The Growth of LSS in a Dark Energy Dominated Universe A Century of Cosmology

Venice, August 2007

The Growth of LSS in a Dark Energy Dominated Universe

A Century of Cosmology

Marc Davis

UC Berkeley

Venice, August 2007

DEEP2 pre-selects high-z galaxies using observed

colors

DEEP2 mask selection

Targeted galaxies are enclosed with white curves

Solid slits are objects selected on a given mask.

dotted and dashed lines are galaxies from neighboring masks.

Venice, August 2007

DEEP2 slitmask spectroscopy

Using custom-milled slitmasks with DEIMOS we obtained spectra of ~150 targets at a time. A total of 400 slitmasks was required for the survey; we tilted slits up to 30 degrees to obtain rotation curves.

position

Venice, August 2007

A Redshift Survey at z=1:• 3 sq. degrees • 4 fields (0.5o x <2o)• 80 Keck nights, one-hour exposures to RAB=24.1• primarily z~0.75-1.4 (pre-selected using BRI photometry)• 46,585 unique redshifts, error ~30 km/s• ~5·106 h-3 Mpc3

• 1200 l/mm: ~6500-9200 Å• 1.0” slit: FWHM 68 km/s• z=0.7-1.4 spans lookback time ~6.0 - 8.0 Gyr ago• Within DEEP2 we are surveying 2.5 Gyr or ~20% of the history of the Universe, and SDSS/2dF comparisons give ~3x this baseline

Venice, August 2007

Redshift Distribution of DEEP2 Survey

Venice, August 2007

DEEP2 Status Update

• DEEP2 began observations in July 2002.

• Observations are now >95% finished, with >49k spectra in hand and 3 of 4 fields completed.

• Follow-up observations have begun.

•ALL the data is already public:

http://deep.berkeley.edu/DR3

• The catalog and 2d spectra is all available, and others are releasing Chandra, Spitzer, HST, ….

13

Brian F. Gerke

Evrard et al. 02Hubble volume simulations

ΛCDMτCDM

o 1015 Mo

* 10 14.5-15Mo

. 1014-14.5 Mo

Ω=1 Ω=0.3,ΩΛ=0.7

Cluster abundance depends on cosmology

2PIGG:Eke et al 2004

DEE

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erke

et a

l 200

5

z=0.75

z=1.0

Venice, August 2007

Redshift Maps in 4 Fields: z=0.7-1.3

Cone diagram of 1/12 of the full DEEP2 sample

Venice, August 2007

Galaxy groups in DEEP2

, zposition

•Overdensities identified in redshift space.

•Use the VDM algorithm of Marinoni et al. (2002).

•Group in early DEEP2 data s~250 km/sec

Venice, August 2007

DEEP2 Group Catalog

Gerke et al. 2005, astro-ph/0410721

Shown are groups for 3 fields --length of ellipse proportional to velocity dispersion

Groups with >350 km/s

Venice, August 2007

Real Groups/Mock Groups

x-r redshift plot

y-r redshift plot

X-y projected on sky

galaxies shown in 3 projections

Real or Mock???

Why search for groups in DEEP2?•Apparent abundance of groups: dN(,z)/dzd Provides a useful test of dark energy eq. of state (Newman et al, 2002)

•differences in the volume element varies by 3x between w=0 and w=-1

•For groups of modest-mass, the evolution of dispersion is 2nd order

•Heavy black curve is ΩT=.3 DEIMOS took ~7 years to build; at time of designing science expt. ΩT was still undetermined, and DE was not discussed.

Size of the Universe versus w

Abundance versus Redshift

Simulated Data!!

Gerke etal 2008

Measured dispersion with galaxies compared to reality-- tremendous scatter!

Venice, August 2007

Dispersion with galaxies

Venice, August 2007

Brian F. Gerke

We can reconstruct the quantity we need with the VDM

Successful above ~350 km/s

• We want to measure N(σ, z) to constrain cosmology. • Tests on the mock catalogs indicate that we can measure N(σ,z) in DEEP2 accurately for σ>350 km/s.

Venice, August 2007

Brian F. Gerke

Projected constraints

Computed with DM halos in simulated DEEP2 and 2dF light cones, constructed from the Millennium Run.

In each panel, the suppressed parameter is held fixed.

input cosmology

DEEP2 Cluster Counts

•DEEP2 survey counted ~300 groups•Velocity dispersion measured in each case•Counts of N(, z) is a strong test of w•Have not got mock catalogs with the evolving color selection, making it difficult to proceed•B. Gerke will have results out “soon”

Measuring Kaiser infall in (rp,)

•The blue galaxies show fully developed coherent infall pattern on scales >5 Mpc, as expected.

•The red galaxies have very extended fingers of god, as expected.

Coil et al, 2008

Kaiser infall, MOCKS

Millenium mocks, not a bad approximation

Coil et al, 2008

Venice, August 2007

• DEEP2 observations are >99% done

•Work not yet published is study of galaxy clustering

• DR3 has occurred this August: http://deep.berkeley.edu/DR3

• AEGIS ApJL special issue

• Way too many new results to cover in one talk!

Conclusions on DEEP2

Venice, August 2007

By combining area with depth, AEGIS allows us to study rare objects in detail…

B. Gerke, JN et al. 2006, AEGIS ApJL, Accepted

Venice, August 2007

Like a spectroscopically identified, dual AGN at z=0.7

H

[OIII] 4959

[OIII]5007

/ z

posi

tion

Venice, August 2007

HST reveals a fairly-normal early-type host