29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 1 The SKAMP Project & Virtual Observatory Considerations

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 2 The SKAMP Project & Virtual Observatory Considerations Outline: SKA (Square Kilometre Array) overview SKAMP (SKA Molonglo Prototype) Project oAims & Overview oStatus SKAMP VO Considerations oData & data-pipeline

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 3 The SKA will be 100 times more sensitive than present radiotelescopes VLA and Arecibo were such large advances that collecting area unchanged for decades… Need technology shift to progress!

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 4 Probing the distant universe HSTVLASKA In the past few years, optical telescopes have begun to probe the ‘normal’ galaxy population to z~3

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 5 Proposed SKA Specifications (SKA Technical Workshop, 1997)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 6 SKA Design Considerations Large collecting area for high sensitivity (1 km 2 ), 100x sensitivity of current VLA. Array elements (stations) distributed over a wide area for high resolution (needed to avoid confusion at very faint flux levels). For good uv plane coverage (especially for HI observations), stations can’t be too sparse. SKA will be an international US$1 billion project

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 7 US ATA Australia Luneburg Lenses Dutch phased array SKA antenna concepts China (Arecibo like) Canada Large reflector Australia cylindrical paraboloid

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 8 The Square Kilometre Array Molonglo Prototype (SKAMP) 1.6 km 12 m ··· 44 antenna segments ··· ············ ················· ························· 88 FX Correlator ~90 Inputs ~4000 Baselines ~2000 Frequency Channels ··················································· Interference Mitigation Antennas Data Processing, Storage and Serving Goal: To equip the Molonglo telescope with new feeds, low-noise amplifiers, digital filterbank and FX correlator with the joint aims of: developing and testing SKA- relevant technologies and providing a new capability for low-frequency radio astronomy in Australia

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 9 Team: Anne Green 1, Tim Adams 1, John Bunton 2, Duncan Campbell-Wilson 1, Aaron Chippendale 1,3, Bevan Jones 4, Michael Kesteven 3, Dimiter Nedialkov 1, Andrew Parfitt 2, Elaine Sadler 1, George “Ñima” Warr 1,3 [1] School of Physics, University of Sydney [2] Telecommunications and Industrial Physics, CSIRO [3] Australia Telescope National Facility, CSIRO [4] Argus Technologies The Square Kilometre Array Molonglo Prototype (SKAMP)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 10 SKAMP Funding $25,000 USyd Sesqui seed funding for SKAMP Stage I $1.7 million MNRF funding for components & technician for SKAMP Stage II & III $240,000 ARC Linkage Project for ultra- wideband linefeed for SKAMP Stage III Awaiting outcome (late March ’03): $192,000 ARC Linkage (CSIRO) 3-year Post- Doctoral Fellow for Control & Pipeline system

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 11 From MOST to SKA Prototype Current Survey ( ): The Sydney University Molonglo Sky Survey (SUMSS), imaging the whole southern sky (δ < -30°) at 843 MHz to mJy sensitivity with 45” resolution (i.e. similar to NVSS). [843 MHz, 12hr synthesis, 2.7° diameter field] Next: Use existing telescope as SKA testbed and science facility: Frequency agility: MHz (250 MHz BW) Multi-beaming (3 independent fanbeams) 2048 Spectral channels, 4000 baselines Continuous uv coverage Wide field of view (1.5°-1420 MHz, 8°-300 MHz) 1.6 km 12 m ··· 44 antenna segments ··· FX Correlator ~90 Inputs ~4000 Baselines ~2000 Frequency Channels ···················································

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 12 From MOST to SKA Prototype A three stage approach… I.2003 Narrowband continuum correlator (843 MHz, 4 MHz bandwidth, 88+8 stations = 4,560 baselines) [In parallel with SUMSS] II.2004 Increase bandwidth and add spectral capability ( MHz, 4,560 baselines, 2,000 frequency channels) [Use existing linefeed] III.2006 New linefeed + enhanced correlator ( MHz, 250 MHz bandwidth, 4,560 baselines, 2,000 frequency channels)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 13 Continuous uv coverage gives excellent image quality  Continuous uv coverage from 90 m to 1.6 km in 12hr synthesis  SKA will also have fully-sampled uv data 1.6 km 750 m (Bock et al. 1999)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 14 Stage I correlator will enable high-dynamic range imaging MOST imaging dynamic range is :1 (similar to intrinsic dynamic range of VLA) Use of self- calibration on VLA has enabled imaging dynamic ranges of :1 A correlator will allow use of self- calibration methods on MOST Current imaging dynamic range of MOST limits imaging of faint sources (eg young supernova remnants) near bright sources (eg Galactic Centre) (MGPS Green et. al.)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 15 Stage II FX correlator enables spectroscopic measurements MHz 2,000 spectral channel FX correlator enables, eg: Measurements of HI absorption at z = 0.7 to 0.8 that capitalise on the large collecting area of MOST Measurements of the recombination lines of C and H enabling determination of constrains on the physical conditions in the ISM (Anantharamaiah & Kantharia 1999) Stage II enables Ω HI measurements at z = 0.7 to 0.8, where other methods are not well constrained (Lane 2000) (Lane and Briggs 2001)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 16 Stage III Science Goals: 1. Radio galaxy spectral index FX correlator: wide-band radio spectrometry Radio spectral index measurements over the range 300 –1400 MHz are an efficient way of selecting high- redshift (z>3) radio galaxies (e.g. de Breuck et al. 2000). Radio galaxy TN at z=5.19 (van Breugel et al. 1999)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 17 Stage III Science Goals: 2. High-redshift HI in galaxies HIPASS (500s) Molonglo (10x12 h) (12 h) log 10 M lim (HI) (M ⊙ ) Typical bright spiral HI in the nearby Circinus galaxy (Jones et al. 1999) The Molonglo telescope will reach HI mass limits typical of bright spiral galaxies at z=0.2 (lookback time ~3 Gyr), allowing a direct measurement of evolution in the HI mass function.

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 18 Stage III Science Goals: 3. Other science projects FX correlator (2048 channels, each 0.2–25 km/s)  Redshifted HI absorption (z=0 to 3)  OH megamasers  Galactic recombination lines (H,C) Pointing agility  Rapid response to GRBs Independent fan beams  Monitoring programs (SETI, pulsars etc.) Optional 64 fanbeams within main beam  Pulsar searches (high sensitivity, wide field of view)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 19 SKA Molonglo Prototype Technologies  Multibeaming  Wide instantaneous field of view  Digital beamforming  Wide-band FX correlator (2,048 channels, 3,828 baselines) “Mega MOST” ~1 million frequency-image points on sky  Remote operation Collecting area 18,000 m 2 ~= 1% of SKA (i.e. equivalent to 1 SKA station)  Frequency and pointing agility  Wide-band line feeds and LNAs  Cylindrical antenna prototype  Adaptive null steering and adaptive noise cancellation (RFI)

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 20 Status of SKAMP Stage I Continuum Correlator Conceptual design complete Input intermediate-frequency signal tap and SUMSS isolation circuit complete and in production Digitiser, delay and fringe-stopping unit: oInternal FPGA design 60% complete oCircuit board design 20% complete (ADC prototyped) Correlator: oInternal FPGA design 80% complete oCircuit board design 50% complete Work commenced on control & pipeline system

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 21 VO Considerations – SKAMP produces masses of raw data Cylindrical Parabolic Collectors (Two collinear 778 m x 12 m) MHz Feed and LNA (7,400 feeds, 14,800 LNAs) Delay line beamforming (Over 9 feeds) Analog to Digital Converter (1,600 8 bit 250 MHz BW ADCs) Digital delay beamforming (80 10 m x 10 m patches) Digital filterbank (160) (Two 250 MHz/patch) FX Correlator (3,160 baselines, 2,048 channels) Signal processing & storage (imaging, spectrometer, searching...) Independent fanbeams (3 within 9 feed field of view) 400 GB/s raw data rate = 17 PB/12 hr obs 52 MB/s for 1s correlator dump period = 2.2 TB/12 hr obs 0.8 MB/s for 60s correlator dump period = 37 GB/12 hr obs Interference mitigation for low-earth-orbit satellites may require 0.1s or faster correlator dumps. 500 MB/s per beam SKAMP Stage I continuum correlator dumps 4,560 baselines per second for one (4 MHz wide) frequency band.  SKAMP I gives 1.6 GB/12 hr observation.  SKAMP III

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 22 SKAMP Data Pipeline Intention is to create an automated data pipeline. Stage I data to be stored in RP-FITS format utilising modified ATNF software routines. Initially MIRIAD will be used to invert the visibility data into images for comparison with SUMSS images. Aaron Chippendale investigating high dynamic range imaging and use of AIPS++ routines to invert data. We will investigate implementing interference mitigation algorithms in the pipeline. Daniel Mitchell has done some preliminary calculations on the correlator dump time required for this.

29 Jan 2003 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr 23 The End