Dark Energy Camera and Survey

1
Dark Energy Camera and Survey
Response to NOAO Announcement of Opportunity for
Blanco instrumentation partnership
Abundance and evolution from number density as
a function of mass and z
Galaxy clusters
Weak gravi- tational lensing
Cosmic shear/shear-shear correlations
(statistical study of effect of large scale
structures). Also use shear effects and
correlation due to foreground galaxies.
68 C.L. constraints on w and WDE using
shear-shear correleations and galaxy shear
correlations Along with the joint power of all
the power spectra.
Redshift distribution for the SPT DES cluster
survey for two different models separated by 3s.
Forecasts of the constraints on the dark energy
equation of state for the SPTDES survey compared
with other forecasts. Note forecasts depend on
priorssystematics.
Spatial distribution of galaxies
Type Ia Supernovae
Type Ia are standardizable
candles. The DES provides an
opportunity to collect 1900 SNe light curves out
to z 0.75.
Large scale structure of
galaxy clusters, which can be
studied using angular clustering, is related to
cosmology through breaks in the power spectrum in
different redshift shells because of the horizon
size at matter-radiation equality and through
baryon acoustic oscilliations. An initial
estimate shows a w determined to 13.
Projected constraints on WM and w from the DES SN
survey assuming a flat cosmology along with joint
constraints from SNe 2dF. The right figure
marginalizes over WM.
Telescope, the cage, and the focal plane
Data acquisition
Our reference design is the NOAO-developed Monsoon
system for data acquisition. We are exploring
using front-end chips on the focal plane. We
are also considering using the Monsoon
detector head electronics (DHE) as the
front-end.
The existing 4m Blanco telescope at Cerro
Tololo already provides imaging capabilities at
its prime focus. We propose to replace the
entire cage with a imager that will be more
than times more powerful than the existing
imager in the i and z bands.
Cross section view of the dewar and CCD focal
plane array
Typical QE curves of CCDs that show the higher QE
in the near IR for LBNL thick, high resistivity
devices.
Cross section of the Blanco telescope showing the
cage holding the Dark Energy Camera
CCDs
We require large format CCDs with high QE in the
near IR (1 mm). Our reference design uses LBNL
developed thick (250mm), fully depleted 2K x 4K
devices.
Monte Carlo simulations showing photo- metric
redshift results of 0.5L and 2L cluster
galaxies.
Prime focus cage showing elements including the
corrector, filters, shutter, the focal plane
along with various interfaces to the Blanco
telescope.
Photometric calibration error after 3 and 5
yrs. The scale spans the range from 0.2 to 0.2
Photometric Redshifts
We require accurate galaxy photometric redshifts
to z1. Use g, r, i, z filter bands to be
sensitive to the Lyman break or the 4000A break
in the redshift range of interest.
Spectrum of a red elliptical galaxy at z 0,
0.5, and 1 with the 4000A break feature marked.
Also shown are the g, r, i, z filter bandpasses.
Paths of constant airmass for one tiling
Survey strategy
We aim to cover 5000 sq deg with tiling hexagons
in the region of the south galactic cap (to
overlap the South Pole Telescope SZE). Our
reference survey area also includes area along
the equator that overlaps with existing SDSS/VLT
maps. historical weather data has been analyzed
and estimates that we will be able to complete
the survey in 5 years with a 3 sq deg FOV camera.
Dark Energy Camera and Survey Fermilab, Univ. of
Illinois, Univ. of Chicago, LBNL, Cerro-Tololo
Inter-American Observatory
Dirbe map of galactic dust