Nanshan vlbi station By LIU Xiang & ZHANG Jin Urumqi Observatory, NAOC

1. Nanshan vlbi station • By • LIU Xiang & ZHANG Jin • Urumqi Observatory, NAOC

2. Urumqi Observatory, NAOC Urumqi Observatory, NAOC

3. The 25m radio telescope The 25m radio telescope

4. The EVN for astronomy

5. IVS for geodesy

6. LFVN & radar vlbi (vlbr)

7. Vlbi astrophysics---12 GPS sources at S/X The EVN vlbi images recently made by the P.I. Liu Xiang, with the stations Eb,Wz,Mc,Nt,Ma,On,Yb,Sh,Ur Observed in 2002/06/04 e.g.

8. J0146+2110s

9. J0146+2110x

10. J0906+0342s

11. J0906+0342x

12. J1135+4258s

13. J1135+4258x

14. GPS sources at S/X & L • Previously 10 sources observed with the EVN in 1999 & 2000, see the paper made by the P.I. Liu Xiang et al. in A&A, 2002, 385, 768; • one CSO 1345+125 and 3 CSO candidates were detected and one exotic source 1751+278 imaged for the first time with vlbi. • With the stations: Eb, Wz, Wb, Jb, Cm, On, Mc, Nt, Ma, Tr, Ny-Alessund, Sh, Ur, and MERLIN (at L-band)

15. Youngest radio galaxy OQ208 • The baby radio galaxy with age of 200+/-130yr, see Chin. Phys. Lett. 2000, Liu Xiang, Stanghellini et al. , 5th EVN vlbi symposium, and Stanghellini, Liu et al in preparation.

16. FFA & Thomson scattering • FFA firstly proposed by Kameno et al. in HALCA observation for this source confirmed by our ground observations. • I firstly suggested to explain the optical thin part of this source with Thomson scattering

17. The radar vlbi • Signals transmitted from Evpatoria RT-70, received with mk2 or S2 terminals at stations Bear lake, Noto,Urumqi,etc. • The ability of the Evpatoria RT-70 radar complex to perform research on space debris was investigated in four trial experiments during 2001-2003. The echo-signals of 25 objects at geostationary, highly elliptical and medium-altitude orbits were recorded on magnetic tapes at radio telescopes in Russia, Italy, China and Poland. The multi-antenna system configuration gives potential to supplement the classic radar data with precise angular observations using the technique of Very Long Baseline Interferometry. The first stage of such processing was fulfilled by the correlator in N. Novgorod, Russia. The cross-correlation of transmitted and received signals was obtained for the 11 objects on the Evpatoria-Bear Lakes, Evpatoria-Urumqi and Evpatoria-Noto baselines. This activity also promoted developing the optical observations of geostationary objects, conducted for the improvement of the radar target ephemerides.

18. I.E.Molotov, G.Tuccari, B.N.Lipatov, A.A.Konovalenko, V.M.Agapov, X.Liu, X.Y.Hong, Yu.N.Gorshenkov. On development of near real-time system for VLBI radar measurements of space debris parameters. Proceedings of 17th International Symposium on Space Fligth Dynamics X. Liu, I. Molotov, S. Likhachev, X. Hong, S. Ananthakrishnan, V.Balasubramanian. LFVN: New VLBI Project in the Asia-Pacific Area. 2001 Asia-Pacific Radio Science Conference, AP-RASC'01 Chuo University, Tokyo, Japan, August 1-4 2001 Radio Science- Communications, Environment, and Energy Conference Digest, p. 387

19. Fig. left. Power spectrum of sounding signals transmitted from Evpatoria RT-70, sky frequency 5010.024 MHz, RCP, 27.05.01, 23:35 UT, VLBR01.1 (120 kW). • Fig. right. Echo (second peak) of 4th stage of Proton received in Urumqi RT-25, LCP. Autocorrelation spectrum of 2 MHz , 27.05.01, 23:35 UT, FFT 1024, 34 s integration, VLBR01.1.

20. Fig. left. Cross-correlation spectrum (transmitted-received signals) for Evpatoria - Urumqi baseline, FFT 512 channels. • Fig. right. Cross-correlation spectrum (transmitted-received signals) for Evpatoria – Bear Lakes baseline, FFT 512.

21. Vlbi goedesy • IVS---International vlbi Servise for geodesy and astrometry • APSG---Asia Pacific Space Geodesy, and the

22. Single dish observations • 1, Pulsar timing, e.g. Pular timing at Urumqi Astronomical Observatory: Observing system and results, N.Wang, R.N.Manchester, J.Zhang X.J.Wu, A.Yusup, A.G.Lyne, K.S..Cheng and M.Z.Chen, MNRAS, 2001 • 脉冲星PSR B0329+54的多波段观测,伊.艾力,吴鑫基,张晋,王娜, 康连生,金声震,张洪波,王维侠，天体物理学报, 2000 • 2, Astronomical maser, e.g. a new 4096 channel spectrometer is undertesting

23. The vlbi system • 25m, pointing error ~15” rms • Surface accuracy ~0.75mm rms • Receiver parameters • Band Freq range LO Pol. Tsys SEFD • 1.3 cm 22100-22400 22000 LCP 170K 2580Jy • 3.6 cm 8200-8600 8080 RCP 45 373 • 6 cm 4750-5150 4620 LCP 40* 368 • 13 cm 2150-2450 2020 RCP 80 1080 • 18 cm 1450-1750 1300 dual 20 240 • 49cm/30 cm under construction, 49cm is available with cross feed • 92 cm 317-337 0 line 90 1265

24. The vlbi terminals • Mk2---still work for radar vlbi • Mk4---work for normal vlbi • K4---- has some problem for tape driving • Mk5---could be installed in 2004 spring • Time system • The H-maser & GPS (TAC) • Stability 1s—e-12, 10s—e-13, >100s—e-14 • Freq accuracy +/-5*10^-13, freq resolution 7*10^-14