 yr long spectroscopic monitoring campaign

Best place to observe the redshift drift: the Lyman- forest.

Cosmic Dynamics Experiment

Can we collect enough photons to achieve the required accuracy? Yes: 20 known QSOs with 2 < z < 5 are bright enough to achieve a radial velocity accuracy

• f 3 cm/s with 3200 hours
• n a 42-m ELT.

3 c m / s 4 cm/s

Cosmic Dynamics Experiment

Simulations: 2.2 nights/month

• ver 15 years will

deliver any one of these sets of points. Different sets correspond to different target selection strategies. t = 15 years

Grows with time Shrinks with observing time

Cosmic Dynamics Experiment

• 1.7 nights/month over 20

years will unequivocally prove the existence of dark energy without assuming flatness, using any other cosmological constraints or making any

• ther astrophysical

assumption whatsoever.

• Provides independent

confirmation of SNIa results, using a different method and complementary redshift range.

• Data will enable lots of
• ther science (e.g. varying ),

enormous legacy value.

t = 20 years

Age of Universe

14.2 ± 2.5 Gyr UVES

Cayrel et al. 2001

Part 2: Evolution of the components of the Universe

• History of the mass assembly of galaxies:

multiwavelength surveys, 3D studies of galaxies

• Ly forest as probe of distant galaxies

and IGM

• GRBs: galaxies and IGM far and near

2.5x2.5’

e.g FIRES - Franx et al

FIRES: Deep infrared imaging of distant galaxies with ISAAC on the VLT

(Labbe, Franx et al. 2003) Imaging in 1-2.5m infrared bands corresponds to optical at z ~3 Excess of high redshift (z~3) galaxies in HDFS compared to HDFN

HDFS

Faint (~26 AB) and sharp (FWHM~0.45”)

MS1054-03

GOODS South: CDFS

ISAAC maps in J, H and K (Vanzella et al. 2005, 2007) Spectroscopy with FORS 2 and VIMOS

HAWK-I

• High Acuity, Wide field

K-band Imaging

• Attached to ESO’s VLT

HAWK-I

• First Light: 31 July 2007
• Serpens Star

Forming Region

• Four quadrants

First Light: 31 July 2007 Serpens Star Forming Region One quadrant

VVDS

• 6,500 galaxies studied

with VIMOS

• 3D atlas of the Universe

from z=0.83 to 0.93 (I.e. 7 billion years ago)

• Colour-density evolves

with time and depends on the galaxy environnement

• (See also COSMOS)
• O. Cucciati et al. 2006

In the future, ELT will be required for spectroscopy and study of physical properties

• f galaxies to be found in surveys with HAWK-

I,VISTA, Herschel, ALMA, JWST Excellent synergy of 8-10m telescopes with HST, Spitzer and other facilities

Galaxy formation and evolution

UV-selected galaxies at z>2

Spatially resolved velocity gradient measured in all galaxies. Three best cases: rotation curves on wide radial scales; robust determination of dynamical mass.

Rotation curves and dynamical evolution of galaxies at z~2 Foerster Schreiber et al. (2006)

1”~8Kpc H map Velocity map

A large protodisk galaxy at z=2.4

Genzel et al. 2006

• SINFONI maps of H-alpha
• em. line separated in 65 km/s

bins.

• SF occurs in luminous

complexes

• Large dynamical mass

The strong deviations (c-d) from a simple rotation pattern indicate a (70- 100km/s) radial component. A large, massive protodisk is channelling gas towards a growing bulge hosting an accreting massive BH. Star formation in the disk with no evidence for a major merger

An example from the E-ELT Design Reference Mission (in preparation):

The Physics and Mass Assembly of Galaxies

Results of Simulations

(P.Rosati, M.Puech, A.Cimatti, S.Toft)

Aim:

Provide t

the u ultimate t test o

• f g

galaxy formation t theories: e epoch a and m mode o

• f ba

baryonic m mass b build-up

• Spatially resolved spectroscopy of a sample of massive

galaxies at 2<z<~5

dir

irect kin inematic ics of stars and gas in in the fi first generatio ion of massiv ive gala laxie ies in in the range 0.1<Mstar<5x1011 M

dynamic

ical l masses, ages, metallic llicit itie ies

dif

ifferentia ial l evolu lutio ion of dis isk and spheroid idal l components as a

• funct. of z

physic

ical l channels ls of mass assembly ly from z5

3D datacube « IFU data » V.F. map Emission line flux map sky subtraction

• atm. Abs.

Readout noise,dark, etc.

M.Puech

Reference case (z=4, M* galaxy)

z=4, HAB=24.5 (M* @z=4) Vmax 200 km/s Log(M*)=10.7 M EWrf=30A (OII in H band) RH=200 mas, Rgal= 4RH=0.8”(5.6 kpc) D=42m ExpTime=24h R=5000 Pixel=50 mas Sky=16.4 in H (1.3 mag brighter than ETC) Multi Object AO PSF with EE=12-37%

in100mas=2pxl

Physical params Instrumemt params

Reference case (z=4, M* galaxy)

12% EE 37% EE

Rotating disk Mergers

z=5.6 (OII in K) disk galaxy at different masses

0.1 M* 0.5 M* 1.0 M* 5 M* 10 M* MOAO PSF (EE=44% in 0.1”)

Scaling relations

• Reliable Kinematic studies out to z~6 of super-

L* galaxies, and down to 0.1 M* at z=2 Minimum <S/N> for kinematic studies:

Damped Ly- Systems

Only way to detect directly H2 at high z

Metals :

• > Metallicities
• > Dust content
• > Kinematics

Molecules H2 + CI, CI* :

• > Density/Temperature
• > UV flux (excitation)

H2 constrains the time variation of µ=me/mp and can help determining Tof CMB in the past

Star- Formation ? Winds ? HI :

Highest z detection of H2

• Damped Ly-alpha system at

z=4.224 towards quasar PSS J 1443+2724

• H2 , with low dissociation rate.
• High metallicity

SF took place when Universe was ~1 billion years old CMB T at z=4.2: 14.2K

Ledoux et al. 2006

UVES/VLT

GRB afterglow spectra: rich in information on high-z hosts

metallicity Z ~ 0.01 Zsun redshift z = 3.97

GRB 050730: Starling et al. 2005

Most distant GRB for which the distance had been measured ( 1999, VLT ANTU + FORS1)

Redshift z = 4.50

2005: even more distant GRB

• GRB 050904
• Observations were done between

24.7 and 26 hours after the burst with ISAAC and FORS2

• Photometric redshift: 6.3

(confirmed by SUBARU)

Chincarini et al., 2005

ISAAC

I-dropout z=6.3

Subaru spectrum of GRB 050904 at z=6.295

Kawai et al. (2006)

GRB Spectra

• Rapid Response Mode on VLT
• Taking detailed spectra within minutes of

Swift detection

• Fully automated
• Record: 7 min after burst

VLT+UVES observations of GRB 060418

Vreeswijk et al. 2006

GRB 060418 rapidly localized by Swift Swift automatically triggered the VLT Rapid-Response Mode start first exposure 10 min after burst trigger time series 3, 5, 10, 20, 40 min and 80 min different setting resolution 7 km/s, coverage 330-670nm and up to 950nm signal-to-noise ratios: 10-20 per pixel per spectrum

Absorption line systems at 4 different z. For GRB, z=1.49. At z=1.1, absorber with clear dust bump at 2175A. Absorbers at lower z are faint galaxies.

(Ellison et al. 2006)

Intervening galaxies

UV pumping

The time variation of the column density of fine structure lines of FeII and Ni II cannot be fitted with models invoking collisional excitation

• r IR photons.

A good fit is obtained with UV pumping, provided that the neutral cloud is at a distance: 1.7 ±0.2 kpc from the GRB. HI and metallicity measurements from optical spectroscopy may not be representative of the GRB region

Swift/VLT Large Programme to study GRB host galaxies

PI: J. Hjorth

typically 24-26 mag current telescope sizes limit such studies

R band K band

GRBs: Goals for ELT

• Study the host galaxy population and their use as tracers
• f star formation. How do they relate to other high-z

galaxy samples?

• Incredibly detailed studies of the afterglow spectra –

hosts, individual star-forming regions and progenitors

• Study the re-ionisation epoch through absorption studies
• f distant, bright GRB afterglows
• Confirm the GRB-SNe connection out to larger distances
• GRBs may provide a cosmological probe that extends

the range covered by Type Ia Sne (Ghirlanda et al. 2006)