Review of developments in Australasia and mainland Asia Steven Tingay Swinburne University of Technology Next Generation correlator meeting, JIVE June,

1.Current correlator developments in Australasia CABB (Ferris: Day 1) SKAMP (Bunton: Day 3; de Souza: Day 3) NTD/xNTD(Bunton: Day 3) - Langman: Day 3 LFD(Bunton: Day 3) VLBI/eVLBI (Deller: Day 2) 2.Current correlator developments in mainland Asia PAST FAST VLBI/CE-1 (Zhang: Day 1; Weimin: Day 2) GMRT(Gupta: Day 1) Horses for courses………

Compact Array Broadband Backend (CABB) First major upgrade to ATCA correlator since construction in 1988 (CABB funded under MNRF2001) Current ATCA correlator: 6 antenna inputs; 2 dual polarisation (linear) IFs (∆ MAX = 128 MHz); XF; max number of channels = 4096; ASIC-based. CABB: 8 inputs (2 extra for VLBI or RFI mitigation); 2 dual polarisation (linear) IFs (∆ MAX = 2 GHz); polyphase digital filter bank for channelisation, then cross-multiply; max number of channels = 2000 (initially); FPGA-based. Phased introduction of operational system over next 2 Years Dick Ferris to present details (

SKA Molonglo Prototype (SKAMP) (John Bunton/Ludi de Souza) –96 stations (feeds), digital filterbank FX, FPGA-based;; –Stage 1: continuum, ∆ = MHz; –Stage 2: 2048 channel spectral line, ∆ = MHz; –Final: 2048 channel spectral line, ∆ = MHz (Extended) New Technology Demonstrator (NTD/xNTD) (John Bunton) –20 x 15m dishes, FPA with >30 beams; –22800 baseline/polarisation products, ∆ = 256 MHz ; –Spectral-line, FPGA-based (same correlator board as SKAMP??); –Very similar instrument to KAT (Alan Langman); –Located at Mileura station in Western Australia. Low Frequency Demonstrator (LFD) (John Bunton) –500 tile array with full stokes, ∆ = 32 MHz, 4000 channels; –Common correlation engine with SKAMP and NTD/xNTD; –CSIRO/MIT/University joint project;

DiFX software correlator astronomy.swin.edu.au/ska (Adam Deller) Complements new high data rate disk-based recording system 300 processor Beowulf cluster/Cray XD-1/Cray XT-3; FX correlator (filter bank option); Services Australian and global VLBI arrays; Six antennas up to 1 Gbps ( ∆ <= 128 MHz) ; Currently offered as part of ATNF (high sensitivity, high spectral resolution, niche experiments); Will replace ATNF S2 correlator (<128 Mbps and <4096 channels) within 12 months; Natural compatibility with all other disk-based recorders (Mark5, K5, PC-EVN etc); Used for eVLBI tests and real-time fringe checking; Promotes collaboration in non-traditional but important areas.

Primeval Structure Telescope (PAST) web.phys.cmu.edu/~past/overview.html – Observe the epoch of reionisation at redshift ; – 80 phased arrays x 127 antennas per phased array; – 10,000 log periodic antennas in the Ulastai Valley, China; – Software correlator using ~100 COTS PCs. Five hundred metre Aperture Spherical Telescope (FAST) – Multi-beam receivers for surveys; – Wide bandwidth, full polarisation; VLBI spacecraft tracking/Chang’E-1 Lunar mission Real-time software correlator (Zheng Weimin, Xiuzhong Zhang) – Determination of lunar orbiter position, lunar gravity field; – Correlation in software a la Huygens VLBI experiments; – Real-time correlation with COTS PC cluster.

Giant Metrewave Radio Telescope (GMRT) (Yashwant Gupta) –30 x 45m antennas, MHz; –Bandwidth upgrade from 32 MHz to 400 MHz; –Upgrade of current 30 antenna, 256 channel, FX correlator required -> 32 antenna, 8192 channel; –Enhanced beamforming capabilities for multi-beam pulsar searching; –Software vs hardware ???

Summary A lot of diverse activity across the region. Large and small developments, upgrades (e.g. CABB, SKAMP, GMRT) and new facilities (e.g. xNTD, FAST, LFD); SKA demonstrators (CABB, SKAMP, xNTD, LFD, FAST); Niche facilities (Software correlators for VLBI); Specialised experiments (PAST); Other small developments (e.g. Uni.Tas. FPGA developments) Other planned/proposed developments (e.g. Australian geodetic VLBI array using software correlator.)