# Presentation: 916326

## The SZ effect: Surveys and Cosmology

- Michele Limon     Columbia University

## Structure Formation

- Standard ΛCDM Model
- Box Size 43 Mpc3
- 30 > z > 0

- http://cosmicweb.uchicago.edu/filaments.html

- In typical structure formation scenarios, low mass clusters emerge in significant numbers at z~2-3

## Group/Cluster Formation

- Standard ΛCDM Model
- Box Size 4.3 Mpc3
- 30 > z > 0

- http://cosmicweb.uchicago.edu/group.html

## Galaxy Clusters

- Early types

**POSS**

**Chandra**

*M*gal ≈ 0.02 *M*tot

*M*gas ≈ 0.1 *M*tot

*T*gas ≈ (1-15) *keV*

*M*tot ≈ 1014 – 1015 *Solar Masses*

*R *≈ 1 *Mpc*

- Galaxies

- Gas

- Dark
- Matter

*N*gal ≈ 10 – 1000

- Poor groups – rich clusters

- Heated by infall

## Why Clusters

-  Theory:

- Clusters relatively simple objects.  Evolution of massive
- cluster abundance determined by gravity.  Clusters
- straddle the epoch of dark energy domination 0<z<3.

-  Why Do We Need Yet Another Cosmological Probe?

- - Degeneracies differ from CMB, SNe, Galaxies
-  Systematics are different
-  Unique exponential dependence
-  Modelability

- Adapted from Zoltan Haiman

## How to find Clusters

- Optical/IR imaging: Early type galaxy colors (e.g., darkCAM, DES, ISCS, LSST, Pan-starrs, RCS1&2 ,...)
- Good contrast
- Relation to mass
- X-ray imaging: Lx from hot gas (e.g., review by Rosati et al. 2002, XCS)
- Good contrast
- T tightly correlated to mass
- All-sky surveys  - shallow
- Deeper serendipitous - limited area, inhomogeneous
- Weak lensing: shear/aperture mass (e.g., DUNE, JDEM)
- Direct relation to mass
- Projection effect
- SZ Survey

**Notes:**
Shear and SZ are perhaps closest to mass homogeneity, but not exactly.

## Sunyaev-Zel'dovic Effect

- In the Rayleigh-Jeans Regime:

## Thermal & Kinetic SZ Effect

- Thermal and kinetic SZ effect for a cluster with a peculiar velocity of 500 km s–1 (Carlstrom et al. 2002).

- -  = 2.34 mm

- o = 1.38 mm

- + = 0.80 mm

- - = 128 GHz

- o = 218 GHz

- + = 370 GHz

- For Tcmb =2.726K

## SZ Effect: why it is so nice

- SZ and X-ray maps (insert). Mohr 2002

- SZ contours are 0.75 K and X-ray scales are the same.

- Z = 0.17

- Z = 0.54

- Z = 0.83

- 1) The very distinct spectral signature
- 2) Measures the total thermal content of  the cluster
- 3) Temperature decrement more or less redshift independent
- 4) Less susceptible to complicated cluster substructure, core
-     physics (proportional to density and not density squared as in Xrays)

## SZ Spectral Signature

*M *= 1015*M*
*T* = 9 keV
*z* = 0.43

*M *= 2×1014*M*
*T* = 3 keV
*z* = 0.43

## Potential for different methods to constrain “w”

- Levine, Shultz & White 2002

- Cluster Surveys are
- complementary to already well established  cosmological probes

## Sensitivity of Cluster Redshift Distribution to Dark Energy Equation of State

- Increasing **w** keeping ******E**** **fixed has the following effects:
- It decreases volume surveyed
- It decreases growth rate of perturbations

- Fig courtesy Joe Mohr

## Clusters Surveys

- _Interferometers:_ ∼10-100 sq. deg.
- Arcminute MicroKelvin Imager (AMI) (in operation)  first image: astro-ph/0509215
- 10 new antennas (3.7m) + Ryle Telescope (12.8m), 13.5 -- 18 GHz,
- Array for Microwave Background Anisotropy (AMIBA)
- 19 antennas (0.3m), 90 GHz, Mauna Loa Hawaii
- SZ Array  (in operation)
- 8 antennas (3.5m), 30 GHz + 90GHz follow-up,   OVRO + BIMA = CARMA
- _Bolometer arrays:_ ∼100-4000 sq. deg.
- ACBAR: 4 band-4element array at                       South Pole (in operation)
- BOLOCAM: 150 element array                             CSO Mauna Kea (in operation)
- APEX: ALMA  prototype, 300 element array         Llano de Chajnantor (Chile)  (in operation)
- ACT: Atacama plateau, 3 x 1000 element array   Cerro Toco (Chile)  (in operation)
- SPT: 10m dish, 1000 element array                     South Pole  (in operation)
- _Planck:_ ∼40000 sq. deg. = all-sky
-  ∼10,000 clusters                                        L2 launch 2008/2009

## AMI

| Sub-array	 | AMI-SA | AMI-LA |
| --- | --- | --- |
| Primary dish diameter	 | 3.7 m | 12.8 m |
| Antenna efficiency	 | 0.75 | .067 |
| Number of antennas	 | 10 | 8 |
| Number of baselines	 | 45 | 28
 |
| Range of baseline lengths	 | 4 – 20 m | 18 – 120 m |
| Primary beam (FWHM at 15 GHz)	 | 18’ | 5.5’ |
| Observing frequency	 | 13.5 – 18 GHZ |  |
| Effective Bandwidth	 | 4.5 GHz |  |
| Number of frequency channels	 | 6 |  |
| Bandwidth of each freq. channel	 | 0.75
 |  |
| System temperature (zenith)	 | 25 k |  |
| Polarization measured	 | I + Q |  |
| Site	 | MRAO, Cambridge UK |  |
| Flux sensitivity	 | 30 mJy s-1/2 | 3 mJy s-1/2 |

- Small Array

- Large Array

## AMIBA

| AMiBA Spec |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- |
| Dual-channel receiver |  | MMIC; L and R |  | Platform | 6 m configurable; carbon fiber |  |
| Operation frequency |  | 86-102 GHz |  | Correlator | analog (bandwidth 16 GHz) |  |
| Site |  | Mauna Loa, Big Island, Hawaii (3400 m in elevation)  |  |  |  |  |
| Mounting system |  | Hexapod (  ±30°   in polarization;          30° - 90°        in elevation)  |  |  |  |  |
| 7-element (2006-2008) |  |  |  |  |  |  |
| Antenna | 60-cm Cassegrain; carbon fiber |  | Synthesized resolution |  |  | 6 arcmin |
| FOV | 23 arcmin |  | Observation type |  |  | targeted |
| 13-element (2009-) |  |  |  |  |  |  |
| Antenna | 120-cm Cassegrain; carbon fiber |  | Synthesized resolution |  |  | 2 arcmin |
| FOV | 11 arcmin |  | Observation type |  |  | targeted and survey |

## SZA

- http://astro.uchicago.edu/sza/

- http://calvin.phys.columbia.edu/group_web/sza.html

## ACBAR operates on the 2m Viper Telescope

- Large AZ chop (~3°)
-  + small beams (~4-5)

- Ground shield blocks emission from EL< 25o.

- Panel lowers for low-EL observations

- = broad -space coverage
- (~75 <  < 3000) *and* sensitivity to   clusters over a wide redshift range

- Skirt reflects primary spill-over to sky.

- Chopping  tertiary mirror

- http://cosmology.berkeley.edu/group/swlh/acbar/

## Bolocam

- Observes at Caltech  Submillimeter Observatory     (10.4 m dish)
- Hexagonal array of 144 bolometers
- Array has a 7.5’ field-of-view with individual beam sizes of 30” FWHM
- Sensitivity from the ground limited by temporal water vapor fluctuations
- False detection rate is non-negligible

- http://www.cso.caltech.edu/bolocam

## ACT: Atacama Cosmology Telescope

-  Remote Controlled
-  Flexible Focal Plane
-  Near the ALMA Site

-  6 Meter Aperture
-  Low Ground Pickup (< 20μK dc)
-  No Moving Optics

## APEX-SZ: Atacama Pathfinder Experiment

- 16,500 feet in Chilean Andes.
- 12m on-axis ALMA prototype
- Berkeley SZ Receiver:
- 330  Bolometer array
- 25% telescope time
- Could discover 4000 Clusters/2yrs
- Mass limit > 4x1014 M0
- First Light Fall 2004
- Observations in progress

- UC Berkeley/LBNL, MPI-Bonn/Munich,
- Cardiff

## SPT: South Pole Telescope

- First light achieved with the 10m South Pole Telescope, February 16, 2007.
- Maps of Jupiter made, showing telescope and optics working as designed.
-  Plan to do 4,000 sq. degree survey at 90, 150 and 220 GHz at ~ arc minute resolution.

- The SPT is a collaboration between the U of Chicago, UC Berkley, Case Western Reserve University, U of Illinois, and Smithsonian Astrophysical Observatory

## How many clusters?

| Name | Frequency
(GHz) | Beam FWHM
(arcmin) | Noise
(K/beam) | S/N=5
(deg-2) | Total |
| --- | --- | --- | --- | --- | --- |
| AMI | 15 | 1.5 | 8 | 16 | ~150 |
| SPT  | 150 | 1 | 10 | 11 | ~40000 |
|  | 220 | 0.7 | 60 |  |  |
|  | 275 | 0.6 | 100 |  |  |
| ACT | 145 | 1.7 | 1.7 | 40 | ~4000 |
|  | 225 | 1.1 | 4.8 |  |  |
|  | 265 | 0.93 | 7.8 |  |  |
| Planck | 143 | 7.1 | 6 | 0.35 | ~10,000 |
|  | 217 | 5 | 13 |  |  |
|  | 353 | 5 | 40 |  |  |

- Adapted from J. Bartlett

**Notes:**
Mention high l CMB science.

## Clusters at high z

- Adapted from J. Bartlett

- ~100s of Planck clusters
- at z>1 (unresolved)

- ~1000s of SPT clusters
- at z>1

- SPT: 4000 deg2

- Planck:
- 30000 deg2

- Bartlett 2001

**Notes:**
Mention high l CMB science.

## Summary

***These surveys provide us an opportunity to probe  the enigma of dark energy with high precision, while at the same time probing the high l structure of the CMB***

## Sunyaev-Zel'dovic Effect

- e-

- γ

- γ

## PolarBear

- Ground-Based 3 meter Telescope at White Mountain CA
- Characterize E-modes
- Search for B-modes

## Why Clusters

## SZ Effect: Equation

- The SZ temperature is a line-of-sight pressure integral of electron density (*n*e) and gas temperature (*T*e).
- The SZ temperature decrement is redshift-independent: When the CMB photons interacted with the cluster, *T*CMB(*z*) was hotter and this compensates for cosmological dimming.

- In the Rayleigh-Jeans Regime:

## Why Clusters

## Why Clusters

- SZ effect ideally suited for cluster surveying
- Efficient at high z
- Roughly uniform mass selection out to z>1
- Expectations 2007-2010: 10s => 1000s @ z>1
- Interferometers ~ 100 (~10% at z>1)
- Bolometer cameras ~ 1,000 - 10,000 (~10% at z>1)
- Planck ~10,000 all sky (~1% at z>1)