Large Scale Structure in 2MRS & 6dF

Ofer Lahav (University College London)

6dF workshop, AAO/Sydney, 26-27 April 2005

LSS in 2MRS• The Local Group Dipole

• Wiener reconstruction

• Future work with 2MRS+2MASS+6dF

Pirin Erdogdu (Cambridge/Ankara),

John Huchra (CfA), Ofer Lahav (UCL)

& the 2MRS/6dF teams

The Near IR Local Universe

2MRS + mock ZoA

~25000 galaxiesKs < 11.25

Huchra & 2MRS/6dF teams

Random ZoA

Interpolated ZoA

2MRS vs. PSCz radial selection fn

Spectral PCA types in 2MASS

62% E’s in 2MASS35% E’s in 2dF

Madgwick, OL et al.

Dipole – weighting schemes

m0.6/b

g / <M/L> L/ (4 r2)

L = (7.67+- 1.02) x 108 L_sun h Mpc-3

Number and Flux dipolesin the LG frame

15o @ 50 Mpc/h

24o @ 130 Mpc/h

m < 0.37+- 0.20< 0.57 +- 0.07b2mrs > 0.85 +- 0.15

(for m = 0.30)

Erdogdu et al.,In preparation

Out to 200 Mpc/h – CMB frame

Dipole – Wiener reconstruction

0.40.6

2MRS dipole directions @ 130 Mpc/h

Spherical harmonics

Wiener filtering

) Redshift distortion Signal/(Signal+Noise)

Fisher, OL et al (1995)

WF 2MRS @ 2000 km/sec

Erdogdu et al.

WF 2MRS @ 4000 km/sec

WF 2MRS @ 6000 km/sec

WF 2MRS @ 10000 km/sec

WF 2MRS velocity fieldCMB frame

Erdogdu et al.

WF 2MRS velocity fieldLG frame

The Concordance Model

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

Photometric redshifts

Photometric redshifts

Photo-z Other work:

* HYPERZ: Bolozonella et al., 2000, A&A, 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, …

Artificial Neural Network

Output:redshift

Input:magnitudes

SDSS data (ugriz; r < 17.77)

ANNz (5:10:10:1) HYPERZ

2MASS + photo-z

z = 0.02

z=0 cyan z=0.05 yellow

z=0.08 red

Collister & Lahav, ANNz

Future work and interests @ 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

Clustering of Red vs. Blue 2dF galaxies

Madgwick, Hawkins, Lahav & 2dFGRS team, astro-ph/0303668

Great Walls of the Universe

Ratio of bulk flows with massive neutrinos =0.04

Elgaroy&Lahav, NJP, 2005Elgaroy&Lahav, NJP, 2005

An empirical test of

the halo model

Non-linear clusteringP(k) = Plin(k) + Phalo(k)

Co-added profile of 2dF groupsTruncated NFW fit with C = 2.4 +- 0.3A. Collister & OL, astro-ph/0412516

Future work and interests @ 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