The KAT/SKA project and Related Research

Catherine Cress (UKZN/KAT/UWC)

The Square Kilometer Array (SKA)

radio telescope for 2020+1000's of dishes spread over 1500km+1 km2 collecting area0.1-22GHz?US$1 billion+17 countries

will be built in South Africa or Australia

SA demonstrator projects:KAT, meerKAT, BigKAT> R800million committed

Other demonstrators:xNTD, ATA, LOFAR, etc

SKA Science

* Galaxy Evolution, Cosmology and dark energy

* Reionisation epoch (time of first stars and quasars)

* Pulsars, Black Holes and Gravitational Waves SKA will find large number of binary pulsar systems: good for testing GR in strong fields: see effects of QG?

* Planet Formation and SETI

* Cosmic Magnetism www.ska.ac.za

SKA layout and site

Survey figure of merit:Field-of-view*(collecting area/system temp)2*bandwidth

KAT Now:

* first dish being made at Hartrao

* >20 Engineers at KAT office in Cape Town+ team of ~8 in JHB

* Postgrad bursary program of over 25 students – (engineering & science)

SKA/KAT-related research at UKZN(/UWC?)

* Science for SKA: eg. measuring sound speed of dark energy (Torres-Rodriguez, Cress)

* Clustering of HI-detected galaxies (Passmoor, Cress)

* HI-studies with KAT – z-distributions, configurations etc.

* Radio Galaxy/optical cross-correlations to measure bias (relationship between dark and luminous matter) (Nhanombe, Elbouchefry, Passmoor, Harpaul, Cress)

* N-body simulations for galaxy evolution studies (Bryan, Cress)

* Detecting background of gravitational waves with pulsar array (Moodley, Warne)

SKA/KAT-related research at UKZN(/UWC?)- Results

* Science for SKA: eg. measuring sound speed of dark energy dark energy sound speed potentially distinguishable: test quintessence hypothesis

* Clustering of HI-detected galaxies: HI galaxies antibiased wrt DM

* Radio Galaxy/optical cross-correlations

* N-body simulations for galaxy evolution: coherent figure rotation over long periods

SKA/KAT-related research at UKZN(/UWC?) - Results

HI observations with (meer)KAT

HI observations with KAT:

M31 at z=0.001 with 2km, 500m and 200m baselines

Large beams: confusion, even in redshift space

SKA/KAT related research at other institutions

* see UCT talks

* pulsars, masers – UJ, Wits, UNISA, Hartrao

* Rhodes – instrumentation, masers with VLBI?

Other Research at UKZN

Atacama Cosmology Telescope project

New generation CMB experiment from WMAP group (members from Princeton, UPenn, Rutgers, others & UKZN)mm telescope being built in Chile Will discover many cluster of galaxies through sunyaev-zeldovich effectMuch optical follow-up required in South to measure redshifts and masses of clustersPerfect high-profile project for SALT

Project goals:

•* Identify ~1000 clusters of galaxies though • Sunyaev-Zeldovich effect to constrain w to +/-10% (w in dark energy equation of state) and limit neutrino mass to 0.1ev •* Get CMB fluctuations in the 200<l<10000 range • => info on primordial spectrum to constrain• physics generating initial density fluctuations,(&) • study reionisation, gravitational lensing of CMB

Other research at UKZN(with Kavi Moodley and students)

Atacama Cosmology Telescope:- SALT observations- simulations to study cluster identification with clustered point sources- Blanco Cosmology Survey (deep optical, 50 sq deg in south)- theory

Spanish Planck collaboration- simulations to study cluster identification (with optical info) - SALT observations?

Galaxy Evolution simulations

CMB theory

the KAT/SKA project viewed from just outside the project team in 2005:

in 2007:

* funding* people development (see 2006 bursary conference)* site * first dish production* strong international support – SKADS etc.

MBAC on ACT 1.7’ beam w/ 2X

noise

High-Res SZ Simulations

Planck (2008)

Sunyaev-Zeldovich effect:

Hot gas (107K) in environment of clusters of galaxies.

CMB photons upscattered to higher frequencies

by inverse Compton effect (hot e-’s give up energy

to radio photons =>in direction of clusters get hole

in CMB sky at radio ’s, bright patch at mm ’s.

Optical Xray

Effect of varying w (in equation of state of dark energy)on number density of clusters over a given SZ detection threshold

Top to bottom at peak: w= -1, -0.6, -0.3, 0

Haiman et al (2001)