Eric M. Wilcots

University of Wisconsin-Madison

VLA/EVLA/VLBA (US)

ATCA (Australia)

DRAO (Canada)

WRST (Netherlands)

GMRT (India)

GBT (US) Arecibo (US) Parkes (Australia) Effelsberg

(Germany)

Improve continuum sensitivity by factors of 5 below 10 GHz and factors of 20 between 10 and 50 GHz

Continual frequency coverage between 1 and 50 GHz (maybe down to 300 MHz)

New correlator – up to 262,144 channels! Longer baselines – 0.004 arcsec at 50 GHz to

0.2 arcsec at 1 GHz (phase 2)

VLA EVLA Phase 1

EVLA Phase 2

Point source sensitivity

10μJy 0.8μJy 0.6μJy

bandwidth 0.1 GHz 8 GHz 8 GHz

# of channels

16 16,384 16,384

Freq. resolution

381 Hz 1 Hz 1 Hz

Angular resolution

0.”4 0.”4 0.”04

Extragalactic magnetic fields

Diffuse extragalactic synchrotron sources

13 cm (2.3 GHz) radar mapping of planets/moons

Mapping deep atmospheres of giant planets

H2CO in star forming regions

Extragalactic radio recombination lines

Imaging of thermal emission in star forming regions

“Cradle of Life” – formation and growth of planetary systems (terrestrial planets) terrestrial planet growth

“Strong-field Tests of Gravity” – pulsar and black hole physics pulsar/BH binaries

“Origin and Evolution of Cosmic Magnetism” –magnetic fields, anyone? all-sky RM survey with 20-30” separation between sources

“Galaxy Evolution and Cosmology” – cosmic star formation, HI surveys, Dark Energy Billion Galaxy HI Survey

“Epoch of Reionization” highly redshifted HI line

Frequency Range needed for SKA Science

ATA (Berkeley/SETI)

EVLA (Expanded VLA) – ongoing◦ Joint US/Mexico/Canada

◦ $200 million

◦ New Mexico

◦ In progress

KAT/MeerKAT (RSA)◦ In development

ASKAP (AUS)◦ In development

LOFAR (Netherlands)

LWA (US)

MWA (AUS/US)

FAST (China)◦ proposed

LOFAR (Netherlands)◦ In progress

◦ Construction phase to start this summer after critical systems design review

◦ 30-250 MHz

◦ Antenna stations spread over Netherlands, elsewhere in Europe

◦ EoR/high-z

MIT, CfA, ATNF, Aus. Universities, WA Overview

◦ 80-300 MHz (Low Freq. Demonstrator) 8000 dipole antennas Static FoV ~ 25 degrees (150 MHz) Redshifted 21 cm, heliosphere, transient radio sky ~$10M

◦ 800-1600 MHz (xNTD) 3500 sq m (20 x 15m dishes) Tsys ~ 50 K 256 MHz instantaneous bandwidth 30 independent beams 30 sq degree FoV HI, continuum surveys

NRL, Los Alamos, UNM, UT-Austin

Overview◦ 10-88 MHz

◦ Dipole technology

◦ Baslines 50600 m, resolution ~10”

◦ Collecting area ~106 m2

Aperture 3535 m2

Tsys 55 K Uncooled

Freq 700-1750 MHz

Bandwidth 512 MHz

Channels 65536

Max baseline 1500 m 35” resolution

FoV 5.1 deg2 Feed array

Funding/Timeline◦ $42M (KAT) + $70M (MeerKAT) from DST◦ $24M site infrastructure establishment◦ $1.7M “human capital development” Research chairs (UCT/UWC)

Postdoctoral fellowships

Student bursaries

◦ $4.3M operations/management

◦ 1st seven antennas 2009

Timeline: KAT Big KAT (450 antennas)

ASKAP, 700-1800 MHz, with strawman 30 12m dishes with PAF, upgrade/expansion to 45.

5-sigma detectionsfor all southern-hemisphere, “shallow” (1 yr) surveystrawman, expansion FOV 30 deg2 – depends on success of PAF technology -N=600,000

Johnston et al. 2007

Similar simulationfor a deep (1 yr)single pointing,N= 100,000

Johnston et al. 2007

Frequency Range: 100 MHz – 25 GHz Instantaneous BW: 25% of central freq. Configuration: bmin = 20m, 20% of

collecting area within 1km, 50% within 5 km, 75% within 150 km, bmax=3000 km (angular resolution < 0.02 / f (GHz) arcsec)

FoV: 1 sq deg2 (1.4 GHz), 200 sq deg2 (700 MHz)

Sensitivity 50 times the EVLA

US◦ LNSD (Large N/Small D) design◦ ~4200 12m dishes

Canada◦ LAR (Large Adaptive Reflector)◦ Receiver package suspended over collecting area

Europe◦ Tiles/cylinders

Australia◦ Spherical lens

India◦ 25m dishes

China◦ Multiple Arecibos

Inner core

Station

Reference Design

Wide-angle radio camera +

radio “fish-eye lens”

Site Selection 2008/2009◦ Western Australia & South Africa are the two

finalists

Final Specs 2008/2009

System Design 2008-2012

Phase 1 Construction (10%) 2012-2015

Redshifted HI

SKA Survey Metric

SKA/ALMA

Epoch of Reionization

Does the LX-L1.4GHz correlation extend to lower mass systems (i.e. galaxy groups)?

Full census of Galactic Pulsars – 10,000 pulsars◦ 10% will be ms pulsars

◦ 1% will be relativistic binaries tests of strong field general relativity

Detection of Crab-like pulsars in the Local Volume probe the IGM in the local Universe

Cosmic Magnetism via RM Survey

SKA could play Unique Role in Disk Studies

• SKA will have best resolution/sensitivity for thermal

emission (20 GHz)

• For direct detection of structure in disks induced by

planets, sub-AU resolution is key.

•High angular resolution probes terrestrial planet region

and enables following evolution over orbital timescales.

•Short centimeter wavelengths are critical for tracking

grain growth from sub-micron interstellar size particles

to “pebbles”.Bate et al. 2003

“As we know, there are known knowns. There are things we know we know. We

also know there are known unknowns. That is to say we know there are some things we do not know. But there are also unknown uknowns, the ones we

don’t know we don’t know.”Someone Famous

SKA Director: Richard Schilizzi (Netherlands)

Project engineer: Peter Hall (Australia)

SKA Engineering and Science Working Groups

Separate international consortia in Europe, South Africa, Australia, US

Cornell – Lead Institution MIT/Haystack NRL Virginia Tech Wisconsin Illinois NRAO Cal Tech/JPL Berkeley/SETI Institute

Cornell et al submitted Technology Development Project (TDP) to NSF in January◦ Demonstrators/costing

Did not submit a site selection proposal…. Limited (no?) funding available Gearing up for the Decadal Survey

Technology Demonstration◦ Can focal plane arrays actually work on a large

scale?◦ Software/data transport◦ Wide-band receivers◦ Cryogenics on a large scale

Science◦ Evolving science case

Money…..◦ This ain’t cheap $1.5B

◦ Europeans (~$50M), Australians (~$35M), South Africans (~$200M) have all started spending real money

◦ US…..