Transcript The view from 20 years ago

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.
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
U.C. Santa Cruz
D. Phillips
S. Kassin
K. Noeske
A. Metevier
L. Lin
N. Konidaris
G. Graves
J. Harker
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
(Harvard)
A. Connolly (Pitt.)
DEEP2 has been made possible by
DEIMOS, a new instrument on Keck II
DEIMOS:
• 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
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Optics are key to the success of DEIMOS
Complex design by Harlan Epps
Brilliant work by Dave Hilyard
DEEP2 pre-selects high-z
galaxies using observed
colors
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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.
DEEP2 slitmask spectroscopy
l
position
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.
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AEGIS: the All-wavelength Extended Groth
Strip International Survey
Spitzer MIPS, IRAC
DEEP2 spectra
and Caltech/JPL
Ks imaging
HST/ACS
V,I (Cycle 13)
DEEP2/CFHT
B,R,I
GALEX NUV+FUV
Chandra & XMM:
XMM
Chandra (1.6Ms)
Plus VLA (6 & 21
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cm), SCUBA, etc….
X-ray analysis - detection and photometry
• 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
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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)
• 47,000 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
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Redshift Distribution of DEEP2
Survey
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DEEP2 Status Update
• 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:
http://deep.berkeley.edu/DR4
• The catalog and 2d spectra is all available, and others are
releasing Chandra, Spitzer, GALEX, HST, ….
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Cluster abundance depends on
cosmology
CDM
CDM
=0.3, =0.7
=1
o 1015 Mo
* 10 14.5-15Mo
. 1014-14.5 Mo
Hubble volume simulations
Brian F. Gerke
Evrard et al. 02
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2PIGG:Ek
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e et al
2004
Redshift Maps in 4 Fields: z=0.7-1.3
Cone diagram of 1/12 of the full DEEP2 sample
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Galaxy groups in DEEP2
•Overdensities identified in redshift space.
•Use the VDM algorithm of Marinoni et al. (2002).
position
l, z
•Group in early DEEP2 data s~250 km/sec
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DEEP2 Group Catalog
Groups with >350 km/s
Shown are groups for 3 fields
--length of ellipse proportional to velocity dispersion
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Gerke et al. 2005, astro-ph/0410721
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 T=.3
DEIMOS took ~7 years to
build; at time of designing
science expt. T was still
undetermined, and DE was
not discussed.
Projected constraints
Computed with DM
halos in simulated
DEEP2 and 2dF
light cones,
constructed from
the Millennium Run.
input cosmology
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Brian F. Gerke
In each panel, the
suppressed
parameter is held
fixed.
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,)
et al, 2008
•The blue galaxies show fully developed coherentCoil
infall
pattern on scales >5 Mpc, as expected.
•The red galaxies have very extended fingers of god, as
expected.
Kaiser infall, MOCKS
Coil et al, 2008
Millenium mocks, not a bad approximation
By combining area with depth, AEGIS
allows us to study rare objects in detail…
B. Gerke, JN et al. 2006, AEGIS ApJL, Accepted
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Like a spectroscopically
identified, dual AGN at z=0.7
Hb
[OIII]
5007
position
[OIII]
4959
l/ z
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HST reveals a fairly-normal early-type
host
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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
•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
• DEEP2 observations are >99% done
•Work not yet published is study of galaxy clustering
• DR4 has occurred this August:
http://deep.berkeley.edu/DR4
• AEGIS ApJL special issue
• Way too many new results to cover in one talk!
•A Spectroscopic survey has many followups!
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