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The DEEP2 Redshift Survey. Marc Davis UC Berkeley. The DEEP2 Galaxy Redshift Survey used the DEIMOS spectrograph at the Keck II telescope to study both galaxy properties and large-scale structure at z~ 1. The DEEP2 Collaboration. Other Institutions J. Newman (LBNL) A. Coil (Arizona)

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The deep2 redshift survey
The DEEP2 Redshift Survey

Marc Davis

UC Berkeley

Granada, October 2007

The deep2 collaboration

The DEEP2 Galaxy Redshift Survey used the DEIMOS spectrograph at the Keck II telescope to study both galaxy properties and large-scale structure at z~1.

The DEEP2 Collaboration

Other Institutions

J. Newman (LBNL)

A. Coil (Arizona)

C. Willmer (Arizona)

B. Weiner (Arizona)

R. Schiavon (UVA)

C. Conroy (Princeton)

N. Kaiser (Hawaii)

D. Finkbeiner


A. Connolly (Pitt.)

U.C. Santa Cruz

D. Phillips

S. Kassin

K. Noeske

A. Metevier

L. Lin

N. Konidaris

G. Graves

J. Harker

U.C. Berkeley

M. Davis (PI)

D. Croton

M. Cooper

B. Gerke

R. Yan

U.C. Santa Cruz

S. Faber (Co-PI)

D. Koo

P. Guhathakurta

Deep2 has been made possible by deimos a new instrument on keck ii
DEEP2 has been made possible by DEIMOS, a new instrument on Keck II


  • PI: Faber

  • wide-field multiplexing (up to 160 slitlets over a 16’x4’ field)

  • high resolution (R~5000)

  • spectral range (~2600 Å at highest resolution)

  • CCD array of 8k x 8k

Granada, October 2007

Optics are key to the success of deimos

Optics are key to the success of DEIMOS Keck II

Complex design by Harlan Epps

Brilliant work by Dave Hilyard

Deep2 mask selection

DEEP2 mask selection Keck II

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.

Deep2 slitmask spectroscopy
DEEP2 slitmask spectroscopy Keck II



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.

Granada, October 2007

Aegis the a ll wavelength e xtended g roth strip i nternational s urvey




Chandra & XMM:


Chandra (1.6Ms)

AEGIS:the All-wavelength Extended Groth Strip International Survey

Spitzer MIPS, IRAC

DEEP2 spectra and Caltech/JPL Ks imaging


V,I (Cycle 13)

Plus VLA (6 & 21 cm), SCUBA, etc….

Granada, October 2007

X ray analysis detection and photometry
X-ray analysis - detection and photometry Keck II

  • P.Nandra et al.

  • Each square has integration time of 200 ksec

  • Source selection and photometry by own method

    • Elliptical shaped PSFs

  • All data will be released in August, 2007

1.6 Ms

Granada, October 2007

A redshift survey at z 1
A Redshift Survey at z=1: Keck II

  • 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)

  • 47,000 unique redshifts, error ~30 km/s

  • ~5·106 h-3Mpc3

  • 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

Granada, October 2007

Redshift distribution of deep2 survey
Redshift Distribution of DEEP2 Survey Keck II

Granada, October 2007

Deep2 status update
DEEP2 Status Update Keck II

  • DEEP2 began observations in July 2002.

  • Observations are now >99% finished, with >49k spectra in hand and 3 of 4 fields completed.

  • Follow-up observations have begun.

  • ALL the data is already public:


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

Granada, October 2007

Cluster abundance depends on cosmology

τ Keck IICDM


Ω=0.3, ΩΛ =0.7


o 1015 Mo

*10 14.5-15Mo

. 1014-14.5 Mo

Cluster abundance depends on cosmology

Evrard et al. 02

Hubble volume simulations

Granada, October 2007

Brian F. Gerke

DEEP2: Gerke et al 2005 Keck II

2PIGG:Eke et al 2004



Granada, October 2007

Redshift Maps in 4 Fields: z=0.7-1.3 Keck II

Cone diagram of 1/12 of the full DEEP2 sample

Granada, October 2007

Galaxy groups in deep2

position Keck II

l, z

Galaxy groups in DEEP2

  • Overdensities identified in redshift space.

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

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

Granada, October 2007

Deep2 group catalog
DEEP2 Group Catalog Keck II

Groups with >350 km/s

Shown are groups for 3 fields

--length of ellipse proportional to velocity dispersion

Granada, October 2007

Gerke et al. 2005,astro-ph/0410721

Why search for groups in deep2

  • 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

Why search for groups in DEEP2?

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

Projected constraints
Projected constraints Keck II

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

Granada, October 2007

Brian F. Gerke

Deep2 cluster counts

DEEP2 Cluster Counts Keck II

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 r p

Measuring Kaiser infall in Keck II(rp,)

Coil et al, 2008

  • 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.

Kaiser infall mocks

Kaiser infall, MOCKS Keck II

Coil et al, 2008

Millenium mocks, not a bad approximation

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

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

Granada, October 2007

Like a spectroscopically identified dual agn at z 0 7
Like a spectroscopically identified, dual AGN at objects in detail…z=0.7







l/ z

Granada, October 2007

Hst reveals a fairly normal early type host
HST reveals a fairly-normal early-type host objects in detail…

Granada, October 2007

Rotation curves of 88 galaxies with hst and deimos s spatial resolution

Rotation Curves of 88 galaxies with HST and DEIMOS’s Spatial Resolution

Study evolution of Spirals

Metevier et al, 2007, in process

Ly alpha emission seen in many slits

Ly-alpha emission seen in many slits Spatial Resolution

Slits are 1” long, more than 50% blank field, giving > 1 sq arcminute for deep search, 3 < z < 6

Searching by “eye” for asymmetric emission lines

So far they have searched ~20% of fields and found 9 clean systems

Sawicki et al, in preparation

Conclusions on deep2
Conclusions on DEEP2 Spatial Resolution

  • DEEP2 observations are >99% done

  • Work not yet published is study of galaxy clustering

  • DR4 has occurred this August:

  • AEGIS ApJL special issue

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

  • A Spectroscopic survey has many followups!

Granada, October 2007