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DiFX at KASI. Jongsoo Kim and Taehyun Jung Korea Astronomy and Space Science Institute http://jskim.kasi.re.kr/difx. Korean VLBI Network. 3 × 21m Antennas Maximum Baseline : 480 km 4 Channel (22/43/86/129 GHz ), LCP/RCP Simultaneous Observing System
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DiFX atKASI Jongsoo Kim and Taehyun Jung Korea Astronomy and Space Science Institute http://jskim.kasi.re.kr/difx
Korean VLBI Network • 3 × 21m Antennas • Maximum Baseline : 480 km • 4 Channel (22/43/86/129 GHz), LCP/RCP • Simultaneous Observing System • Multi-Frequency Phase Referencing • Correlators: Daejeon(HW), DiFX(SW) Yonsei Ulsan Tamna - 2 -
Performance tests Korea : KVN antennaYonsei (Seoul), Ulsan,Tanma (Jeju) Japan : VERA antennaMizusawa, Ishigaki, Iriki,Ogasawara 1.4 mas@22GHz0.7 mas@43GHz East Sea
Improved image (22GHz) of M87 by KVN+VERA Total flux : 1.18 Jy Peak flux : 1.04 Jy/beam Image rms : 4 mJy/beam Total flux : 1.55 Jy Peak flux : 1.08 Jy/beam Image rms : 2 mJy/beam
DiFXsystem • one difx server: 16 cores (E5-2690), 64GB memory, CentOS 6.3 • Storage: 120TB+80TB RAID 6, direct attached to server • Mark5 unit: Mark 5B+(SDK8.3), 5C(SDK9.2), direct connection to server with 1GE
Operations • Just started normal operations for KVN only following standard procedure • Fuse or mk5cp • vex2difx • calcif2 • mpifxcorr • difx2mark4, fourfit • difx2fits
Performance • mk5cp: ~ 0.51 Gbit/sec • mpifxcorr with 16 cores: ~24 hours correlation time for a 12 hour 1Gbps observation with 3 KVN antennas
Future Plan • “native” Mark5 correlation • infiniband upgrade • Correlation for KVN+VERA • Require copy of VERA 2000 tape to Mark 5 diskpack or storage