1. Yingxi Zuo, Ji Yang Purple Mountain Observatory, CAS Sino-German workshop on radioastronomy Sep 13, 2005 Urumqi Delingha 13.7-m mm-Wave Telescope

2. OUTLINE Site Overview Telescope Description Technical Upgrade Activities Future Plans Science Activities

3. Site Overview -- General Information Location: – 35km from Delingha City, Qinghai, China Longitude: 97  33.6E Latitude: 37  22.4N Altitude: 3200 m Dry & Cold in Winter Delinha Nanjing

4. Site Overview -- Atmospheric Opacity @ f LO =112.6 GHz

5. Telescope Description – System Block Diagram Be able to observe CO(1-0) and its isotopes simultaneously

6. Telescope Description -- Current Status (1) Antenna Performance – Enclosed in a High-Transparency Radome (85-90%) – Diameter: 13.7 m – Pointing Accuracy: < 10” over the whole sky – Beamwidth (HPBW): ~60” – Aperture Efficiency: 39% – Main Beam Efficiency: 77% – Surface Accuracy: ~0.1 mm

7. Telescope Description -- Current Status (2) Receiver – 85 to 115 GHz SIS Receiver – T SYS : typically ranging from 180 to 250K (DSB @EL=60°) Backends – Continuum backends (Bandwidth 800MHz) Total Power (TP) Chopping Modulation (SP) – Spectrum Backends AOS1: Center 70MHz / BW 43MHz / 1024 chs AOS2: Center 70MHz / BW 43MHz / 1024 chs AOS3: Center 225MHz / BW 145MHz / 1024 chs Observation Mode – Position-Switch, spectral mapping – 12 CO (J=1-0), 13 CO (J=1-0), C 18 O (J=1-0) observation simultaneously – Fast beam switching (chopper-wheel modulating), continuum mapping

8. Upgrade Activities (1) -- Multi-Line System (2002) Observing 12 CO, 13 CO, C 18 O (J=1-0) lines simultaneously, Because of the DSB Receiver 109.78 GHz ⇓ AOS1 110.20 GHz ⇓ AOS2 115.27 GHz ⇓ AOS3 Set to 112.6 GHz

9. Upgrade Activities (1) -- Multi-Line System An example of simultaneously observations of CO(J=1-0) and its isotopes, toward NGC 2264. The on-source integration time is 60 seconds and T sys =248K.

10. Upgrade Activities (2) -- SIS Mixer Stability Improvement Below 100 GHz (2004) The SIS mixer is designed to operate in the range of 90-115 GHz, but … Below 100 GHz, the pumped quantum steps are too flat to stably bias (very large dynamic resistance at the step) DC bias is very sensitive to noise and interference Solution: putting a shunt resistance in the DC bias circuit of the mixer, parallel to the SIS junction. Reducing the dynamic resistance Pumped I-V curve @90GHz, Without any shunt resistance in the DC bias circuit Pumped I-V curve @90GHz, with a 36  resistance paralleled to the SIS junction

11. Upgrade Activities (2) -- SIS Mixer Stability Improvement Below 100 GHz (2004) After putting a shunt resistance, the stability improved significantly, in the range of 85-115 GHz (f LO ). See the red points. The black points indicate the case before (without any shunt resistance).

12. Upgrade Activities (2) -- SIS Mixer Stability Improvement Below 100 GHz (2004) Five-point mapping toward an SiO(J=2-1) maser source at 86.243GHz, to verify telescope pointing on the northern sky Source: R-CAS Line:SiO ( =1, J=2-1) It is possible to take five- point mapping observations toward SiO maser sources at 86.243GHz to verify the telescope pointing on the northern hemisphere

13. Upgrade Activities (3) -- Near Field Receiver Beam Measurement System (2004) Measuring the receiver (including all the optical components) beam pattern to determine – Whether all the optical components are well aligned or not – Receiver beam axis (other than the mechanical axis) – Antenna illumination, edge taper

14. Upgrade Activities (3) -- Near Field Receiver Beam Measurement System (2004) A probe source is mounted on an x-y motion stage Probe scanning area: 500×500 mm The scanning measurement should be taken at (at least) two different distances from the receiver to determine the beam axis. Then using a laser beam memorizes the axis for further aligning the receiver with the sub-reflector. Scalar measurement, only measured the power, the phase information may included in the future

15. Upgrade Activities (3) -- Near Field Receiver Beam Measurement System (2004) x scan @2m y scan @2m The red circle indicates the sub-reflector edge. The edge taper is about –10dB Map @1.5m

16. Upgrade Activities (4) -- Subreflector Real-Time Control (2004) The subreflector is relatively large (1.08m) and heavy It will tilt and drop down a bit with EL getting low due to gravity, affecting the alignment (between subref. and Rx, and between subref. and main dish) This can be corrected by re-positioning the subref. – Re-position Z1 axis and Y axis simultaneously while EL changes

17. Upgrade Activities (4) -- Subreflector Real-Time Control (2004) Measured 2-D beam pattern EL=71° Saturn map EL=35° Jupiter map

18. Future Plans Antenna servo system updating Digital Spectrometer with 500MHz BW Joining east-Asia mm-wave VLBI network

19. Science Activities Physical structure study of Galactic molecular clouds High-velocity outflows from young stellar objects Interstellar chemistry Molecular gas distributions in the Galactic star form regions Galactic dynamics Star evolution and molecular gas of late stars Large-scale molecular line survey for cold IRAS sources in the Galaxy ……

20. Recent Selected Publication (I) -- Molecular Clouds & Star form Regions Ao, Yiping; Yang, Ji; Sunada, Kazuyoshi, 13CO, C18O, and CS Observations toward Massive Dense Cores, AJ, 128...1716A, 2004 Qin S.L., Wu Y.F., et al, Star Formation in Molecular Cloud Associated with IRAS 07028-1100 ， 2004 ， Chinese Physics Letter ， Vol.21 No.8, 1677 J. Sun, et al., A study of molecular clouds with compact HII regions in Galactic Science in China (A), 2001 Y. Xu, D. Jiang, X. Zheng, M. Gu, Z. Yu, C. Pei High-Velocity H2O Maser Associated Massive Star Formation Regions Chin. Phys. Lett., 18(12), 1663-1665(2001) J. Sun, Y. C. Sun, New detected CO(J=1-0) emission from planetary nebulae Science in China (Series A), 43(2), 217, (2001) Y. Wu, J. WU, and J. Wang, A search for massive dense cores with 13 CO J=1-0 line A&A, 2001, December 12

21. Recent Selected Publication (II) -- Molecular Outflow Xu Y., Yang J., Zheng X.W., et al, Discovery of Multiple outflows in IRAS06056+2131, 2004 ， Chin. Phys. Lett., Vol.21, No.10, 2071-2072 SUN K.F., WU Y.F., A New High-velocity Molecular Outflow of IRADS 19282+1814 ， 2003 ， Chinese Astronomy and Astrophysics ， 27, 73-78 Y. Xu, D. R. Jiang, C. Y. Yang et al., High-velocity gas associated ultra-compact HII regions. Science in China(A), 32, 177-184, 2002 S. Qin, Y. Wu New high-velocity bipolar outflows in S39 and IRAS 06306+0232 Science in China (Series A), 2001 Y. Wu, C. Yang, Y. Li, et al. High-velocity molecular outflows near massive young stellar objects Science in China (Series A), 42(7), 732, (1999)

22. Recent Selected Publication (III) -- Survey of Molecular Lines from IRAS Sources J. Yang, Z. Jiang, M. Wang, B. Ju, & H. Wang A Large-Scale Molecular Line Survey for Cold IRAS Sources in the Galaxy: I. The CO (J=1-0) Data ApJS, v141,157, (2002). J. Yang, Z. Jiang, M. Wang, H. Wang, R. Mao, B. Ju, &Y. Ao Molecular Line Studies of Galactic Young Stellar Objects APRM2002_OHP (invited talk) ， Japan, 2002 Ji Yang Galactic Star Forming Regions: Local and Distant in Proceedings of 3rd OCPA3(invited talk) ， 2000

23. Recent Selected Publications (IV) – Other Topics Wu Y.F. ， Wang J.Z. ， Wu J.W., A Search for Extremely Young Stellar Objects ， 2003 ， Chin. Phys. Lett. ， Vol.20, No.8, 1409 Y. Xu, X. Zheng, D. Jiang, et al, An H2O flare in GGD25, Chinese Science Bulletin, 46(1), 35- 38(2001) J.J. Zhou and X.W. Zheng, Short Time Variability of the Water Masers in W51M, Astrophysics and Space Science, 275, 431-439(2001) Y. Xu, X. W. Zheng, et al, Rapid time variation of water maser emission in W3(OH) and NGC6334C, Astronomy and Astrophysics, 364 （ 2000 ）， 232. Y. Wu, Wang, Wu, Yan, Lei, Sun, Wang, A 13CO mapping study for massive molecular cloud cores, Science in China (A), 44(4), 536-544(2001) C. C. Pei, R. Q. Mao, Q. Zeng, Molecular lines and continuum from W51A, Science in China (A), 44(9), 1209-1215(2001) Y. Wu ， H. Yan ， J. Wu ， Y. Zhao, A mapping study for massive dense cores, Imaging at radio through sub-millimeter wavelengths, ASP Conference Series, 217(2000),96.

24. Sample Spectral Lines Obtained from the 13.7-m Telescope Besides CO, 13 CO and C 18 O, the telescope can be used to observe many other molecular lines in the 3mm band, such as HCO+, N2H+, CN, CS, CH 3 CN, SO, HC 3 N, CH 3 OH, OCS, SiO, HCN, CH 13 CN, …, from molecular clouds and circumstellar envelope. Following are some examples of molecular transition spectra obtained from our telescope.

25. HC 3 N Line Toward IRC+10216

26. CH 3 OH Line Toward Orion

27. CN Hyperfine Transitions Toward Orion

28. N2H+ Lines Toward L134N

29. HCO+(1-0) Line Toward S140

30. H13CN (1-0) Line Toward OrionA

31. Welcome to Delingha http://www.pmodlh.ac.cn Open Time: September 1 – May 31 Proposal submission (all over the year) proposal@pmodlh.ac.cn