Local LSS after 2dFGRS

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Local LSS after 2dFGRS SDSS
?

• John Peacock UCL 28 June
  2004

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Redshift survey progress
mid-1980s few thousand
Now 2dFGRS SDSS ( 500,000 total )
only 2,000,000 z 3
Achievements of 2dFGRS

• Pure fluctuation issues
• Shape of P(k) and W h
• Hints of baryon wiggles ? baryon fraction
• Redshift-space distortions ? s8
• Joint with WMAP ? unique standard model
• Galaxy-formation issues
• LFs and bias as f(type)
• LFs and SFR as f(environment)
• Groups and properties as f(halo mass)

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2dFGRS in COLOUR
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Relative bias and stochasticity
25 Mpc cells relative bias b 1.34 correlation
coefficient r 0.96
Joint lognormal model
Wild et al. 2004
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Looking for groups in 2dFGRS
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Groups in 2dFGRS
Eke, Frenk, Cole, Baugh 2dFGRS 2003
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Mock 2dFGRS from Hubble volume
real space
Eke, Frenk, Cole, Baugh 2dFGRS 2003
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Mock 2dFGRS from Hubble volume
z-space
Eke, Frenk, Cole, Baugh 2dFGRS 2003
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Halo mass-to-light ratios
Nmin2, zmax0.07
sim
Factor of 4 decrease in M/L from rich clusters to
poor groups
ideal
Group luminosity
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The halo model
Neyman Scott Shane (1953) random clump model
correlations arise from pairs in the same clump
Application to CDM, following Benson, Cole,
Frenk, Baugh, Lacey 2000 Peacock Smith 2000
Seljak 2000, 2002
Berlind et al. 2002, 2003
Yang, van den Bosch, Mo et al. 2002a,
2002b, 2003
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Power from haloes of different mass
NL total
PS mass function and NFW halo profile gives
correct small-scale clustering from random
haloes. Add linear large-scale power for complete
model.
Lin
M1015
M1010
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Origin of antibiased power-law galaxy spectrum
Weight mass in haloes as M-a for M Mmin a
0.5 and Mmin 1012 works for 2dF Can measure
linear power at k 16
Prediction matches correlation data
Zehavi et al. astro-ph/0301280 Luminous SDSS
galaxies need weight M-0.11 for M Mmin
1013.6
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Galaxy formation models
Can we predict correctly how haloes are occupied
by galaxies?
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The overcooling problem
Preferred baryon density is now 1.5 x older
values Too much cooling at all masses. Can cure
with SN feedback only at low masses
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Colours and luminosity functions
Mergers
Cooling flows
Too many bright blue galaxies Too many faint red
galaxies
2dFGRS
Durham semianalytics
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Global remapping of relation between luminosity
and mass for each colour separately
Do this for two very different semianalytics (1)
Superwinds (2) half-baryon fudge
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Fake 1-degree slices, to limits B19.5, 21.5, 22.5
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cluster 6x density
Matches 2dFGRS LF(r) from Croton et al.
void 23
Outline survey possibility

• Science goals
• Halo M/L to local group level measure
  efficiency peak
• Detailed conditional luminosity functions
• Void LFs to deeper levels
• B
• 47,000 new galaxies at z
• 88 fields _at_ 400 fibres 30 perfect nights
• Must have photo-z selection to remove z 0.2
• SDSS Southern repeated strip ideal

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Baryon wiggles as a ruler
Blake/Glazebrook proposal 2 x 106 gs over 600
deg2 0.5 26
Wiggles in the halo model
NL total
P Plin Phalo Both terms depend on halo mass
try ranges from 109 to 1013
Lin
M1015
M1010
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Wiggles in the halo model
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Wiggles in the halo model
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Wiggles in the halo model
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Wiggles in the halo model