17 may 04leonidas moustakas stsci 1 high redshift (z~4) galaxies & clustering lexi moustakas...

17 may 04 leonidas moustakasSTScI

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High redshift (z~4) High redshift (z~4) galaxiesgalaxies

& clustering& clusteringLexi Moustakas

STScI


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creditcredit

Everybody at GOODS & ODT!

Soo Lee (JHU)(advisor: M. Giavalisco)

Paul Allen (MSO, PhD@Oxf)

Emily MacDonald (Oxf)(advisor: G. Dalton)


3 GOODS: Giavalisco et al 2004Montage courtesy of F. Summers

total GOODS: ~320 arcmin2

see M. Giavalisco talk see M. Giavalisco talk tomorrow!tomorrow!


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Finding high-z galaxies: Finding high-z galaxies: z~4z~4

The Lyman-dropout technique, B-V vs V-z (for z~4) -- multiwavelength is KEY

The space-based GOODS data use the z-band & are extremely deep compared to the ground -- ~2-3 mag fainter.

In total GOODS ACS area, ~2000 z~4 galaxies

B-dropouts, z~4

Giavalisco et al. 2004


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LBG redshift distributions,LBG redshift distributions,from monte carlo from monte carlo

simulationssimulations

B V i

The redshift distributions are well-constrained through simulations.

The completeness is more difficult to pin down.

(The B-drops are the z~4).

Giavalisco & S. Lee 2004


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morphologies of faint z~4 morphologies of faint z~4 galaxiesgalaxies

The sizes of star forming galaxies above z~1 are sub-arcsec (Ferguson et al 2004)

As shown here, the morphologies are varied and can be complex

The pair/group statistics are crucial for characterizing environment

VizViz

1''1''

from the v1.0 GOODS data

Check out the scale!


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clustering of faint z~4 clustering of faint z~4 galaxiesgalaxies

With the angular correlation function measured directly, and a simulated N(z), we invert & calculate the spatial correlation function

(r) = (r/r0)- ,

usually assumed to be a power-law on relatively large scales, with characteristic scale r0.

S. Lee et al. 2004, in prep.

w(theta) vs angular separation

}}

nb: many neighbors within 10-20arcsec!


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clustering with app. clustering with app. magnitudemagnitude

Clustering measured in the GOODS data to different magnitude limits. (The error bars are smaller than the points!)

There is evidence for stronger clustering in the brighter samples... (See also Giavalisco & Dickinson 2001).

GOODS data from S. Lee et al. 2004, in prep.

spatial clustering vs limiting apparent magnitude


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clustering with abs. clustering with abs. magnitudemagnitude

Transform (approximately) to rest-frame BJ magnitudes

The brightest point is sub-L*

What happens if one goes to much brighter absolute magnitudes??

=> We don't know from GOODS! Area is not large enough to find very rare objects...

spatial clustering vs absolute magnitude (approximate)


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The Oxford-Dartmouth The Oxford-Dartmouth Thirty-Degree (ODT) Thirty-Degree (ODT)

SurveySurveyMacDonald et al 2004, MNRAS, in pressMacDonald et al 2004, MNRAS, in press

5 limits completion vega to dateU > 25B 26.0V 25.5 R 25.25 >23 deg2

i 24.5Z 22

K < 19 > 3.5 deg2

MacDonald et al. 2004Moustakas et al in prep (K-band part)

andr 0018+3452lynx 0909+4050herc 1639+4524

virgo 1200+0300


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The ODT Survey: The ODT Survey: A wide-field multi-A wide-field multi- survey survey

The Andromeda field of the ODT Survey

A GOODS Field

MacDonald et al. 2004


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clustering of bright z~4 clustering of bright z~4 galaxiesgalaxies

Clustering measurements of B-drops in ODT Survey, from a ~2deg2 subset

Allen et al. 2004, MNRAS

N(z)'s 'realized', and angular correlation function inverted.

These LBG samples are bright, with i<24.5 (2mag brighter than GOODS)

Allen et al. 2004

}}

nb: no neighbors within 10-20arcsec!


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L-dependent clustering at L-dependent clustering at z~4z~4

GOODS: S. Lee et al.ODT: P. Allen et al.


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L* is around here

GOODS: S. Lee et al.ODT: P. Allen et al.


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z~0

GOODS: S. Lee et al.ODT: P. Allen et al.2dF: Norberg et al. 2002


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cosmic variance in this cosmic variance in this resultresult

Assuming simple galaxy-halo correlation larger volumes = less cosmic variance smaller clustering = less cosmic variance

We calculate a similar level of cosmic variance across the z~4 result -- GOODS: small volume but small clustering -> cv~20% ODT-S: large volume but large clustering -> cv~40%

To bring the high-L variance down to 20%, need >10 times more area! But even that isn't enough.

Why is that? -- Onwards, to:


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beyond sweet peasbeyond sweet peas

Clustering, (dark matter) masses, and environment

With analytic LCDM, we can connect the clustering to the minimum dark matter halo mass.

Combining the clustering with the space densities, a Halo Occupation Distribution (HOD) formalism can constrain the number of galaxies per halo vs halo-mass

Adding luminosity information to this, the Conditional Luminosity Function (CLF)

Let's quickly consider the Halo Occupation formalism


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dark matter halo massesdark matter halo masses

Moustakas & Somerville 2002

There can be many galaxies in each dark matter "halo", or none. Theaverage behavior can be parametrizedwith the Halo Occupation Function,or Distribution

N(M>Mmin) = (M/M1)

Mmin - threshold halo mass ** from clustering

M1 - 'typical' mass ** from clustering & density

- mass function slope ** from small-scale clustering!

"bias" comes from the clustering,which fixes the 'minimum' DM halo mass

space density

bia

s


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galaxies' dark matter galaxies' dark matter haloshalos

Here we plot the results for z~0 ellipticals, z~1.2 EROs, and z~3 LBGs (LAM & Somerville '02)

The occupation function parameters can be constrained through the measured clustering strength and the space density

The SLOPE (a 'free' parameter in this plot), can be constrained by very small-scale statistics

M&S02


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clustering evolutionclustering evolution The simplest model hasa

galaxies following the dark matter they're associated with -- 'galaxy conserving model' (Fry 1996)

See the behavior of populations with properties established at different redshifts. Do they 'connect'?

corr

ela

tion

scale

lin

ear

bia

s

The different z~4 galaxies may have different histories & futures...


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ConclusionsConclusions There is evidence for luminosity-

dependent clustering in galaxies, at z~4 as well as locally

Need 'complete' census at all scales => DEPTH >10s of square degrees or more will

be required to characterize this: => LARGE SOLID ANGLE To constrain the SLOPE of the

occupation function, we need very sub-few-arcsec pair/group info.: => HIGH SPATIAL RESOLUTION

A multi-wavelength SNAP/JDEM/LEGASY type mission would clean this up...

17 may 04leonidas moustakas stsci 1 high redshift (z~4) galaxies & clustering lexi moustakas...

Documents

clustering of bright

goods odt

high redshift z

lee et

morphologies of faint

giavalisco et

summerstotal goods

goods datacheck