# Presentation: 322926

## Presentations to Blanco Instrument Review Panel

- Intro and Science 1 		*Mohr*
- Science 2 and Context 	*Frieman*
- Survey Design 		*Annis*
- Instrument 			*Flaugher*
- Optical Design 		*Kent*
- Data Management 		*Plante*
- Project Management	 	*Peoples*

- Blanco Instrument Review

- August '04 - Joe Mohr

## Toward an Understanding of the Dark Energy/ Cosmic Acceleration

- Measuring (relative) distances or volumes out to z~2
- Measuring the growth rate of cosmic structures
- Detecting dark energy clustering in the power spectrum of density fluctuations
- Measure evolution of gravitational potential wells using the Integrated Sachs-Wolfe effect
- Laboratory experiments and theoretical progress

- Blanco Instrument Review

- August '04 - Joe Mohr

## Key Techniques for Measuring the Dark Energy Equation of State Parameter

- Type Ia Supernovae as standard candles
- Power spectrum measurements using galaxies or clusters
- Cosmic Microwave Background anisotropy
- Weak lensing measurements
- Galaxy cluster surveys

- Blanco Instrument Review

- August '04 - Joe Mohr

## The Dark Energy Survey

- A study of the dark energy using four independent and complementary techniques
- Galaxy cluster surveys
- Galaxy angular power spectrum
- Weak lensing
- SN Ia distances
- Two linked, multiband optical surveys
- 5000 deg2 g, r, i and z
- Repeated observations of 40 deg2
- Instrument and schedule
- New 3 deg2 camera on the Blanco 4m on Cerro Tololo
- Construction: 2004-2009
- Survey Operations: 30% of telescope time over 5 years

- Blanco Instrument Review

- August '04 - Joe Mohr

## The Dark Energy Survey Collaboration

- Fermilab- Camera building, Survey Planning and Simulations
- Annis, Dodelson, Flaugher, Frieman, Gladders*, Hui, Kent, Lin, Limon, Peoples, Scarpine, Stebbins, Stoughton, Tucker and Wester
- *Carnegie Fellow, Carnegie Observatories
- U Illinois- Data Management, Data Acquisition, SPT
- Brunner, Karliner, Mohr, Plante, Selen and Thaler
- U Chicago- SPT, Simulations, Corrector
- Carlstrom, Dodelson, Frieman, Hu, Kent, Sheldon and Wechsler
- LBNL- Red Sensitive CCD Detectors
- Aldering, Bebek, Levi, Perlmutter and Roe
- CTIO- Telescope & Camera Operations
- Abbott, Smith, Suntzeff and Walker

- Blanco Instrument Review

- August '04 - Joe Mohr

## Cluster Survey Studies of the Dark Energy are Complementary and Competitive

- Cluster constraints on dark energy:
- The cluster redshift distribution, the cluster power spectrum and 30% accurate mass measurements for 100 clusters between z of 0.3-1.2
- Fiducial cosmology (WMAP: 8=0.84, m=0.27); 29000 clusters in the 4000 deg2 SPT survey.
- The joint constraints on w and m:
- Curvature free to vary (dashed); fixed (solid)
- Marginalized constant w 68% uncertainty is 0.046 (flat) or 0.071 (curvature varying)
- Parameter degeneracies complementary

- SPT: Majumdar & Mohr 2003
- SNAP: Perlmutter & Schmidt 2003
- WMAP: Spergel et al 2003

- Blanco Instrument Review

- August '04 - Joe Mohr

## Cluster Redshift Distribution is Sensitive to the Dark Energy Equation of State Parameter

- Raising **w** at fixed ******E**:
- decreases volume surveyed

- decreases growth rate of density perturbations

**w** constraints:

- Blanco Instrument Review

- August '04 - Joe Mohr

## Precision Cosmology with Clusters

- Requirements
- Quantitative understanding of the formation of dark matter halos in an expanding universe
- Clean way of selecting a large number (~104) of massive dark matter halos (galaxy clusters) over a range of redshifts
- Crude redshift estimates for each cluster
- Observables that can be used as mass estimates at all redshifts
- Technique called self-calibration provides a framework for determining cosmology and mass-observable relation simultaneously

- Blanco Instrument Review

- August '04 - Joe Mohr

## 10m South Pole Telescope (SPT)and 1000 Element Bolometer Array

- 10m South Pole Telescope (SPT)and 1000 Element Bolometer Array

_**Low noise, precision telescope**_
-  20 um rms surface
-  1 arc second pointing
-  1.0 arcminute at 2 mm
-  ‘chop’ entire telescope
-  3 levels of shielding
-  ~1 m radius on primary
-   inner moving shields
-   outer fixed shields

_**SZE and CMB Anisotropy **_
-    - 4000 sq deg SZE survey
-    - deep CMB anisotropy fields
-    - deep CMB Polarization fields

_**1000 Element Bolometer Array**_
-    - 3 to 4 interchangeable bands      (90) 150, 250 & 270 GHz
-    - APEX-SZ style horn fed spider web absorbers

_**People**_
- Carlstrom (UC)
- Holzapfel (UCB)
- Lee (UCB,LBNL)
- Leitch (UC)
- Meyer (UC)
- Mohr (U Illinois)Padin (UC)
- Pryke (UC)
- Ruhl (CWRU)
- Spieler (LBNL)
- Stark (CfA)

*NSF-OPP funded & scheduled for Nov 2006 deployment*
*DoE (LBNL) funding of readout development*

- Blanco Instrument Review

- August '04 - Joe Mohr

## SPT Structure and Shielding

- Blanco Instrument Review

- August '04 - Joe Mohr

## SPT Survey Region

- SPT will survey all the extragalactic sky south of declination =-300
- This corresponds to approximately 4000 deg2 of reasonably clean sky
- north of =-750
- 20hr <  < 7hr
- This region is easily observable with the Blanco 4m on Cerro Tololo

- Blanco Instrument Review

- August '04 - Joe Mohr

## DES Cluster Photo-z’s

- DES data will enable cluster photometric redshifts with z~0.02 for all SPT clusters out to z~1.3

- Figure from Huan Lin

- Uses Monte-carlo estimates of galaxy photo-z uncertainties, which include appropriate photometric noise [Huan Lin]
- Uses halo occupation number N(M) measured in ~100 local groups and clusters [Y-T Lin, Mohr & Stanford 2004]
- Adopts redshift evolution of N(M)~(1+z) and passive evolution of galactic stars

- Blanco Instrument Review

- August '04 - Joe Mohr

## Why a Large SZE Cluster Survey?

- Improved halo mass estimates- the mass-observable relations in the optical are not as clean
- ~100% rms in optical- see below- versus 10%-25% in SZE
- Improved cluster selection- projection and environment issues are not as severe (optical data complementary)
- What about X-ray surveys (serendipitous and with DUO)?

- Blanco Instrument Review

- August '04 - Joe Mohr

## DES Galaxy Angular Power Spectrum

- DES main survey will yield photo-z’s on approximately 300 million galaxies extending beyond a redshift z~1
- Photo-z uncertainties are too large to allow a full study of the 3D galaxy clustering, but we can study the angular clustering within redshift shells to z~1
- Features in the angular power spectrum reflect “standard rods” that follow from simple physical arguments and can be calibrated using CMB anisotropy data.
- Apparent sizes of features provide angular diameter distances to each redshift shell (i.e. Cooray et al 2001).  The clustering *amplitude* is unimportant, and so the unknown galaxy bias is no problem.

- Blanco Instrument Review

- August '04 - Joe Mohr

## Galaxy Angular Power Spectrum Cosmology

- We use the galaxy angular power spectrum within redshift shells, concentrating only on the portion with 50 < ell < 300
- We marginalize over 5 halo model parameters in each redshift bin

- With Planck priors, constraints on a constant equation of state parameter w are better than w~0.1

**Figures from Wayne Hu **

- Blanco Instrument Review

- August '04 - Joe Mohr

## Presentations to Blanco Instrument Review Panel

**Presentations to ****Blanco Instrument Review Panel**

- Intro and Science 1 		*Mohr*
- Science 2 and Context 	*Frieman*
- Survey Design 		*Annis*
- Instrument 			*Flaugher*
- Optical Design 		*Kent*
- Data Management 		*Plante*
- Project Management	 	*Peoples*

- Blanco Instrument Review

- August '04 - Joe Mohr