The Clustering of Red Galaxies & EROs

Michael Brown (NOAO->Princeton)Buell Jannuzi (NOAO)

Arjun Dey (NOAO)Glenn Tiede (Bowling Green)

Tod Lauer (NOAO)Alyson Ford (NOAO->Swinburne)

Lissa Miller (NOAO->Yale)NDWFS Survey Team

The Clustering of Red Galaxies & EROs

MGCT, Baltimore, September 2004

Imaging of 18 square degrees with KPNO & CTIO telescopes.

Limiting magnitudes of BW

~26.5, R~25.5, I~25.0, & K~19.0.

Comoving volume to z~5 is 0.3 Gpc3.

9 square degree BW

RIK imaging data release on October 22.

Imaging with Spitzer (IRAC+MIPS), Chandra, & GALEX.

4 to 10m spectroscopy including 10k Hectospec redshifts

Two preliminary clustering studies : Red Galaxies and EROs.

orDoes evolveinto ?

z~2 z~0 z~0

Kinematics of z>1 galaxies can have large uncertainties.

Stellar masses of z>1 galaxies are uncertain.

SED evolution of z>1 galaxies is uncertain.

Clu

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Str

engt

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Luminosity (BJ)

L* Bright

Redshift

Spatial clustering : Data and Models

Stars ~3x1010 MSun

Flux limited samples mix redshifts, SEDs and luminosities.

Galaxy clustering is a function of SED and luminosity at z~0.

Angular scale

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ngthw(1')=0.024g=1.81

Tracing galaxy evolution via clustering

Select galaxies as a function of restframe properties & epoch.

Imaging surveys can cover large volumes to great depth.

Requires accurate photometric redshifts.

Use clustering to identify galaxies in massive DM halos.

Connect galaxies populations as an evolutionary sequence.

However, does clustering evolve as predicted by the models?

How does clustering evolve?

Smail et al. (2003)

How does galaxy clustering evolve?

Select the same galaxy population as a function of redshift.

Select galaxies with comparatively slow SED evolution.

Select galaxies with accurate photometric redshifts.

Brown et al. (2003), ApJ, 597, 225.

5325 0.3<z<0.9 red galaxies from ~1 sq degree.

Selected subsamples by luminosity, redshift and SED.

Compared measured clustering with the models, 2dF & SDSS.

Red galaxy apparent colours

PEGASE ModelsNDWFS

LBGs

FBGs

Spectroscopic Redshift

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Red galaxy BW

RI photometric zs

Angular clustering

Angular scale

~L*

Restframe BW

-R>1.44

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Redshift

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Redshift distributions

Evolution corrected luminosity

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Red galaxies at 0.3<z<0.9

2dF

NDWFS

Redshift

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~L* red galaxies at 0.3<z<0.9

NDWFS

SDSS

2dF

Red galaxy clustering at 0.3<z<0.9

Brown et al. (2003), ApJ, 597, 225.

Spatial clustering is correlated with luminosity (mass).

Spatial clustering is weakly correlated with redshift.

Spatial clustering is consistent with hierarchical models.

The full survey area is required for robust tests of models.

Next NDWFS data release is on October 22.

R-K>5, z~1 Extremely Red Objects

Brown et al. (2004), ApJ, submitted.

EROs are presumed to be the progenitors of local ellipticals.

Dusty starbursts and galaxies with “old” stellar populations.

Extreme clustering? Possibly with r0>10 Mpc for <L*?

617 K<18.4 EROs selected from ~1 sq degree.

Largest ERO sample size by 2x. Largest ERO volume by 4x.

Extremely luminous galaxies, with L~3L*(z=0).

Angular Scale

Ang

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Angular clustering

Spectroscopic Redshift

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Extremely Red Objects

Redshift

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Redshift distributions

Red galaxies and K<18.4 EROs

Redshift

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EROs3L* Red

2dF

SDSS

LCDM

K-band magnitude limit

Ang

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at 1

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Are <L* EROs strongly clustered?

Completed preliminary z<1.4 studies with ~1 sq degree.

Galaxy clustering is a function of luminosity and mass.

Galaxy clustering does not evolve rapidly with redshift.

Observed clustering is consistent with hierarchical models.

ERO clustering is strong, but not unusually strong.

Larger area will robustly test hierarchical models.

We will use galaxy clustering to measure galaxy evolution.

Next imaging data release is 22 October 2004.