1. CODEX 2006 - LP Concept study for the COsmic Dynamics EXperiment

2. CODEX 2006 - LP ESO: G. Avila, B. Delabre, H. Dekker, S. D’Odorico, J. Liske, L. Pasquini, P. Shaver Observatoire Geneve : M. Dessauges-Zavadsky, M. Fleury, C. Lovis, M. Mayor, F. Pepe, D. Queloz, S. Udry INAF-Trieste: P. Bonifacio, S. Cristiani, V. D’Odorico, P. Molaro, M. Nonino, E. Vanzella Institute of Astronomy Cambridge: M. Haehnelt, M. Murphy, M. Viel Others: F. Bouchy (Marseille), S. Borgani (Daut-Ts), A. Grazian (Roma), S. Levshakov, (St-Petersburg), L. Moscardini (OABo-INAF), S. Zucker (Tel Aviv), T. Wilklind (ESA) The Team

3. CODEX 2006 - LP Directly measure the expansion of the Universe by observing the change of redshift with a time interval of a few (10-20) years ”It should be possible to choose between various models of the expanding universe if the deceleration of a given galaxy could be measured. Precise predictions of the expected change in z=d / 0 for reasonable observing times (say 100 years) is exceedingly small. Nevertheless, the predictions are interesting, since they form part of the available theory for the evolution of the universe” Sandage 1962 ApJ 136,319 The experiment

4. CODEX 2006 - LP t 0 =actual epoch t e =emission epoch Cosmic Signal In a homogeneous, isotropic Universe a FRW metric

5. CODEX 2006 - LP Why measure dynamics? All the results so far obtained in the ‘concordance model’ assumes that GR in the FRW formulation is the correct theory.  ~0.7 : but we do not know what  is and how it evolves. If GR holds, geometry and dynamics are related, matter and energy content of the Universe determine both. Dynamics has, however, never been measured. All other experiments, extremely successful such as High Z SNae search and WMAP measure geometry: dimming of magnitudes and scattering at the recombination surface.

6. CODEX 2006 - LP The change in sign is the signature of the non zero cosmological constant The Signal Is SMALL!

7. CODEX 2006 - LP How to Measure this signal? Masers : in principle very good candidates: lines are very narrow and measurements accurate: however they sit at the center of huge potential wells: large peculiar motions, larger than the Cosmic Signal are expected Radio Galaxies with ALMA : The CODEX aim has been independently studied for ALMA: as for Masers, local motions of the emitters are real killers. Few radio galaxies so far observed show variability at a level much higher than the signal we should detect Ly  forest: Absorption from the many intervening lines in front of high Z QSOs are the most promising candidates. Simulations, observations and analysis all concur in indicating that Ly  forest and associated metal lines are produced by systems sitting in a warm IGM following beautifully the Hubble flow !

8. CODEX 2006 - LP QSO absorption lines To Earth CIV SiIVCIISiII Ly  em Ly  forest Lyman limit Ly  NV em SiIV em Ly  em Ly  SiII Quasar CIV em

9. CODEX 2006 - LP A LARGE signal.. But this is for 10 7 years… Having much less time at our disposal the shift is much smaller.. Why can we conceive to detect It NOW?

10. CODEX 2006 - LP What’s new VLT-UVES & Keck HIRES observed hundreds of QSOs at High Res (R>40000), z between 2 and 5, V=16-18. Ly  clouds have been extensively simulated: their hot gas belongs to the IGM and they trace the Hubble flow Exoplanets (HARPS) long term accuracy 1m/s, short term (hours) 0.1m/s (and largely understood) ELT !! LOT OF PHOTONS (we need them!!)

11. CODEX 2006 - LP Simulating the dependence on resolution ( Ly  forest only) Results of simulations (1) Above a R~50000 there is no more gain for the Ly  Forest. Higher Resolution is required by metal lines and Calibration accuracy.

12. CODEX 2006 - LP Results of simulation (1): real spectrum Dependence on cumulative S/N/pixel (0.015 A)

13. CODEX 2006 - LP Simulating the dependence on Z Results of Simulation (1) Information “saturates”: a) Too many lines b) High Redshift makes them broader.

14. CODEX 2006 - LP Many simulations have been carried out independently by 3 groups; using observed and fully simulated spectra. A very good agreement is found, and we can produce a simple scaling law:  v = 1.4*(2350/(S/N))(30/N QSO ) 0.5 (5/(1+Z)) 1.8 cm/sec Where  v is the total uncertainty (difference between 2 epochs) while the other parameters refers to the characteristics of one epoch observation; Pixel size considered: 0.0125. About half of the signal is coming from the metal lines associated to the Ly  Results of simulations (2)

15. CODEX 2006 - LP The full experiment DT=10 yrs 1500 Hours Metals V=16.5 Eff. 15% Results of simulations (3)

16. CODEX 2006 - LP Result of simulations (4) N QSO = 30 randomly distributed in the range 2 < z QSO <4.5 S/N = 3000 per 0.0125 Å pixel/epoch (no metal lines used)  t = 20 years Green points: 0.1 z bins Blue: 0.5 z bins Red line: Model with H 0 =70 Km/s/Mpc Ω m =0.3 Ω  =0.7 The cosmic signal is Detected at >99% significance(!) The full experiment

17. CODEX 2006 - LP Can we do it ? Telescope + Instrument Efficiency required to complete the experiment under the following assumptions: V=16.5 QSO 36 QSO each S/N 2000 (0.015 pixel), for a total of 2000 obs. hs/epoch ( 1cm/sec/yr) Red line: VLT+UVES peak efficiency In 1 st approx. precision scales as D for a given efficiency.

18. CODEX 2006 - LP QSO have been selected from existing catalogues and compilations (Veron, SDSS ) Selection criteria: magnitude and z Magnitudes: redwards of Ly , selected band depends on z Verification of targets and reference mission In this Figure only the 5 brightest QSOs of each 0.25 z bin are shown. Hypothesis: e.g. 2000 h observations with an 80 m telescope and 14% efficiency; all QSO brighter or around the iso-accuracy lines are suitable.

19. CODEX 2006 - LP With a telescope in the range of the 30-40m, will the experiment still be possible ? Scaling to a smaller telescope diameter 1)Increase the timeline; with 20 yrs (double), accuracy also scales to 2 cm/sec, inverse to D tel 2)Use the full spectral range, including, e.g. the Ly  region (contaminated by Ly  ) 20 yrs baseline

20. CODEX 2006 - LP Ly  =  v acc ~100 Km/sec T acc ~10 9 yr.. negligible Metal systems associated to damped Ly  :  v acc ~3-400 Km/sec T acc ~10 8 BUT hundreds systems-statistically level out Different from the maser and radio-galaxy case… Calls for many line of sight PECULIAR MOTIONS

21. CODEX 2006 - LP

22. Detailed, state of the art hydrodynamical simulations confirm that the effects are negligible PECULIAR MOTIONS: Simulations

23. CODEX 2006 - LP Peculiar motions at the Earth The solar acceleration in the Galaxy will be measured with an accuracy of ~ 0.5 mm/sec/yr by GAIA ParameterInduced error on the correction [cm s -1 ] Comment Earth orbital velocity - Solar system ephemerides< 0.1JPL DE405 Earth rotation - Geoid shape - Observatory coordinates - Observatory altitude - Precession/nutation corrections ~ 0.5 < 0.1 Any location in atm. along photon path may be chosen Target coordinates - RA and DEC - Proper motion - Parallax ? ~ 0 70 mas  1 cm s -1 negligible Relativistic corrections - Local gravitational potential< 0.1 Timing - Flux-weighted date of observation? 0.6 s  1 cm s -1

24. CODEX 2006 - LP 3 outstanding projects were selected: - Cosmological variation of the Fine-Structure Constant 3 outstanding projects were selected: - Cosmological variation of the Fine-Structure Constant: CODEX will exceed the accuracy of the OKLO reactor (D  /  ~5x 10 -9 ) Beyond expansion…. - Terrestrial planets in extra-solar systems: - Terrestrial planets in extra-solar systems: Radial velocity of earth mass planets, spectroscopy of transits - Primordial nucleosynthesis: - Primordial nucleosynthesis: probing SBB nucleosynthesis: primordial Li 7, Li 6 /Li 7 Many additional applications (as from 8m science..): Asteroseismology, Cosmochronometers, First Stars, Temperature evolution of CMB, Chemical evolution of IGM..

25. CODEX 2006 - LP Variability of Physical Constants Variability of Physical Constants Fundamental Constants play an important role in our understanding of nature. Test of fundamental physics. Higher dimensional theories constants are defined in full dim space: string theories predict extra dimensions of space and dynamical dimensionless constants The existence of extra dimensions of space is related to the properties of dark energy, dark matter and cosmic inflation. One of the 9 hottest main questions

26. CODEX 2006 - LP ‘Local’ Constraints α was larger in the past Oklo (t=1.8 Gyr, Z=0.14) Δα/α  4.5  10 -8 Lamoreaux & Torgerson 2004 Δα/α =(+8 ± 8)  10 -7 Olive et al. 2004 from meteorites (z~0.4) For 10 Gyr => Δα/α < 3.8×10 -5 Laboratory measurements

27. CODEX 2006 - LP Astrophysical Constraints VLT/UVES 23 systems Δα/α=(+0.6±0.6)×10 -6 Chand et al 2004 Keck/Hires 143 systems Δα/α=(-0.57±0.11)×10 -5 Murphy et al 2004

28. CODEX 2006 - LP Fujii & Iwamoto 2005 : apparent oscillatory time- dependence The behavior is produced by the scalar field responsible for the acceleration of the universe SIDAM Method Δα/α = (+0.4±1.5)×10 -6 Levshakov et al. 2004, Quast et al. 2004

29. CODEX 2006 - LP Expected Improvement The astronomical measurement of  is based on the difference of measured wavelengths. The uncertainty   is caused by errors in wavelengths   scales with (S/N) -1 ad with (  ) 3/2 ( see e.g Bohlin et al. 83,  is the pixel size and the lines are resolved ) For UVES  =0.02, S/N~70, 23 systems (Chand et al. 2004)   ~ 6x10 -7 For CODEX:  =0.5  uves, S/N~30 S/N uves, 40 systems: a gain of : 2.8 x 30 x 1.3 ~ 1.1x10 2 with respect to UVES or   ~ 5x10 -9

30. CODEX 2006 - LP Planets Planets Earth (and other) planets discovered with other techniques need accurate radial velocity measurements for confirmation and mass determination; ESO-ESA WG report explicitly recommends ESO for new accurate RV facility (Earth mass signal in habitable zone: 3-10 cm/sec) Three main applications: 1)Discover and confirmation of rocky planets 2) Search for long period planets 3) Jupiter mass planets around faint stars

31. CODEX 2006 - LP Example of an instrument tank: HARPS

32. CODEX 2006 - LP The HARPS Experience O-C < 80 cm/sec Th-Th < 10 cm/sec

33. CODEX 2006 - LP The HARPS Experience (cont’d) Harps is finding planets with small O-C, small masses

34. CODEX 2006 - LP Planets: HARPS Planets: HARPS New candidate O-C: 1.1 m/sec Red: Gaseous giant planets Blue: Icy planets Green : Rocky planets

35. CODEX 2006 - LP Planets: low mass Planets: low mass Main problem: sources of ‘Noise’ : Photon noise, Oscillations, Activity-induced jitter Oscillations and Jitter are ubiquitus ( cf. Figure K2V-G2IV stars with HARPS ) Solution: many epoch measurements to average the effects but EXPENSIVE: ~10’s - ~100 hours/star Bonus: Very high S/N spectra to study the spectrum at different planet phases 1)Observe stars that have high probability of hosting earths 2)Follow-up and confirmation of planet candidates discovered by other facilities

36. CODEX 2006 - LP Jupiters around faint stars With HARPS it is shown that  v =1m/sec with a S/N~80/pixel With CODEX @ ELT S/N~80 in 10 min for V~16.5 and  v =10m/sec in 1 hour V~21.5 (!) Hot Jupiters in Solar Stars of Clusters, Bulge, Sagittarius, LMC … Studying planet formation in very different environments seems one of the natural next steps

37. CODEX 2006 - LP Primordial Nucleosynthesis and the early universe WMAP and BBN : Real Disagreement ?

38. CODEX 2006 - LP Primordial 6 Li ? Li 6 /Li 7 Plateau?? Asplund et al. 2005 Conventional way: 7 Li depleted, 6 Li produced in the early Galaxy by  +  Decaying particles at the BBN epoch change the final abundances. Jedamzik (2004) has shown that decaying neutralinos could deplete 7 Li and synthesize 6 Li.

39. CODEX 2006 - LP Codex Li Observations Measure 7 Li and 6 Li/ 7 Li in a variety of metal - poor populations in the Galaxy and in other galaxies (GC, Bulge, Sagittarius, LMC..) Measure 6 Li/ 7 Li in metal poor ISM, with D primordial values by using QSOs as lighthouses.

40. CODEX 2006 - LP Interstellar Li (and 7 Li/ 6 Li) Knauth Federman Lambert 2003 Mc Donald R=360000 SNR=500 t exp 10h EW 7 Li=0.4 mA, 6 Li= 0.04 mA Interstellar Li today only available for solar material IS 7 Li/ 6 Li in metal poor material (HVCs Complex C, MCs …)

41. CODEX 2006 - LP CODEX design parameters Location Underground in nested stabilized environment Telescope diameter 100 m FeedCoude’ + Fibre or Fibre only Oerall DQE 14% Coude’ + Fibre, 9% Fibre only Entrance aperture 0.65 arcsec (1 arcsec for a 60 m. Tel.) Wavelength range 400 – 680 nm Spectral Resolution 150 000 Number of Spectrographs 5 (11 for 1 arcsec aperture at 100 m) Main disperser 5 x R4 echelle 42 l/mm 160 x 20 cm Crossdisperser5 x VPHG 1500 l/mm 20 x 10 cm Camera5 x F/1.4-2.8 CCD5 x 8K x 8K (15 um pixels) No Optimization or trade-off done yet

42. CODEX 2006 - LP How to improve RV accuracy and stability Scramblers to reduce effect of guiding errors Image dissector, multiple instruments Simultaneous wavelength calibration Use of wavelength calibration “laser comb” Fully passive instrument, ultra-high temperature stability Instrument in vacuum tank High precision control of detector temperature Underground facility, zero human access

43. CODEX 2006 - LP Entrance aperture 1” on 60 m or 0.65” on 100 m 37 Fibres array, 8 fibres/spectrograph OWL Fiber feed + Pre-slit Lightpipe: forming an homogeneously illuminated Slit & scrambling

44. CODEX 2006 - LP Light from fibres enters here CODEX Unit Spectrograph B. Delabre ESO

45. CODEX 2006 - LP Underground hall 20 x 30 m; height 8 m 1 K Instrument room 10 x 20 m; height 5 m Instrument room 10 x 20 m; height 5 m 0.1 K Control room and aux. equipment (laser) 1 K Instrument tanks, dia. ~ 2.5 x 4 m, Instrument tanks, dia. ~ 2.5 x 4 m, 0.01 K Optical bench and detector 0.001 K CODEX laboratory floor plan

46. CODEX 2006 - LP Challenges & Feedback  Calibration source, stable, reproducible, equally spaced.. LASER COMB  CCD control (thermal… )  High throughput of the spectrograph and injection system: EFFICIENT COUDE’ FOCUS  Light scrambling capabilities (1 cm/sec  0.0000003 arcsec centering accuracy on a slit…) TELESCOPE POINTING AND CENTERING ~0.02 arcsec  System aspects (from pointing to calibration to data reduction) ALL aspects strongly suggest extensive prototyping

47. CODEX 2006 - LP  CODEX Lab CODEX @ ELT A visible H-R spectrograph designed to test GR and able to address fundamental questions Spectrograph feasible even for a seeing - limited case up to 100m telescope diameter H-R must be coupled to extremely high accuracy and stability Prototype at VLT

48. CODEX 2006 - LP CODEX @ ELT More info & discussion at the Aveiro Conference on Precision Spectroscopy in Astrophysics 11-15 September 2006, Aveiro, Portugal http://www.oal.ul.pt/psa2006

49. CODEX 2006 - LP CODEX Planning and Costs The preliminary project plan shows that the full development time for 1 full prototype operating for 3 years at the VLT + 5 CODEX unit spectrographs is 12 years, with a HW cost of 24 ME and ~100 FTEs Starting with Phase A in 2006, CODEX could be operated at OWL in 2019. The project is larger, but comparable to big VLT instrumens Each CODEX unit comparable to e.g. UVES Estimates are based on the experience with UVES and HARPS (Optics, Vacuum Vessel…) and MUSE (same CCD) preliminary tenders

50. CODEX 2006 - LP Once QSOs are established targets, through basic knowledge and simulations we determine the spectrograph parameters. Spectral range: QSO in the range Z~1.5 - 5. At higher Z too many absorbers wipe out information, Ly  is visible from earth at Z>1.8 For lower Z, metal lines only can be used. But to span a large Z range is important also to link it to lower Z experiments: ideal range 300-680 nm. UV: trade-off (less sensitivity, few Ly  absorbers..) Resolving Power : Ly  line have a typical width of 20-30 Km/sec and R=50000 would suffice. Higher spectral resolution is required by metallic lines (b<~3 Km/sec) and by calibration accuracy requirement; R~150000 Such a resolution is challenging for any seeing limited ELT: the final number will be a trade off between size, sky aperture, detector noise… BASIC SPECTROGRAPH REQUIREMENTS

51. CODEX 2006 - LP Calibration System: Laser Frequency Comb  Metrology labs recently revolutionized by introduction  of femtosecond-pulsed, self-referenced lasers driven by atomic clock standards Cesium atomic clock n 2n (or even GPS signal!)  Result is a reproducible, stable “comb” of evenly spaced lines who’s frequencies are known a priori to better than 1 in 10 15 I(1)I(1) n2n2n

52. CODEX 2006 - LP Laser Comb: Advantages and Challenges Advantages:  Absolute calibration: long term frequency stability  Evenly spaced and highly precise frequencies allow mapping of distortions, drifts and intra-pixel sensitivity variations of CCD  Naturally fibre feed system. HARPS prototype possible. Challenges:  Line-spacing currently limited to 1GHz by laser size and energy considerations. We need ~10–15GHz. New technology needed. Development project underway with Max Plank of Quantum Optics.  Transmission of non-linear optical fibre questionable as low as <400nm. Existing technology can probably be extended.

53. CODEX 2006 - LP CODEX Image and Pupil Evolution Several new features : Anamorphic collimator Pupil Slicer Anamorphic Crossidsperser (Slanted VPH)

54. CODEX 2006 - LP  CODEX Lab CODEX @ OWL

55. CODEX 2006 - LP Variability of fine structure Variability of fine structure α α = e 2 /hc Characterize the strength of the electromagnetic interaction Fine and hyperfine structure of n=1 level H

56. CODEX 2006 - LP With the assumptions of homogeneity and isotropy, the concordance model finds a FRW metric with a non zero cosmological constant Standard Cosmological Model

57. CODEX 2006 - LP Since the discovery of Hubble in the late 20’ of the expansion of the universe, this became one of the pillars of “Big Bang” cosmology. Later additions are the CMB and the Primordial Nucleosynthesis Although not all believe this ‘big bang’ a large consensus exists among cosmologists, who have produced a ‘standard model’ Historical background in short

58. CODEX 2006 - LP Comb: spectra simulations R=100k,  =15GHz, =5000Å Total velocity precision better than 1cms -1 in a single shot for SNR ~ 1000 (4500-6500Å)

59. CODEX 2006 - LP Geometry tells us that the Universe is Expanding, so why bother to measure dynamics? Measurement of the dynamics of the Universe can be compared to basic experiments such as the measurement of the principle of equivalence between Inertial and Gravitational mass… Without it, it is like measuring the geometrical orbits of planets w/o measuring their accelerations… (e.g. No 2nd Kepler law..) If we do not measure, we do not know

60. CODEX 2006 - LP COMPONENTCOST (KE) Calibration Unit450 Acquisition-guiding system350 Fibre Fed (includes scrambler)350 Transport & Insurance450 Integration & Test cost500 Project management, miscellanea700 CODEX Lab and facilities500 TOTAL COMMON3300 CODEX HARDWARE COSTS: COMMON MODULE Special Laboratory cost not included

61. CODEX 2006 - LP CODEX HARDWARE COSTS: SINGLE SPECTROGRAPH COMPONENTCOST (KE) Comments Spectrograph Optics 1300 includes X-disperser Echelle Grating 60020x160 cm mosaic of 2 UVES echelles Spectrograph Mechanics 400Includes optical bench Spectrograph Electronics 100 Vacuum System 500 Criogeny and CCDs 6004 4Kx4K CCDs + Cryostat + Controller TOTAL/Spectro3500

62. CODEX 2006 - LP Direct measurement ! Bias-free determination of cosmological parameters Different redshift (CMB, SNIa) Not dependent from evolutionary effects of sources Legacy Mission to future astronomers (First epoch measurements)

63. CODEX 2006 - LP The Concept Study Work Structure Organized according to the Statement of Work agreed by all partners in 5 work packages: WP1000 Management (L.Pasquini, ESO, PI) WP2100 Main Science Case (S. Cristiani, INAF-Trieste) WP2200 Science Methodology (F. Pepe, Obs. Geneve) WP 2300 Immediate Science Cases (P. Molaro, INAF-Trieste) WP 3000 Technical Design (H. Dekker, ESO)