The SKAMP Project & Virtual Observatory Considerations

1. The SKAMP Project & Virtual Observatory Considerations 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 • Aims & Overview • Status • SKAMP VO Considerations • Data & data-pipeline 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! ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

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

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

6. SKA Design Considerations • Large collecting area for high sensitivity (1 km2), 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 (especiallyfor HI observations), stations can’t be too sparse. SKA will be an international US$1 billionproject ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

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

8. 1.6 km ··· 44 antenna segments ··· ··· 44 antenna segments ··· 12 m ··················································· ··················································· ············ ············ 1 2 3 ················· 44 45 ························· 88 89 90 FX Correlator ~90 Inputs ~4000 Baselines ~2000 Frequency Channels Interference Mitigation Antennas Data Processing, Storage and Serving The Square Kilometre Array Molonglo Prototype (SKAMP) 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 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

9. The Square Kilometre Array Molonglo Prototype (SKAMP) Team: Anne Green1, Tim Adams1, John Bunton2, Duncan Campbell-Wilson1, Aaron Chippendale1,3, Bevan Jones4, Michael Kesteven3, Dimiter Nedialkov1, Andrew Parfitt2, Elaine Sadler1, George “Ñima” Warr1,3 [1] School of Physics, University of Sydney [2] Telecommunications and Industrial Physics, CSIRO [3] Australia Telescope National Facility, CSIRO [4] Argus Technologies 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 ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

11. 1.6 km ··· 44 antenna segments ··· ··· 44 antenna segments ··· 12 m ··················································· ··················································· FX Correlator ~90 Inputs ~4000 Baselines ~2000 Frequency Channels From MOST to SKA Prototype Current Survey (1997-2003):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 SKAtestbed and science facility: • Frequency agility: 300-1420 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) ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

12. From MOST to SKA PrototypeA three stage approach… • 2003 Narrowband continuum correlator (843MHz, 4MHz bandwidth, 88+8 stations = 4,560 baselines) [In parallel with SUMSS] • 2004 Increase bandwidth and add spectral capability (800-850 MHz, 4,560 baselines, 2,000 frequency channels) [Use existing linefeed] • 2006 New linefeed + enhanced correlator (300-1420 MHz, 250MHz bandwidth, 4,560 baselines, 2,000 frequency channels) ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

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

14. Stage I correlator will enable high-dynamic range imaging MOST imaging dynamic range is 100-200:1 (similar to intrinsic dynamic range of VLA) Use of self-calibration on VLA has enabled imaging dynamic ranges of 105-106:1 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) ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr (MGPS Green et. al.)

15. Stage II FX correlator enables spectroscopic measurements • 800-850 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) (Lane 2000) Stage II enables ΩHI measurements at z = 0.7 to 0.8, where other methods are not well constrained (Lane and Briggs 2001) 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 TN0924-2201 at z=5.19(van Breugel et al. 1999) ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

17. Stage III Science Goals: 2. High-redshift HI in galaxies HIPASS (500s) (12 h) Molonglo (10x12 h) log10 Mlim (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. ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

18. Stage III Science Goals: 3. Other science projects • Redshifted HI absorption (z=0 to 3) • OH megamasers • Galactic recombination lines (H,C) FX correlator (2048 channels, each 0.2–25 km/s) 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) 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 • Frequency and pointing agility • Wide-band line feeds and LNAs • Cylindrical antenna prototype • Adaptive null steering and adaptive noise cancellation (RFI) Collecting area 18,000 m2~= 1% of SKA (i.e. equivalent to 1 SKA station) 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: • Internal FPGA design 60% complete • Circuit board design 20% complete (ADC prototyped) • Correlator: • Internal FPGA design 80% complete • Circuit board design 50% complete • Work commenced on control & pipeline system ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

21. VO Considerations – SKAMP produces masses of raw data  SKAMP III Cylindrical Parabolic Collectors (Two collinear 778 m x 12 m) 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. 300-1420 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) 400 GB/s raw data rate = 17 PB/12 hr obs Digital delay beamforming (80 10 m x 10 m patches) Digital filterbank (160) (Two polarisations @ 250 MHz/patch) Independent fanbeams (3 within 9 feed field of view) 500 MB/s per beam 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. FX Correlator (3,160 baselines, 2,048 channels) ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr Signal processing & storage (imaging, spectrometer, searching...)

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. ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr

23. The End  ANITA Workshop - SKAMP & VO Considerations - G. "Ñima" Warr