Di FX at KASI Jongsoo Kim and Taehyun

Di. FX at KASI Jongsoo Kim and Taehyun Jung Korea Astronomy and Space Science Institute http: //jskim. kasi. re. kr/difx

Korean VLBI Network v v v Yonsei 3 × 21 m Antennas Maximum Baseline : 480 km 4 Channel (22/43/86/129 GHz), LCP/RCP Simultaneous Observing System Multi-Frequency Phase Referencing Correlators: Daejeon(HW), Di. FX(SW) Ulsan Tamna -2 -

22/43/86/129 GHz Receivers -3 -

Performance tests Korea : KVN antenna Yonsei (Seoul), Ulsan, Tanma (Jeju) Japan : VERA antenna Mizusawa, Ishigaki, Iriki, Ogasawara 1. 4 mas@22 GHz 0. 7 mas@43 GHz East Sea

Improved image (22 GHz) of M 87 by KVN+VERA Total flux : 1. 18 Jy Peak flux : 1. 04 Jy/beam Image rms : 4 m. Jy/beam Total flux : 1. 55 Jy Peak flux : 1. 08 Jy/beam Image rms : 2 m. Jy/beam

Daejeon Correlator@KJCC

Di. FX system • one difx server: 16 cores (E 5 -2690), 64 GB memory, Cent. OS 6. 3 • Storage: 120 TB+80 TB RAID 6, direct attached to server • Mark 5 unit: Mark 5 B+(SDK 8. 3), 5 C(SDK 9. 2), direct connection to server with 1 GE

Operations • Just started normal operations for KVN only following standard procedure – Fuse or mk 5 cp – vex 2 difx – calcif 2 – mpifxcorr – difx 2 mark 4, fourfit – difx 2 fits

Example

Performance • mk 5 cp: ~ 0. 51 Gbit/sec • mpifxcorr with 16 cores: ~24 hours correlation time for a 12 hour 1 Gbps observation with 3 KVN antennas

Future Plan • “native” Mark 5 correlation • infiniband upgrade • Correlation for KVN+VERA – Require copy of VERA 2000 tape to Mark 5 diskpack or storage