Large Scale Structure in 2MRS

1
Large Scale Structure in 2MRS 6dF

Ofer Lahav (University
College London)
6dF workshop, AAO/Sydney, 26-27 April 2005
2
LSS in 2MRS

• The Local Group Dipole
• Wiener reconstruction
• Future work with 2MRS2MASS6dF
• Pirin Erdogdu (Cambridge/Ankara),
• John Huchra (CfA), Ofer Lahav (UCL)
• the 2MRS/6dF teams

3
F
2MASS Galactic chart
4
The Near IR Local Universe
5
2MRS mock ZoA
Random ZoA
25000 galaxies Ks lt 11.25 Huchra 2MRS/6dF
teams
Interpolated ZoA
6
2MRS vs. PSCz radial selection fn

7
Spectral PCA types in 2MASS
62 Es in 2MASS 35 Es in 2dF
Madgwick, OL et al.
8
Dipole weighting schemes
??m0.6/b
g / ltM/Lgt L/ (4 ? r2)
?L (7.67- 1.02) x 108 L_sun h Mpc-3
9
Number and Flux dipolesin the LG frame

• lt 0.57 - 0.07
• b2mrs gt 0.85 - 0.15
• (for ?m 0.30)

?m lt 0.37- 0.20
15o _at_ 50 Mpc/h
24o _at_ 130 Mpc/h
Erdogdu et al., In preparation
10
Out to 200 Mpc/h- LG frame
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Number and Flux dipolesin the CMB frame
12
Out to 200 Mpc/h CMB frame
13
Dipole Wiener reconstruction
?0.4 ?0.6
14
2MRS dipole directions _at_ 130 Mpc/h
15
Spherical harmonics
16
Wiener filtering
Redshift distortion
)
Signal/(SignalNoise)
Fisher, OL et al (1995)
17
WF 2MRS _at_ 2000 km/sec
Erdogdu et al.
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WF 2MRS _at_ 4000 km/sec
19
WF 2MRS _at_ 6000 km/sec
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WF 2MRS _at_ 10000 km/sec
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WF 2MRS velocity fieldCMB frame
Erdogdu et al.
22
WF 2MRS velocity fieldLG frame
23
The Concordance Model

• Bulk flows are expected to have in linear
  theory
• For ?m lt 1 lower amplitude and larger coherence
  length than in ?m1 universe
• Bulk flows are not sensitive to Dark Energy

24
Photometric redshifts
25
Photometric redshifts
26
Photo-z

• Other work
• HYPERZ Bolozonella et al., 2000, AA, 363,
  476
• Csabai et al,. 2003, AJ, 125, 580
• ANNz
• Firth, Lahav Somerville, 2003, MNRAS,
  339, 1195
• Collister Lahav, 2004, PASP, 116, 345
• http//www.ast.cam.ac.uk/aac
• Applications to SDSS LRGs, Dark Energy
  Survey, 2MASS,

27
Artificial Neural Network

Output redshift
Input magnitudes
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SDSS data (ugriz r lt 17.77)
ANNz (510101)
HYPERZ

29

Photo-z with ANNz
DES (griz) 5-yr alone
DES VISTA (YJHKs)
?z0.08
?z 0.13

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2MASS photo-z
?z 0.02
Collister Lahav, ANNz
z0 cyan z0.05 yellow z0.08 red
31
The 2dFGRS Team Members
I.J. Baldry, C.M. Baugh, J. Bland-Hawthorn, T.J.
Bridges, R.D. Cannon, S. Cole, C.A. Collins, M.
Colless (PI),W.J. Couch, N.G.J. Cross, G.B.
Dalton, R. DePropris, S.P. Driver, G.
Efstathiou, R.S. Ellis, C.S. Frenk, K.
Glazebrook, E. Hawkins, C.A. Jackson, O. Lahav,
I.J. Lewis, S.L. Lumsden, S. Maddox (PI), D.S.
Madgwick, S. Moody, P. Norberg, J.A. Peacock
(PI), B.A. Peterson, W. Sutherland, K.
Taylor http//www.mso.anu.edu.au/2dFGRS/ On
2dF Sociology see OL, astro-ph/0105351
32
2dFGRS PhD students collaborators
Spectral classification (PCA) S. Folkes, S.
Ronen, D. Madgwick Biasing from 2dFCMB S.
Bridle Neutrino mass O. Elgaroy Wiener
Reconstruction P. Erdogdu Stochastic
Biasing V. Wild Testing the halo model A.
Collister
Ofer Lahav, UCL
33
Future work and interests _at_ London

• Compare predicted 2MRS peculiar velocities with
  observed 6dF pec vel.
• Combine 2MRS with 2MASS photo-z
• and 6dF
• Cosmological parameters
• Halo model biasing
• The cosmic web
• Galaxy spectral classification

Alexandra Abate, Sarah Bridle, Ofer Lahav, Anais
Rassat
34
Clustering of Red vs. Blue 2dF galaxies
Madgwick, Hawkins, Lahav 2dFGRS team,
astro-ph/0303668
35
Whats next?The 6dF NIR Galaxy Survey

• 2MASS NIR selected
• 150k redshifts
• (Southern hemisphere)
• Peculiar Velocities
• for 15k galaxies
• Reconstruction of
• the MASS distribution

36
Great Walls of the Universe
37
The 2dFGRS Power Spectrum
Linear
Non-linear
50 Mpc/h
8 Mpc/h
38
The latest2dFGRS power spectrum
Cole et al. 2005
39
The SDSS LRG correlation fn(Eisenstein et al
2005)
40
Weighing Neutrinos with 2dFGRS

• Free streaming effect
• Wn/Wm lt 0.13
• Total n mass Mlt 1.8 eV
• 0.001 lt Wn lt 0.04
• (Oscillations) (2dF)
• a Four-Component Universe ?

Wn 0.05
0.01
0.00
Elgaroy , Lahav 2dFGRS team, astro-ph/0204152
, PRL
41
Absolute Masses of Neutrinos

• Based on
• measured
• squared mass
• differences
• from solar and
• atmospheric
• oscillations
• Assuming
• m1 lt m2 lt m3

Elgaroy Lahav, JCAP 03

42
Ratio of bulk flows with massive neutrinos ??
0.04

ElgaroyLahav, NJP, 2005
43
Principal Component Analysis

• Projections on the
• First two eigen-spectra
• Cf. traditional
• line indices

44
PCA for data compression(by a factor 1000)

• h 0.5 pc1 pc2

Madgwick, OL et al.
45
Correlation Function per Type
dP / n 1?(r) dV
?(r) (r/r0)-?
Why a power law?
Madgwick 2dFGRS
46
An empirical test of the halo model

• Pgal(k) Pgal(1h)(k) Pgal(2h)(k)
• The 1-halo term depends on
• the halo mass function,
• the halo occupation number
• the radial distribution of the galaxies within
  the halo
• The 2-halo also term depends on the above,
• roughly
• Pgal(2h) (k) bgal2 Pdm(lin) (k)
• Each of the three terms can actually be measured
  directly from
• e.g 2dFGRS
• Is the model satisfied for all, blue and red
  galaxies?

Collister OL, astro-ph/0412516
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2dFGRS galaxy groups
Eke et al. 2004
48
An empirical test of the halo model
Non-linear clustering P(k) Plin(k) Phalo(k)

Co-added profile of 2dF groups Truncated NFW fit
with C 2.4 - 0.3
A. Collister OL, astro-ph/0412516
49
The halo model
P(k) Plin(k) Phalo(k)
Red galaxies
?1.05 0.19
C3.90.5

Blue galaxies
? 0.880.17
C1.30.2
ltNMgt (M/M0)? for M gt Mcut

50
Relative biasing (Blue/Red)
51
Future work and interests _at_ UCL

• Compare predicted 2MRS peculiar velocities with
  observed 6dF pec vel.
• Combine 2MRS with 2MASS photo-z
• and 6dF
• Cosmological parameters
• Halo model biasing
• The cosmic web
• Galaxy spectral classification

Alexandra Abate, Sarah Bridle, Ofer Lahav, Anais
Rassat
52
University College London http//www.star.ucl.ac.
uk

• ASTROPHYSICS _at_ UCL
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• 15 pos-docs, 35 PhDs, 15 support stuff
• Research
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  Instrumentation, Mill Hill Observatory
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