1. Large-Scale Structure beyond the 2dF Galaxy Redshift Survey Gavin Dalton Kyoto FMOS Workshop January 2004 (Oxford & RAL)

2. Overview  Summary of 2dFGRS design  Key results… defining contemporary cosmology  Key results… galaxies as tracers of LSS  Key results… relationship to CMB measurements  FMOS Possibilities – LSS beyond z=1  Input data: Wide-Field IR imaging surveys  Survey Design Issues

3. Results from the 2dF Galaxy Redshift Survey Target: 250,000 redshifts to B<19.45 (median z = 0.11) 250 nights AAT 4m time 1997-2002

4. SGP Final 2dFGRS Sky Coverage NGP Final redshift total: 221,283

5. 2dFGRS Redshift distribution  N(z) Still shows significant clustering at z < 0.1  The median redshift of the survey is = 0.11  Almost all objects have z < 0.3.

6. Cone diagram: 4-degree wedge

7. Fine detail: 2-deg NGP slices (1-deg steps) 2dFGRS: b J < 19.45 SDSS: r < 17.8

8. 2dFGRS power-spectrum results Dimensionless power: d (fractional variance in density) / d ln k Percival et al. MNRAS 327, 1279 (2001)

9. Confidence limits ‘Prior’: h = 0.7 ± 10% & n = 1  m h = 0.20 ± 0.03 Baryon fraction = 0.15 ± 0.07

10. Power spectrum: Feb 2001 vs ‘final’

11. Model fits: Feb 2001 vs ‘final’  m h = 0.20 ± 0.03 Baryon fraction = 0.15 ± 0.07  m h = 0.18 ± 0.02 Baryon fraction = 0.17 ± 0.06 if n = 1: or  m h = 0.18 e 1.3(n-1)

12. Conclusions from P(k) Lack of oscillations. Must have collisionless component CDM models work Low density if n=1 and h=0.7 apply possibilities for error: Isocurvature?  =1 plus extra ‘radiation’? Massive neutrinos? Scale-dependent bias? (assumed  gals Q  mass )

13. Redshift-space clustering  z-space distortions due to peculiar velocities are quantified by correlation fn  ( ,  ).  Two effects visible: –Small separations on sky: ‘Finger-of- God’; –Large separations on sky: flattening along line of sight r  

14.  and   Fit quadrupole/monopole ratio of  ( ,  ) as a function of r with model having    0.6 /b and  p (pairwise velocity dispersion) as parameters  Best fit for r > 8 h -1 Mpc (allowing for correlated errors) gives:  =  0.6 /b = 0.43  0.07  p = 385  50 km s -1  Applies at z = 0.17, L =1.9 L* (significant corrections) Model fits to z- space distortions  = 0.3,0.4,0.5;  p = 400  = 0.4,  p = 300,500  99%

15. Mean spectrum PC1 PC2 PC3 Early Late Galaxy Properties: Spectral classification by PCA  Apply Principal Component analysis to spectra.  PC1: emission lines correlate with blue continuum.  PC2: strength of emission lines without continuum.  PC3: strength of Balmer lines w.r.t. other emission.  Define spectral types as sequence of increasing strength of emission lines  Instrumentally robust  Meaning: SFR sequence

16. 2dFGRS in COLOUR passive active R magnitudes from SuperCosmos Rest-frame colour gives same information as spectral type,  but to higher z

19. Clustering as f(L) Clustering increases at high luminosity: b(L) / b(L*) = 0.85 + 0.15(L/L*) suggests << L* galaxies are slightly antibiased - and IRAS g’s even more so: b = 0.8

20. Redshift-space distortions and galaxy type Passive:  =  m 0.6 /b = 0.46  0.13  p = 618  50 km s -1 Active:  =  m 0.6 /b = 0.54  0.15  p = 418  50 km s -1 Consistent with  m = 0.26, b passive = 1.2, b active = 0.9

21. Power spectrum and galaxy type shape independent of galaxy type within uncertainty on spectrum

22. Relation to CMB results Combining LSS & CMB breaks degeneracies: LSS measures  m h only if power index n is known CMB measures n and  m h 3 (only if curvature is known) curvature total density baryons

23. 2dFGRS + CMB: Flatness CMB alone has a geometrical degeneracy: large curvature is not ruled out Adding 2dFGRS power spectrum forces flatness: | 1 -  tot | < 0.04 Efstathiou et al. MNRAS 330, L29 (2002)

24. Detailed constraints for flat models (CMB + 2dFGRS only: no priors) Preferred model is scalar-dominated and very nearly scale-invariant Percival et al. MNRAS 337, 1068 (2002)

25. Impact of WMAP

26. likelihood contours pre-WMAP + 2dFGRS 147024 gals scalar only, flat models

27. likelihood contours post-WMAP + 2dFGRS 147024 gals scalar only, flat models - WMAP reduces errors by factor 1.5 to 2

28. likelihood contours post-WMAP + 2dFGRS 213947gals scalar only, flat models

29. Vacuum equation of state (P = w  c 2 ) w shifts present horizon, so different  m needed to keep CMB peak location for given h w < - 0.54 similar limit from Supernovae: w < - 0.8 overall 2dFGRS

30. Key Points  Basic underlying cosmology now well determined  CMB + 2dFGRS implies flatness –CMB + Flatness measures  m h 3.4 = 0.078 – hence h = 0.71 ± 5%,  m = 0.26 ± 0.04  w < - 0.54 by adding HST data on h (agrees with SN)  Clustering enhanced as F(L)  Different bias for different galaxy types, but shape of P(k) is identical.  Many diverse science goals realised in a single survey design

31. FMOS Possibilities for LSS at z>1  Wavelength Range (single exposure) 0.9  m< <1.8  m –OII enters at z=1.4 –4000Å break enters at z=1.2 –Hα enters at z=0.4 –OII leaves at z=3.8 –Hα leaves at z=1.74 Complex p(z) due to atmospheric bands and OH mask. New field setup time is FAST  Sensitivity: Clear IDs for H=20 magnitude limit: 20 minutes for late-types (50 minutes for early types) [But P(k) shape insensitive to type!!!]  Could obtain as many as 7000 galaxy spectra/night!

32. Input Data: Wide-Field IR Surveys  Natural starting point is the UKIDSS DXS 35 square degrees to K=21.5, J=22.5 (5  ) ~ 60000 galaxies (zP1, HO20) UKIDSS fields: 2-year plan LAS DXS UDS GPS GCS

33. Upcoming wide-field IR imaging - VISTA 1.67 degree focal plane, 16 2048x2048 HgCdTe arrays Single instrument survey telescope

34. VISTA Capabilities  FOV 1.67 degrees  Pixel sampling 0.33 arcseconds  YJHK filter set as baseline (3 empty slots)  70% of VISTA time must be dedicated to ‘public’ surveys with emphasis on meeting the science goals of the original VISTA consortium  Extension of UKIDSS DXS in 1 year would cover 500 square degrees.  Commissioning begins April 2006  Data processing and archiving in common with UKIDSS – fast access to final catalogues.  ESO effectively committed to supporting UKIDSS/VISTA operations with complementary VST surveys.

35. FMOS Survey Design Issues  Optimal survey speed influenced by reconfiguration and field acquisition times… –Possibilities for large-scale surveys with relatively bright limits.  Optimal use of telescope time may dictate merged surveys (c.f. 2dF GRS & QSO surveys) with multiple science goals (i.e. evolution; clusters; EROs; SWIRE all may be included in LSS survey).  Input data for ambitious surveys will be available on appropriate timescales, but much preparation required. –No problem with spreading a large survey over several years since effectively no competition! – e.g. think in terms of a survey of ~100 FMOS nights over 5 years.